1 #include "ffmpeg_capture.h"
13 #include <libavcodec/avcodec.h>
14 #include <libavformat/avformat.h>
15 #include <libavutil/avutil.h>
16 #include <libavutil/error.h>
17 #include <libavutil/frame.h>
18 #include <libavutil/imgutils.h>
19 #include <libavutil/mem.h>
20 #include <libavutil/pixfmt.h>
21 #include <libavutil/opt.h>
22 #include <libswscale/swscale.h>
32 #include <movit/colorspace_conversion_effect.h>
34 #include "bmusb/bmusb.h"
35 #include "shared/ffmpeg_raii.h"
36 #include "ffmpeg_util.h"
38 #include "image_input.h"
39 #include "ref_counted_frame.h"
40 #include "shared/timebase.h"
46 #define FRAME_SIZE (8 << 20) // 8 MB.
49 using namespace std::chrono;
50 using namespace bmusb;
51 using namespace movit;
52 using namespace Eigen;
56 steady_clock::time_point compute_frame_start(int64_t frame_pts, int64_t pts_origin, const AVRational &video_timebase, const steady_clock::time_point &origin, double rate)
58 const duration<double> pts((frame_pts - pts_origin) * double(video_timebase.num) / double(video_timebase.den));
59 return origin + duration_cast<steady_clock::duration>(pts / rate);
62 bool changed_since(const std::string &pathname, const timespec &ts)
68 if (stat(pathname.c_str(), &buf) != 0) {
69 fprintf(stderr, "%s: Couldn't check for new version, leaving the old in place.\n", pathname.c_str());
72 return (buf.st_mtim.tv_sec != ts.tv_sec || buf.st_mtim.tv_nsec != ts.tv_nsec);
75 bool is_full_range(const AVPixFmtDescriptor *desc)
77 // This is horrible, but there's no better way that I know of.
78 return (strchr(desc->name, 'j') != nullptr);
81 AVPixelFormat decide_dst_format(AVPixelFormat src_format, bmusb::PixelFormat dst_format_type)
83 if (dst_format_type == bmusb::PixelFormat_8BitBGRA) {
84 return AV_PIX_FMT_BGRA;
86 if (dst_format_type == FFmpegCapture::PixelFormat_NV12) {
87 return AV_PIX_FMT_NV12;
90 assert(dst_format_type == bmusb::PixelFormat_8BitYCbCrPlanar);
92 // If this is a non-Y'CbCr format, just convert to 4:4:4 Y'CbCr
93 // and be done with it. It's too strange to spend a lot of time on.
94 // (Let's hope there's no alpha.)
95 const AVPixFmtDescriptor *src_desc = av_pix_fmt_desc_get(src_format);
96 if (src_desc == nullptr ||
97 src_desc->nb_components != 3 ||
98 (src_desc->flags & AV_PIX_FMT_FLAG_RGB)) {
99 return AV_PIX_FMT_YUV444P;
102 // The best for us would be Cb and Cr together if possible,
103 // but FFmpeg doesn't support that except in the special case of
104 // NV12, so we need to go to planar even for the case of NV12.
105 // Thus, look for the closest (but no worse) 8-bit planar Y'CbCr format
106 // that matches in color range. (This will also include the case of
107 // the source format already being acceptable.)
108 bool src_full_range = is_full_range(src_desc);
109 const char *best_format = "yuv444p";
110 unsigned best_score = numeric_limits<unsigned>::max();
111 for (const AVPixFmtDescriptor *desc = av_pix_fmt_desc_next(nullptr);
113 desc = av_pix_fmt_desc_next(desc)) {
114 // Find planar Y'CbCr formats only.
115 if (desc->nb_components != 3) continue;
116 if (desc->flags & AV_PIX_FMT_FLAG_RGB) continue;
117 if (!(desc->flags & AV_PIX_FMT_FLAG_PLANAR)) continue;
118 if (desc->comp[0].plane != 0 ||
119 desc->comp[1].plane != 1 ||
120 desc->comp[2].plane != 2) continue;
122 // 8-bit formats only.
123 if (desc->flags & AV_PIX_FMT_FLAG_BE) continue;
124 if (desc->comp[0].depth != 8) continue;
126 // Same or better chroma resolution only.
127 int chroma_w_diff = desc->log2_chroma_w - src_desc->log2_chroma_w;
128 int chroma_h_diff = desc->log2_chroma_h - src_desc->log2_chroma_h;
129 if (chroma_w_diff < 0 || chroma_h_diff < 0)
132 // Matching full/limited range only.
133 if (is_full_range(desc) != src_full_range)
136 // Pick something with as little excess chroma resolution as possible.
