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"
42 #define FRAME_SIZE (8 << 20) // 8 MB.
45 using namespace std::chrono;
46 using namespace bmusb;
47 using namespace movit;
48 using namespace Eigen;
52 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)
54 const duration<double> pts((frame_pts - pts_origin) * double(video_timebase.num) / double(video_timebase.den));
55 return origin + duration_cast<steady_clock::duration>(pts / rate);
58 bool changed_since(const std::string &pathname, const timespec &ts)
64 if (stat(pathname.c_str(), &buf) != 0) {
65 fprintf(stderr, "%s: Couldn't check for new version, leaving the old in place.\n", pathname.c_str());
68 return (buf.st_mtim.tv_sec != ts.tv_sec || buf.st_mtim.tv_nsec != ts.tv_nsec);
71 bool is_full_range(const AVPixFmtDescriptor *desc)
73 // This is horrible, but there's no better way that I know of.
74 return (strchr(desc->name, 'j') != nullptr);
77 AVPixelFormat decide_dst_format(AVPixelFormat src_format, bmusb::PixelFormat dst_format_type)
79 if (dst_format_type == bmusb::PixelFormat_8BitBGRA) {
80 return AV_PIX_FMT_BGRA;
82 if (dst_format_type == FFmpegCapture::PixelFormat_NV12) {
83 return AV_PIX_FMT_NV12;
86 assert(dst_format_type == bmusb::PixelFormat_8BitYCbCrPlanar);
88 // If this is a non-Y'CbCr format, just convert to 4:4:4 Y'CbCr
89 // and be done with it. It's too strange to spend a lot of time on.
90 // (Let's hope there's no alpha.)
91 const AVPixFmtDescriptor *src_desc = av_pix_fmt_desc_get(src_format);
92 if (src_desc == nullptr ||
93 src_desc->nb_components != 3 ||
94 (src_desc->flags & AV_PIX_FMT_FLAG_RGB)) {
95 return AV_PIX_FMT_YUV444P;
98 // The best for us would be Cb and Cr together if possible,
99 // but FFmpeg doesn't support that except in the special case of
100 // NV12, so we need to go to planar even for the case of NV12.
101 // Thus, look for the closest (but no worse) 8-bit planar Y'CbCr format
102 // that matches in color range. (This will also include the case of
103 // the source format already being acceptable.)
104 bool src_full_range = is_full_range(src_desc);
105 const char *best_format = "yuv444p";
106 unsigned best_score = numeric_limits<unsigned>::max();
107 for (const AVPixFmtDescriptor *desc = av_pix_fmt_desc_next(nullptr);
109 desc = av_pix_fmt_desc_next(desc)) {
110 // Find planar Y'CbCr formats only.
111 if (desc->nb_components != 3) continue;
112 if (desc->flags & AV_PIX_FMT_FLAG_RGB) continue;
113 if (!(desc->flags & AV_PIX_FMT_FLAG_PLANAR)) continue;
114 if (desc->comp[0].plane != 0 ||
115 desc->comp[1].plane != 1 ||
116 desc->comp[2].plane != 2) continue;
118 // 8-bit formats only.
119 if (desc->flags & AV_PIX_FMT_FLAG_BE) continue;
120 if (desc->comp[0].depth != 8) continue;
122 // Same or better chroma resolution only.
123 int chroma_w_diff = desc->log2_chroma_w - src_desc->log2_chroma_w;
124 int chroma_h_diff = desc->log2_chroma_h - src_desc->log2_chroma_h;
125 if (chroma_w_diff < 0 || chroma_h_diff < 0)
128 // Matching full/limited range only.
129 if (is_full_range(desc) != src_full_range)
132 // Pick something with as little excess chroma resolution as possible.
