]> git.sesse.net Git - nageru/blobdiff - mixer.cpp
Add a compressor (kindly relicensed by Rune Holm). Fixed for now, and only to get...
[nageru] / mixer.cpp
index 1ac5d53ee03e40484194f8f3039c10233f547f12..43e39b6c18e8518b8b0ecee7df91ebf0d2a0b269 100644 (file)
--- a/mixer.cpp
+++ b/mixer.cpp
@@ -1,32 +1,26 @@
 #define WIDTH 1280
 #define HEIGHT 720
+#define EXTRAHEIGHT 30
 
 #undef Success
 
 #include "mixer.h"
 
 #include <assert.h>
-#include <effect.h>
-#include <effect_chain.h>
-#include <effect_util.h>
 #include <epoxy/egl.h>
-#include <features.h>
-#include <image_format.h>
 #include <init.h>
-#include <overlay_effect.h>
-#include <padding_effect.h>
-#include <resample_effect.h>
-#include <resource_pool.h>
-#include <saturation_effect.h>
+#include <movit/effect_chain.h>
+#include <movit/effect_util.h>
+#include <movit/flat_input.h>
+#include <movit/image_format.h>
+#include <movit/resource_pool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/time.h>
 #include <time.h>
 #include <util.h>
-#include <white_balance_effect.h>
-#include <ycbcr.h>
-#include <ycbcr_input.h>
+#include <algorithm>
 #include <cmath>
 #include <condition_variable>
 #include <cstddef>
 #include <mutex>
 #include <string>
 #include <thread>
+#include <utility>
 #include <vector>
 
-#include "bmusb.h"
+#include "bmusb/bmusb.h"
 #include "context.h"
 #include "h264encode.h"
 #include "pbo_frame_allocator.h"
 #include "ref_counted_gl_sync.h"
+#include "timebase.h"
 
 class QOpenGLContext;
 
@@ -50,64 +46,50 @@ using namespace std::placeholders;
 
 Mixer *global_mixer = nullptr;
 
-Mixer::Mixer(const QSurfaceFormat &format)
-       : mixer_surface(create_surface(format)),
-         h264_encoder_surface(create_surface(format))
+namespace {
+
+void convert_fixed24_to_fp32(float *dst, size_t out_channels, const uint8_t *src, size_t in_channels, size_t num_samples)
+{
+       for (size_t i = 0; i < num_samples; ++i) {
+               for (size_t j = 0; j < out_channels; ++j) {
+                       uint32_t s1 = *src++;
+                       uint32_t s2 = *src++;
+                       uint32_t s3 = *src++;
+                       uint32_t s = s1 | (s1 << 8) | (s2 << 16) | (s3 << 24);
+                       dst[i * out_channels + j] = int(s) * (1.0f / 4294967296.0f);
+               }
+               src += 3 * (in_channels - out_channels);
+       }
+}
+
+}  // namespace
+
+Mixer::Mixer(const QSurfaceFormat &format, unsigned num_cards)
+       : httpd("test.ts", WIDTH, HEIGHT),
+         num_cards(num_cards),
+         mixer_surface(create_surface(format)),
+         h264_encoder_surface(create_surface(format)),
+         compressor(48000.0f)
 {
+       httpd.start(9095);
+
        CHECK(init_movit(MOVIT_SHADER_DIR, MOVIT_DEBUG_OFF));
        check_error();
 
+       // Since we allow non-bouncing 4:2:2 YCbCrInputs, effective subpixel precision
+       // will be halved when sampling them, and we need to compensate here.
+       movit_texel_subpixel_precision /= 2.0;
+
        resource_pool.reset(new ResourcePool);
-       output_channel[OUTPUT_LIVE].parent = this;
-       output_channel[OUTPUT_PREVIEW].parent = this;
+       theme.reset(new Theme("theme.lua", resource_pool.get(), num_cards));
+       for (unsigned i = 0; i < NUM_OUTPUTS; ++i) {
+               output_channel[i].parent = this;
+       }
 
        ImageFormat inout_format;
        inout_format.color_space = COLORSPACE_sRGB;
        inout_format.gamma_curve = GAMMA_sRGB;
 