137 unsigned score = (1 << (chroma_w_diff)) << chroma_h_diff;
138 if (score < best_score) {
140 best_format = desc->name;
143 return av_get_pix_fmt(best_format);
146 YCbCrFormat decode_ycbcr_format(const AVPixFmtDescriptor *desc, const AVFrame *frame, bool is_mjpeg)
149 AVColorSpace colorspace = frame->colorspace;
150 switch (colorspace) {
151 case AVCOL_SPC_BT709:
152 format.luma_coefficients = YCBCR_REC_709;
154 case AVCOL_SPC_BT470BG:
155 case AVCOL_SPC_SMPTE170M:
156 case AVCOL_SPC_SMPTE240M:
157 format.luma_coefficients = YCBCR_REC_601;
159 case AVCOL_SPC_BT2020_NCL:
160 format.luma_coefficients = YCBCR_REC_2020;
162 case AVCOL_SPC_UNSPECIFIED:
163 format.luma_coefficients = (frame->height >= 720 ? YCBCR_REC_709 : YCBCR_REC_601);
166 fprintf(stderr, "Unknown Y'CbCr coefficient enum %d from FFmpeg; choosing Rec. 709.\n",
168 format.luma_coefficients = YCBCR_REC_709;
172 format.full_range = is_full_range(desc);
173 format.num_levels = 1 << desc->comp[0].depth;
174 format.chroma_subsampling_x = 1 << desc->log2_chroma_w;
175 format.chroma_subsampling_y = 1 << desc->log2_chroma_h;
177 switch (frame->chroma_location) {
178 case AVCHROMA_LOC_LEFT:
179 format.cb_x_position = 0.0;
180 format.cb_y_position = 0.5;
182 case AVCHROMA_LOC_CENTER:
183 format.cb_x_position = 0.5;
184 format.cb_y_position = 0.5;
186 case AVCHROMA_LOC_TOPLEFT:
187 format.cb_x_position = 0.0;
188 format.cb_y_position = 0.0;
190 case AVCHROMA_LOC_TOP:
191 format.cb_x_position = 0.5;
192 format.cb_y_position = 0.0;
194 case AVCHROMA_LOC_BOTTOMLEFT:
195 format.cb_x_position = 0.0;
196 format.cb_y_position = 1.0;
198 case AVCHROMA_LOC_BOTTOM:
199 format.cb_x_position = 0.5;
200 format.cb_y_position = 1.0;
203 fprintf(stderr, "Unknown chroma location coefficient enum %d from FFmpeg; choosing center.\n",
204 frame->chroma_location);
205 format.cb_x_position = 0.5;
206 format.cb_y_position = 0.5;
210 if (is_mjpeg && !format.full_range) {
211 // Limited-range MJPEG is only detected by FFmpeg whenever a special
212 // JPEG comment is set, which means that in practice, the stream is
213 // almost certainly generated by Futatabi. Override FFmpeg's forced
214 // MJPEG defaults (it disregards the values set in the mux) with what
216 format.luma_coefficients = YCBCR_REC_709;
217 format.cb_x_position = 0.0;
218 format.cb_y_position = 0.5;
221 format.cr_x_position = format.cb_x_position;
222 format.cr_y_position = format.cb_y_position;
226 RGBTriplet get_neutral_color(AVDictionary *metadata)
228 if (metadata == nullptr) {
229 return RGBTriplet(1.0f, 1.0f, 1.0f);
231 AVDictionaryEntry *entry = av_dict_get(metadata, "WhitePoint", nullptr, 0);
232 if (entry == nullptr) {
233 return RGBTriplet(1.0f, 1.0f, 1.0f);
236 unsigned x_nom, x_den, y_nom, y_den;
237 if (sscanf(entry->value, " %u:%u , %u:%u", &x_nom, &x_den, &y_nom, &y_den) != 4) {
238 fprintf(stderr, "WARNING: Unable to parse white point '%s', using default white point\n", entry->value);
239 return RGBTriplet(1.0f, 1.0f, 1.0f);
242 double x = double(x_nom) / x_den;
243 double y = double(y_nom) / y_den;
244 double z = 1.0 - x - y;
246 Matrix3d rgb_to_xyz_matrix = movit::ColorspaceConversionEffect::get_xyz_matrix(COLORSPACE_sRGB);
247 Vector3d rgb = rgb_to_xyz_matrix.inverse() * Vector3d(x, y, z);
249 return RGBTriplet(rgb[0], rgb[1], rgb[2]);
254 FFmpegCapture::FFmpegCapture(const string &filename, unsigned width, unsigned height)
255 : filename(filename), width(width), height(height), video_timebase{1, 1}
257 description = "Video: " + filename;
259 last_frame = steady_clock::now();
261 avformat_network_init(); // In case someone wants this.
265 FFmpegCapture::FFmpegCapture(int srt_sock, const string &stream_id)
266 : srt_sock(srt_sock),
267 width(0), // Don't resize; SRT streams typically have stable resolution, and should behave much like regular cards in general.
