]> git.sesse.net Git - bmusb/blobdiff - bmusb.cpp
Add an RGBA pixel type.
[bmusb] / bmusb.cpp
index 4f64d6c443c0348dbc2386d94fb8bfbd2f45e824..f01e0de97e6d1caf9b425f0324ba134e67dae037 100644 (file)
--- a/bmusb.cpp
+++ b/bmusb.cpp
-// Intensity Shuttle USB3 prototype capture driver, v0.3
-// Can download 8-bit and 10-bit UYVY/v210 frames from HDMI, quite stable
+// Intensity Shuttle USB3 capture driver, v0.6.0
+// Can download 8-bit and 10-bit UYVY/v210-ish frames from HDMI, quite stable
 // (can do captures for hours at a time with no drops), except during startup
 // 576p60/720p60/1080i60 works, 1080p60 does not work (firmware limitation)
 // Audio comes out as 8-channel 24-bit raw audio.
 
-#include <stdio.h>
-#include <stdlib.h>
+#if (defined(__i386__) || defined(__x86_64__)) && defined(__GNUC__)
+#define HAS_MULTIVERSIONING 1
+#endif
+
+#include <assert.h>
+#include <errno.h>
 #include <libusb.h>
-#include <arpa/inet.h>
 #include <unistd.h>
-#include <string.h>
-#include <fcntl.h>
+#include <netinet/in.h>
+#include <pthread.h>
+#include <sched.h>
 #include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#if HAS_MULTIVERSIONING
+#include <immintrin.h>
+#endif
+#include "bmusb/bmusb.h"
+
 #include <algorithm>
+#include <atomic>
+#include <chrono>
+#include <condition_variable>
+#include <cstddef>
+#include <cstdint>
+#include <deque>
 #include <functional>
 #include <memory>
-#include <deque>
-#include <utility>
 #include <mutex>
-#include <condition_variable>
-#include <thread>
 #include <stack>
-#include <atomic>
-#include "bmusb.h"
+#include <string>
+#include <thread>
 
 using namespace std;
+using namespace std::chrono;
+using namespace std::placeholders;
 
-static int current_register = 0;
-
-#define NUM_REGISTERS 60
-uint8_t register_file[NUM_REGISTERS];
-
-#define WIDTH 1280
-#define HEIGHT 750  /* 30 lines ancillary data? */
-//#define WIDTH 1920
-//#define HEIGHT 1125  /* ??? lines ancillary data? */
+#define USB_VENDOR_BLACKMAGIC 0x1edb
+#define MIN_WIDTH 640
 #define HEADER_SIZE 44
 //#define HEADER_SIZE 0
 #define AUDIO_HEADER_SIZE 4
 
-//#define FRAME_SIZE (WIDTH * HEIGHT * 2 + HEADER_SIZE)  // UYVY
-//#define FRAME_SIZE (WIDTH * HEIGHT * 2 * 4 / 3 + HEADER_SIZE)  // v210
-#define FRAME_SIZE (8 << 20)
+#define FRAME_SIZE (8 << 20)  // 8 MB.
+#define USB_VIDEO_TRANSFER_SIZE (128 << 10)  // 128 kB.
 
-FILE *audiofp;
+namespace bmusb {
 
-FrameAllocator::Frame current_video_frame;
-FrameAllocator::Frame current_audio_frame;
+card_connected_callback_t BMUSBCapture::card_connected_callback = nullptr;
+bool BMUSBCapture::hotplug_existing_devices = false;
 
-struct QueuedFrame {
-       uint16_t timecode;
-       uint16_t format;
-       FrameAllocator::Frame frame;
-};
+namespace {
 
-mutex queue_lock;
-condition_variable queues_not_empty;
-deque<QueuedFrame> pending_video_frames;
-deque<QueuedFrame> pending_audio_frames;
+FILE *audiofp;
 
 thread usb_thread;
 atomic<bool> should_quit;
 
-FrameAllocator::~FrameAllocator() {}
+int v210_stride(int width)
+{
+       return (width + 5) / 6 * 4 * sizeof(uint32_t);
+}
 
-#define NUM_QUEUED_FRAMES 8
-class MallocFrameAllocator : public FrameAllocator {
-public:
-       MallocFrameAllocator(size_t frame_size);
-       Frame alloc_frame() override;
-       void release_frame(Frame frame) override;
+int find_xfer_size_for_width(PixelFormat pixel_format, int width)
+{
+       // Video seems to require isochronous packets scaled with the width;
+       // seemingly six lines is about right, rounded up to the required 1kB
+       // multiple.
+       // Note that for 10-bit input, you'll need to increase size accordingly.
+       int stride;
+       if (pixel_format == PixelFormat_10BitYCbCr) {
+               stride = v210_stride(width);
+       } else {
+               stride = width * sizeof(uint16_t);
+       }
+       int size = stride * 6;
+       if (size % 1024 != 0) {
+               size &= ~1023;
+               size += 1024;
+       }
+       return size;
+}
 
-private:
-       size_t frame_size;
+void change_xfer_size_for_width(PixelFormat pixel_format, int width, libusb_transfer *xfr)
+{
+       assert(width >= MIN_WIDTH);
+       size_t size = find_xfer_size_for_width(pixel_format, width);
+       int num_iso_pack = xfr->length / size;
+       if (num_iso_pack != xfr->num_iso_packets ||
+           size != xfr->iso_packet_desc[0].length) {
+               xfr->num_iso_packets = num_iso_pack;
+               libusb_set_iso_packet_lengths(xfr, size);
+       }
+}
 
-       mutex freelist_mutex;
-       stack<unique_ptr<uint8_t[]>> freelist;  // All of size <frame_size>.
+struct VideoFormatEntry {
+       uint16_t normalized_video_format;
+       unsigned width, height, second_field_start;
+       unsigned extra_lines_top, extra_lines_bottom;
+       unsigned frame_rate_nom, frame_rate_den;
+       bool interlaced;
 };
 
