]> git.sesse.net Git - nageru/commitdiff
Support true variable input frame rate instead of hard-coding to 60.
authorSteinar H. Gunderson <sgunderson@bigfoot.com>
Mon, 16 Nov 2015 20:39:54 +0000 (21:39 +0100)
committerSteinar H. Gunderson <sgunderson@bigfoot.com>
Mon, 16 Nov 2015 20:39:54 +0000 (21:39 +0100)
defs.h
h264encode.cpp
mixer.cpp
mixer.h

diff --git a/defs.h b/defs.h
index 2b578983c686032c89236ce0fbdc9b95bc12936e..9bed232f39db10a0c9d41b9ef2eab25daab5771c 100644 (file)
--- a/defs.h
+++ b/defs.h
@@ -1,9 +1,8 @@
 #ifndef _DEFS_H
 #define _DEFS_H
 
-// OUTPUT_FREQUENCY/FPS must be an integer for now.
 #define OUTPUT_FREQUENCY 48000
-#define FPS 60
+#define MAX_FPS 60
 #define WIDTH 1280
 #define HEIGHT 720
 
index d20683518784fd51c1a15d8089b46e26d7981678..a359726b4a874484305e0d6b32adc8ef7c249887 100644 (file)
@@ -114,7 +114,6 @@ static  int frame_width = 176;
 static  int frame_height = 144;
 static  int frame_width_mbaligned;
 static  int frame_height_mbaligned;
-static  int frame_rate = FPS;
 static  unsigned int frame_bitrate = 0;
 static  unsigned int frame_slices = 1;
 static  double frame_size = 0;
@@ -122,7 +121,7 @@ static  int initial_qp = 15;
 //static  int initial_qp = 28;
 static  int minimal_qp = 0;
 static  int intra_period = 30;
-static  int intra_idr_period = FPS;
+static  int intra_idr_period = MAX_FPS;  // About a second; more at lower frame rates. Not ideal.
 static  int ip_period = 3;
 static  int rc_mode = -1;
 static  int rc_default_modes[] = {
@@ -619,7 +618,7 @@ static int build_packed_slice_buffer(unsigned char **header_buffer)
 //
 // Getting pts and dts right with variable frame rate (VFR) and B-frames can be a
 // bit tricky. We assume first of all that the frame rate never goes _above_
-// <frame_rate>, which gives us a frame period N. The decoder can always decode
+// MAX_FPS, which gives us a frame period N. The decoder can always decode
 // in at least this speed, as long at dts <= pts (the frame is not attempted
 // presented before it is decoded). Furthermore, we never have longer chains of
 // B-frames than a fixed constant C. (In a B-frame chain, we say that the base
@@ -712,7 +711,7 @@ void encoding2display_order(
         *displaying_order = encoding_order;
         // IDR frames are a special case; I honestly can't find the logic behind
         // why this is the right thing, but it seems to line up nicely in practice :-)
-        *pts_lag = TIMEBASE / frame_rate;
+        *pts_lag = TIMEBASE / MAX_FPS;
     } else if (((encoding_order_gop - 1) % ip_period) != 0) { /* B frames */
         *frame_type = FRAME_B;
         *displaying_order = encoding_order - 1;
@@ -873,7 +872,7 @@ static int process_cmdline(int argc, char *argv[])
     }
 
     if (frame_bitrate == 0)
-        frame_bitrate = frame_width * frame_height * 12 * frame_rate / 50;
+        frame_bitrate = frame_width * frame_height * 12 * MAX_FPS / 50;
         
     if (coded_fn == NULL) {
         struct stat buf;
@@ -1661,7 +1660,7 @@ void H264Encoder::save_codeddata(storage_task task)
 
     string data;
 
-    const int64_t global_delay = (ip_period - 1) * (TIMEBASE / frame_rate);  // So we never get negative dts.
+    const int64_t global_delay = (ip_period - 1) * (TIMEBASE / MAX_FPS);  // So we never get negative dts.
 