-       YCbCrFormat input_ycbcr_format;
-       input_ycbcr_format.chroma_subsampling_x = 2;
-       input_ycbcr_format.chroma_subsampling_y = 1;
-       input_ycbcr_format.cb_x_position = 0.0;
-       input_ycbcr_format.cr_x_position = 0.0;
-       input_ycbcr_format.cb_y_position = 0.5;
-       input_ycbcr_format.cr_y_position = 0.5;
-       input_ycbcr_format.luma_coefficients = YCBCR_REC_601;
-       input_ycbcr_format.full_range = false;
-
-       YCbCrFormat output_ycbcr_format;
-       output_ycbcr_format.chroma_subsampling_x = 1;
-       output_ycbcr_format.chroma_subsampling_y = 1;
-       output_ycbcr_format.luma_coefficients = YCBCR_REC_601;
-       output_ycbcr_format.full_range = false;
-
-       // Main chain.
-       chain.reset(new EffectChain(WIDTH, HEIGHT, resource_pool.get()));
-       check_error();
-       input[0] = new YCbCrInput(inout_format, input_ycbcr_format, WIDTH, HEIGHT, YCBCR_INPUT_SPLIT_Y_AND_CBCR);
-       chain->add_input(input[0]);
-       input[1] = new YCbCrInput(inout_format, input_ycbcr_format, WIDTH, HEIGHT, YCBCR_INPUT_SPLIT_Y_AND_CBCR);
-       chain->add_input(input[1]);
-       resample_effect = chain->add_effect(new ResampleEffect(), input[0]);
-       padding_effect = chain->add_effect(new IntegralPaddingEffect());
-       float border_color[] = { 0.0f, 0.0f, 0.0f, 1.0f };
-       CHECK(padding_effect->set_vec4("border_color", border_color));
-
-       resample2_effect = chain->add_effect(new ResampleEffect(), input[1]);
-       Effect *saturation_effect = chain->add_effect(new SaturationEffect());
-       CHECK(saturation_effect->set_float("saturation", 0.3f));
-       Effect *wb_effect = chain->add_effect(new WhiteBalanceEffect());
-       CHECK(wb_effect->set_float("output_color_temperature", 3500.0));
-       padding2_effect = chain->add_effect(new IntegralPaddingEffect());
-
-       chain->add_effect(new OverlayEffect(), padding_effect, padding2_effect);
-
-       chain->add_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED);
-       chain->add_ycbcr_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED, output_ycbcr_format, YCBCR_OUTPUT_SPLIT_Y_AND_CBCR);
-       chain->set_dither_bits(8);
-       chain->set_output_origin(OUTPUT_ORIGIN_TOP_LEFT);
-       chain->finalize();
-
        // Display chain; shows the live output produced by the main chain (its RGBA version).
        display_chain.reset(new EffectChain(WIDTH, HEIGHT, resource_pool.get()));
        check_error();
@@ -117,43 +99,36 @@ Mixer::Mixer(const QSurfaceFormat &format)
        display_chain->set_dither_bits(0);  // Don't bother.
        display_chain->finalize();
 
-       // Preview chain (always shows just first input for now).
-       preview_chain.reset(new EffectChain(WIDTH, HEIGHT, resource_pool.get()));
-       check_error();
-       preview_input = new YCbCrInput(inout_format, input_ycbcr_format, WIDTH, HEIGHT, YCBCR_INPUT_SPLIT_Y_AND_CBCR);
-       preview_chain->add_input(preview_input);
-       preview_chain->add_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED);
-       preview_chain->set_dither_bits(0);  // Don't bother.
-       preview_chain->finalize();
-
-       h264_encoder.reset(new H264Encoder(h264_encoder_surface, WIDTH, HEIGHT, "test.mp4"));
-
-       printf("Configuring first card...\n");
-       cards[0].usb = new BMUSBCapture(0x1edb, 0xbd3b);  // 0xbd4f
-       cards[0].usb->set_frame_callback(std::bind(&Mixer::bm_frame, this, 0, _1, _2, _3, _4, _5, _6, _7));
-       cards[0].frame_allocator.reset(new PBOFrameAllocator(1280 * 750 * 2 + 44, 1280, 720));
-       cards[0].usb->set_video_frame_allocator(cards[0].frame_allocator.get());
-       cards[0].usb->configure_card();
-       cards[0].surface = create_surface(format);
-#if NUM_CARDS == 2
-       cards[1].surface = create_surface(format);
-#endif
-
-       if (NUM_CARDS == 2) {
-               printf("Configuring second card...\n");
-               cards[1].usb = new BMUSBCapture(0x1edb, 0xbd4f);
-               cards[1].usb->set_frame_callback(std::bind(&Mixer::bm_frame, this, 1, _1, _2, _3, _4, _5, _6, _7));
-               cards[1].frame_allocator.reset(new PBOFrameAllocator(1280 * 750 * 2 + 44, 1280, 720));
-               cards[1].usb->set_video_frame_allocator(cards[1].frame_allocator.get());
-               cards[1].usb->configure_card();
+       h264_encoder.reset(new H264Encoder(h264_encoder_surface, WIDTH, HEIGHT, &httpd));
+
+       for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
+               printf("Configuring card %d...\n", card_index);
+               CaptureCard *card = &cards[card_index];
+               card->usb = new BMUSBCapture(card_index);
+               card->usb->set_frame_callback(bind(&Mixer::bm_frame, this, card_index, _1, _2, _3, _4, _5, _6, _7));
+               card->frame_allocator.reset(new PBOFrameAllocator(WIDTH * (HEIGHT+EXTRAHEIGHT) * 2 + 44, WIDTH, HEIGHT));
+               card->usb->set_video_frame_allocator(card->frame_allocator.get());
+               card->surface = create_surface(format);
+               card->usb->set_dequeue_thread_callbacks(
+                       [card]{
+                               eglBindAPI(EGL_OPENGL_API);
+                               card->context = create_context(card->surface);
+                               if (!make_current(card->context, card->surface)) {
+                                       printf("failed to create bmusb context\n");
+                                       exit(1);
+                               }
+                       },
+                       [this]{
+                               resource_pool->clean_context();
+                       });
+               card->resampler.reset(new Resampler(48000.0, 48000.0, 2));
+               card->usb->configure_card();
        }
 