133 unsigned score = (1 << (chroma_w_diff)) << chroma_h_diff;
134 if (score < best_score) {
136 best_format = desc->name;
139 return av_get_pix_fmt(best_format);
142 YCbCrFormat decode_ycbcr_format(const AVPixFmtDescriptor *desc, const AVFrame *frame, bool is_mjpeg)
145 AVColorSpace colorspace = frame->colorspace;
146 switch (colorspace) {
147 case AVCOL_SPC_BT709:
148 format.luma_coefficients = YCBCR_REC_709;
150 case AVCOL_SPC_BT470BG:
151 case AVCOL_SPC_SMPTE170M:
152 case AVCOL_SPC_SMPTE240M:
153 format.luma_coefficients = YCBCR_REC_601;
155 case AVCOL_SPC_BT2020_NCL:
156 format.luma_coefficients = YCBCR_REC_2020;
158 case AVCOL_SPC_UNSPECIFIED:
159 format.luma_coefficients = (frame->height >= 720 ? YCBCR_REC_709 : YCBCR_REC_601);
162 fprintf(stderr, "Unknown Y'CbCr coefficient enum %d from FFmpeg; choosing Rec. 709.\n",
164 format.luma_coefficients = YCBCR_REC_709;
168 format.full_range = is_full_range(desc);
169 format.num_levels = 1 << desc->comp[0].depth;
170 format.chroma_subsampling_x = 1 << desc->log2_chroma_w;
171 format.chroma_subsampling_y = 1 << desc->log2_chroma_h;
173 switch (frame->chroma_location) {
174 case AVCHROMA_LOC_LEFT:
175 format.cb_x_position = 0.0;
176 format.cb_y_position = 0.5;
178 case AVCHROMA_LOC_CENTER:
179 format.cb_x_position = 0.5;
180 format.cb_y_position = 0.5;
182 case AVCHROMA_LOC_TOPLEFT:
183 format.cb_x_position = 0.0;
184 format.cb_y_position = 0.0;
186 case AVCHROMA_LOC_TOP:
187 format.cb_x_position = 0.5;
188 format.cb_y_position = 0.0;
190 case AVCHROMA_LOC_BOTTOMLEFT:
191 format.cb_x_position = 0.0;
192 format.cb_y_position = 1.0;
194 case AVCHROMA_LOC_BOTTOM:
195 format.cb_x_position = 0.5;
196 format.cb_y_position = 1.0;
199 fprintf(stderr, "Unknown chroma location coefficient enum %d from FFmpeg; choosing center.\n",
200 frame->chroma_location);
201 format.cb_x_position = 0.5;
202 format.cb_y_position = 0.5;
206 if (is_mjpeg && !format.full_range) {
207 // Limited-range MJPEG is only detected by FFmpeg whenever a special
208 // JPEG comment is set, which means that in practice, the stream is
209 // almost certainly generated by Futatabi. Override FFmpeg's forced
210 // MJPEG defaults (it disregards the values set in the mux) with what
212 format.luma_coefficients = YCBCR_REC_709;
213 format.cb_x_position = 0.0;
214 format.cb_y_position = 0.5;
217 format.cr_x_position = format.cb_x_position;
218 format.cr_y_position = format.cb_y_position;
222 RGBTriplet get_neutral_color(AVDictionary *metadata)
224 if (metadata == nullptr) {
225 return RGBTriplet(1.0f, 1.0f, 1.0f);
227 AVDictionaryEntry *entry = av_dict_get(metadata, "WhitePoint", nullptr, 0);
228 if (entry == nullptr) {
229 return RGBTriplet(1.0f, 1.0f, 1.0f);
232 unsigned x_nom, x_den, y_nom, y_den;
233 if (sscanf(entry->value, " %u:%u , %u:%u", &x_nom, &x_den, &y_nom, &y_den) != 4) {
234 fprintf(stderr, "WARNING: Unable to parse white point '%s', using default white point\n", entry->value);
235 return RGBTriplet(1.0f, 1.0f, 1.0f);
238 double x = double(x_nom) / x_den;
239 double y = double(y_nom) / y_den;
240 double z = 1.0 - x - y;
242 Matrix3d rgb_to_xyz_matrix = movit::ColorspaceConversionEffect::get_xyz_matrix(COLORSPACE_sRGB);
243 Vector3d rgb = rgb_to_xyz_matrix.inverse() * Vector3d(x, y, z);
245 return RGBTriplet(rgb[0], rgb[1], rgb[2]);
250 FFmpegCapture::FFmpegCapture(const string &filename, unsigned width, unsigned height)
251 : filename(filename), width(width), height(height), video_timebase{1, 1}
253 description = "Video: " + filename;
255 last_frame = steady_clock::now();
257 avformat_network_init(); // In case someone wants this.