     va_status = vaMapBuffer(va_dpy, gl_surfaces[task.display_order % SURFACE_NUM].coded_buf, (void **)(&buf_list));
     CHECK_VASTATUS(va_status, "vaMapBuffer");
@@ -1828,7 +1827,6 @@ static int print_input()
     if (rc_mode != -1)
         printf("INPUT: RateControl  : %s\n", rc_to_string(rc_mode));
     printf("INPUT: Resolution   : %dx%dframes\n", frame_width, frame_height);
-    printf("INPUT: FrameRate    : %d\n", frame_rate);
     printf("INPUT: Bitrate      : %d\n", frame_bitrate);
     printf("INPUT: Slieces      : %d\n", frame_slices);
     printf("INPUT: IntraPeriod  : %d\n", intra_period);
@@ -2059,7 +2057,7 @@ void H264Encoder::copy_thread_func()
                int64_t dts;
                if (pts_lag == -1) {
                        assert(last_dts != -1);
-                       dts = last_dts + (TIMEBASE / frame_rate);
+                       dts = last_dts + (TIMEBASE / MAX_FPS);
                } else {
                        dts = pts - pts_lag;
                }
index 42a02521258e93f34c71518c4de0917135c2fad4..936a070129352c4b10a80747e740be1e1ebb2dd0 100644 (file)
--- a/mixer.cpp
+++ b/mixer.cpp
@@ -212,6 +212,57 @@ void deinterleave_samples(const vector<float> &in, vector<float> *out_l, vector<
        }
 }
 
+// Returns length of a frame with the given format, in TIMEBASE units.
+int64_t find_frame_length(uint16_t video_format)
+{
+       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.
+               return TIMEBASE * 100 / 3013;
+       }
+       if ((video_format & 0xe800) != 0xe800) {
+               printf("Video format 0x%04x does not appear to be a video format. Assuming 60 Hz.\n",
+                       video_format);
+               return TIMEBASE / 60;
+       }
+
+       // 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 23.98
+       // and PAL). Rather confusing. But we clear it here nevertheless, because
+       // usually it doesn't mean anything.
+       //
+       // We don't really handle interlaced formats at all yet.
+       uint16_t normalized_video_format = video_format & ~0xe808;
+       if (normalized_video_format == 0x0143) {         // 720p50.
+               return TIMEBASE / 50;
+       } else if (normalized_video_format == 0x0103) {  // 720p60.
+               return TIMEBASE / 60;
+       } else if (normalized_video_format == 0x0121) {  // 720p59.94.
+               return TIMEBASE * 1001 / 60000;
+       } else if (normalized_video_format == 0x01c3 ||  // 1080p30.
+                  normalized_video_format == 0x0003) {  // 1080i60.
+               return TIMEBASE / 30;
+       } else if (normalized_video_format == 0x01e1 ||  // 1080p29.97.
+                  normalized_video_format == 0x0021 ||  // 1080i59.94.
+                  video_format == 0xe901 ||             // NTSC (480i59.94, I suppose).
+                  video_format == 0xe9c1 ||             // Ditto.
+                  video_format == 0xe801) {             // Ditto.
+               return TIMEBASE * 1001 / 30000;
+       } else if (normalized_video_format == 0x0063 ||  // 1080p25.
+                  normalized_video_format == 0x0043 ||  // 1080i50.
+                  video_format == 0xe909) {             // PAL (576i50, I suppose).
+               return TIMEBASE / 25;
+       } else if (normalized_video_format == 0x008e) {  // 1080p24.
+               return TIMEBASE / 24;
+       } else if (normalized_video_format == 0x00a1) {  // 1080p23.98.
+               return TIMEBASE * 1001 / 24000;
+               return TIMEBASE / 25;
+       } else {
+               printf("Unknown video format 0x%04x. Assuming 60 Hz.\n", video_format);
+               return TIMEBASE / 60;
+       }
+}
+
 }  // namespace
 
 void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
@@ -220,6 +271,8 @@ void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
 {
        CaptureCard *card = &cards[card_index];
 
+       int64_t frame_length = find_frame_length(video_format);
+
        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),
@@ -233,13 +286,12 @@ void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
                return;
        }
 
-       int unwrapped_timecode = timecode;
+       int64_t local_pts = card->next_local_pts;
        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;
+               dropped_frames = unwrap_timecode(timecode, card->last_timecode) - card->last_timecode - 1;
        }
-       card->last_timecode = unwrapped_timecode;
+       card->last_timecode = 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;
@@ -251,22 +303,27 @@ void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
        {
                unique_lock<mutex> lock(card->audio_mutex);
 