-MallocFrameAllocator::MallocFrameAllocator(size_t frame_size)
+// Get details for the given video format; returns false if detection was incomplete.
+bool decode_video_format(uint16_t video_format, VideoFormat *decoded_video_format)
+{
+       decoded_video_format->id = video_format;
+       decoded_video_format->interlaced = false;
+
+       // TODO: Add these for all formats as we find them.
+       decoded_video_format->extra_lines_top = decoded_video_format->extra_lines_bottom = decoded_video_format->second_field_start = 0;
+
+       if (video_format == 0x0800) {
+               // No video signal. These green pseudo-frames seem to come at about 30.13 Hz.
+               // It's a strange thing, but what can you do.
+               decoded_video_format->width = 720;
+               decoded_video_format->height = 525;
+               decoded_video_format->stride = 720 * 2;
+               decoded_video_format->extra_lines_top = 0;
+               decoded_video_format->extra_lines_bottom = 0;
+               decoded_video_format->frame_rate_nom = 3013;
+               decoded_video_format->frame_rate_den = 100;
+               decoded_video_format->has_signal = false;
+               return true;
+       }
+       if ((video_format & 0xe000) != 0xe000) {
+               printf("Video format 0x%04x does not appear to be a video format. Assuming 60 Hz.\n",
+                       video_format);
+               decoded_video_format->width = 0;
+               decoded_video_format->height = 0;
+               decoded_video_format->stride = 0;
+               decoded_video_format->extra_lines_top = 0;
+               decoded_video_format->extra_lines_bottom = 0;
+               decoded_video_format->frame_rate_nom = 60;
+               decoded_video_format->frame_rate_den = 1;
+               decoded_video_format->has_signal = false;
+               return false;
+       }
+
+       decoded_video_format->has_signal = true;
+
+       // NTSC (480i59.94, I suppose). A special case, see below.
+       if ((video_format & ~0x0800) == 0xe101 ||
+           (video_format & ~0x0800) == 0xe1c1 ||
+           (video_format & ~0x0800) == 0xe001) {
+               decoded_video_format->width = 720;
+               decoded_video_format->height = 480;
+               if (video_format & 0x0800) {
+                       decoded_video_format->stride = 720 * 2;
+               } else {
+                       decoded_video_format->stride = v210_stride(720);
+               }
+               decoded_video_format->extra_lines_top = 17;
+               decoded_video_format->extra_lines_bottom = 28;
+               decoded_video_format->frame_rate_nom = 30000;
+               decoded_video_format->frame_rate_den = 1001;
+               decoded_video_format->second_field_start = 280;
+               decoded_video_format->interlaced = true;
+               return true;
+       }
+
+       // PAL (576i50, I suppose). A special case, see below.
+       if ((video_format & ~0x0800) == 0xe109 ||
+           (video_format & ~0x0800) == 0xe1c9 ||
+           (video_format & ~0x0800) == 0xe009 ||
+           (video_format & ~0x0800) == 0xe3e9 ||
+           (video_format & ~0x0800) == 0xe3e1) {
+               decoded_video_format->width = 720;
+               decoded_video_format->height = 576;
+               if (video_format & 0x0800) {
+                       decoded_video_format->stride = 720 * 2;
+               } else {
+                       decoded_video_format->stride = v210_stride(720);
+               }
+               decoded_video_format->extra_lines_top = 22;
+               decoded_video_format->extra_lines_bottom = 27;
+               decoded_video_format->frame_rate_nom = 25;
+               decoded_video_format->frame_rate_den = 1;
+               decoded_video_format->second_field_start = 335;
+               decoded_video_format->interlaced = true;
+               return true;
+       }
+
+       // 0x8 seems to be a flag about availability of deep color on the input,
+       // except when it's not (e.g. it's the only difference between NTSC
+       // and PAL). Rather confusing. But we clear it here nevertheless, because
+       // usually it doesn't mean anything. 0x0800 appears to be 8-bit input
+       // (as opposed to 10-bit).
+       //
+       // 0x4 is a flag I've only seen from the D4. I don't know what it is.
+       uint16_t normalized_video_format = video_format & ~0xe80c;
+       constexpr VideoFormatEntry entries[] = {
+               { 0x01f1,  720,  480,   0, 40,  5, 60000, 1001, false },  // 480p59.94 (believed).
+               { 0x0131,  720,  576,   0, 44,  5,    50,    1, false },  // 576p50.
+               { 0x0011,  720,  576,   0, 44,  5,    50,    1, false },  // 576p50 (5:4).
+               { 0x0143, 1280,  720,   0, 25,  5,    50,    1, false },  // 720p50.
+               { 0x0103, 1280,  720,   0, 25,  5,    60,    1, false },  // 720p60.
+               { 0x0125, 1280,  720,   0, 25,  5,    60,    1, false },  // 720p60.
+               { 0x0121, 1280,  720,   0, 25,  5, 60000, 1001, false },  // 720p59.94.
+               { 0x01c3, 1920, 1080,   0, 41,  4,    30,    1, false },  // 1080p30.
+               { 0x0003, 1920, 1080, 583, 20, 25,    30,    1,  true },  // 1080i60.
+               { 0x01e1, 1920, 1080,   0, 41,  4, 30000, 1001, false },  // 1080p29.97.
+               { 0x0021, 1920, 1080, 583, 20, 25, 30000, 1001,  true },  // 1080i59.94.
+               { 0x0063, 1920, 1080,   0, 41,  4,    25,    1, false },  // 1080p25.
+               { 0x0043, 1920, 1080, 583, 20, 25,    25,    1,  true },  // 1080i50.
+               { 0x0083, 1920, 1080,   0, 41,  4,    24,    1, false },  // 1080p24.
+               { 0x00a1, 1920, 1080,   0, 41,  4, 24000, 1001, false },  // 1080p23.98.
+       };
+       for (const VideoFormatEntry &entry : entries) {
+               if (normalized_video_format == entry.normalized_video_format) {
+                       decoded_video_format->width = entry.width;
+                       decoded_video_format->height = entry.height;
+                       if (video_format & 0x0800) {
+                               decoded_video_format->stride = entry.width * 2;
+                       } else {
+                               decoded_video_format->stride = v210_stride(entry.width);
+                       }
+                       decoded_video_format->second_field_start = entry.second_field_start;
+                       decoded_video_format->extra_lines_top = entry.extra_lines_top;
+                       decoded_video_format->extra_lines_bottom = entry.extra_lines_bottom;
+                       decoded_video_format->frame_rate_nom = entry.frame_rate_nom;
+                       decoded_video_format->frame_rate_den = entry.frame_rate_den;
+                       decoded_video_format->interlaced = entry.interlaced;
+                       return true;
+               }
+       }
+
+       printf("Unknown video format 0x%04x (normalized 0x%04x). Assuming 720p60.\n", video_format, normalized_video_format);
+       decoded_video_format->width = 1280;
+       decoded_video_format->height = 720;
+       decoded_video_format->stride = 1280 * 2;
+       decoded_video_format->frame_rate_nom = 60;
+       decoded_video_format->frame_rate_den = 1;
+       return false;
+}
+
+}  // namespace
+
+FrameAllocator::~FrameAllocator() {}
+
+MallocFrameAllocator::MallocFrameAllocator(size_t frame_size, size_t num_queued_frames)
        : frame_size(frame_size)
 {
-       for (int i = 0; i < NUM_QUEUED_FRAMES; ++i) {
+       for (size_t i = 0; i < num_queued_frames; ++i) {
                freelist.push(unique_ptr<uint8_t[]>(new uint8_t[frame_size]));
        }
 }
@@ -105,14 +272,13 @@ FrameAllocator::Frame MallocFrameAllocator::alloc_frame()
 
 void MallocFrameAllocator::release_frame(Frame frame)
 {
+       if (frame.overflow > 0) {
+               printf("%d bytes overflow after last (malloc) frame\n", int(frame.overflow));
+       }
        unique_lock<mutex> lock(freelist_mutex);
        freelist.push(unique_ptr<uint8_t[]>(frame.data));
 }
 
-FrameAllocator *video_frame_allocator = nullptr;
-FrameAllocator *audio_frame_allocator = nullptr;
-frame_callback_t frame_callback = nullptr;
-
 bool uint16_less_than_with_wraparound(uint16_t a, uint16_t b)
 {
        if (a == b) {
@@ -125,8 +291,9 @@ bool uint16_less_than_with_wraparound(uint16_t a, uint16_t b)
        }
 }
 
-void queue_frame(uint16_t format, uint16_t timecode, FrameAllocator::Frame frame, deque<QueuedFrame> *q)
+void BMUSBCapture::queue_frame(uint16_t format, uint16_t timecode, FrameAllocator::Frame frame, deque<QueuedFrame> *q)
 {
+       unique_lock<mutex> lock(queue_lock);
        if (!q->empty() && !uint16_less_than_with_wraparound(q->back().timecode, timecode)) {
                printf("Blocks going backwards: prev=0x%04x, cur=0x%04x (dropped)\n",
                        q->back().timecode, timecode);
@@ -138,11 +305,7 @@ void queue_frame(uint16_t format, uint16_t timecode, FrameAllocator::Frame frame
        qf.format = format;
        qf.timecode = timecode;
        qf.frame = frame;
-
-       {
-               unique_lock<mutex> lock(queue_lock);
-               q->push_back(move(qf));
-       }
+       q->push_back(move(qf));
        queues_not_empty.notify_one();  // might be spurious
 }
 
@@ -160,24 +323,49 @@ void dump_audio_block(uint8_t *audio_start, size_t audio_len)
        fwrite(audio_start + AUDIO_HEADER_SIZE, 1, audio_len - AUDIO_HEADER_SIZE, audiofp);
 }
 
-void dequeue_thread()
+void BMUSBCapture::dequeue_thread_func()
 {
-       for ( ;; ) {
+       char thread_name[16];
+       snprintf(thread_name, sizeof(thread_name), "bmusb_dequeue_%d", card_index);
+       pthread_setname_np(pthread_self(), thread_name);
+
+       if (has_dequeue_callbacks) {
+               dequeue_init_callback();
+       }
+       while (!dequeue_thread_should_quit) {
                unique_lock<mutex> lock(queue_lock);
-               queues_not_empty.wait(lock, []{ return !pending_video_frames.empty() && !pending_audio_frames.empty(); });
+               queues_not_empty.wait(lock, [this]{ return dequeue_thread_should_quit || (!pending_video_frames.empty() && !pending_audio_frames.empty()); });
+
+               if (dequeue_thread_should_quit) break;
 
                uint16_t video_timecode = pending_video_frames.front().timecode;
                uint16_t audio_timecode = pending_audio_frames.front().timecode;
-               if (video_timecode < audio_timecode) {
+               AudioFormat audio_format;
+               audio_format.bits_per_sample = 24;
+               audio_format.num_channels = 8;
+               if (uint16_less_than_with_wraparound(video_timecode, audio_timecode)) {
                        printf("Video block 0x%04x without corresponding audio block, dropping.\n",
                                video_timecode);
-                       video_frame_allocator->release_frame(pending_video_frames.front().frame);
+                       QueuedFrame video_frame = pending_video_frames.front();
                        pending_video_frames.pop_front();
-               } else if (audio_timecode < video_timecode) {
-                       printf("Audio block 0x%04x without corresponding video block, dropping.\n",
+                       lock.unlock();
+                       video_frame_allocator->release_frame(video_frame.frame);
+               } else if (uint16_less_than_with_wraparound(audio_timecode, video_timecode)) {
+                       printf("Audio block 0x%04x without corresponding video block, sending blank frame.\n",
                                audio_timecode);
-                       audio_frame_allocator->release_frame(pending_audio_frames.front().frame);
+                       QueuedFrame audio_frame = pending_audio_frames.front();
                        pending_audio_frames.pop_front();
+                       lock.unlock();
+                       audio_format.id = audio_frame.format;
+
+                       // Use the video format of the pending frame.
+                       QueuedFrame video_frame = pending_video_frames.front();
+                       VideoFormat video_format;
+                       decode_video_format(video_frame.format, &video_format);
+
+                       frame_callback(audio_timecode,
+                                      FrameAllocator::Frame(), 0, video_format,
+                                      audio_frame.frame, AUDIO_HEADER_SIZE, audio_format);
                } else {
                        QueuedFrame video_frame = pending_video_frames.front();
                        QueuedFrame audio_frame = pending_audio_frames.front();
@@ -192,37 +380,56 @@ void dequeue_thread()
                        dump_audio_block(audio_frame.frame.data, audio_frame.data_len); 
 #endif
 