        BMUSBCapture::start_bm_thread();
 
-       for (int card_index = 0; card_index < NUM_CARDS; ++card_index) {
+       for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
                cards[card_index].usb->start_bm_capture();
-               input[card_index]->set_pixel_data(0, nullptr, 0);
-               input[card_index]->set_pixel_data(1, nullptr, 0);
        }
 
        //chain->enable_phase_timing(true);
@@ -170,45 +145,153 @@ Mixer::Mixer(const QSurfaceFormat &format)
                "    gl_FragColor = texture2D(cbcr_tex, tc0); \n"
                "} \n";
        cbcr_program_num = resource_pool->compile_glsl_program(cbcr_vert_shader, cbcr_frag_shader);
+
+       r128.init(2, 48000);
+       r128.integr_start();
 }
 
 Mixer::~Mixer()
 {
        resource_pool->release_glsl_program(cbcr_program_num);
        BMUSBCapture::stop_bm_thread();
+
+       for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
+               {
+                       unique_lock<mutex> lock(bmusb_mutex);
+                       cards[card_index].should_quit = true;  // Unblock thread.
+                       cards[card_index].new_data_ready_changed.notify_all();
+               }
+               cards[card_index].usb->stop_dequeue_thread();
+       }
+}
+
+namespace {
+
+int unwrap_timecode(uint16_t current_wrapped, int last)
+{
+       uint16_t last_wrapped = last & 0xffff;
+       if (current_wrapped > last_wrapped) {
+               return (last & ~0xffff) | current_wrapped;
+       } else {
+               return 0x10000 + ((last & ~0xffff) | current_wrapped);
+       }
+}
+
+float find_peak(const vector<float> &samples)
+{
+       float m = fabs(samples[0]);
+       for (size_t i = 1; i < samples.size(); ++i) {
+               m = std::max(m, fabs(samples[i]));
+       }
+       return m;
+}
+
+void deinterleave_samples(const vector<float> &in, vector<float> *out_l, vector<float> *out_r)
+{
+       size_t num_samples = in.size() / 2;
+       out_l->resize(num_samples);
+       out_r->resize(num_samples);
+
+       const float *inptr = in.data();
+       float *lptr = &(*out_l)[0];
+       float *rptr = &(*out_r)[0];
+       for (size_t i = 0; i < num_samples; ++i) {
+               *lptr++ = *inptr++;
+               *rptr++ = *inptr++;
+       }
 }
 