260 FFmpegCapture::~FFmpegCapture()
262 if (has_dequeue_callbacks) {
263 dequeue_cleanup_callback();
265 swr_free(&resampler);
268 void FFmpegCapture::configure_card()
270 if (video_frame_allocator == nullptr) {
271 owned_video_frame_allocator.reset(new MallocFrameAllocator(FRAME_SIZE, NUM_QUEUED_VIDEO_FRAMES));
272 set_video_frame_allocator(owned_video_frame_allocator.get());
274 if (audio_frame_allocator == nullptr) {
275 // Audio can come out in pretty large chunks, so increase from the default 1 MB.
276 owned_audio_frame_allocator.reset(new MallocFrameAllocator(1 << 20, NUM_QUEUED_AUDIO_FRAMES));
277 set_audio_frame_allocator(owned_audio_frame_allocator.get());
281 void FFmpegCapture::start_bm_capture()
287 producer_thread_should_quit.unquit();
288 producer_thread = thread(&FFmpegCapture::producer_thread_func, this);
291 void FFmpegCapture::stop_dequeue_thread()
297 producer_thread_should_quit.quit();
298 producer_thread.join();
301 std::map<uint32_t, VideoMode> FFmpegCapture::get_available_video_modes() const
303 // Note: This will never really be shown in the UI.
307 snprintf(buf, sizeof(buf), "%ux%u", width, height);
310 mode.autodetect = false;
312 mode.height = height;
313 mode.frame_rate_num = 60;
314 mode.frame_rate_den = 1;
315 mode.interlaced = false;
317 return {{ 0, mode }};
320 void FFmpegCapture::producer_thread_func()
322 char thread_name[16];
323 snprintf(thread_name, sizeof(thread_name), "FFmpeg_C_%d", card_index);
324 pthread_setname_np(pthread_self(), thread_name);
326 while (!producer_thread_should_quit.should_quit()) {
327 string filename_copy;
329 lock_guard<mutex> lock(filename_mu);
330 filename_copy = filename;
333 string pathname = search_for_file(filename_copy);
334 if (pathname.empty()) {
335 fprintf(stderr, "%s not found, sleeping one second and trying again...\n", filename_copy.c_str());
336 send_disconnected_frame();
337 producer_thread_should_quit.sleep_for(seconds(1));
340 should_interrupt = false;
341 if (!play_video(pathname)) {
343 fprintf(stderr, "Error when playing %s, sleeping one second and trying again...\n", pathname.c_str());
344 send_disconnected_frame();
345 producer_thread_should_quit.sleep_for(seconds(1));
349 // Probably just EOF, will exit the loop above on next test.
352 if (has_dequeue_callbacks) {
353 dequeue_cleanup_callback();
354 has_dequeue_callbacks = false;
358 void FFmpegCapture::send_disconnected_frame()
360 // Send an empty frame to signal that we have no signal anymore.
361 FrameAllocator::Frame video_frame = video_frame_allocator->alloc_frame();
362 if (video_frame.data) {
363 VideoFormat video_format;
364 video_format.width = width;
365 video_format.height = height;
366 video_format.frame_rate_nom = 60;
367 video_format.frame_rate_den = 1;
368 video_format.is_connected = false;
369 if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
370 video_format.stride = width * 4;
371 video_frame.len = width * height * 4;
372 memset(video_frame.data, 0, video_frame.len);
374 video_format.stride = width;
375 current_frame_ycbcr_format.luma_coefficients = YCBCR_REC_709;
376 current_frame_ycbcr_format.full_range = true;
377 current_frame_ycbcr_format.num_levels = 256;
378 current_frame_ycbcr_format.chroma_subsampling_x = 2;
379 current_frame_ycbcr_format.chroma_subsampling_y = 2;
380 current_frame_ycbcr_format.cb_x_position = 0.0f;
381 current_frame_ycbcr_format.cb_y_position = 0.0f;
382 current_frame_ycbcr_format.cr_x_position = 0.0f;
383 current_frame_ycbcr_format.cr_y_position = 0.0f;
384 video_frame.len = width * height * 2;
385 memset(video_frame.data, 0, width * height);
386 memset(video_frame.data + width * height, 128, width * height); // Valid for both NV12 and planar.
389 frame_callback(-1, AVRational{1, TIMEBASE}, -1, AVRational{1, TIMEBASE}, timecode++,
390 video_frame, /*video_offset=*/0, video_format,
391 FrameAllocator::Frame(), /*audio_offset=*/0, AudioFormat());
392 last_frame_was_connected = false;
396 bool FFmpegCapture::play_video(const string &pathname)
398 // Note: Call before open, not after; otherwise, there's a race.