-                       frame_callback(video_timecode,
-                                      video_frame.frame, HEADER_SIZE, video_frame.format,
-                                      audio_frame.frame, AUDIO_HEADER_SIZE, audio_frame.format);
+                       VideoFormat video_format;
+                       audio_format.id = audio_frame.format;
+                       if (decode_video_format(video_frame.format, &video_format)) {
+                               frame_callback(video_timecode,
+                                              video_frame.frame, HEADER_SIZE, video_format,
+                                              audio_frame.frame, AUDIO_HEADER_SIZE, audio_format);
+                       } else {
+                               frame_callback(video_timecode,
+                                              FrameAllocator::Frame(), 0, video_format,
+                                              audio_frame.frame, AUDIO_HEADER_SIZE, audio_format);
+                       }
                }
        }
-}
-
-void add_current_frame(const uint8_t *start, const uint8_t *end)
-{
-       if (current_video_frame.data == nullptr ||
-           current_video_frame.len > current_video_frame.size) return;
-       if (start == end) return;
-
-       int bytes = end - start;
-       if (current_video_frame.len + bytes > current_video_frame.size) {
-               printf("%d bytes overflow after last video frame\n", current_video_frame.len + bytes - current_video_frame.size);
-               //dump_frame();
-       } else {
-               memcpy(current_video_frame.data + current_video_frame.len, start, bytes);
-               current_video_frame.len += bytes;
+       if (has_dequeue_callbacks) {
+               dequeue_cleanup_callback();
        }
 }
 
-void start_new_frame(const uint8_t *start)
+void BMUSBCapture::start_new_frame(const uint8_t *start)
 {
        uint16_t format = (start[3] << 8) | start[2];
        uint16_t timecode = (start[1] << 8) | start[0];
 
        if (current_video_frame.len > 0) {
+               current_video_frame.received_timestamp = steady_clock::now();
+
+               // If format is 0x0800 (no signal), add a fake (empty) audio
+               // frame to get it out of the queue.
+               // TODO: Figure out if there are other formats that come with
+               // no audio, and treat them the same.
+               if (format == 0x0800) {
+                       FrameAllocator::Frame fake_audio_frame = audio_frame_allocator->alloc_frame();
+                       if (fake_audio_frame.data == nullptr) {
+                               // Oh well, it's just a no-signal frame anyway.
+                               printf("Couldn't allocate fake audio frame, also dropping no-signal video frame.\n");
+                               current_video_frame.owner->release_frame(current_video_frame);
+                               current_video_frame = video_frame_allocator->alloc_frame();
+                               return;
+                       }
+                       queue_frame(format, timecode, fake_audio_frame, &pending_audio_frames);
+               }
                //dump_frame();
                queue_frame(format, timecode, current_video_frame, &pending_video_frames);
+
+               // Update the assumed frame width. We might be one frame too late on format changes,
+               // but it's much better than asking the user to choose manually.
+               VideoFormat video_format;
+               if (decode_video_format(format, &video_format)) {
+                       assumed_frame_width = video_format.width;
+               }
        }
        //printf("Found frame start, format 0x%04x timecode 0x%04x, previous frame length was %d/%d\n",
        //      format, timecode,
@@ -237,27 +444,12 @@ void start_new_frame(const uint8_t *start)
        //}
 }
 
-void add_current_audio(const uint8_t *start, const uint8_t *end)
-{
-       if (current_audio_frame.data == nullptr ||
-           current_audio_frame.len > current_audio_frame.size) return;
-       if (start == end) return;
-
-       int bytes = end - start;
-       if (current_audio_frame.len + bytes > current_audio_frame.size) {
-               printf("%d bytes overflow after last audio block\n", current_audio_frame.len + bytes - current_audio_frame.size);
-               //dump_audio_block();
-       } else {
-               memcpy(current_audio_frame.data + current_audio_frame.len, start, bytes);
-               current_audio_frame.len += bytes;
-       }
-}
-
-void start_new_audio_block(const uint8_t *start)
+void BMUSBCapture::start_new_audio_block(const uint8_t *start)
 {
        uint16_t format = (start[3] << 8) | start[2];
        uint16_t timecode = (start[1] << 8) | start[0];
        if (current_audio_frame.len > 0) {
+               current_audio_frame.received_timestamp = steady_clock::now();
                //dump_audio_block();
                queue_frame(format, timecode, current_audio_frame, &pending_audio_frames);
        }
@@ -266,10 +458,11 @@ void start_new_audio_block(const uint8_t *start)
        current_audio_frame = audio_frame_allocator->alloc_frame();
 }
 