-void Mixer::bm_frame(int card_index, uint16_t timecode,
+}  // namespace
+
+void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
                      FrameAllocator::Frame video_frame, size_t video_offset, uint16_t video_format,
                     FrameAllocator::Frame audio_frame, size_t audio_offset, uint16_t audio_format)
 {
        CaptureCard *card = &cards[card_index];
-       if (!card->thread_initialized) {
-               printf("initializing context for bmusb thread %d\n", card_index);
-               eglBindAPI(EGL_OPENGL_API);
-               card->context = create_context();
-               if (!make_current(card->context, card->surface)) {
-                       printf("failed to create bmusb context\n");
-                       exit(1);
+
+       if (audio_frame.len - audio_offset > 30000) {
+               printf("Card %d: Dropping frame with implausible audio length (len=%d, offset=%d) [timecode=0x%04x video_len=%d video_offset=%d video_format=%x)\n",
+                       card_index, int(audio_frame.len), int(audio_offset),
+                       timecode, int(video_frame.len), int(video_offset), video_format);
+               if (video_frame.owner) {
+                       video_frame.owner->release_frame(video_frame);
+               }
+               if (audio_frame.owner) {
+                       audio_frame.owner->release_frame(audio_frame);
                }
-               card->thread_initialized = true;
-       }       
-
-       if (video_frame.len - video_offset != 1280 * 750 * 2) {
-               printf("dropping frame with wrong length (%ld)\n", video_frame.len - video_offset);
-               FILE *fp = fopen("frame.raw", "wb");
-               fwrite(video_frame.data, video_frame.len, 1, fp);
-               fclose(fp);
-               //exit(1);
-               card->usb->get_video_frame_allocator()->release_frame(video_frame);
-               card->usb->get_audio_frame_allocator()->release_frame(audio_frame);
                return;
        }
+
+       int unwrapped_timecode = timecode;
+       int dropped_frames = 0;
+       if (card->last_timecode != -1) {
+               unwrapped_timecode = unwrap_timecode(unwrapped_timecode, card->last_timecode);
+               dropped_frames = unwrapped_timecode - card->last_timecode - 1;
+       }
+       card->last_timecode = unwrapped_timecode;
+
+       // Convert the audio to stereo fp32 and add it.
+       size_t num_samples = (audio_frame.len >= audio_offset) ? (audio_frame.len - audio_offset) / 8 / 3 : 0;
+       vector<float> audio;
+       audio.resize(num_samples * 2);
+       convert_fixed24_to_fp32(&audio[0], 2, audio_frame.data + audio_offset, 8, num_samples);
+
+       // Add the audio.
+       {
+               unique_lock<mutex> lock(card->audio_mutex);
+
+               int unwrapped_timecode = timecode;
+               if (dropped_frames > 60 * 2) {
+                       fprintf(stderr, "Card %d lost more than two seconds (or time code jumping around), resetting resampler\n",
+                               card_index);
+                       card->resampler.reset(new Resampler(48000.0, 48000.0, 2));
+               } else if (dropped_frames > 0) {
+                       // Insert silence as needed.
+                       fprintf(stderr, "Card %d dropped %d frame(s) (before timecode 0x%04x), inserting silence.\n",
+                               card_index, dropped_frames, timecode);
+                       vector<float> silence;
+                       silence.resize((48000 / 60) * 2);
+                       for (int i = 0; i < dropped_frames; ++i) {
+                               card->resampler->add_input_samples((unwrapped_timecode - dropped_frames + i) / 60.0, silence.data(), (48000 / 60));
+                       }
+               }
+               card->resampler->add_input_samples(unwrapped_timecode / 60.0, audio.data(), num_samples);
+       }
+
+       // Done with the audio, so release it.
+       if (audio_frame.owner) {
+               audio_frame.owner->release_frame(audio_frame);
+       }
+
        {
                // Wait until the previous frame was consumed.
-               std::unique_lock<std::mutex> lock(bmusb_mutex);
-               card->new_data_ready_changed.wait(lock, [card]{ return !card->new_data_ready; });
+               unique_lock<mutex> lock(bmusb_mutex);
+               card->new_data_ready_changed.wait(lock, [card]{ return !card->new_data_ready || card->should_quit; });
+               if (card->should_quit) return;
        }
+
+       if (video_frame.len - video_offset != WIDTH * (HEIGHT+EXTRAHEIGHT) * 2) {
+               if (video_frame.len != 0) {
+                       printf("Card %d: Dropping video frame with wrong length (%ld)\n",
+                               card_index, video_frame.len - video_offset);
+               }
+               if (video_frame.owner) {
+                       video_frame.owner->release_frame(video_frame);
+               }
+
+               // Still send on the information that we _had_ a frame, even though it's corrupted,
+               // so that pts can go up accordingly.
+               {
+                       unique_lock<mutex> lock(bmusb_mutex);
+                       card->new_data_ready = true;
+                       card->new_frame = RefCountedFrame(FrameAllocator::Frame());
+                       card->new_data_ready_fence = nullptr;
+                       card->dropped_frames = dropped_frames;
+                       card->new_data_ready_changed.notify_all();
+               }
+               return;
+       }
+
        const PBOFrameAllocator::Userdata *userdata = (const PBOFrameAllocator::Userdata *)video_frame.userdata;
        GLuint pbo = userdata->pbo;
        check_error();
@@ -222,95 +305,32 @@ void Mixer::bm_frame(int card_index, uint16_t timecode,
        // Upload the textures.
        glBindTexture(GL_TEXTURE_2D, userdata->tex_y);
        check_error();
-       glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 1280, 720, GL_RED, GL_UNSIGNED_BYTE, BUFFER_OFFSET((1280 * 750 * 2 + 44) / 2 + 1280 * 25 + 22));
+       glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, WIDTH, HEIGHT, GL_RED, GL_UNSIGNED_BYTE, BUFFER_OFFSET((WIDTH * (HEIGHT+EXTRAHEIGHT) * 2 + 44) / 2 + WIDTH * 25 + 22));
        check_error();
        glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr);
        check_error();
-       glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 1280/2, 720, GL_RG, GL_UNSIGNED_BYTE, BUFFER_OFFSET(1280 * 25 + 22));
+       glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, WIDTH/2, HEIGHT, GL_RG, GL_UNSIGNED_BYTE, BUFFER_OFFSET(WIDTH * 25 + 22));
        check_error();
        glBindTexture(GL_TEXTURE_2D, 0);
        check_error();
        GLsync fence = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, /*flags=*/0);              
        check_error();
        assert(fence != nullptr);
+
        {
-               std::unique_lock<std::mutex> lock(bmusb_mutex);
+               unique_lock<mutex> lock(bmusb_mutex);
                card->new_data_ready = true;
                card->new_frame = RefCountedFrame(video_frame);
                card->new_data_ready_fence = fence;
+               card->dropped_frames = dropped_frames;
                card->new_data_ready_changed.notify_all();
        }
-
-       // Video frame will be released when last user of card->new_frame goes out of scope.
-        card->usb->get_audio_frame_allocator()->release_frame(audio_frame);
 }
-       
-void Mixer::place_rectangle(Effect *resample_effect, Effect *padding_effect, float x0, float y0, float x1, float y1)
-{
-       float srcx0 = 0.0f;
-       float srcx1 = 1.0f;
-       float srcy0 = 0.0f;
-       float srcy1 = 1.0f;
-
-       // Cull.
-       if (x0 > 1280.0 || x1 < 0.0 || y0 > 720.0 || y1 < 0.0) {
-               CHECK(resample_effect->set_int("width", 1));
-               CHECK(resample_effect->set_int("height", 1));
-               CHECK(resample_effect->set_float("zoom_x", 1280.0));
-               CHECK(resample_effect->set_float("zoom_y", 720.0));
-               CHECK(padding_effect->set_int("left", 2000));
-               CHECK(padding_effect->set_int("top", 2000));
-               return; 
-       }
 