-               int unwrapped_timecode = timecode;
-               if (dropped_frames > FPS * 2) {
+               if (dropped_frames > MAX_FPS * 2) {
                        fprintf(stderr, "Card %d lost more than two seconds (or time code jumping around), resetting resampler\n",
                                card_index);
                        card->resampling_queue.reset(new ResamplingQueue(OUTPUT_FREQUENCY, OUTPUT_FREQUENCY, 2));
                } else if (dropped_frames > 0) {
-                       // Insert silence as needed.
+                       // Insert silence as needed. (The number of samples could be nonintegral,
+                       // but resampling will save us then.)
                        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((OUTPUT_FREQUENCY / FPS) * 2);
+                       silence.resize((OUTPUT_FREQUENCY * frame_length / TIMEBASE) * 2);
                        for (int i = 0; i < dropped_frames; ++i) {
-                               card->resampling_queue->add_input_samples((unwrapped_timecode - dropped_frames + i) / double(FPS), silence.data(), (OUTPUT_FREQUENCY / FPS));
+                               card->resampling_queue->add_input_samples(local_pts / double(TIMEBASE), silence.data(), silence.size() / 2);
+                               // Note that if the format changed in the meantime, we have
+                               // no way of detecting that; we just have to assume the frame length
+                               // is always the same.
+                               local_pts += frame_length;
                        }
                }
-               card->resampling_queue->add_input_samples(unwrapped_timecode / double(FPS), audio.data(), num_samples);
+               card->resampling_queue->add_input_samples(local_pts / double(TIMEBASE), audio.data(), num_samples);
+               card->next_local_pts = local_pts + frame_length;
        }
 
        // Done with the audio, so release it.
@@ -296,6 +353,7 @@ void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
                        unique_lock<mutex> lock(bmusb_mutex);
                        card->new_data_ready = true;
                        card->new_frame = RefCountedFrame(FrameAllocator::Frame());
+                       card->new_frame_length = frame_length;
                        card->new_data_ready_fence = nullptr;
                        card->dropped_frames = dropped_frames;
                        card->new_data_ready_changed.notify_all();
@@ -332,6 +390,7 @@ void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
                unique_lock<mutex> lock(bmusb_mutex);
                card->new_data_ready = true;
                card->new_frame = RefCountedFrame(video_frame);
+               card->new_frame_length = frame_length;
                card->new_data_ready_fence = fence;
                card->dropped_frames = dropped_frames;
                card->new_data_ready_changed.notify_all();
@@ -355,6 +414,7 @@ void Mixer::thread_func()
 
        while (!should_quit) {
                CaptureCard card_copy[MAX_CARDS];
+               int num_samples[MAX_CARDS];
 
                {
                        unique_lock<mutex> lock(bmusb_mutex);
@@ -368,10 +428,15 @@ void Mixer::thread_func()
                                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_frame_length = card->new_frame_length;
                                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();
+
+                               int num_samples_times_timebase = OUTPUT_FREQUENCY * card->new_frame_length + card->fractional_samples;
+                               num_samples[card_index] = num_samples_times_timebase / TIMEBASE;
+                               card->fractional_samples = num_samples_times_timebase % TIMEBASE;
                        }
                }
 
@@ -380,13 +445,15 @@ void Mixer::thread_func()
                        {
                                // Signal to the audio thread to process this frame.
                                unique_lock<mutex> lock(audio_mutex);
-                               audio_pts_queue.push(pts_int);
-                               audio_pts_queue_changed.notify_one();
+                               audio_task_queue.push(AudioTask{pts_int, num_samples[0]});
+                               audio_task_queue_changed.notify_one();
                        }
                        if (frame_num != card_copy[0].dropped_frames) {
-                               // For dropped frames, increase the pts.
+                               // For dropped frames, increase the pts. Note that if the format changed
+                               // in the meantime, we have no way of detecting that; we just have to
+                               // assume the frame length is always the same.
                                ++dropped_frames;
-                               pts_int += TIMEBASE / FPS;
+                               pts_int += card_copy[0].new_frame_length;
                        }
                }
 
@@ -415,7 +482,7 @@ void Mixer::thread_func()
                // 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 / FPS;
+                       pts_int += card_copy[0].new_frame_length;
                        continue;
                }
 
@@ -480,7 +547,7 @@ void Mixer::thread_func()
                const int64_t av_delay = TIMEBASE / 10;  // Corresponds to the fixed delay in resampling_queue.h. TODO: Make less hard-coded.
                h264_encoder->end_frame(fence, pts_int + av_delay, input_frames);
                ++frame;
-               pts_int += TIMEBASE / FPS;
+               pts_int += card_copy[0].new_frame_length;
 