+#if 0
 static void dump_pack(const libusb_transfer *xfr, int offset, const libusb_iso_packet_descriptor *pack)
 {
        //      printf("ISO pack%u length:%u, actual_length:%u, offset:%u\n", i, pack->length, pack->actual_length, offset);
-       for (int j = 0; j < pack->actual_length; j++) {
+       for (unsigned j = 0; j < pack->actual_length; j++) {
        //for (int j = 0; j < min(pack->actual_length, 16u); j++) {
                printf("%02x", xfr->buffer[j + offset]);
                if ((j % 16) == 15)
@@ -280,11 +473,317 @@ static void dump_pack(const libusb_transfer *xfr, int offset, const libusb_iso_p
                        printf(" ");
        }
 }
+#endif
+
+void memcpy_interleaved(uint8_t *dest1, uint8_t *dest2, const uint8_t *src, size_t n)
+{
+       assert(n % 2 == 0);
+       uint8_t *dptr1 = dest1;
+       uint8_t *dptr2 = dest2;
+
+       for (size_t i = 0; i < n; i += 2) {
+               *dptr1++ = *src++;
+               *dptr2++ = *src++;
+       }
+}
+
+void add_to_frame(FrameAllocator::Frame *current_frame, const char *frame_type_name, const uint8_t *start, const uint8_t *end)
+{
+       if (current_frame->data == nullptr ||
+           current_frame->len > current_frame->size ||
+           start == end) {
+               return;
+       }
+
+       int bytes = end - start;
+       if (current_frame->len + bytes > current_frame->size) {
+               current_frame->overflow = current_frame->len + bytes - current_frame->size;
+               current_frame->len = current_frame->size;
+               if (current_frame->overflow > 1048576) {
+                       printf("%d bytes overflow after last %s frame\n",
+                               int(current_frame->overflow), frame_type_name);
+                       current_frame->overflow = 0;
+               }
+               //dump_frame();
+       } else {
+               if (current_frame->interleaved) {
+                       uint8_t *data = current_frame->data + current_frame->len / 2;
+                       uint8_t *data2 = current_frame->data2 + current_frame->len / 2;
+                       if (current_frame->len % 2 == 1) {
+                               ++data;
+                               swap(data, data2);
+                       }
+                       if (bytes % 2 == 1) {
+                               *data++ = *start++;
+                               swap(data, data2);
+                               ++current_frame->len;
+                               --bytes;
+                       }
+                       memcpy_interleaved(data, data2, start, bytes);
+                       current_frame->len += bytes;
+               } else {
+                       memcpy(current_frame->data + current_frame->len, start, bytes);
+                       current_frame->len += bytes;
+               }
+       }
+}
+
+#if 0
+void avx2_dump(const char *name, __m256i n)
+{
+       printf("%-10s:", name);
+       printf(" %02x", _mm256_extract_epi8(n, 0));
+       printf(" %02x", _mm256_extract_epi8(n, 1));
+       printf(" %02x", _mm256_extract_epi8(n, 2));
+       printf(" %02x", _mm256_extract_epi8(n, 3));
+       printf(" %02x", _mm256_extract_epi8(n, 4));
+       printf(" %02x", _mm256_extract_epi8(n, 5));
+       printf(" %02x", _mm256_extract_epi8(n, 6));
+       printf(" %02x", _mm256_extract_epi8(n, 7));
+       printf(" ");
+       printf(" %02x", _mm256_extract_epi8(n, 8));
+       printf(" %02x", _mm256_extract_epi8(n, 9));
+       printf(" %02x", _mm256_extract_epi8(n, 10));
+       printf(" %02x", _mm256_extract_epi8(n, 11));
+       printf(" %02x", _mm256_extract_epi8(n, 12));
+       printf(" %02x", _mm256_extract_epi8(n, 13));
+       printf(" %02x", _mm256_extract_epi8(n, 14));
+       printf(" %02x", _mm256_extract_epi8(n, 15));
+       printf(" ");
+       printf(" %02x", _mm256_extract_epi8(n, 16));
+       printf(" %02x", _mm256_extract_epi8(n, 17));
+       printf(" %02x", _mm256_extract_epi8(n, 18));
+       printf(" %02x", _mm256_extract_epi8(n, 19));
+       printf(" %02x", _mm256_extract_epi8(n, 20));
+       printf(" %02x", _mm256_extract_epi8(n, 21));
+       printf(" %02x", _mm256_extract_epi8(n, 22));
+       printf(" %02x", _mm256_extract_epi8(n, 23));
+       printf(" ");
+       printf(" %02x", _mm256_extract_epi8(n, 24));
+       printf(" %02x", _mm256_extract_epi8(n, 25));
+       printf(" %02x", _mm256_extract_epi8(n, 26));
+       printf(" %02x", _mm256_extract_epi8(n, 27));
+       printf(" %02x", _mm256_extract_epi8(n, 28));
+       printf(" %02x", _mm256_extract_epi8(n, 29));
+       printf(" %02x", _mm256_extract_epi8(n, 30));
+       printf(" %02x", _mm256_extract_epi8(n, 31));
+       printf("\n");
+}
+#endif
+
+#ifndef HAS_MULTIVERSIONING
+
+const uint8_t *add_to_frame_fastpath(FrameAllocator::Frame *current_frame, const uint8_t *start, const uint8_t *limit, const char sync_char)
+{
+       // No fast path possible unless we have multiversioning.
+       return start;
+}
+
+#else  // defined(HAS_MULTIVERSIONING)
+
+__attribute__((target("sse4.1")))
+const uint8_t *add_to_frame_fastpath_core(FrameAllocator::Frame *current_frame, const uint8_t *aligned_start, const uint8_t *limit, const char sync_char);
+
+__attribute__((target("avx2")))
+const uint8_t *add_to_frame_fastpath_core(FrameAllocator::Frame *current_frame, const uint8_t *aligned_start, const uint8_t *limit, const char sync_char);
+
+// Does a memcpy and memchr in one to reduce processing time.
+// Note that the benefit is somewhat limited if your L3 cache is small,
+// as you'll (unfortunately) spend most of the time loading the data
+// from main memory.
+//
+// Complicated cases are left to the slow path; it basically stops copying
+// up until the first instance of "sync_char" (usually a bit before, actually).
+// This is fine, since 0x00 bytes shouldn't really show up in normal picture
+// data, and what we really need this for is the 00 00 ff ff marker in video data.
+__attribute__((target("default")))
+const uint8_t *add_to_frame_fastpath(FrameAllocator::Frame *current_frame, const uint8_t *start, const uint8_t *limit, const char sync_char)
+{
+       // No fast path possible unless we have SSE 4.1 or higher.
+       return start;
+}
+
+__attribute__((target("sse4.1", "avx2")))
+const uint8_t *add_to_frame_fastpath(FrameAllocator::Frame *current_frame, const uint8_t *start, const uint8_t *limit, const char sync_char)
+{
+       if (current_frame->data == nullptr ||
+           current_frame->len > current_frame->size ||
+           start == limit) {
+               return start;
+       }
+       size_t orig_bytes = limit - start;
+       if (orig_bytes < 128) {
+               // Don't bother.
+               return start;
+       }
+
+       // Don't read more bytes than we can write.
+       limit = min(limit, start + (current_frame->size - current_frame->len));
+
+       // Align end to 32 bytes.
+       limit = (const uint8_t *)(intptr_t(limit) & ~31);
+
+       if (start >= limit) {
+               return start;
+       }
+
+       // Process [0,31] bytes, such that start gets aligned to 32 bytes.
+       const uint8_t *aligned_start = (const uint8_t *)(intptr_t(start + 31) & ~31);
+       if (aligned_start != start) {
+               const uint8_t *sync_start = (const uint8_t *)memchr(start, sync_char, aligned_start - start);
+               if (sync_start == nullptr) {
+                       add_to_frame(current_frame, "", start, aligned_start);
+               } else {
+                       add_to_frame(current_frame, "", start, sync_start);
+                       return sync_start;
+               }
+       }
+
+       // Make the length a multiple of 64.
+       if (current_frame->interleaved) {
+               if (((limit - aligned_start) % 64) != 0) {
+                       limit -= 32;
+               }
+               assert(((limit - aligned_start) % 64) == 0);
+       }
+
+       return add_to_frame_fastpath_core(current_frame, aligned_start, limit, sync_char);
+}
+
+__attribute__((target("avx2")))
+const uint8_t *add_to_frame_fastpath_core(FrameAllocator::Frame *current_frame, const uint8_t *aligned_start, const uint8_t *limit, const char sync_char)
+{
+       const __m256i needle = _mm256_set1_epi8(sync_char);
+
+       const __restrict __m256i *in = (const __m256i *)aligned_start;
+       if (current_frame->interleaved) {
+               __restrict __m256i *out1 = (__m256i *)(current_frame->data + (current_frame->len + 1) / 2);
+               __restrict __m256i *out2 = (__m256i *)(current_frame->data2 + current_frame->len / 2);
+               if (current_frame->len % 2 == 1) {
+                       swap(out1, out2);
+               }
+
+               __m256i shuffle_cw = _mm256_set_epi8(
+                       15, 13, 11, 9, 7, 5, 3, 1, 14, 12, 10, 8, 6, 4, 2, 0,
+                       15, 13, 11, 9, 7, 5, 3, 1, 14, 12, 10, 8, 6, 4, 2, 0);
+               while (in < (const __m256i *)limit) {
+                       // Note: For brevity, comments show lanes as if they were 2x64-bit (they're actually 2x128).
+                       __m256i data1 = _mm256_stream_load_si256(in);         // AaBbCcDd EeFfGgHh
+                       __m256i data2 = _mm256_stream_load_si256(in + 1);     // IiJjKkLl MmNnOoPp
+
+                       __m256i found1 = _mm256_cmpeq_epi8(data1, needle);
+                       __m256i found2 = _mm256_cmpeq_epi8(data2, needle);
+                       __m256i found = _mm256_or_si256(found1, found2);
+
+                       data1 = _mm256_shuffle_epi8(data1, shuffle_cw);       // ABCDabcd EFGHefgh
+                       data2 = _mm256_shuffle_epi8(data2, shuffle_cw);       // IJKLijkl MNOPmnop
+               
+                       data1 = _mm256_permute4x64_epi64(data1, 0b11011000);  // ABCDEFGH abcdefgh
+                       data2 = _mm256_permute4x64_epi64(data2, 0b11011000);  // IJKLMNOP ijklmnop
+
+                       __m256i lo = _mm256_permute2x128_si256(data1, data2, 0b00100000);
+                       __m256i hi = _mm256_permute2x128_si256(data1, data2, 0b00110001);
+
+                       _mm256_storeu_si256(out1, lo);  // Store as early as possible, even if the data isn't used.
+                       _mm256_storeu_si256(out2, hi);
+
+                       if (!_mm256_testz_si256(found, found)) {
+                               break;
+                       }
+
+                       in += 2;
+                       ++out1;
+                       ++out2;
+               }
+               current_frame->len += (uint8_t *)in - aligned_start;
+       } else {
+               __m256i *out = (__m256i *)(current_frame->data + current_frame->len);
+               while (in < (const __m256i *)limit) {
+                       __m256i data = _mm256_load_si256(in);
+                       _mm256_storeu_si256(out, data);  // Store as early as possible, even if the data isn't used.
+                       __m256i found = _mm256_cmpeq_epi8(data, needle);
+                       if (!_mm256_testz_si256(found, found)) {
+                               break;
+                       }
+
+                       ++in;
+                       ++out;
+               }
+               current_frame->len = (uint8_t *)out - current_frame->data;
+       }
+
+       //printf("managed to fastpath %ld/%ld bytes\n", (const uint8_t *)in - (const uint8_t *)aligned_start, orig_bytes);
+       return (const uint8_t *)in;
+}
+
+__attribute__((target("sse4.1")))
+const uint8_t *add_to_frame_fastpath_core(FrameAllocator::Frame *current_frame, const uint8_t *aligned_start, const uint8_t *limit, const char sync_char)
+{
+       const __m128i needle = _mm_set1_epi8(sync_char);
+
+       const __m128i *in = (const __m128i *)aligned_start;
+       if (current_frame->interleaved) {
+               __m128i *out1 = (__m128i *)(current_frame->data + (current_frame->len + 1) / 2);
+               __m128i *out2 = (__m128i *)(current_frame->data2 + current_frame->len / 2);
+               if (current_frame->len % 2 == 1) {
+                       swap(out1, out2);
+               }
+
+               __m128i mask_lower_byte = _mm_set1_epi16(0x00ff);
+               while (in < (const __m128i *)limit) {
+                       __m128i data1 = _mm_load_si128(in);
+                       __m128i data2 = _mm_load_si128(in + 1);
+                       __m128i data1_lo = _mm_and_si128(data1, mask_lower_byte);
+                       __m128i data2_lo = _mm_and_si128(data2, mask_lower_byte);
+                       __m128i data1_hi = _mm_srli_epi16(data1, 8);
+                       __m128i data2_hi = _mm_srli_epi16(data2, 8);
+                       __m128i lo = _mm_packus_epi16(data1_lo, data2_lo);
+                       _mm_storeu_si128(out1, lo);  // Store as early as possible, even if the data isn't used.
+                       __m128i hi = _mm_packus_epi16(data1_hi, data2_hi);
+                       _mm_storeu_si128(out2, hi);
+                       __m128i found1 = _mm_cmpeq_epi8(data1, needle);
+                       __m128i found2 = _mm_cmpeq_epi8(data2, needle);
+                       if (!_mm_testz_si128(found1, found1) ||
+                           !_mm_testz_si128(found2, found2)) {
+                               break;
+                       }
+
+                       in += 2;
+                       ++out1;
+                       ++out2;
+               }
+               current_frame->len += (uint8_t *)in - aligned_start;
+       } else {
+               __m128i *out = (__m128i *)(current_frame->data + current_frame->len);
+               while (in < (const __m128i *)limit) {
+                       __m128i data = _mm_load_si128(in);
+                       _mm_storeu_si128(out, data);  // Store as early as possible, even if the data isn't used.
+                       __m128i found = _mm_cmpeq_epi8(data, needle);
+                       if (!_mm_testz_si128(found, found)) {
+                               break;
+                       }
+
+                       ++in;
+                       ++out;
+               }
+               current_frame->len = (uint8_t *)out - current_frame->data;
+       }
+
+       //printf("managed to fastpath %ld/%ld bytes\n", (const uint8_t *)in - (const uint8_t *)aligned_start, orig_bytes);
+       return (const uint8_t *)in;
+}
+
+#endif  // defined(HAS_MULTIVERSIONING)
 