269 pixel_format(bmusb::PixelFormat_8BitYCbCrPlanar),
272 if (stream_id.empty()) {
273 description = "SRT stream";
275 description = stream_id;
277 play_as_fast_as_possible = true;
279 last_frame = steady_clock::now();
283 FFmpegCapture::~FFmpegCapture()
285 if (has_dequeue_callbacks) {
286 dequeue_cleanup_callback();
288 swr_free(&resampler);
290 if (srt_sock != -1) {
296 void FFmpegCapture::configure_card()
298 if (video_frame_allocator == nullptr) {
299 owned_video_frame_allocator.reset(new MallocFrameAllocator(FRAME_SIZE, NUM_QUEUED_VIDEO_FRAMES));
300 set_video_frame_allocator(owned_video_frame_allocator.get());
302 if (audio_frame_allocator == nullptr) {
303 // Audio can come out in pretty large chunks, so increase from the default 1 MB.
304 owned_audio_frame_allocator.reset(new MallocFrameAllocator(1 << 20, NUM_QUEUED_AUDIO_FRAMES));
305 set_audio_frame_allocator(owned_audio_frame_allocator.get());
309 void FFmpegCapture::start_bm_capture()
315 producer_thread_should_quit.unquit();
316 producer_thread = thread(&FFmpegCapture::producer_thread_func, this);
319 void FFmpegCapture::stop_dequeue_thread()
325 producer_thread_should_quit.quit();
326 producer_thread.join();
329 std::map<uint32_t, VideoMode> FFmpegCapture::get_available_video_modes() const
331 // Note: This will never really be shown in the UI.
335 snprintf(buf, sizeof(buf), "%ux%u", sws_last_width, sws_last_height);
338 mode.autodetect = false;
339 mode.width = sws_last_width;
340 mode.height = sws_last_height;
341 mode.frame_rate_num = 60;
342 mode.frame_rate_den = 1;
343 mode.interlaced = false;
345 return {{ 0, mode }};
348 void FFmpegCapture::producer_thread_func()
350 char thread_name[16];
351 snprintf(thread_name, sizeof(thread_name), "FFmpeg_C_%d", card_index);
352 pthread_setname_np(pthread_self(), thread_name);
354 while (!producer_thread_should_quit.should_quit()) {
355 string filename_copy;
357 lock_guard<mutex> lock(filename_mu);
358 filename_copy = filename;
362 if (srt_sock == -1) {
363 pathname = search_for_file(filename_copy);
365 pathname = description;
367 if (pathname.empty()) {
368 send_disconnected_frame();
372 producer_thread_should_quit.sleep_for(seconds(1));
373 fprintf(stderr, "%s not found, sleeping one second and trying again...\n", filename_copy.c_str());
376 should_interrupt = false;
377 if (!play_video(pathname)) {
379 send_disconnected_frame();
383 fprintf(stderr, "Error when playing %s, sleeping one second and trying again...\n", pathname.c_str());
384 producer_thread_should_quit.sleep_for(seconds(1));
389 send_disconnected_frame();
393 // Probably just EOF, will exit the loop above on next test.
396 if (has_dequeue_callbacks) {
397 dequeue_cleanup_callback();
398 has_dequeue_callbacks = false;
402 void FFmpegCapture::send_disconnected_frame()
404 // Send an empty frame to signal that we have no signal anymore.
405 FrameAllocator::Frame video_frame = video_frame_allocator->alloc_frame();
406 size_t frame_width = width == 0 ? global_flags.width : width;
407 size_t frame_height = height == 0 ? global_flags.height : height;
408 if (video_frame.data) {
409 VideoFormat video_format;
410 video_format.width = frame_width;
411 video_format.height = frame_height;
412 video_format.frame_rate_nom = 60;
413 video_format.frame_rate_den = 1;
414 video_format.is_connected = false;
415 if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
416 video_format.stride = frame_width * 4;
417 video_frame.len = frame_width * frame_height * 4;
418 memset(video_frame.data, 0, video_frame.len);
420 video_format.stride = frame_width;
421 current_frame_ycbcr_format.luma_coefficients = YCBCR_REC_709;
422 current_frame_ycbcr_format.full_range = true;
423 current_frame_ycbcr_format.num_levels = 256;
424 current_frame_ycbcr_format.chroma_subsampling_x = 2;
425 current_frame_ycbcr_format.chroma_subsampling_y = 2;
426 current_frame_ycbcr_format.cb_x_position = 0.0f;
427 current_frame_ycbcr_format.cb_y_position = 0.0f;
428 current_frame_ycbcr_format.cr_x_position = 0.0f;
429 current_frame_ycbcr_format.cr_y_position = 0.0f;
430 video_frame.len = frame_width * frame_height * 2;
431 memset(video_frame.data, 0, frame_width * frame_height);
432 memset(video_frame.data + frame_width * frame_height, 128, frame_width * frame_height); // Valid for both NV12 and planar.
