+// A fake capture device that sends single-color frames at a given rate.
+// Mostly useful for testing themes without actually hooking up capture devices.
+
+#include "fake_capture.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <unistd.h>
+#if __SSE2__
+#include <immintrin.h>
+#endif
+#include <cstddef>
+
+#include "bmusb.h"
+
+#define FRAME_SIZE (8 << 20) // 8 MB.
+
+// Pure-color inputs: Red, green, blue, white.
+#define NUM_COLORS 4
+constexpr uint8_t ys[NUM_COLORS] = { 81, 145, 41, 235 };
+constexpr uint8_t cbs[NUM_COLORS] = { 90, 54, 240, 128 };
+constexpr uint8_t crs[NUM_COLORS] = { 240, 34, 110, 128 };
+
+using namespace std;
+
+namespace bmusb {
+namespace {
+
+// We don't bother with multiversioning for this, because SSE2
+// is on my default for all 64-bit compiles, which is really
+// the target user segment here.
+
+void memset2(uint8_t *s, const uint8_t c[2], size_t n)
+{
+ size_t i = 0;
+#if __SSE2__
+ const uint8_t c_expanded[16] = {
+ c[0], c[1], c[0], c[1], c[0], c[1], c[0], c[1],
+ c[0], c[1], c[0], c[1], c[0], c[1], c[0], c[1]
+ };
+ __m128i cc = *(__m128i *)c_expanded;
+ __m128i *out = (__m128i *)s;
+
+ for ( ; i < (n & ~15); i += 16) {
+ _mm_storeu_si128(out++, cc);
+ _mm_storeu_si128(out++, cc);
+ }
+
+ s = (uint8_t *)out;
+#endif
+ for ( ; i < n; ++i) {
+ *s++ = c[0];
+ *s++ = c[1];
+ }
+}
+
+void memset4(uint8_t *s, const uint8_t c[4], size_t n)
+{
+ size_t i = 0;
+#if __SSE2__
+ const uint8_t c_expanded[16] = {
+ c[0], c[1], c[2], c[3], c[0], c[1], c[2], c[3],
+ c[0], c[1], c[2], c[3], c[0], c[1], c[2], c[3]
+ };
+ __m128i cc = *(__m128i *)c_expanded;
+ __m128i *out = (__m128i *)s;
+
+ for ( ; i < (n & ~7); i += 8) {
+ _mm_storeu_si128(out++, cc);
+ _mm_storeu_si128(out++, cc);
+ }
+
+ s = (uint8_t *)out;
+#endif
+ for ( ; i < n; ++i) {
+ *s++ = c[0];
+ *s++ = c[1];
+ *s++ = c[2];
+ *s++ = c[3];
+ }
+}
+
+} // namespace
+
+FakeCapture::FakeCapture(unsigned width, unsigned height, unsigned fps, unsigned audio_frequency, int card_index)
+ : width(width), height(height), fps(fps), audio_frequency(audio_frequency)
+{
+ char buf[256];
+ snprintf(buf, sizeof(buf), "Fake card %d", card_index + 1);
+ description = buf;
+
+ y = ys[card_index % NUM_COLORS];
+ cb = cbs[card_index % NUM_COLORS];
+ cr = crs[card_index % NUM_COLORS];
+}
+
+FakeCapture::~FakeCapture()
+{
+ if (has_dequeue_callbacks) {
+ dequeue_cleanup_callback();
+ }
+}
+
+void FakeCapture::configure_card()
+{
+ if (video_frame_allocator == nullptr) {
+ 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) {
+ owned_audio_frame_allocator.reset(new MallocFrameAllocator(65536, NUM_QUEUED_AUDIO_FRAMES));
+ set_audio_frame_allocator(owned_audio_frame_allocator.get());
+ }
+}
+
+void FakeCapture::start_bm_capture()
+{
+ producer_thread_should_quit = false;
+ producer_thread = thread(&FakeCapture::producer_thread_func, this);
+}
+
+void FakeCapture::stop_dequeue_thread()
+{
+ producer_thread_should_quit = true;
+ producer_thread.join();
+}
+
+std::map<uint32_t, VideoMode> FakeCapture::get_available_video_modes() const
+{
+ VideoMode mode;
+
+ char buf[256];
+ snprintf(buf, sizeof(buf), "%ux%u", width, height);
+ mode.name = buf;
+
+ mode.autodetect = false;
+ mode.width = width;
+ mode.height = height;
+ mode.frame_rate_num = fps;
+ mode.frame_rate_den = 1;
+ mode.interlaced = false;
+