-void decode_packs(const libusb_transfer *xfr, const char *sync_pattern, int sync_length, function<void(const uint8_t *start, const uint8_t *end)> add_callback, function<void(const uint8_t *start)> start_callback)
+void decode_packs(const libusb_transfer *xfr,
+                  const char *sync_pattern,
+                  int sync_length,
+                  FrameAllocator::Frame *current_frame,
+                  const char *frame_type_name,
+                  function<void(const uint8_t *start)> start_callback)
 {
        int offset = 0;
-       for (unsigned i = 0; i < xfr->num_iso_packets; i++) {
+       for (int i = 0; i < xfr->num_iso_packets; i++) {
                const libusb_iso_packet_descriptor *pack = &xfr->iso_packet_desc[i];
 
                if (pack->status != LIBUSB_TRANSFER_COMPLETED) {
@@ -293,19 +792,22 @@ void decode_packs(const libusb_transfer *xfr, const char *sync_pattern, int sync
 //exit(5);
                }
 
-               const unsigned char *iso_start = xfr->buffer + offset;
-               for (int iso_offset = 0; iso_offset < pack->actual_length; ) {  // Usually runs only one iteration.
-                       const unsigned char* start_next_frame = (const unsigned char *)memmem(iso_start + iso_offset, pack->actual_length - iso_offset, sync_pattern, sync_length);
+               const uint8_t *start = xfr->buffer + offset;
+               const uint8_t *limit = start + pack->actual_length;
+               while (start < limit) {  // Usually runs only one iteration.
+                       start = add_to_frame_fastpath(current_frame, start, limit, sync_pattern[0]);
+                       if (start == limit) break;
+                       assert(start < limit);
+
+                       const unsigned char* start_next_frame = (const unsigned char *)memmem(start, limit - start, sync_pattern, sync_length);
                        if (start_next_frame == nullptr) {
                                // add the rest of the buffer
-                               add_callback(iso_start + iso_offset, iso_start + pack->actual_length);
+                               add_to_frame(current_frame, frame_type_name, start, limit);
                                break;
                        } else {
-                               add_callback(iso_start + iso_offset, start_next_frame);
-                               start_callback(start_next_frame + sync_length);
-
-                               int suboffset = start_next_frame - iso_start;
-                               iso_offset = suboffset + sync_length;  // skip sync
+                               add_to_frame(current_frame, frame_type_name, start, start_next_frame);
+                               start = start_next_frame + sync_length;  // skip sync
+                               start_callback(start);
                        }
                }
 #if 0
@@ -315,23 +817,42 @@ void decode_packs(const libusb_transfer *xfr, const char *sync_pattern, int sync
        }
 }
 
-static void cb_xfr(struct libusb_transfer *xfr)
+void BMUSBCapture::cb_xfr(struct libusb_transfer *xfr)
 {
-       if (xfr->status != LIBUSB_TRANSFER_COMPLETED) {
-               fprintf(stderr, "transfer status %d\n", xfr->status);
+       if (xfr->status != LIBUSB_TRANSFER_COMPLETED &&
+           xfr->status != LIBUSB_TRANSFER_NO_DEVICE) {
+               fprintf(stderr, "error: transfer status %d\n", xfr->status);
                libusb_free_transfer(xfr);
                exit(3);
        }
 
+       assert(xfr->user_data != nullptr);
+       BMUSBCapture *usb = static_cast<BMUSBCapture *>(xfr->user_data);
+
+       if (xfr->status == LIBUSB_TRANSFER_NO_DEVICE) {
+               if (!usb->disconnected) {
+                       fprintf(stderr, "Device went away, stopping transfers.\n");
+                       usb->disconnected = true;
+                       if (usb->card_disconnected_callback) {
+                               usb->card_disconnected_callback();
+                       }
+               }
+               // Don't reschedule the transfer; the loop will stop by itself.
+               return;
+       }
+
        if (xfr->type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS) {
                if (xfr->endpoint == 0x84) {
-                       decode_packs(xfr, "DeckLinkAudioResyncT", 20, add_current_audio, start_new_audio_block);
+                       decode_packs(xfr, "DeckLinkAudioResyncT", 20, &usb->current_audio_frame, "audio", bind(&BMUSBCapture::start_new_audio_block, usb, _1));
                } else {
-                       decode_packs(xfr, "\x00\x00\xff\xff", 4, add_current_frame, start_new_frame);
+                       decode_packs(xfr, "\x00\x00\xff\xff", 4, &usb->current_video_frame, "video", bind(&BMUSBCapture::start_new_frame, usb, _1));
+
+                       // Update the transfer with the new assumed width, if we're in the process of changing formats.
+                       change_xfer_size_for_width(usb->current_pixel_format, usb->assumed_frame_width, xfr);
                }
        }
        if (xfr->type == LIBUSB_TRANSFER_TYPE_CONTROL) {
-               const libusb_control_setup *setup = libusb_control_transfer_get_setup(xfr);
+               //const libusb_control_setup *setup = libusb_control_transfer_get_setup(xfr);
                uint8_t *buf = libusb_control_transfer_get_data(xfr);
 #if 0
                if (setup->wIndex == 44) {
@@ -341,19 +862,19 @@ static void cb_xfr(struct libusb_transfer *xfr)
                                setup->wIndex, buf[0], buf[1], buf[2], buf[3]);
                }
 #else
-               memcpy(register_file + current_register, buf, 4);
-               current_register = (current_register + 4) % NUM_REGISTERS;
-               if (current_register == 0) {
+               memcpy(usb->register_file + usb->current_register, buf, 4);
+               usb->current_register = (usb->current_register + 4) % NUM_BMUSB_REGISTERS;
+               if (usb->current_register == 0) {
                        // read through all of them
                        printf("register dump:");
-                       for (int i = 0; i < NUM_REGISTERS; i += 4) {
-                               printf(" 0x%02x%02x%02x%02x", register_file[i], register_file[i + 1], register_file[i + 2], register_file[i + 3]);
+                       for (int i = 0; i < NUM_BMUSB_REGISTERS; i += 4) {
+                               printf(" 0x%02x%02x%02x%02x", usb->register_file[i], usb->register_file[i + 1], usb->register_file[i + 2], usb->register_file[i + 3]);
                        }
                        printf("\n");
                }
                libusb_fill_control_setup(xfr->buffer,
                    LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_ENDPOINT_IN, /*request=*/214, /*value=*/0,
-                       /*index=*/current_register, /*length=*/4);
+                       /*index=*/usb->current_register, /*length=*/4);
 #endif
        }
 
@@ -370,68 +891,214 @@ static void cb_xfr(struct libusb_transfer *xfr)
        }
 #endif
 
-end:
-       if (libusb_submit_transfer(xfr) < 0) {
-               fprintf(stderr, "error re-submitting URB\n");
+       int rc = libusb_submit_transfer(xfr);
+       if (rc < 0) {
+               fprintf(stderr, "error re-submitting URB: %s\n", libusb_error_name(rc));
                exit(1);
        }
 }
 