435 frame_callback(-1, AVRational{1, TIMEBASE}, -1, AVRational{1, TIMEBASE}, timecode++,
436 video_frame, /*video_offset=*/0, video_format,
437 FrameAllocator::Frame(), /*audio_offset=*/0, AudioFormat());
438 last_frame_was_connected = false;
443 if (card_disconnected_callback != nullptr) {
444 card_disconnected_callback();
449 bool FFmpegCapture::play_video(const string &pathname)
451 // Note: Call before open, not after; otherwise, there's a race.
452 // (There is now, too, but it tips the correct way. We could use fstat()
453 // if we had the file descriptor.)
454 timespec last_modified;
456 if (stat(pathname.c_str(), &buf) != 0) {
457 // Probably some sort of protocol, so can't stat.
458 last_modified.tv_sec = -1;
460 last_modified = buf.st_mtim;
463 AVFormatContextWithCloser format_ctx;
464 if (srt_sock == -1) {
466 format_ctx = avformat_open_input_unique(pathname.c_str(), /*fmt=*/nullptr,
468 AVIOInterruptCB{ &FFmpegCapture::interrupt_cb_thunk, this });
471 // SRT socket, already opened.
472 AVInputFormat *mpegts_fmt = av_find_input_format("mpegts");
473 format_ctx = avformat_open_input_unique(&FFmpegCapture::read_srt_thunk, this,
474 mpegts_fmt, /*options=*/nullptr,
475 AVIOInterruptCB{ &FFmpegCapture::interrupt_cb_thunk, this });
480 if (format_ctx == nullptr) {
481 fprintf(stderr, "%s: Error opening file\n", pathname.c_str());
485 if (avformat_find_stream_info(format_ctx.get(), nullptr) < 0) {
486 fprintf(stderr, "%s: Error finding stream info\n", pathname.c_str());
490 int video_stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_VIDEO);
491 if (video_stream_index == -1) {
492 fprintf(stderr, "%s: No video stream found\n", pathname.c_str());
496 int audio_stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_AUDIO);
497 int subtitle_stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_SUBTITLE);
498 has_last_subtitle = false;
500 // Open video decoder.
501 const AVCodecParameters *video_codecpar = format_ctx->streams[video_stream_index]->codecpar;
502 AVCodec *video_codec = avcodec_find_decoder(video_codecpar->codec_id);
503 video_timebase = format_ctx->streams[video_stream_index]->time_base;
504 AVCodecContextWithDeleter video_codec_ctx = avcodec_alloc_context3_unique(nullptr);
505 if (avcodec_parameters_to_context(video_codec_ctx.get(), video_codecpar) < 0) {
506 fprintf(stderr, "%s: Cannot fill video codec parameters\n", pathname.c_str());
509 if (video_codec == nullptr) {
510 fprintf(stderr, "%s: Cannot find video decoder\n", pathname.c_str());
513 if (avcodec_open2(video_codec_ctx.get(), video_codec, nullptr) < 0) {
514 fprintf(stderr, "%s: Cannot open video decoder\n", pathname.c_str());
517 unique_ptr<AVCodecContext, decltype(avcodec_close)*> video_codec_ctx_cleanup(
518 video_codec_ctx.get(), avcodec_close);
520 // Used in decode_ycbcr_format().
521 is_mjpeg = video_codecpar->codec_id == AV_CODEC_ID_MJPEG;
523 // Open audio decoder, if we have audio.
524 AVCodecContextWithDeleter audio_codec_ctx;
525 if (audio_stream_index != -1) {
526 audio_codec_ctx = avcodec_alloc_context3_unique(nullptr);
527 const AVCodecParameters *audio_codecpar = format_ctx->streams[audio_stream_index]->codecpar;
528 audio_timebase = format_ctx->streams[audio_stream_index]->time_base;
529 if (avcodec_parameters_to_context(audio_codec_ctx.get(), audio_codecpar) < 0) {
530 fprintf(stderr, "%s: Cannot fill audio codec parameters\n", pathname.c_str());
533 AVCodec *audio_codec = avcodec_find_decoder(audio_codecpar->codec_id);
534 if (audio_codec == nullptr) {
535 fprintf(stderr, "%s: Cannot find audio decoder\n", pathname.c_str());
538 if (avcodec_open2(audio_codec_ctx.get(), audio_codec, nullptr) < 0) {
539 fprintf(stderr, "%s: Cannot open audio decoder\n", pathname.c_str());
543 unique_ptr<AVCodecContext, decltype(avcodec_close)*> audio_codec_ctx_cleanup(
544 audio_codec_ctx.get(), avcodec_close);
549 bool first_frame = true;
550 while (!producer_thread_should_quit.should_quit()) {
551 if (process_queued_commands(format_ctx.get(), pathname, last_modified, /*rewound=*/nullptr)) {
554 if (should_interrupt.load()) {
555 // Check as a failsafe, so that we don't need to rely on avio if we don't have to.