                // The live frame just shows the RGBA texture we just rendered.
                // It owns rgba_tex now.
@@ -539,28 +606,28 @@ void Mixer::thread_func()
 void Mixer::audio_thread_func()
 {
        while (!should_quit) {
-               int64_t frame_pts_int;
+               AudioTask task;
 
                {
                        unique_lock<mutex> lock(audio_mutex);
-                       audio_pts_queue_changed.wait(lock, [this]{ return !audio_pts_queue.empty(); });
-                       frame_pts_int = audio_pts_queue.front();
-                       audio_pts_queue.pop();
+                       audio_task_queue_changed.wait(lock, [this]{ return !audio_task_queue.empty(); });
+                       task = audio_task_queue.front();
+                       audio_task_queue.pop();
                }
 
-               process_audio_one_frame(frame_pts_int);
+               process_audio_one_frame(task.pts_int, task.num_samples);
        }
 }
 
-void Mixer::process_audio_one_frame(int64_t frame_pts_int)
+void Mixer::process_audio_one_frame(int64_t frame_pts_int, int num_samples)
 {
        vector<float> samples_card;
        vector<float> samples_out;
        for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
-               samples_card.resize((OUTPUT_FREQUENCY / FPS) * 2);
+               samples_card.resize(num_samples * 2);
                {
                        unique_lock<mutex> lock(cards[card_index].audio_mutex);
-                       if (!cards[card_index].resampling_queue->get_output_samples(double(frame_pts_int) / TIMEBASE, &samples_card[0], OUTPUT_FREQUENCY / FPS)) {
+                       if (!cards[card_index].resampling_queue->get_output_samples(double(frame_pts_int) / TIMEBASE, &samples_card[0], num_samples)) {
                                printf("Card %d reported previous underrun.\n", card_index);
                        }
                }
diff --git a/mixer.h b/mixer.h
index 8f74cc53206300ff6ee3f036dbd99859489351f4..6cd912637f2ec081f5f33b8890854c240247152a 100644 (file)
--- a/mixer.h
+++ b/mixer.h
@@ -177,7 +177,7 @@ private:
        void place_rectangle(movit::Effect *resample_effect, movit::Effect *padding_effect, float x0, float y0, float x1, float y1);
        void thread_func();
        void audio_thread_func();
-       void process_audio_one_frame(int64_t frame_pts_int);
+       void process_audio_one_frame(int64_t frame_pts_int, int num_samples);
        void subsample_chroma(GLuint src_tex, GLuint dst_dst);
        void release_display_frame(DisplayFrame *frame);
        double pts() { return double(pts_int) / TIMEBASE; }
@@ -209,13 +209,19 @@ private:
                bool new_data_ready = false;  // Whether new_frame contains anything.
                bool should_quit = false;
                RefCountedFrame new_frame;
+               int64_t new_frame_length;  // In TIMEBASE units.
                GLsync new_data_ready_fence;  // Whether new_frame is ready for rendering.
                std::condition_variable new_data_ready_changed;  // Set whenever new_data_ready is changed.
                unsigned dropped_frames = 0;  // Before new_frame.
 
+               // Accumulated errors in number of 1/TIMEBASE samples. If OUTPUT_FREQUENCY divided by
+               // frame rate is integer, will always stay zero.
+               unsigned fractional_samples = 0;
+
                std::mutex audio_mutex;
                std::unique_ptr<ResamplingQueue> resampling_queue;  // Under audio_mutex.
                int last_timecode = -1;  // Unwrapped.
+               int64_t next_local_pts = 0;  // Beginning of next frame, in TIMEBASE units.
        };
        CaptureCard cards[MAX_CARDS];  // protected by <bmusb_mutex>
 
@@ -268,9 +274,13 @@ private:
 
        std::unique_ptr<ALSAOutput> alsa;
 
+       struct AudioTask {
+               int64_t pts_int;
+               int num_samples;
+       };
        std::mutex audio_mutex;
-       std::condition_variable audio_pts_queue_changed;
-       std::queue<int64_t> audio_pts_queue;
+       std::condition_variable audio_task_queue_changed;
+       std::queue<AudioTask> audio_task_queue;  // Under audio_mutex.
 };
 
 extern Mixer *global_mixer;