-void usb_thread_func()
+int BMUSBCapture::cb_hotplug(libusb_context *ctx, libusb_device *dev, libusb_hotplug_event event, void *user_data)
 {
-       printf("usb thread started\n");
+       if (card_connected_callback != nullptr) {
+               libusb_device_descriptor desc;
+                if (libusb_get_device_descriptor(dev, &desc) < 0) {
+                       fprintf(stderr, "Error getting device descriptor for hotplugged device %p, killing hotplug\n", dev);
+                       libusb_unref_device(dev);
+                       return 1;
+               }
 
+               if ((desc.idVendor == USB_VENDOR_BLACKMAGIC && desc.idProduct == 0xbd3b) ||
+                   (desc.idVendor == USB_VENDOR_BLACKMAGIC && desc.idProduct == 0xbd4f)) {
+                       card_connected_callback(dev);  // Callback takes ownership.
+                       return 0;
+               }
+       }
+       libusb_unref_device(dev);
+       return 0;
+}
+
+void BMUSBCapture::usb_thread_func()
+{
        sched_param param;
        memset(&param, 0, sizeof(param));
        param.sched_priority = 1;
        if (sched_setscheduler(0, SCHED_RR, &param) == -1) {
                printf("couldn't set realtime priority for USB thread: %s\n", strerror(errno));
        }
+       pthread_setname_np(pthread_self(), "bmusb_usb_drv");
        while (!should_quit) {
-               int rc = libusb_handle_events(nullptr);
+               timeval sec { 1, 0 };
+               int rc = libusb_handle_events_timeout(nullptr, &sec);
                if (rc != LIBUSB_SUCCESS)
                        break;
        }
 }
 
-FrameAllocator *get_video_frame_allocator()
+namespace {
+
+struct USBCardDevice {
+       uint16_t product;
+       uint8_t bus, port;
+       libusb_device *device;
+};
+
+const char *get_product_name(uint16_t product)
 {
-       return video_frame_allocator;
+       if (product == 0xbd3b) {
+               return "Intensity Shuttle";
+       } else if (product == 0xbd4f) {
+               return "UltraStudio SDI";
+       } else {
+               assert(false);
+               return nullptr;
+       }
 }
 
-void set_video_frame_allocator(FrameAllocator *allocator)
+string get_card_description(int id, uint8_t bus, uint8_t port, uint16_t product)
 {
-       video_frame_allocator = allocator;
+       const char *product_name = get_product_name(product);
+
+       char buf[256];
+       snprintf(buf, sizeof(buf), "USB card %d: Bus %03u Device %03u  %s",
+               id, bus, port, product_name);
+       return buf;
 }
 
-FrameAllocator *get_audio_frame_allocator()
+vector<USBCardDevice> find_all_cards()
 {
-       return audio_frame_allocator;
+       libusb_device **devices;
+       ssize_t num_devices = libusb_get_device_list(nullptr, &devices);
+       if (num_devices == -1) {
+               fprintf(stderr, "Error finding USB devices\n");
+               exit(1);
+       }
+       vector<USBCardDevice> found_cards;
+       for (ssize_t i = 0; i < num_devices; ++i) {
+               libusb_device_descriptor desc;
+                if (libusb_get_device_descriptor(devices[i], &desc) < 0) {
+                       fprintf(stderr, "Error getting device descriptor for device %d\n", int(i));
+                       exit(1);
+               }
+
+               uint8_t bus = libusb_get_bus_number(devices[i]);
+               uint8_t port = libusb_get_port_number(devices[i]);
+
+               if (!(desc.idVendor == USB_VENDOR_BLACKMAGIC && desc.idProduct == 0xbd3b) &&
+                   !(desc.idVendor == USB_VENDOR_BLACKMAGIC && desc.idProduct == 0xbd4f)) {
+                       libusb_unref_device(devices[i]);
+                       continue;
+               }
+
+               found_cards.push_back({ desc.idProduct, bus, port, devices[i] });
+       }
+       libusb_free_device_list(devices, 0);
+
+       // Sort the devices to get a consistent ordering.
+       sort(found_cards.begin(), found_cards.end(), [](const USBCardDevice &a, const USBCardDevice &b) {
+               if (a.product != b.product)
+                       return a.product < b.product;
+               if (a.bus != b.bus)
+                       return a.bus < b.bus;
+               return a.port < b.port;
+       });
+
+       return found_cards;
+}
+
+libusb_device_handle *open_card(int card_index, string *description)
+{
+       vector<USBCardDevice> found_cards = find_all_cards();
+
+       for (size_t i = 0; i < found_cards.size(); ++i) {
+               string tmp_description = get_card_description(i, found_cards[i].bus, found_cards[i].port, found_cards[i].product);
+               fprintf(stderr, "%s\n", tmp_description.c_str());
+               if (i == size_t(card_index)) {
+                       *description = tmp_description;
+               }
+       }
+
+       if (size_t(card_index) >= found_cards.size()) {
+               fprintf(stderr, "Could not open card %d (only %d found)\n", card_index, int(found_cards.size()));
+               exit(1);
+       }
+
+       libusb_device_handle *devh;
+       int rc = libusb_open(found_cards[card_index].device, &devh);
+       if (rc < 0) {
+               fprintf(stderr, "Error opening card %d: %s\n", card_index, libusb_error_name(rc));
+               exit(1);
+       }
+
+       for (size_t i = 0; i < found_cards.size(); ++i) {
+               libusb_unref_device(found_cards[i].device);
+       }
+
+       return devh;
 }
 
-void set_audio_frame_allocator(FrameAllocator *allocator)
+libusb_device_handle *open_card(unsigned card_index, libusb_device *dev, string *description)
 {
-       audio_frame_allocator = allocator;
+       uint8_t bus = libusb_get_bus_number(dev);
+       uint8_t port = libusb_get_port_number(dev);
+
+       libusb_device_descriptor desc;
+       if (libusb_get_device_descriptor(dev, &desc) < 0) {
+               fprintf(stderr, "Error getting device descriptor for device %p\n", dev);
+               exit(1);
+       }
+
+       *description = get_card_description(card_index, bus, port, desc.idProduct);
+
+       libusb_device_handle *devh;
+       int rc = libusb_open(dev, &devh);
+       if (rc < 0) {
+               fprintf(stderr, "Error opening card %p: %s\n", dev, libusb_error_name(rc));
+               exit(1);
+       }
+
+       return devh;
 }
 
-void set_frame_callback(frame_callback_t callback)
+}  // namespace
+
+unsigned BMUSBCapture::num_cards()
 {
-       frame_callback = callback;
+       int rc = libusb_init(nullptr);
+       if (rc < 0) {
+               fprintf(stderr, "Error initializing libusb: %s\n", libusb_error_name(rc));
+               exit(1);
+       }
+
+       vector<USBCardDevice> found_cards = find_all_cards();
+       unsigned ret = found_cards.size();
+       for (size_t i = 0; i < found_cards.size(); ++i) {
+               libusb_unref_device(found_cards[i].device);
+       }
+       return ret;
 }
 
-void start_bm_capture()
+void BMUSBCapture::set_pixel_format(PixelFormat pixel_format)
+{
+       current_pixel_format = pixel_format;
+       update_capture_mode();
+}
+
+void BMUSBCapture::configure_card()
 {
        if (video_frame_allocator == nullptr) {
-               set_video_frame_allocator(new MallocFrameAllocator(FRAME_SIZE));  // FIXME: leak.
+               owned_video_frame_allocator.reset(new MallocFrameAllocator(FRAME_SIZE, NUM_QUEUED_VIDEO_FRAMES));
+               set_video_frame_allocator(owned_video_frame_allocator.get());
        }
        if (audio_frame_allocator == nullptr) {
-               set_audio_frame_allocator(new MallocFrameAllocator(65536));  // FIXME: leak.
+               owned_audio_frame_allocator.reset(new MallocFrameAllocator(65536, NUM_QUEUED_AUDIO_FRAMES));
+               set_audio_frame_allocator(owned_audio_frame_allocator.get());
        }
-       thread(dequeue_thread).detach();
+       dequeue_thread_should_quit = false;
+       dequeue_thread = thread(&BMUSBCapture::dequeue_thread_func, this);
 
        int rc;
        struct libusb_transfer *xfr;
-       vector<libusb_transfer *> iso_xfrs;
 
        rc = libusb_init(nullptr);
        if (rc < 0) {
@@ -439,7 +1106,12 @@ void start_bm_capture()
                exit(1);
        }
 