399 // (There is now, too, but it tips the correct way. We could use fstat()
400 // if we had the file descriptor.)
401 timespec last_modified;
403 if (stat(pathname.c_str(), &buf) != 0) {
404 // Probably some sort of protocol, so can't stat.
405 last_modified.tv_sec = -1;
407 last_modified = buf.st_mtim;
410 auto format_ctx = avformat_open_input_unique(pathname.c_str(), nullptr, nullptr, AVIOInterruptCB{ &FFmpegCapture::interrupt_cb_thunk, this });
411 if (format_ctx == nullptr) {
412 fprintf(stderr, "%s: Error opening file\n", pathname.c_str());
416 if (avformat_find_stream_info(format_ctx.get(), nullptr) < 0) {
417 fprintf(stderr, "%s: Error finding stream info\n", pathname.c_str());
421 int video_stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_VIDEO);
422 if (video_stream_index == -1) {
423 fprintf(stderr, "%s: No video stream found\n", pathname.c_str());
427 int audio_stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_AUDIO);
428 int subtitle_stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_SUBTITLE);
429 has_last_subtitle = false;
431 // Open video decoder.
432 const AVCodecParameters *video_codecpar = format_ctx->streams[video_stream_index]->codecpar;
433 AVCodec *video_codec = avcodec_find_decoder(video_codecpar->codec_id);
434 video_timebase = format_ctx->streams[video_stream_index]->time_base;
435 AVCodecContextWithDeleter video_codec_ctx = avcodec_alloc_context3_unique(nullptr);
436 if (avcodec_parameters_to_context(video_codec_ctx.get(), video_codecpar) < 0) {
437 fprintf(stderr, "%s: Cannot fill video codec parameters\n", pathname.c_str());
440 if (video_codec == nullptr) {
441 fprintf(stderr, "%s: Cannot find video decoder\n", pathname.c_str());
444 if (avcodec_open2(video_codec_ctx.get(), video_codec, nullptr) < 0) {
445 fprintf(stderr, "%s: Cannot open video decoder\n", pathname.c_str());
448 unique_ptr<AVCodecContext, decltype(avcodec_close)*> video_codec_ctx_cleanup(
449 video_codec_ctx.get(), avcodec_close);
451 // Used in decode_ycbcr_format().
452 is_mjpeg = video_codecpar->codec_id == AV_CODEC_ID_MJPEG;
454 // Open audio decoder, if we have audio.
455 AVCodecContextWithDeleter audio_codec_ctx;
456 if (audio_stream_index != -1) {
457 audio_codec_ctx = avcodec_alloc_context3_unique(nullptr);
458 const AVCodecParameters *audio_codecpar = format_ctx->streams[audio_stream_index]->codecpar;
459 audio_timebase = format_ctx->streams[audio_stream_index]->time_base;
460 if (avcodec_parameters_to_context(audio_codec_ctx.get(), audio_codecpar) < 0) {
461 fprintf(stderr, "%s: Cannot fill audio codec parameters\n", pathname.c_str());
464 AVCodec *audio_codec = avcodec_find_decoder(audio_codecpar->codec_id);
465 if (audio_codec == nullptr) {
466 fprintf(stderr, "%s: Cannot find audio decoder\n", pathname.c_str());
469 if (avcodec_open2(audio_codec_ctx.get(), audio_codec, nullptr) < 0) {
470 fprintf(stderr, "%s: Cannot open audio decoder\n", pathname.c_str());
474 unique_ptr<AVCodecContext, decltype(avcodec_close)*> audio_codec_ctx_cleanup(
475 audio_codec_ctx.get(), avcodec_close);
480 bool first_frame = true;
481 while (!producer_thread_should_quit.should_quit()) {
482 if (process_queued_commands(format_ctx.get(), pathname, last_modified, /*rewound=*/nullptr)) {
485 if (should_interrupt.load()) {
486 // Check as a failsafe, so that we don't need to rely on avio if we don't have to.