-       // Clip. (TODO: Clip on upper/left sides, too.)
-       if (x1 > 1280.0) {
-               srcx1 = (1280.0 - x0) / (x1 - x0);
-               x1 = 1280.0;
-       }
-       if (y1 > 720.0) {
-               srcy1 = (720.0 - y0) / (y1 - y0);
-               y1 = 720.0;
-       }
-
-       float x_subpixel_offset = x0 - floor(x0);
-       float y_subpixel_offset = y0 - floor(y0);
-
-       // Resampling must be to an integral number of pixels. Round up,
-       // and then add an extra pixel so we have some leeway for the border.
-       int width = int(ceil(x1 - x0)) + 1;
-       int height = int(ceil(y1 - y0)) + 1;
-       CHECK(resample_effect->set_int("width", width));
-       CHECK(resample_effect->set_int("height", height));
-
-       // Correct the discrepancy with zoom. (This will leave a small
-       // excess edge of pixels and subpixels, which we'll correct for soon.)
-       float zoom_x = (x1 - x0) / (width * (srcx1 - srcx0));
-       float zoom_y = (y1 - y0) / (height * (srcy1 - srcy0));
-       CHECK(resample_effect->set_float("zoom_x", zoom_x));
-       CHECK(resample_effect->set_float("zoom_y", zoom_y));
-       CHECK(resample_effect->set_float("zoom_center_x", 0.0f));
-       CHECK(resample_effect->set_float("zoom_center_y", 0.0f));
-
-       // Padding must also be to a whole-pixel offset.
-       CHECK(padding_effect->set_int("left", floor(x0)));
-       CHECK(padding_effect->set_int("top", floor(y0)));
-
-       // Correct _that_ discrepancy by subpixel offset in the resampling.
-       CHECK(resample_effect->set_float("left", -x_subpixel_offset / zoom_x));
-       CHECK(resample_effect->set_float("top", -y_subpixel_offset / zoom_y));
-
-       // Finally, adjust the border so it is exactly where we want it.
-       CHECK(padding_effect->set_float("border_offset_left", x_subpixel_offset));
-       CHECK(padding_effect->set_float("border_offset_right", x1 - (floor(x0) + width)));
-       CHECK(padding_effect->set_float("border_offset_top", y_subpixel_offset));
-       CHECK(padding_effect->set_float("border_offset_bottom", y1 - (floor(y0) + height)));
-}
-       
 void Mixer::thread_func()
 {
        eglBindAPI(EGL_OPENGL_API);
-       QOpenGLContext *context = create_context();
+       QOpenGLContext *context = create_context(mixer_surface);
        if (!make_current(context, mixer_surface)) {
                printf("oops\n");
                exit(1);
@@ -319,114 +339,95 @@ void Mixer::thread_func()
        struct timespec start, now;
        clock_gettime(CLOCK_MONOTONIC, &start);
 
-       while (!should_quit) {
-               ++frame;
-
-               //int width0 = lrintf(848 * (1.0 + 0.2 * sin(frame * 0.02)));
-               int width0 = 848;
-               int height0 = lrintf(width0 * 9.0 / 16.0);
-
-               //float top0 = 96 + 48 * sin(frame * 0.005);
-               //float left0 = 96 + 48 * cos(frame * 0.006);
-               float top0 = 48;
-               float left0 = 16;
-               float bottom0 = top0 + height0;
-               float right0 = left0 + width0;
-
-               int width1 = 384;
-               int height1 = 216;
-       
-               float bottom1 = 720 - 48;
-               float right1 = 1280 - 16;
-               float top1 = bottom1 - height1;
-               float left1 = right1 - width1;
-       
-               if (current_source == SOURCE_INPUT1) {
-                       top0 = 0.0;
-                       bottom0 = HEIGHT;
-                       left0 = 0.0;
-                       right0 = WIDTH;
-
-                       top1 = HEIGHT + 10;
-                       bottom1 = HEIGHT + 20;
-                       left1 = WIDTH + 10;
-                       right1 = WIDTH + 20;
-               } else if (current_source == SOURCE_INPUT2) {
-                       top1 = 0.0;
-                       bottom1 = HEIGHT;
-                       left1 = 0.0;
-                       right1 = WIDTH;
-
-                       top0 = HEIGHT + 10;
-                       bottom0 = HEIGHT + 20;
-                       left0 = WIDTH + 10;
-                       right0 = WIDTH + 20;
-               } else {
-                       float t = 0.5 + 0.5 * cos(frame * 0.006);
-                       float scale0 = 1.0 + t * (1280.0 / 848.0 - 1.0);
-                       float tx0 = 0.0 + t * (-16.0 * scale0);
-                       float ty0 = 0.0 + t * (-48.0 * scale0);
-
-                       top0 = top0 * scale0 + ty0;
-                       bottom0 = bottom0 * scale0 + ty0;
-                       left0 = left0 * scale0 + tx0;
-                       right0 = right0 * scale0 + tx0;
-
-                       top1 = top1 * scale0 + ty0;
-                       bottom1 = bottom1 * scale0 + ty0;
-                       left1 = left1 * scale0 + tx0;
-                       right1 = right1 * scale0 + tx0;
-               }
+       int frame = 0;
+       int dropped_frames = 0;
 