-       struct libusb_device_handle *devh = libusb_open_device_with_vid_pid(nullptr, 0x1edb, 0xbd3b);
+       if (dev == nullptr) {
+               devh = open_card(card_index, &description);
+       } else {
+               devh = open_card(card_index, dev, &description);
+               libusb_unref_device(dev);
+       }
        if (!devh) {
                fprintf(stderr, "Error finding USB device\n");
                exit(1);
@@ -451,19 +1123,22 @@ void start_bm_capture()
                fprintf(stderr, "Error getting configuration: %s\n", libusb_error_name(rc));
                exit(1);
        }
+
+#if 0
        printf("%d interface\n", config->bNumInterfaces);
        for (int interface_number = 0; interface_number < config->bNumInterfaces; ++interface_number) {
                printf("  interface %d\n", interface_number);
                const libusb_interface *interface = &config->interface[interface_number];
                for (int altsetting = 0; altsetting < interface->num_altsetting; ++altsetting) {
-                       printf("    alternate setting %d\n", altsetting);
                        const libusb_interface_descriptor *interface_desc = &interface->altsetting[altsetting];
+                       printf("    alternate setting %d\n", interface_desc->bAlternateSetting);
                        for (int endpoint_number = 0; endpoint_number < interface_desc->bNumEndpoints; ++endpoint_number) {
                                const libusb_endpoint_descriptor *endpoint = &interface_desc->endpoint[endpoint_number];
                                printf("        endpoint address 0x%02x\n", endpoint->bEndpointAddress);
                        }
                }
        }
+#endif
 
        rc = libusb_set_configuration(devh, /*configuration=*/1);
        if (rc < 0) {
@@ -480,14 +1155,22 @@ void start_bm_capture()
        // Alternate setting 1 is output, alternate setting 2 is input.
        // Card is reset when switching alternates, so the driver uses
        // this “double switch” when it wants to reset.
+       //
+       // There's also alternate settings 3 and 4, which seem to be
+       // like 1 and 2 except they advertise less bandwidth needed.
        rc = libusb_set_interface_alt_setting(devh, /*interface=*/0, /*alternate_setting=*/1);
        if (rc < 0) {
                fprintf(stderr, "Error setting alternate 1: %s\n", libusb_error_name(rc));
+               if (rc == LIBUSB_ERROR_NOT_FOUND) {
+                       fprintf(stderr, "This is usually because the card came up in USB2 mode.\n");
+                       fprintf(stderr, "In particular, this tends to happen if you boot up with the\n");
+                       fprintf(stderr, "card plugged in; just unplug and replug it, and it usually works.\n");
+               }
                exit(1);
        }
        rc = libusb_set_interface_alt_setting(devh, /*interface=*/0, /*alternate_setting=*/2);
        if (rc < 0) {
-               fprintf(stderr, "Error setting alternate 1: %s\n", libusb_error_name(rc));
+               fprintf(stderr, "Error setting alternate 2: %s\n", libusb_error_name(rc));
                exit(1);
        }
 #if 0
@@ -527,6 +1210,8 @@ void start_bm_capture()
        //
        //    so only first 16 bits count, and 0x0100 is a mask for ok/stable signal?
        //
+       //    Bottom 16 bits of this register seem to be firmware version number (possibly not all all of them).
+       //
        //    28 and 32 seems to be analog audio input levels (one byte for each of the eight channels).
        //    however, if setting 32 with HDMI embedded audio, it is immediately overwritten back (to 0xe137002a).
        //
@@ -536,6 +1221,11 @@ void start_bm_capture()
        //    36 can be set to 0 with no apparent effect (all of this tested on both video and audio),
        //    but the driver sets it to 0x8036802a at some point.
        //
+       //    all of this is on request 214/215. other requests (192, 219,
+       //    222, 223, 224) are used for firmware upgrade. Probably best to
+       //    stay out of it unless you know what you're doing.
+       //
+       //
        // register 16:
        // first byte is 0x39 for a stable 576p60 signal, 0x2d for a stable 720p60 signal, 0x20 for no signal
        //
@@ -546,6 +1236,8 @@ void start_bm_capture()
        //   0x20 - 720p??
        //   0x30 - 576p??
 
+       update_capture_mode();
+
        struct ctrl {
                int endpoint;
                int request;
@@ -555,111 +1247,14 @@ void start_bm_capture()
        static const ctrl ctrls[] = {
                { LIBUSB_ENDPOINT_IN,  214, 16, 0 },
                { LIBUSB_ENDPOINT_IN,  214,  0, 0 },
-               { LIBUSB_ENDPOINT_IN,  214,  0, 0 },
-               { LIBUSB_ENDPOINT_IN,  214,  4, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 16, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 20, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 24, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 28, 0 },
-               { LIBUSB_ENDPOINT_IN,  215, 32, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 36, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 40, 0 },
-               { LIBUSB_ENDPOINT_IN,  216, 44, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 48, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 52, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 40, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 40, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 40, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 24, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 40, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 40, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 40, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 24, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 40, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 40, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },  // packet 354
-               { LIBUSB_ENDPOINT_IN,  214, 24, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 12, 0 },
-               { LIBUSB_ENDPOINT_IN,  214, 40, 0 },
-               // more...
+
                //{ LIBUSB_ENDPOINT_OUT, 215,  0, 0x80000100 },
-               //{ LIBUSB_ENDPOINT_OUT, 215,  0, 0x09000000 },  // wow, some kind of mode
-
-               // seems to capture on HDMI, clearing the 0x20000000 bit seems to activate 10-bit
-               // capture (v210).
-               // clearing the 0x08000000 bit seems to change the capture format (other source?)
-               // 0x10000000 = analog audio instead of embedded audio, it seems
-               // 0x3a000000 = component video? (analog audio)
-               // 0x3c000000 = composite video? (analog audio)
-               // 0x3e000000 = s-video? (analog audio)
-               { LIBUSB_ENDPOINT_OUT, 215,  0, 0x29000000 },
                //{ LIBUSB_ENDPOINT_OUT, 215,  0, 0x09000000 },
-
-               //{ LIBUSB_ENDPOINT_OUT, 215, 28, 0xffffffff },
-               //{ LIBUSB_ENDPOINT_OUT, 215, 32, 0xffffffff },
-               //{ LIBUSB_ENDPOINT_OUT, 215, 28, 0x40404040 },
-               //{ LIBUSB_ENDPOINT_OUT, 215, 32, 0x40404040 },
-               //{ LIBUSB_ENDPOINT_OUT, 215, 36, 0x8036802a },
                { LIBUSB_ENDPOINT_OUT, 215, 24, 0x73c60001 },  // latch for frame start?
-               //{ LIBUSB_ENDPOINT_OUT, 215, 24, 0x13370001 },  // latch for frame start?
                { LIBUSB_ENDPOINT_IN,  214, 24, 0 },  // 
-               //{ LIBUSB_ENDPOINT_OUT, 215,  4, 0x00000000 },  // appears to have no e fect
-               //{ LIBUSB_ENDPOINT_OUT, 215,  8, 0x00000000 },  // appears to have no effect
-               //{ LIBUSB_ENDPOINT_OUT, 215, 20, 0x00000000 },  // appears to have no effect
-               //{ LIBUSB_ENDPOINT_OUT, 215, 28, 0x00000000 },  // appears to have no effect
-               //{ LIBUSB_ENDPOINT_OUT, 215, 32, 0x00000000 },  // appears to have no effect
-               //{ LIBUSB_ENDPOINT_OUT, 215, 36, 0x00000000 },  // appears to have no effect
-#if 0
-               { LIBUSB_ENDPOINT_OUT, 215,  0 },
-               { LIBUSB_ENDPOINT_OUT, 215,  0 },
-               { LIBUSB_ENDPOINT_OUT, 215, 28 },
-               { LIBUSB_ENDPOINT_OUT, 215, 32 },
-               { LIBUSB_ENDPOINT_OUT, 215, 36 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215,  0 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-               { LIBUSB_ENDPOINT_OUT, 215, 24 },
-#endif
        };
 
-       for (int req = 0; req < sizeof(ctrls) / sizeof(ctrls[0]); ++req) {
+       for (unsigned req = 0; req < sizeof(ctrls) / sizeof(ctrls[0]); ++req) {
                uint32_t flipped = htonl(ctrls[req].data);
                static uint8_t value[4];
                memcpy(value, &flipped, sizeof(flipped));
@@ -671,12 +1266,18 @@ void start_bm_capture()
                        fprintf(stderr, "Error on control %d: %s\n", ctrls[req].index, libusb_error_name(rc));
                        exit(1);
                }
-               
+
+               if (ctrls[req].index == 16 && rc == 4) {
+                       printf("Card firmware version: 0x%02x%02x\n", value[2], value[3]);
+               }
+
+#if 0
                printf("rc=%d: ep=%d@%d %d -> 0x", rc, ctrls[req].endpoint, ctrls[req].request, ctrls[req].index);
                for (int i = 0; i < rc; ++i) {
                        printf("%02x", value[i]);
                }
                printf("\n");
+#endif
        }
 
 #if 0
@@ -709,6 +1310,7 @@ void start_bm_capture()
            LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_ENDPOINT_IN, /*request=*/214, /*value=*/0,
                /*index=*/44, /*length=*/4);
        libusb_fill_control_transfer(xfr, devh, cmdbuf, cb_xfr, &completed, 0);
+       xfr->user_data = this;
        libusb_submit_transfer(xfr);
 
