git.sesse.net Git - nageru/blob - nageru/ffmpeg_capture.cpp

   1 #include "ffmpeg_capture.h"
   2
   3 #include <assert.h>
   4 #include <pthread.h>
   5 #include <stdint.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <sys/stat.h>
  10 #include <unistd.h>
  11
  12 extern "C" {
  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>
  23 }
  24
  25 #include <chrono>
  26 #include <cstdint>
  27 #include <utility>
  28 #include <vector>
  29 #include <unordered_set>
  30
  31 #include <Eigen/Core>
  32 #include <Eigen/LU>
  33 #include <movit/colorspace_conversion_effect.h>
  34
  35 #include "bmusb/bmusb.h"
  36 #include "shared/ffmpeg_raii.h"
  37 #include "ffmpeg_util.h"
  38 #include "flags.h"
  39 #include "image_input.h"
  40 #include "ref_counted_frame.h"
  41 #include "shared/timebase.h"
  42
  43 #ifdef HAVE_SRT
  44 #include <srt/srt.h>
  45 #endif
  46
  47 using namespace std;
  48 using namespace std::chrono;
  49 using namespace bmusb;
  50 using namespace movit;
  51 using namespace Eigen;
  52
  53 namespace {
  54
  55 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)
  56 {
  57         const duration<double> pts((frame_pts - pts_origin) * double(video_timebase.num) / double(video_timebase.den));
  58         return origin + duration_cast<steady_clock::duration>(pts / rate);
  59 }
  60
  61 bool changed_since(const std::string &pathname, const timespec &ts)
  62 {
  63         if (ts.tv_sec < 0) {
  64                 return false;
  65         }
  66         struct stat buf;
  67         if (stat(pathname.c_str(), &buf) != 0) {
  68                 fprintf(stderr, "%s: Couldn't check for new version, leaving the old in place.\n", pathname.c_str());
  69                 return false;
  70         }
  71         return (buf.st_mtim.tv_sec != ts.tv_sec || buf.st_mtim.tv_nsec != ts.tv_nsec);
  72 }
  73
  74 bool is_full_range(const AVPixFmtDescriptor *desc)
  75 {
  76         // This is horrible, but there's no better way that I know of.
  77         return (strchr(desc->name, 'j') != nullptr);
  78 }
  79
  80 AVPixelFormat decide_dst_format(AVPixelFormat src_format, bmusb::PixelFormat dst_format_type)
  81 {
  82         if (dst_format_type == bmusb::PixelFormat_8BitBGRA) {
  83                 return AV_PIX_FMT_BGRA;
  84         }
  85         if (dst_format_type == FFmpegCapture::PixelFormat_NV12) {
  86                 return AV_PIX_FMT_NV12;
  87         }
  88
  89         assert(dst_format_type == bmusb::PixelFormat_8BitYCbCrPlanar);
  90
  91         // If this is a non-Y'CbCr format, just convert to 4:4:4 Y'CbCr
  92         // and be done with it. It's too strange to spend a lot of time on.
  93         // (Let's hope there's no alpha.)
  94         const AVPixFmtDescriptor *src_desc = av_pix_fmt_desc_get(src_format);
  95         if (src_desc == nullptr ||
  96             src_desc->nb_components != 3 ||
  97             (src_desc->flags & AV_PIX_FMT_FLAG_RGB)) {
  98                 return AV_PIX_FMT_YUV444P;
  99         }
 100
 101         // The best for us would be Cb and Cr together if possible,
 102         // but FFmpeg doesn't support that except in the special case of
 103         // NV12, so we need to go to planar even for the case of NV12.
 104         // Thus, look for the closest (but no worse) 8-bit planar Y'CbCr format
 105         // that matches in color range. (This will also include the case of
 106         // the source format already being acceptable.)
 107         bool src_full_range = is_full_range(src_desc);
 108         const char *best_format = "yuv444p";
 109         unsigned best_score = numeric_limits<unsigned>::max();
 110         for (const AVPixFmtDescriptor *desc = av_pix_fmt_desc_next(nullptr);
 111              desc;
 112              desc = av_pix_fmt_desc_next(desc)) {
 113                 // Find planar Y'CbCr formats only.
 114                 if (desc->nb_components != 3) continue;
 115                 if (desc->flags & AV_PIX_FMT_FLAG_RGB) continue;
 116                 if (!(desc->flags & AV_PIX_FMT_FLAG_PLANAR)) continue;
 117                 if (desc->comp[0].plane != 0 ||
 118                     desc->comp[1].plane != 1 ||
 119                     desc->comp[2].plane != 2) continue;
 120
 121                 // 8-bit formats only.
 122                 if (desc->flags & AV_PIX_FMT_FLAG_BE) continue;
 123                 if (desc->comp[0].depth != 8) continue;
 124
 125                 // Same or better chroma resolution only.
 126                 int chroma_w_diff = src_desc->log2_chroma_w - desc->log2_chroma_w;
 127                 int chroma_h_diff = src_desc->log2_chroma_h - desc->log2_chroma_h;
 128                 if (chroma_w_diff < 0 || chroma_h_diff < 0)
 129                         continue;
 130
 131                 // Matching full/limited range only.
 132                 if (is_full_range(desc) != src_full_range)
 133                         continue;
 134
 135                 // Pick something with as little excess chroma resolution as possible.