489 UniqueFrame audio_frame = audio_frame_allocator->alloc_frame();
490 AudioFormat audio_format;
494 AVFrameWithDeleter frame = decode_frame(format_ctx.get(), video_codec_ctx.get(), audio_codec_ctx.get(),
495 pathname, video_stream_index, audio_stream_index, subtitle_stream_index, audio_frame.get(), &audio_format, &audio_pts, &error);
499 if (frame == nullptr) {
500 // EOF. Loop back to the start if we can.
501 if (format_ctx->pb != nullptr && format_ctx->pb->seekable == 0) {
502 // Not seekable (but seemingly, sometimes av_seek_frame() would return 0 anyway,
506 if (av_seek_frame(format_ctx.get(), /*stream_index=*/-1, /*timestamp=*/0, /*flags=*/0) < 0) {
507 fprintf(stderr, "%s: Rewind failed, not looping.\n", pathname.c_str());
510 if (video_codec_ctx != nullptr) {
511 avcodec_flush_buffers(video_codec_ctx.get());
513 if (audio_codec_ctx != nullptr) {
514 avcodec_flush_buffers(audio_codec_ctx.get());
516 // If the file has changed since last time, return to get it reloaded.
517 // Note that depending on how you move the file into place, you might
518 // end up corrupting the one you're already playing, so this path
519 // might not trigger.
520 if (changed_since(pathname, last_modified)) {
527 VideoFormat video_format = construct_video_format(frame.get(), video_timebase);
528 UniqueFrame video_frame = make_video_frame(frame.get(), pathname, &error);
534 if (last_pts == 0 && pts_origin == 0) {
535 pts_origin = frame->pts;
537 steady_clock::time_point now = steady_clock::now();
538 if (play_as_fast_as_possible) {
539 video_frame->received_timestamp = now;
540 audio_frame->received_timestamp = now;
541 next_frame_start = now;
543 next_frame_start = compute_frame_start(frame->pts, pts_origin, video_timebase, start, rate);
544 if (first_frame && last_frame_was_connected) {
545 // If reconnect took more than one second, this is probably a live feed,
546 // and we should reset the resampler. (Or the rate is really, really low,
547 // in which case a reset on the first frame is fine anyway.)
548 if (duration<double>(next_frame_start - last_frame).count() >= 1.0) {
549 last_frame_was_connected = false;
552 video_frame->received_timestamp = next_frame_start;
554 // The easiest way to get all the rate conversions etc. right is to move the
555 // audio PTS into the video PTS timebase and go from there. (We'll get some
556 // rounding issues, but they should not be a big problem.)
557 int64_t audio_pts_as_video_pts = av_rescale_q(audio_pts, audio_timebase, video_timebase);
558 audio_frame->received_timestamp = compute_frame_start(audio_pts_as_video_pts, pts_origin, video_timebase, start, rate);
560 if (audio_frame->len != 0) {
561 // The received timestamps in Nageru are measured after we've just received the frame.
562 // However, pts (especially audio pts) is at the _beginning_ of the frame.
563 // If we have locked audio, the distinction doesn't really matter, as pts is
564 // on a relative scale and a fixed offset is fine. But if we don't, we will have
565 // a different number of samples each time, which will cause huge audio jitter
566 // and throw off the resampler.
568 // In a sense, we should have compensated by adding the frame and audio lengths
569 // to video_frame->received_timestamp and audio_frame->received_timestamp respectively,
570 // but that would mean extra waiting in sleep_until(). All we need is that they
571 // are correct relative to each other, though (and to the other frames we send),
572 // so just align the end of the audio frame, and we're fine.
573 size_t num_samples = (audio_frame->len * 8) / audio_format.bits_per_sample / audio_format.num_channels;
574 double offset = double(num_samples) / OUTPUT_FREQUENCY -
575 double(video_format.frame_rate_den) / video_format.frame_rate_nom;
576 audio_frame->received_timestamp += duration_cast<steady_clock::duration>(duration<double>(offset));
579 if (duration<double>(now - next_frame_start).count() >= 0.1) {
580 // If we don't have enough CPU to keep up, or if we have a live stream
581 // where the initial origin was somehow wrong, we could be behind indefinitely.
582 // In particular, this will give the audio resampler problems as it tries
583 // to speed up to reduce the delay, hitting the low end of the buffer every time.