        // set up an asynchronous transfer of register 24
@@ -720,6 +1322,7 @@ void start_bm_capture()
            LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_ENDPOINT_IN, /*request=*/214, /*value=*/0,
                /*index=*/24, /*length=*/4);
        libusb_fill_control_transfer(xfr, devh, cmdbuf2, cb_xfr, &completed2, 0);
+       xfr->user_data = this;
        libusb_submit_transfer(xfr);
 #endif
 
@@ -732,35 +1335,46 @@ void start_bm_capture()
            LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_ENDPOINT_IN, /*request=*/214, /*value=*/0,
                /*index=*/current_register, /*length=*/4);
        libusb_fill_control_transfer(xfr, devh, cmdbuf3, cb_xfr, &completed3, 0);
+       xfr->user_data = this;
        //libusb_submit_transfer(xfr);
 
-       audiofp = fopen("audio.raw", "wb");
+       //audiofp = fopen("audio.raw", "wb");
 
        // set up isochronous transfers for audio and video
        for (int e = 3; e <= 4; ++e) {
-               //int num_transfers = (e == 3) ? 6 : 6;
                int num_transfers = 6;
                for (int i = 0; i < num_transfers; ++i) {
+                       size_t buf_size;
                        int num_iso_pack, size;
                        if (e == 3) {
-                               // Video seems to require isochronous packets scaled with the width; 
-                               // seemingly six lines is about right, rounded up to the required 1kB
-                               // multiple.
-                               size = WIDTH * 2 * 6;
-                               // Note that for 10-bit input, you'll need to increase size accordingly.
-                               //size = size * 4 / 3;
-                               if (size % 1024 != 0) {
-                                       size &= ~1023;
-                                       size += 1024;
-                               }
-                               num_iso_pack = (2 << 20) / size;  // 2 MB.
-                               printf("Picking %d packets of 0x%x bytes each\n", num_iso_pack, size);
+                               // Allocate for minimum width (because that will give us the most
+                               // number of packets, so we don't need to reallocate, but we'll
+                               // default to 720p for the first frame.
+                               size = find_xfer_size_for_width(PixelFormat_8BitYCbCr, MIN_WIDTH);
+                               num_iso_pack = USB_VIDEO_TRANSFER_SIZE / size;
+                               buf_size = USB_VIDEO_TRANSFER_SIZE;
                        } else {
                                size = 0xc0;
                                num_iso_pack = 80;
+                               buf_size = num_iso_pack * size;
                        }
                        int num_bytes = num_iso_pack * size;
-                       uint8_t *buf = new uint8_t[num_bytes];
+                       assert(size_t(num_bytes) <= buf_size);
+#if LIBUSB_API_VERSION >= 0x01000105
+                       uint8_t *buf = libusb_dev_mem_alloc(devh, num_bytes);
+#else
+                       uint8_t *buf = nullptr;
+#endif
+                       if (buf == nullptr) {
+                               fprintf(stderr, "Failed to allocate persistent DMA memory ");
+#if LIBUSB_API_VERSION >= 0x01000105
+                               fprintf(stderr, "(probably too old kernel; use 4.6.0 or newer).\n");
+#else
+                               fprintf(stderr, "(compiled against too old libusb-1.0).\n");
+#endif
+                               fprintf(stderr, "Will go slower, and likely fail due to memory fragmentation after a few hours.\n");
+                               buf = new uint8_t[num_bytes];
+                       }
 
                        xfr = libusb_alloc_transfer(num_iso_pack);
                        if (!xfr) {
@@ -769,29 +1383,34 @@ void start_bm_capture()
                        }
 
                        int ep = LIBUSB_ENDPOINT_IN | e;
-                       libusb_fill_iso_transfer(xfr, devh, ep, buf, num_bytes,
+                       libusb_fill_iso_transfer(xfr, devh, ep, buf, buf_size,
                                num_iso_pack, cb_xfr, nullptr, 0);
                        libusb_set_iso_packet_lengths(xfr, size);
+                       xfr->user_data = this;
+
+                       if (e == 3) {
+                               change_xfer_size_for_width(current_pixel_format, assumed_frame_width, xfr);
+                       }
+
                        iso_xfrs.push_back(xfr);
                }
        }
+}
 
-       {
-               int i = 0;
-               for (libusb_transfer *xfr : iso_xfrs) {
-                       rc = libusb_submit_transfer(xfr);
-                       ++i;
-                       if (rc < 0) {
-                               //printf("num_bytes=%d\n", num_bytes);
-                               fprintf(stderr, "Error submitting iso to endpoint 0x%02x, number %d: %s\n",
-                                       xfr->endpoint, i, libusb_error_name(rc));
-                               exit(1);
-                       }
+void BMUSBCapture::start_bm_capture()
+{
+       int i = 0;
+       for (libusb_transfer *xfr : iso_xfrs) {
+               int rc = libusb_submit_transfer(xfr);
+               ++i;
+               if (rc < 0) {
+                       //printf("num_bytes=%d\n", num_bytes);
+                       fprintf(stderr, "Error submitting iso to endpoint 0x%02x, number %d: %s\n",
+                               xfr->endpoint, i, libusb_error_name(rc));
+                       exit(1);
                }
        }
 
-       usb_thread = thread(usb_thread_func);
-
 
 #if 0
        libusb_release_interface(devh, 0);
@@ -803,8 +1422,108 @@ out:
 #endif
 }
 
-void stop_bm_capture()
+void BMUSBCapture::stop_dequeue_thread()
+{
+       dequeue_thread_should_quit = true;
+       queues_not_empty.notify_all();
+       dequeue_thread.join();
+}
+
+void BMUSBCapture::start_bm_thread()
+{
+       // Devices leaving are discovered by seeing the isochronous packets
+       // coming back with errors, so only care about devices joining.
+       if (card_connected_callback != nullptr) {
+               if (libusb_hotplug_register_callback(
+                       nullptr, LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED, hotplug_existing_devices ? LIBUSB_HOTPLUG_ENUMERATE : LIBUSB_HOTPLUG_NO_FLAGS,
+                       USB_VENDOR_BLACKMAGIC, LIBUSB_HOTPLUG_MATCH_ANY, LIBUSB_HOTPLUG_MATCH_ANY,
+                       &BMUSBCapture::cb_hotplug, nullptr, nullptr) < 0) {
+                       fprintf(stderr, "libusb_hotplug_register_callback() failed\n");
+                       exit(1);
+               }
+       }
+
+       should_quit = false;
+       usb_thread = thread(&BMUSBCapture::usb_thread_func);
+}
+
+void BMUSBCapture::stop_bm_thread()
 {
        should_quit = true;
        usb_thread.join();
 }
+
+map<uint32_t, VideoMode> BMUSBCapture::get_available_video_modes() const
+{
+       // The USB3 cards autodetect, and seem to have no provision for forcing modes.
+       VideoMode auto_mode;
+       auto_mode.name = "Autodetect";
+       auto_mode.autodetect = true;
+       return {{ 0, auto_mode }};
+}
+
+uint32_t BMUSBCapture::get_current_video_mode() const
+{
+       return 0;  // Matches get_available_video_modes().
+}
+
+void BMUSBCapture::set_video_mode(uint32_t video_mode_id)
+{
+       assert(video_mode_id == 0);  // Matches get_available_video_modes().
+}
+
+std::map<uint32_t, std::string> BMUSBCapture::get_available_video_inputs() const
+{
+       return {
+               { 0x00000000, "HDMI/SDI" },
+               { 0x02000000, "Component" },
+               { 0x04000000, "Composite" },
+               { 0x06000000, "S-video" }
+       };
+}
+
+void BMUSBCapture::set_video_input(uint32_t video_input_id)
+{
+       assert((video_input_id & ~0x06000000) == 0);
+       current_video_input = video_input_id;
+       update_capture_mode();
+}
+
+std::map<uint32_t, std::string> BMUSBCapture::get_available_audio_inputs() const
+{
+       return {
+               { 0x00000000, "Embedded" },
+               { 0x10000000, "Analog" }
+       };
+}
+
+void BMUSBCapture::set_audio_input(uint32_t audio_input_id)
+{
+       assert((audio_input_id & ~0x10000000) == 0);
+       current_audio_input = audio_input_id;
+       update_capture_mode();
+}
+
+void BMUSBCapture::update_capture_mode()
+{
+       if (devh == nullptr) {
+               return;
+       }
+
+       // Clearing the 0x08000000 bit seems to change the capture format (other source?).
+       uint32_t mode = htonl(0x09000000 | current_video_input | current_audio_input);
+       if (current_pixel_format == PixelFormat_8BitYCbCr) {
+               mode |= htonl(0x20000000);
+       } else {
+               assert(current_pixel_format == PixelFormat_10BitYCbCr);
+       }
+
+       int rc = libusb_control_transfer(devh, LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_ENDPOINT_OUT,
+               /*request=*/215, /*value=*/0, /*index=*/0, (unsigned char *)&mode, sizeof(mode), /*timeout=*/0);
+       if (rc < 0) {
+               fprintf(stderr, "Error on setting mode: %s\n", libusb_error_name(rc));
+               exit(1);
+       }
+}
+
+}  // namespace bmusb