558 UniqueFrame audio_frame = audio_frame_allocator->alloc_frame();
559 AudioFormat audio_format;
563 AVFrameWithDeleter frame = decode_frame(format_ctx.get(), video_codec_ctx.get(), audio_codec_ctx.get(),
564 pathname, video_stream_index, audio_stream_index, subtitle_stream_index, audio_frame.get(), &audio_format, &audio_pts, &error);
568 if (frame == nullptr) {
569 // EOF. Loop back to the start if we can.
570 if (format_ctx->pb != nullptr && format_ctx->pb->seekable == 0) {
571 // Not seekable (but seemingly, sometimes av_seek_frame() would return 0 anyway,
575 if (av_seek_frame(format_ctx.get(), /*stream_index=*/-1, /*timestamp=*/0, /*flags=*/0) < 0) {
576 fprintf(stderr, "%s: Rewind failed, not looping.\n", pathname.c_str());
579 if (video_codec_ctx != nullptr) {
580 avcodec_flush_buffers(video_codec_ctx.get());
582 if (audio_codec_ctx != nullptr) {
583 avcodec_flush_buffers(audio_codec_ctx.get());
585 // If the file has changed since last time, return to get it reloaded.
586 // Note that depending on how you move the file into place, you might
587 // end up corrupting the one you're already playing, so this path
588 // might not trigger.
589 if (changed_since(pathname, last_modified)) {
596 VideoFormat video_format = construct_video_format(frame.get(), video_timebase);
597 if (video_format.frame_rate_nom == 0 || video_format.frame_rate_den == 0) {
598 // Invalid frame rate; try constructing it from the previous frame length.
599 // (This is especially important if we are the master card, for SRT,
600 // since it affects audio. Not all senders have good timebases
601 // (e.g., Larix rounds first to timebase 1000 and then multiplies by
602 // 90 from there, it seems), but it's much better to have an oscillating
603 // value than just locking at 60.
604 if (last_pts != 0 && frame->pts > last_pts) {
605 int64_t pts_diff = frame->pts - last_pts;
606 video_format.frame_rate_nom = video_timebase.den;
607 video_format.frame_rate_den = video_timebase.num * pts_diff;
609 video_format.frame_rate_nom = 60;
610 video_format.frame_rate_den = 1;
613 UniqueFrame video_frame = make_video_frame(frame.get(), pathname, &error);
619 if (last_pts == 0 && pts_origin == 0) {
620 pts_origin = frame->pts;
622 steady_clock::time_point now = steady_clock::now();
623 if (play_as_fast_as_possible) {
624 video_frame->received_timestamp = now;
625 audio_frame->received_timestamp = now;
626 next_frame_start = now;
628 next_frame_start = compute_frame_start(frame->pts, pts_origin, video_timebase, start, rate);
629 if (first_frame && last_frame_was_connected) {
630 // If reconnect took more than one second, this is probably a live feed,
631 // and we should reset the resampler. (Or the rate is really, really low,
632 // in which case a reset on the first frame is fine anyway.)
633 if (duration<double>(next_frame_start - last_frame).count() >= 1.0) {
634 last_frame_was_connected = false;
637 video_frame->received_timestamp = next_frame_start;
639 // The easiest way to get all the rate conversions etc. right is to move the
640 // audio PTS into the video PTS timebase and go from there. (We'll get some
641 // rounding issues, but they should not be a big problem.)
642 int64_t audio_pts_as_video_pts = av_rescale_q(audio_pts, audio_timebase, video_timebase);
643 audio_frame->received_timestamp = compute_frame_start(audio_pts_as_video_pts, pts_origin, video_timebase, start, rate);
645 if (audio_frame->len != 0) {
646 // The received timestamps in Nageru are measured after we've just received the frame.
647 // However, pts (especially audio pts) is at the _beginning_ of the frame.
648 // If we have locked audio, the distinction doesn't really matter, as pts is
649 // on a relative scale and a fixed offset is fine. But if we don't, we will have
650 // a different number of samples each time, which will cause huge audio jitter
651 // and throw off the resampler.
653 // In a sense, we should have compensated by adding the frame and audio lengths
654 // to video_frame->received_timestamp and audio_frame->received_timestamp respectively,
655 // but that would mean extra waiting in sleep_until(). All we need is that they
656 // are correct relative to each other, though (and to the other frames we send),
657 // so just align the end of the audio frame, and we're fine.