584 fprintf(stderr, "%s: Playback %.0f ms behind, resetting time scale\n",
586 1e3 * duration<double>(now - next_frame_start).count());
587 pts_origin = frame->pts;
588 start = next_frame_start = now;
589 timecode += MAX_FPS * 2 + 1;
592 bool finished_wakeup;
593 if (play_as_fast_as_possible) {
594 finished_wakeup = !producer_thread_should_quit.should_quit();
596 finished_wakeup = producer_thread_should_quit.sleep_until(next_frame_start);
598 if (finished_wakeup) {
599 if (audio_frame->len > 0) {
600 assert(audio_pts != -1);
602 if (!last_frame_was_connected) {
603 // We're recovering from an error (or really slow load, see above).
604 // Make sure to get the audio resampler reset. (This is a hack;
605 // ideally, the frame callback should just accept a way to signal
606 // audio discontinuity.)
607 timecode += MAX_FPS * 2 + 1;
609 last_neutral_color = get_neutral_color(frame->metadata);
610 frame_callback(frame->pts, video_timebase, audio_pts, audio_timebase, timecode++,
611 video_frame.get_and_release(), 0, video_format,
612 audio_frame.get_and_release(), 0, audio_format);
614 last_frame = steady_clock::now();
615 last_frame_was_connected = true;
618 if (producer_thread_should_quit.should_quit()) break;
620 bool rewound = false;
621 if (process_queued_commands(format_ctx.get(), pathname, last_modified, &rewound)) {
624 // If we just rewound, drop this frame on the floor and be done.
628 // OK, we didn't, so probably a rate change. Recalculate next_frame_start,
629 // but if it's now in the past, we'll reset the origin, so that we don't
630 // generate a huge backlog of frames that we need to run through quickly.
631 next_frame_start = compute_frame_start(frame->pts, pts_origin, video_timebase, start, rate);
632 steady_clock::time_point now = steady_clock::now();
633 if (next_frame_start < now) {
634 pts_origin = frame->pts;
635 start = next_frame_start = now;
639 last_pts = frame->pts;
644 void FFmpegCapture::internal_rewind()
646 pts_origin = last_pts = 0;
647 start = next_frame_start = steady_clock::now();
650 bool FFmpegCapture::process_queued_commands(AVFormatContext *format_ctx, const std::string &pathname, timespec last_modified, bool *rewound)
652 // Process any queued commands from other threads.
653 vector<QueuedCommand> commands;
655 lock_guard<mutex> lock(queue_mu);
656 swap(commands, command_queue);
658 for (const QueuedCommand &cmd : commands) {
659 switch (cmd.command) {
660 case QueuedCommand::REWIND:
661 if (av_seek_frame(format_ctx, /*stream_index=*/-1, /*timestamp=*/0, /*flags=*/0) < 0) {
662 fprintf(stderr, "%s: Rewind failed, stopping play.\n", pathname.c_str());
664 // If the file has changed since last time, return to get it reloaded.
665 // Note that depending on how you move the file into place, you might
666 // end up corrupting the one you're already playing, so this path
667 // might not trigger.
668 if (changed_since(pathname, last_modified)) {
672 if (rewound != nullptr) {
677 case QueuedCommand::CHANGE_RATE:
678 // Change the origin to the last played frame.
679 start = compute_frame_start(last_pts, pts_origin, video_timebase, start, rate);
680 pts_origin = last_pts;
682 play_as_fast_as_possible = (rate >= 10.0);
693 AVFrameWithDeleter FFmpegCapture::decode_frame(AVFormatContext *format_ctx, AVCodecContext *video_codec_ctx, AVCodecContext *audio_codec_ctx,
694 const std::string &pathname, int video_stream_index, int audio_stream_index, int subtitle_stream_index,
695 FrameAllocator::Frame *audio_frame, AudioFormat *audio_format, int64_t *audio_pts, bool *error)
699 // Read packets until we have a frame or there are none left.