-               place_rectangle(resample_effect, padding_effect, left0, top0, right0, bottom0);
-               place_rectangle(resample2_effect, padding2_effect, left1, top1, right1, bottom1);
-
-               CaptureCard card_copy[NUM_CARDS];
+       while (!should_quit) {
+               CaptureCard card_copy[MAX_CARDS];
 
                {
-                       std::unique_lock<std::mutex> lock(bmusb_mutex);
+                       unique_lock<mutex> lock(bmusb_mutex);
 
                        // The first card is the master timer, so wait for it to have a new frame.
                        // TODO: Make configurable, and with a timeout.
                        cards[0].new_data_ready_changed.wait(lock, [this]{ return cards[0].new_data_ready; });
 
-                       for (int card_index = 0; card_index < NUM_CARDS; ++card_index) {
+                       for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
                                CaptureCard *card = &cards[card_index];
                                card_copy[card_index].usb = card->usb;
                                card_copy[card_index].new_data_ready = card->new_data_ready;
                                card_copy[card_index].new_frame = card->new_frame;
                                card_copy[card_index].new_data_ready_fence = card->new_data_ready_fence;
+                               card_copy[card_index].dropped_frames = card->dropped_frames;
                                card->new_data_ready = false;
                                card->new_data_ready_changed.notify_all();
                        }
                }
 
-               for (int card_index = 0; card_index < NUM_CARDS; ++card_index) {
+               // Resample the audio as needed, including from previously dropped frames.
+               for (unsigned frame_num = 0; frame_num < card_copy[0].dropped_frames + 1; ++frame_num) {
+                       process_audio_one_frame();
+                       if (frame_num != card_copy[0].dropped_frames) {
+                               // For dropped frames, increase the pts.
+                               ++dropped_frames;
+                               pts_int += TIMEBASE / 60;
+                       }
+               }
+
+               if (audio_level_callback != nullptr) {
+                       double loudness_s = r128.loudness_S();
+                       double loudness_i = r128.integrated();
+                       double loudness_range_low = r128.range_min();
+                       double loudness_range_high = r128.range_max();
+
+                       audio_level_callback(loudness_s, 20.0 * log10(peak),
+                                            loudness_i, loudness_range_low, loudness_range_high);
+               }
+
+               for (unsigned card_index = 1; card_index < num_cards; ++card_index) {
+                       if (card_copy[card_index].new_data_ready && card_copy[card_index].new_frame->len == 0) {
+                               ++card_copy[card_index].dropped_frames;
+                       }
+                       if (card_copy[card_index].dropped_frames > 0) {
+                               printf("Card %u dropped %d frames before this\n",
+                                       card_index, int(card_copy[card_index].dropped_frames));
+                       }
+               }
+
+               // If the first card is reporting a corrupted or otherwise dropped frame,
+               // just increase the pts (skipping over this frame) and don't try to compute anything new.
+               if (card_copy[0].new_frame->len == 0) {
+                       ++dropped_frames;
+                       pts_int += TIMEBASE / 60;
+                       continue;
+               }
+
+               for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
                        CaptureCard *card = &card_copy[card_index];
-                       if (!card->new_data_ready)
+                       if (!card->new_data_ready || card->new_frame->len == 0)
                                continue;
 
+                       assert(card->new_frame != nullptr);
                        bmusb_current_rendering_frame[card_index] = card->new_frame;
                        check_error();
 
                        // The new texture might still be uploaded,
                        // tell the GPU to wait until it's there.
-                       if (card->new_data_ready_fence)
+                       if (card->new_data_ready_fence) {
                                glWaitSync(card->new_data_ready_fence, /*flags=*/0, GL_TIMEOUT_IGNORED);
-                       check_error();
-                       glDeleteSync(card->new_data_ready_fence);
-                       check_error();
-                       const PBOFrameAllocator::Userdata *userdata = (const PBOFrameAllocator::Userdata *)card->new_frame->userdata;
-                       input[card_index]->set_texture_num(0, userdata->tex_y);
-                       input[card_index]->set_texture_num(1, userdata->tex_cbcr);
-
-                       if (NUM_CARDS == 1) {
-                               // Set to the other one, too.
-                               input[1]->set_texture_num(0, userdata->tex_y);
-                               input[1]->set_texture_num(1, userdata->tex_cbcr);
+                               check_error();
+                               glDeleteSync(card->new_data_ready_fence);
+                               check_error();
                        }
+                       const PBOFrameAllocator::Userdata *userdata = (const PBOFrameAllocator::Userdata *)card->new_frame->userdata;
+                       theme->set_input_textures(card_index, userdata->tex_y, userdata->tex_cbcr);
                }
 