658 size_t num_samples = (audio_frame->len * 8) / audio_format.bits_per_sample / audio_format.num_channels;
659 double offset = double(num_samples) / OUTPUT_FREQUENCY -
660 double(video_format.frame_rate_den) / video_format.frame_rate_nom;
661 audio_frame->received_timestamp += duration_cast<steady_clock::duration>(duration<double>(offset));
664 if (duration<double>(now - next_frame_start).count() >= 0.1) {
665 // If we don't have enough CPU to keep up, or if we have a live stream
666 // where the initial origin was somehow wrong, we could be behind indefinitely.
667 // In particular, this will give the audio resampler problems as it tries
668 // to speed up to reduce the delay, hitting the low end of the buffer every time.
669 fprintf(stderr, "%s: Playback %.0f ms behind, resetting time scale\n",
671 1e3 * duration<double>(now - next_frame_start).count());
672 pts_origin = frame->pts;
673 start = next_frame_start = now;
674 timecode += MAX_FPS * 2 + 1;
677 bool finished_wakeup;
678 if (play_as_fast_as_possible) {
679 finished_wakeup = !producer_thread_should_quit.should_quit();
681 finished_wakeup = producer_thread_should_quit.sleep_until(next_frame_start);
683 if (finished_wakeup) {
684 if (audio_frame->len > 0) {
685 assert(audio_pts != -1);
687 if (!last_frame_was_connected) {
688 // We're recovering from an error (or really slow load, see above).
689 // Make sure to get the audio resampler reset. (This is a hack;
690 // ideally, the frame callback should just accept a way to signal
691 // audio discontinuity.)
692 timecode += MAX_FPS * 2 + 1;
694 last_neutral_color = get_neutral_color(frame->metadata);
695 frame_callback(frame->pts, video_timebase, audio_pts, audio_timebase, timecode++,
696 video_frame.get_and_release(), 0, video_format,
697 audio_frame.get_and_release(), 0, audio_format);
699 last_frame = steady_clock::now();
700 last_frame_was_connected = true;
703 if (producer_thread_should_quit.should_quit()) break;
705 bool rewound = false;
706 if (process_queued_commands(format_ctx.get(), pathname, last_modified, &rewound)) {
709 // If we just rewound, drop this frame on the floor and be done.
713 // OK, we didn't, so probably a rate change. Recalculate next_frame_start,
714 // but if it's now in the past, we'll reset the origin, so that we don't
715 // generate a huge backlog of frames that we need to run through quickly.
716 next_frame_start = compute_frame_start(frame->pts, pts_origin, video_timebase, start, rate);
717 steady_clock::time_point now = steady_clock::now();
718 if (next_frame_start < now) {
719 pts_origin = frame->pts;
720 start = next_frame_start = now;
724 last_pts = frame->pts;
729 void FFmpegCapture::internal_rewind()
731 pts_origin = last_pts = 0;
732 start = next_frame_start = steady_clock::now();
735 bool FFmpegCapture::process_queued_commands(AVFormatContext *format_ctx, const std::string &pathname, timespec last_modified, bool *rewound)
737 // Process any queued commands from other threads.
738 vector<QueuedCommand> commands;
740 lock_guard<mutex> lock(queue_mu);
741 swap(commands, command_queue);
743 for (const QueuedCommand &cmd : commands) {
744 switch (cmd.command) {
745 case QueuedCommand::REWIND:
746 if (av_seek_frame(format_ctx, /*stream_index=*/-1, /*timestamp=*/0, /*flags=*/0) < 0) {
747 fprintf(stderr, "%s: Rewind failed, stopping play.\n", pathname.c_str());
749 // If the file has changed since last time, return to get it reloaded.
750 // Note that depending on how you move the file into place, you might
751 // end up corrupting the one you're already playing, so this path
752 // might not trigger.
753 if (changed_since(pathname, last_modified)) {
757 if (rewound != nullptr) {
762 case QueuedCommand::CHANGE_RATE:
763 // Change the origin to the last played frame.
764 start = compute_frame_start(last_pts, pts_origin, video_timebase, start, rate);
765 pts_origin = last_pts;
767 play_as_fast_as_possible = (rate >= 10.0);
778 AVFrameWithDeleter FFmpegCapture::decode_frame(AVFormatContext *format_ctx, AVCodecContext *video_codec_ctx, AVCodecContext *audio_codec_ctx,
779 const std::string &pathname, int video_stream_index, int audio_stream_index, int subtitle_stream_index,
780 FrameAllocator::Frame *audio_frame, AudioFormat *audio_format, int64_t *audio_pts, bool *error)
784 // Read packets until we have a frame or there are none left.