700 bool frame_finished = false;
701 AVFrameWithDeleter audio_avframe = av_frame_alloc_unique();
702 AVFrameWithDeleter video_avframe = av_frame_alloc_unique();
705 bool has_audio = false;
708 unique_ptr<AVPacket, decltype(av_packet_unref)*> pkt_cleanup(
709 &pkt, av_packet_unref);
710 av_init_packet(&pkt);
713 if (av_read_frame(format_ctx, &pkt) == 0) {
714 if (pkt.stream_index == audio_stream_index && audio_callback != nullptr) {
715 audio_callback(&pkt, format_ctx->streams[audio_stream_index]->time_base);
717 if (pkt.stream_index == video_stream_index) {
718 if (avcodec_send_packet(video_codec_ctx, &pkt) < 0) {
719 fprintf(stderr, "%s: Cannot send packet to video codec.\n", pathname.c_str());
721 return AVFrameWithDeleter(nullptr);
723 } else if (pkt.stream_index == audio_stream_index) {
725 if (avcodec_send_packet(audio_codec_ctx, &pkt) < 0) {
726 fprintf(stderr, "%s: Cannot send packet to audio codec.\n", pathname.c_str());
728 return AVFrameWithDeleter(nullptr);
730 } else if (pkt.stream_index == subtitle_stream_index) {
731 last_subtitle = string(reinterpret_cast<const char *>(pkt.data), pkt.size);
732 has_last_subtitle = true;
735 eof = true; // Or error, but ignore that for the time being.
738 // Decode audio, if any.
741 int err = avcodec_receive_frame(audio_codec_ctx, audio_avframe.get());
743 if (*audio_pts == -1) {
744 *audio_pts = audio_avframe->pts;
746 convert_audio(audio_avframe.get(), audio_frame, audio_format);
747 } else if (err == AVERROR(EAGAIN)) {
750 fprintf(stderr, "%s: Cannot receive frame from audio codec.\n", pathname.c_str());
752 return AVFrameWithDeleter(nullptr);
757 // Decode video, if we have a frame.
758 int err = avcodec_receive_frame(video_codec_ctx, video_avframe.get());
760 frame_finished = true;
762 } else if (err != AVERROR(EAGAIN)) {
763 fprintf(stderr, "%s: Cannot receive frame from video codec.\n", pathname.c_str());
765 return AVFrameWithDeleter(nullptr);
770 return video_avframe;
772 return AVFrameWithDeleter(nullptr);
775 void FFmpegCapture::convert_audio(const AVFrame *audio_avframe, FrameAllocator::Frame *audio_frame, AudioFormat *audio_format)
777 // Decide on a format. If there already is one in this audio frame,
778 // we're pretty much forced to use it. If not, we try to find an exact match.
779 // If that still doesn't work, we default to 32-bit signed chunked
780 // (float would be nice, but there's really no way to signal that yet).
781 AVSampleFormat dst_format;
782 if (audio_format->bits_per_sample == 0) {
783 switch (audio_avframe->format) {
784 case AV_SAMPLE_FMT_S16:
785 case AV_SAMPLE_FMT_S16P:
786 audio_format->bits_per_sample = 16;
787 dst_format = AV_SAMPLE_FMT_S16;
789 case AV_SAMPLE_FMT_S32:
790 case AV_SAMPLE_FMT_S32P:
792 audio_format->bits_per_sample = 32;
793 dst_format = AV_SAMPLE_FMT_S32;
796 } else if (audio_format->bits_per_sample == 16) {
797 dst_format = AV_SAMPLE_FMT_S16;
798 } else if (audio_format->bits_per_sample == 32) {
799 dst_format = AV_SAMPLE_FMT_S32;
803 audio_format->num_channels = 2;
805 int64_t channel_layout = audio_avframe->channel_layout;
806 if (channel_layout == 0) {
807 channel_layout = av_get_default_channel_layout(audio_avframe->channels);
810 if (resampler == nullptr ||
811 audio_avframe->format != last_src_format ||
812 dst_format != last_dst_format ||
813 channel_layout != last_channel_layout ||
814 audio_avframe->sample_rate != last_sample_rate) {
815 swr_free(&resampler);
816 resampler = swr_alloc_set_opts(nullptr,
817 /*out_ch_layout=*/AV_CH_LAYOUT_STEREO_DOWNMIX,
818 /*out_sample_fmt=*/dst_format,
819 /*out_sample_rate=*/OUTPUT_FREQUENCY,
820 /*in_ch_layout=*/channel_layout,
821 /*in_sample_fmt=*/AVSampleFormat(audio_avframe->format),
822 /*in_sample_rate=*/audio_avframe->sample_rate,
824 /*log_ctx=*/nullptr);
826 if (resampler == nullptr) {
827 fprintf(stderr, "Allocating resampler failed.\n");
831 if (swr_init(resampler) < 0) {
832 fprintf(stderr, "Could not open resample context.\n");