+               // Get the main chain from the theme, and set its state immediately.
+               pair<EffectChain *, function<void()>> theme_main_chain = theme->get_chain(0, pts(), WIDTH, HEIGHT);
+               EffectChain *chain = theme_main_chain.first;
+               theme_main_chain.second();
+
                GLuint y_tex, cbcr_tex;
                bool got_frame = h264_encoder->begin_frame(&y_tex, &cbcr_tex);
                assert(got_frame);
@@ -435,6 +436,7 @@ void Mixer::thread_func()
                GLuint cbcr_full_tex = resource_pool->create_2d_texture(GL_RG8, WIDTH, HEIGHT);
                GLuint rgba_tex = resource_pool->create_2d_texture(GL_RGB565, WIDTH, HEIGHT);  // Saves texture bandwidth, although dithering gets messed up.
                GLuint fbo = resource_pool->create_fbo(y_tex, cbcr_full_tex, rgba_tex);
+               check_error();
                chain->render_to_fbo(fbo, WIDTH, HEIGHT);
                resource_pool->release_fbo(fbo);
 
@@ -455,10 +457,13 @@ void Mixer::thread_func()
                // input frames needed, so that they are not released back
                // until the rendering is done.
                vector<RefCountedFrame> input_frames;
-               for (int card_index = 0; card_index < NUM_CARDS; ++card_index) {
+               for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
                        input_frames.push_back(bmusb_current_rendering_frame[card_index]);
                }
-               h264_encoder->end_frame(fence, input_frames);
+               const int64_t av_delay = TIMEBASE / 10;  // Corresponds to the fixed delay in resampler.h. TODO: Make less hard-coded.
+               h264_encoder->end_frame(fence, pts_int + av_delay, input_frames);
+               ++frame;
+               pts_int += TIMEBASE / 60;
 
                // The live frame just shows the RGBA texture we just rendered.
                // It owns rgba_tex now.
@@ -472,32 +477,33 @@ void Mixer::thread_func()
                live_frame.temp_textures = { rgba_tex };
                output_channel[OUTPUT_LIVE].output_frame(live_frame);
 
-               // The preview frame shows the first input. Note that the textures
-               // are owned by the input frame, not the display frame.
-               const PBOFrameAllocator::Userdata *input0_userdata = (const PBOFrameAllocator::Userdata *)bmusb_current_rendering_frame[0]->userdata;
-               GLuint input0_y_tex = input0_userdata->tex_y;
-               GLuint input0_cbcr_tex = input0_userdata->tex_cbcr;
-               DisplayFrame preview_frame;
-               preview_frame.chain = preview_chain.get();
-               preview_frame.setup_chain = [this, input0_y_tex, input0_cbcr_tex]{
-                       preview_input->set_texture_num(0, input0_y_tex);
-                       preview_input->set_texture_num(1, input0_cbcr_tex);
-               };
-               preview_frame.ready_fence = fence;
-               preview_frame.input_frames = { bmusb_current_rendering_frame[0] };
-               preview_frame.temp_textures = {};
-               output_channel[OUTPUT_PREVIEW].output_frame(preview_frame);
+               // Set up preview and any additional channels.
+               for (int i = 1; i < theme->get_num_channels() + 2; ++i) {
+                       DisplayFrame display_frame;
+                       pair<EffectChain *, function<void()>> chain = theme->get_chain(i, pts(), WIDTH, HEIGHT);  // FIXME: dimensions
+                       display_frame.chain = chain.first;
+                       display_frame.setup_chain = chain.second;
+                       display_frame.ready_fence = fence;
+
+                       // FIXME: possible to do better?
+                       for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
+                               display_frame.input_frames.push_back(bmusb_current_rendering_frame[card_index]);
+                       }
+                       display_frame.temp_textures = {};
+                       output_channel[i].output_frame(display_frame);
+               }
 
                clock_gettime(CLOCK_MONOTONIC, &now);
                double elapsed = now.tv_sec - start.tv_sec +
                        1e-9 * (now.tv_nsec - start.tv_nsec);
                if (frame % 100 == 0) {
-                       printf("%d frames in %.3f seconds = %.1f fps (%.1f ms/frame)\n",
-                               frame, elapsed, frame / elapsed,
+                       printf("%d frames (%d dropped) in %.3f seconds = %.1f fps (%.1f ms/frame)\n",
+                               frame, dropped_frames, elapsed, frame / elapsed,
                                1e3 * elapsed / frame);
                //      chain->print_phase_timing();
                }
 