785 bool frame_finished = false;
786 AVFrameWithDeleter audio_avframe = av_frame_alloc_unique();
787 AVFrameWithDeleter video_avframe = av_frame_alloc_unique();
790 bool has_audio = false;
793 unique_ptr<AVPacket, decltype(av_packet_unref)*> pkt_cleanup(
794 &pkt, av_packet_unref);
795 av_init_packet(&pkt);
798 if (av_read_frame(format_ctx, &pkt) == 0) {
799 if (pkt.stream_index == audio_stream_index && audio_callback != nullptr) {
800 audio_callback(&pkt, format_ctx->streams[audio_stream_index]->time_base);
802 if (pkt.stream_index == video_stream_index) {
803 if (avcodec_send_packet(video_codec_ctx, &pkt) < 0) {
804 fprintf(stderr, "%s: Cannot send packet to video codec.\n", pathname.c_str());
806 return AVFrameWithDeleter(nullptr);
808 } else if (pkt.stream_index == audio_stream_index) {
810 if (avcodec_send_packet(audio_codec_ctx, &pkt) < 0) {
811 fprintf(stderr, "%s: Cannot send packet to audio codec.\n", pathname.c_str());
813 return AVFrameWithDeleter(nullptr);
815 } else if (pkt.stream_index == subtitle_stream_index) {
816 last_subtitle = string(reinterpret_cast<const char *>(pkt.data), pkt.size);
817 has_last_subtitle = true;
820 eof = true; // Or error, but ignore that for the time being.
823 // Decode audio, if any.
826 int err = avcodec_receive_frame(audio_codec_ctx, audio_avframe.get());
828 if (*audio_pts == -1) {
829 *audio_pts = audio_avframe->pts;
831 convert_audio(audio_avframe.get(), audio_frame, audio_format);
832 } else if (err == AVERROR(EAGAIN)) {
835 fprintf(stderr, "%s: Cannot receive frame from audio codec.\n", pathname.c_str());
837 return AVFrameWithDeleter(nullptr);
842 // Decode video, if we have a frame.
843 int err = avcodec_receive_frame(video_codec_ctx, video_avframe.get());
845 frame_finished = true;
847 } else if (err != AVERROR(EAGAIN)) {
848 fprintf(stderr, "%s: Cannot receive frame from video codec.\n", pathname.c_str());
850 return AVFrameWithDeleter(nullptr);
855 return video_avframe;
857 return AVFrameWithDeleter(nullptr);
860 void FFmpegCapture::convert_audio(const AVFrame *audio_avframe, FrameAllocator::Frame *audio_frame, AudioFormat *audio_format)
862 // Decide on a format. If there already is one in this audio frame,
863 // we're pretty much forced to use it. If not, we try to find an exact match.
864 // If that still doesn't work, we default to 32-bit signed chunked
865 // (float would be nice, but there's really no way to signal that yet).
866 AVSampleFormat dst_format;
867 if (audio_format->bits_per_sample == 0) {
868 switch (audio_avframe->format) {
869 case AV_SAMPLE_FMT_S16:
870 case AV_SAMPLE_FMT_S16P:
871 audio_format->bits_per_sample = 16;
872 dst_format = AV_SAMPLE_FMT_S16;
874 case AV_SAMPLE_FMT_S32:
875 case AV_SAMPLE_FMT_S32P:
877 audio_format->bits_per_sample = 32;
878 dst_format = AV_SAMPLE_FMT_S32;
881 } else if (audio_format->bits_per_sample == 16) {
882 dst_format = AV_SAMPLE_FMT_S16;
883 } else if (audio_format->bits_per_sample == 32) {
884 dst_format = AV_SAMPLE_FMT_S32;
888 audio_format->num_channels = 2;
890 int64_t channel_layout = audio_avframe->channel_layout;
891 if (channel_layout == 0) {
892 channel_layout = av_get_default_channel_layout(audio_avframe->channels);
895 if (resampler == nullptr ||
896 audio_avframe->format != last_src_format ||
897 dst_format != last_dst_format ||
898 channel_layout != last_channel_layout ||
899 audio_avframe->sample_rate != last_sample_rate) {
900 swr_free(&resampler);
901 resampler = swr_alloc_set_opts(nullptr,
902 /*out_ch_layout=*/AV_CH_LAYOUT_STEREO_DOWNMIX,
903 /*out_sample_fmt=*/dst_format,
904 /*out_sample_rate=*/OUTPUT_FREQUENCY,
905 /*in_ch_layout=*/channel_layout,
906 /*in_sample_fmt=*/AVSampleFormat(audio_avframe->format),
907 /*in_sample_rate=*/audio_avframe->sample_rate,
909 /*log_ctx=*/nullptr);
911 if (resampler == nullptr) {
912 fprintf(stderr, "Allocating resampler failed.\n");
916 if (swr_init(resampler) < 0) {
917 fprintf(stderr, "Could not open resample context.\n");
921 last_src_format = AVSampleFormat(audio_avframe->format);
922 last_dst_format = dst_format;
923 last_channel_layout = channel_layout;
924 last_sample_rate = audio_avframe->sample_rate;
927 size_t bytes_per_sample = (audio_format->bits_per_sample / 8) * 2;
928 size_t num_samples_room = (audio_frame->size - audio_frame->len) / bytes_per_sample;