836 last_src_format = AVSampleFormat(audio_avframe->format);
837 last_dst_format = dst_format;
838 last_channel_layout = channel_layout;
839 last_sample_rate = audio_avframe->sample_rate;
842 size_t bytes_per_sample = (audio_format->bits_per_sample / 8) * 2;
843 size_t num_samples_room = (audio_frame->size - audio_frame->len) / bytes_per_sample;
845 uint8_t *data = audio_frame->data + audio_frame->len;
846 int out_samples = swr_convert(resampler, &data, num_samples_room,
847 const_cast<const uint8_t **>(audio_avframe->data), audio_avframe->nb_samples);
848 if (out_samples < 0) {
849 fprintf(stderr, "Audio conversion failed.\n");
853 audio_frame->len += out_samples * bytes_per_sample;
856 VideoFormat FFmpegCapture::construct_video_format(const AVFrame *frame, AVRational video_timebase)
858 VideoFormat video_format;
859 video_format.width = width;
860 video_format.height = height;
861 if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
862 video_format.stride = width * 4;
863 } else if (pixel_format == FFmpegCapture::PixelFormat_NV12) {
864 video_format.stride = width;
866 assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
867 video_format.stride = width;
869 video_format.frame_rate_nom = video_timebase.den;
870 video_format.frame_rate_den = frame->pkt_duration * video_timebase.num;
871 if (video_format.frame_rate_nom == 0 || video_format.frame_rate_den == 0) {
872 // Invalid frame rate.
873 video_format.frame_rate_nom = 60;
874 video_format.frame_rate_den = 1;
876 video_format.has_signal = true;
877 video_format.is_connected = true;
881 UniqueFrame FFmpegCapture::make_video_frame(const AVFrame *frame, const string &pathname, bool *error)
885 UniqueFrame video_frame(video_frame_allocator->alloc_frame());
886 if (video_frame->data == nullptr) {
890 if (sws_ctx == nullptr ||
891 sws_last_width != frame->width ||
892 sws_last_height != frame->height ||
893 sws_last_src_format != frame->format) {
894 sws_dst_format = decide_dst_format(AVPixelFormat(frame->format), pixel_format);
896 sws_getContext(frame->width, frame->height, AVPixelFormat(frame->format),
897 width, height, sws_dst_format,
898 SWS_BICUBIC, nullptr, nullptr, nullptr));
899 sws_last_width = frame->width;
900 sws_last_height = frame->height;
901 sws_last_src_format = frame->format;
903 if (sws_ctx == nullptr) {
904 fprintf(stderr, "%s: Could not create scaler context\n", pathname.c_str());
909 uint8_t *pic_data[4] = { nullptr, nullptr, nullptr, nullptr };
910 int linesizes[4] = { 0, 0, 0, 0 };
911 if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
912 pic_data[0] = video_frame->data;
913 linesizes[0] = width * 4;
914 video_frame->len = (width * 4) * height;
915 } else if (pixel_format == PixelFormat_NV12) {
916 pic_data[0] = video_frame->data;
917 linesizes[0] = width;
919 pic_data[1] = pic_data[0] + width * height;
920 linesizes[1] = width;
922 video_frame->len = (width * 2) * height;
924 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(sws_dst_format);
925 current_frame_ycbcr_format = decode_ycbcr_format(desc, frame, is_mjpeg);
927 assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
928 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(sws_dst_format);
930 int chroma_width = AV_CEIL_RSHIFT(int(width), desc->log2_chroma_w);
931 int chroma_height = AV_CEIL_RSHIFT(int(height), desc->log2_chroma_h);
933 pic_data[0] = video_frame->data;
934 linesizes[0] = width;
936 pic_data[1] = pic_data[0] + width * height;
937 linesizes[1] = chroma_width;
939 pic_data[2] = pic_data[1] + chroma_width * chroma_height;
940 linesizes[2] = chroma_width;
942 video_frame->len = width * height + 2 * chroma_width * chroma_height;
944 current_frame_ycbcr_format = decode_ycbcr_format(desc, frame, is_mjpeg);
946 sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
951 int FFmpegCapture::interrupt_cb_thunk(void *unique)
953 return reinterpret_cast<FFmpegCapture *>(unique)->interrupt_cb();
956 int FFmpegCapture::interrupt_cb()
958 return should_interrupt.load();