+#if 0
                // Reset every 100 frames, so that local variations in frame times
                // (especially for the first few frames, when the shaders are
                // compiled etc.) don't make it hard to measure for the entire
@@ -506,8 +512,67 @@ void Mixer::thread_func()
                        frame = 0;
                        start = now;
                }
+#endif
                check_error();
        }
+
+       resource_pool->clean_context();
+}
+
+void Mixer::process_audio_one_frame()
+{
+       vector<float> samples_card;
+       vector<float> samples_out;
+       for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
+               samples_card.resize((48000 / 60) * 2);
+               {
+                       unique_lock<mutex> lock(cards[card_index].audio_mutex);
+                       if (!cards[card_index].resampler->get_output_samples(pts(), &samples_card[0], 48000 / 60)) {
+                               printf("Card %d reported previous underrun.\n", card_index);
+                       }
+               }
+               // TODO: Allow using audio from the other card(s) as well.
+               if (card_index == 0) {
+                       samples_out = move(samples_card);
+               }
+       }
+
+       // Apply a level compressor to get the general level right.
+       // Basically, if it's over about -40 dBFS, we squeeze it down to that level
+       // (or more precisely, near it, since we don't use infinite ratio),
+       // then apply a makeup gain to get it to -12 dBFS. -12 dBFS is, of course,
+       // entirely arbitrary, but from practical tests with speech, it seems to
+       // put ut around -23 LUFS, so it's a reasonable starting point for later use.
+       //
+       // TODO: Hook this up to a UI, so we can see the effects, and/or turn it off
+       // to control the gain manually instead. For now, there's only the #if-ed out
+       // code below.
+       //
+       // TODO: Add the actual compressors/limiters (for taking care of transients)
+       // later in the chain.
+       float threshold = 0.01f;   // -40 dBFS.
+       float ratio = 20.0f;
+       float attack_time = 0.1f;
+       float release_time = 10.0f;
+       float makeup_gain = pow(10.0f, 28.0f / 20.0f);  // +28 dB takes us to -12 dBFS.
+       compressor.process(samples_out.data(), samples_out.size() / 2, threshold, ratio, attack_time, release_time, makeup_gain);
+
+#if 0
+       printf("level=%f (%+5.2f dBFS) attenuation=%f (%+5.2f dB) end_result=%+5.2f dB\n",
+               compressor.get_level(), 20.0 * log10(compressor.get_level()),
+               compressor.get_attenuation(), 20.0 * log10(compressor.get_attenuation()),
+               20.0 * log10(compressor.get_level() * compressor.get_attenuation() * makeup_gain));
+#endif
+
+       // Find peak and R128 levels.
+       peak = std::max(peak, find_peak(samples_out));
+       vector<float> left, right;
+       deinterleave_samples(samples_out, &left, &right);
+       float *ptrs[] = { left.data(), right.data() };
+       r128.process(left.size(), ptrs);
+
+       // Actually add the samples to the output.
+       h264_encoder->add_audio(pts_int, move(samples_out));
 }
 
 void Mixer::subsample_chroma(GLuint src_tex, GLuint dst_tex)
@@ -576,7 +641,7 @@ void Mixer::release_display_frame(DisplayFrame *frame)
 
 void Mixer::start()
 {
-       mixer_thread = std::thread(&Mixer::thread_func, this);
+       mixer_thread = thread(&Mixer::thread_func, this);
 }
 
 void Mixer::quit()
@@ -585,9 +650,24 @@ void Mixer::quit()
        mixer_thread.join();
 }
 
-void Mixer::cut(Source source)
+void Mixer::transition_clicked(int transition_num)
+{
+       theme->transition_clicked(transition_num, pts());
+}
+
+void Mixer::channel_clicked(int preview_num)
 {
-       current_source = source;
+       theme->channel_clicked(preview_num);
+}
+
+Mixer::OutputChannel::~OutputChannel()
+{
+       if (has_current_frame) {
+               parent->release_display_frame(&current_frame);
+       }
+       if (has_ready_frame) {
+               parent->release_display_frame(&ready_frame);
+       }
 }
 
 void Mixer::OutputChannel::output_frame(DisplayFrame frame)
@@ -595,7 +675,7 @@ void Mixer::OutputChannel::output_frame(DisplayFrame frame)
        // Store this frame for display. Remove the ready frame if any
        // (it was seemingly never used).
        {
-               std::unique_lock<std::mutex> lock(frame_mutex);
+               unique_lock<mutex> lock(frame_mutex);
                if (has_ready_frame) {
                        parent->release_display_frame(&ready_frame);
                }
@@ -610,7 +690,7 @@ void Mixer::OutputChannel::output_frame(DisplayFrame frame)
 
 bool Mixer::OutputChannel::get_display_frame(DisplayFrame *frame)
 {
-       std::unique_lock<std::mutex> lock(frame_mutex);
+       unique_lock<mutex> lock(frame_mutex);
        if (!has_current_frame && !has_ready_frame) {
                return false;
        }
@@ -638,9 +718,3 @@ void Mixer::OutputChannel::set_frame_ready_callback(Mixer::new_frame_ready_callb
        new_frame_ready_callback = callback;
        has_new_frame_ready_callback = true;
 }
-
-void Mixer::OutputChannel::set_size(int width, int height)
-{
-       this->width = width;
-       this->height = height;
-}