930 uint8_t *data = audio_frame->data + audio_frame->len;
931 int out_samples = swr_convert(resampler, &data, num_samples_room,
932 const_cast<const uint8_t **>(audio_avframe->data), audio_avframe->nb_samples);
933 if (out_samples < 0) {
934 fprintf(stderr, "Audio conversion failed.\n");
938 audio_frame->len += out_samples * bytes_per_sample;
941 VideoFormat FFmpegCapture::construct_video_format(const AVFrame *frame, AVRational video_timebase)
943 VideoFormat video_format;
944 video_format.width = frame_width(frame);
945 video_format.height = frame_height(frame);
946 if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
947 video_format.stride = frame_width(frame) * 4;
948 } else if (pixel_format == FFmpegCapture::PixelFormat_NV12) {
949 video_format.stride = frame_width(frame);
951 assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
952 video_format.stride = frame_width(frame);
954 video_format.frame_rate_nom = video_timebase.den;
955 video_format.frame_rate_den = frame->pkt_duration * video_timebase.num;
956 video_format.has_signal = true;
957 video_format.is_connected = true;
961 UniqueFrame FFmpegCapture::make_video_frame(const AVFrame *frame, const string &pathname, bool *error)
965 UniqueFrame video_frame(video_frame_allocator->alloc_frame());
966 if (video_frame->data == nullptr) {
970 if (sws_ctx == nullptr ||
971 sws_last_width != frame->width ||
972 sws_last_height != frame->height ||
973 sws_last_src_format != frame->format) {
974 sws_dst_format = decide_dst_format(AVPixelFormat(frame->format), pixel_format);
976 sws_getContext(frame->width, frame->height, AVPixelFormat(frame->format),
977 frame_width(frame), frame_height(frame), sws_dst_format,
978 SWS_BICUBIC, nullptr, nullptr, nullptr));
979 sws_last_width = frame->width;
980 sws_last_height = frame->height;
981 sws_last_src_format = frame->format;
983 if (sws_ctx == nullptr) {
984 fprintf(stderr, "%s: Could not create scaler context\n", pathname.c_str());
989 uint8_t *pic_data[4] = { nullptr, nullptr, nullptr, nullptr };
990 int linesizes[4] = { 0, 0, 0, 0 };
991 if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
992 pic_data[0] = video_frame->data;
993 linesizes[0] = frame_width(frame) * 4;
994 video_frame->len = (frame_width(frame) * 4) * frame_height(frame);
995 } else if (pixel_format == PixelFormat_NV12) {
996 pic_data[0] = video_frame->data;
997 linesizes[0] = frame_width(frame);
999 pic_data[1] = pic_data[0] + frame_width(frame) * frame_height(frame);
1000 linesizes[1] = frame_width(frame);
1002 video_frame->len = (frame_width(frame) * 2) * frame_height(frame);
1004 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(sws_dst_format);
1005 current_frame_ycbcr_format = decode_ycbcr_format(desc, frame, is_mjpeg);
1007 assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
1008 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(sws_dst_format);
1010 int chroma_width = AV_CEIL_RSHIFT(int(frame_width(frame)), desc->log2_chroma_w);
1011 int chroma_height = AV_CEIL_RSHIFT(int(frame_height(frame)), desc->log2_chroma_h);
1013 pic_data[0] = video_frame->data;
1014 linesizes[0] = frame_width(frame);
1016 pic_data[1] = pic_data[0] + frame_width(frame) * frame_height(frame);
1017 linesizes[1] = chroma_width;
1019 pic_data[2] = pic_data[1] + chroma_width * chroma_height;
1020 linesizes[2] = chroma_width;
1022 video_frame->len = frame_width(frame) * frame_height(frame) + 2 * chroma_width * chroma_height;
1024 current_frame_ycbcr_format = decode_ycbcr_format(desc, frame, is_mjpeg);
1026 sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
1031 int FFmpegCapture::interrupt_cb_thunk(void *opaque)
1033 return reinterpret_cast<FFmpegCapture *>(opaque)->interrupt_cb();
1036 int FFmpegCapture::interrupt_cb()
1038 return should_interrupt.load();
1041 unsigned FFmpegCapture::frame_width(const AVFrame *frame) const
1044 return frame->width;
1050 unsigned FFmpegCapture::frame_height(const AVFrame *frame) const
1053 return frame->height;
1060 int FFmpegCapture::read_srt_thunk(void *opaque, uint8_t *buf, int buf_size)
1062 return reinterpret_cast<FFmpegCapture *>(opaque)->read_srt(buf, buf_size);
1065 int FFmpegCapture::read_srt(uint8_t *buf, int buf_size)
1067 SRT_MSGCTRL mc = srt_msgctrl_default;
1068 return srt_recvmsg2(srt_sock, reinterpret_cast<char *>(buf), buf_size, &mc);