+ return {{ 0, mode }};
+}
+
+std::map<uint32_t, std::string> FakeCapture::get_available_video_inputs() const
+{
+ return {{ 0, "Fake video input (single color)" }};
+}
+
+std::map<uint32_t, std::string> FakeCapture::get_available_audio_inputs() const
+{
+ return {{ 0, "Fake audio input (silence)" }};
+}
+
+void FakeCapture::set_video_mode(uint32_t video_mode_id)
+{
+ assert(video_mode_id == 0);
+}
+
+void FakeCapture::set_video_input(uint32_t video_input_id)
+{
+ assert(video_input_id == 0);
+}
+
+void FakeCapture::set_audio_input(uint32_t audio_input_id)
+{
+ assert(audio_input_id == 0);
+}
+
+namespace {
+
+void add_time(double t, timespec *ts)
+{
+ ts->tv_nsec += lrint(t * 1e9);
+ ts->tv_sec += ts->tv_nsec / 1000000000;
+ ts->tv_nsec %= 1000000000;
+}
+
+bool timespec_less_than(const timespec &a, const timespec &b)
+{
+ return make_pair(a.tv_sec, a.tv_nsec) < make_pair(b.tv_sec, b.tv_nsec);
+}
+
+} // namespace
+
+void FakeCapture::producer_thread_func()
+{
+ uint16_t timecode = 0;
+
+ if (has_dequeue_callbacks) {
+ dequeue_init_callback();
+ }
+
+ timespec next_frame;
+ clock_gettime(CLOCK_MONOTONIC, &next_frame);
+ add_time(1.0 / fps, &next_frame);
+
+ while (!producer_thread_should_quit) {
+ timespec now;
+ clock_gettime(CLOCK_MONOTONIC, &now);
+
+ if (timespec_less_than(now, next_frame)) {
+ // Wait until the next frame.
+ if (clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME,
+ &next_frame, nullptr) == -1) {
+ if (errno == EINTR) continue; // Re-check the flag and then sleep again.
+ perror("clock_nanosleep");
+ exit(1);
+ }
+ } else {
+ // We've seemingly missed a frame. If we're more than one second behind,
+ // reset the timer; otherwise, just keep going.
+ timespec limit = next_frame;
+ ++limit.tv_sec;
+ if (!timespec_less_than(now, limit)) {
+ fprintf(stderr, "More than one second of missed fake frames; resetting clock.\n");
+ next_frame = now;
+ }
+ }
+
+ // Figure out when the next frame is to be, then compute the current one.
+ add_time(1.0 / fps, &next_frame);
+
+ VideoFormat video_format;
+ video_format.width = width;
+ video_format.height = height;
+ video_format.frame_rate_nom = fps;
+ video_format.frame_rate_den = 1;
+ video_format.has_signal = true;
+ video_format.is_connected = false;
+
+ FrameAllocator::Frame video_frame = video_frame_allocator->alloc_frame();
+ if (video_frame.data != nullptr) {
+ assert(video_frame.size >= width * height * 2);
+ if (video_frame.interleaved) {
+ uint8_t cbcr[] = { cb, cr };
+ memset2(video_frame.data, cbcr, width * height / 2);
+ memset(video_frame.data2, y, width * height);
+ } else {
+ uint8_t ycbcr[] = { y, cb, y, cr };
+ memset4(video_frame.data, ycbcr, width * height / 2);
+ }
+ video_frame.len = width * height * 2;
+ }
+
+ AudioFormat audio_format;
+ audio_format.bits_per_sample = 32;
+ audio_format.num_channels = 2;
+
+ FrameAllocator::Frame audio_frame = audio_frame_allocator->alloc_frame();
+ if (audio_frame.data != nullptr) {
+ assert(audio_frame.size >= 2 * sizeof(uint32_t) * audio_frequency / fps);
+ audio_frame.len = 2 * sizeof(uint32_t) * audio_frequency / fps;
+ memset(audio_frame.data, 0, audio_frame.len);
+ }
+
+ frame_callback(timecode++,
+ video_frame, 0, video_format,
+ audio_frame, 0, audio_format);
+ }
+ if (has_dequeue_callbacks) {
+ dequeue_cleanup_callback();
+ }
+}
+
+} // namespace bmusb