 136                 unsigned score = (1 << (chroma_w_diff)) << chroma_h_diff;
 137                 if (score < best_score) {
 138                         best_score = score;
 139                         best_format = desc->name;
 140                 }
 141         }
 142         return av_get_pix_fmt(best_format);
 143 }
 144
 145 YCbCrFormat decode_ycbcr_format(const AVPixFmtDescriptor *desc, const AVFrame *frame, bool is_mjpeg, AVColorSpace *last_colorspace, AVChromaLocation *last_chroma_location)
 146 {
 147         YCbCrFormat format;
 148         AVColorSpace colorspace = frame->colorspace;
 149         switch (colorspace) {
 150         case AVCOL_SPC_BT709:
 151                 format.luma_coefficients = YCBCR_REC_709;
 152                 break;
 153         case AVCOL_SPC_BT470BG:
 154         case AVCOL_SPC_SMPTE170M:
 155         case AVCOL_SPC_SMPTE240M:
 156                 format.luma_coefficients = YCBCR_REC_601;
 157                 break;
 158         case AVCOL_SPC_BT2020_NCL:
 159                 format.luma_coefficients = YCBCR_REC_2020;
 160                 break;
 161         case AVCOL_SPC_UNSPECIFIED:
 162                 format.luma_coefficients = (frame->height >= 720 ? YCBCR_REC_709 : YCBCR_REC_601);
 163                 break;
 164         default:
 165                 if (colorspace != *last_colorspace) {
 166                         fprintf(stderr, "Unknown Y'CbCr coefficient enum %d from FFmpeg; choosing Rec. 709.\n",
 167                                 colorspace);
 168                 }
 169                 format.luma_coefficients = YCBCR_REC_709;
 170                 break;
 171         }
 172         *last_colorspace = colorspace;
 173
 174         format.full_range = is_full_range(desc);
 175         format.num_levels = 1 << desc->comp[0].depth;
 176         format.chroma_subsampling_x = 1 << desc->log2_chroma_w;
 177         format.chroma_subsampling_y = 1 << desc->log2_chroma_h;
 178
 179         switch (frame->chroma_location) {
 180         case AVCHROMA_LOC_LEFT:
 181                 format.cb_x_position = 0.0;
 182                 format.cb_y_position = 0.5;
 183                 break;
 184         case AVCHROMA_LOC_CENTER:
 185                 format.cb_x_position = 0.5;
 186                 format.cb_y_position = 0.5;
 187                 break;
 188         case AVCHROMA_LOC_TOPLEFT:
 189                 format.cb_x_position = 0.0;
 190                 format.cb_y_position = 0.0;
 191                 break;
 192         case AVCHROMA_LOC_TOP:
 193                 format.cb_x_position = 0.5;
 194                 format.cb_y_position = 0.0;
 195                 break;
 196         case AVCHROMA_LOC_BOTTOMLEFT:
 197                 format.cb_x_position = 0.0;
 198                 format.cb_y_position = 1.0;
 199                 break;
 200         case AVCHROMA_LOC_BOTTOM:
 201                 format.cb_x_position = 0.5;
 202                 format.cb_y_position = 1.0;
 203                 break;
 204         default:
 205                 if (frame->chroma_location != *last_chroma_location) {
 206                         fprintf(stderr, "Unknown chroma location coefficient enum %d from FFmpeg; choosing center.\n",
 207                                 frame->chroma_location);
 208                 }
 209                 format.cb_x_position = 0.5;
 210                 format.cb_y_position = 0.5;
 211                 break;
 212         }
 213         *last_chroma_location = frame->chroma_location;
 214
 215         if (is_mjpeg && !format.full_range) {
 216                 // Limited-range MJPEG is only detected by FFmpeg whenever a special
 217                 // JPEG comment is set, which means that in practice, the stream is
 218                 // almost certainly generated by Futatabi. Override FFmpeg's forced
 219                 // MJPEG defaults (it disregards the values set in the mux) with what
 220                 // Futatabi sets.
 221                 format.luma_coefficients = YCBCR_REC_709;
 222                 format.cb_x_position = 0.0;
 223                 format.cb_y_position = 0.5;
 224         }
 225
 226         format.cr_x_position = format.cb_x_position;
 227         format.cr_y_position = format.cb_y_position;
 228         return format;
 229 }
 230
 231 RGBTriplet get_neutral_color(AVDictionary *metadata)
 232 {
 233         if (metadata == nullptr) {
 234                 return RGBTriplet(1.0f, 1.0f, 1.0f);
 235         }
 236         AVDictionaryEntry *entry = av_dict_get(metadata, "WhitePoint", nullptr, 0);
 237         if (entry == nullptr) {
 238                 return RGBTriplet(1.0f, 1.0f, 1.0f);
 239         }
 240
 241         unsigned x_nom, x_den, y_nom, y_den;
 242         if (sscanf(entry->value, " %u:%u , %u:%u", &x_nom, &x_den, &y_nom, &y_den) != 4) {
 243                 fprintf(stderr, "WARNING: Unable to parse white point '%s', using default white point\n", entry->value);
 244                 return RGBTriplet(1.0f, 1.0f, 1.0f);
 245         }
 246
 247         double x = double(x_nom) / x_den;
 248         double y = double(y_nom) / y_den;
 249         double z = 1.0 - x - y;
 250
 251         Matrix3d rgb_to_xyz_matrix = movit::ColorspaceConversionEffect::get_xyz_matrix(COLORSPACE_sRGB);
 252         Vector3d rgb = rgb_to_xyz_matrix.inverse() * Vector3d(x, y, z);
 253
 254         return RGBTriplet(rgb[0], rgb[1], rgb[2]);
 255 }
 256
 257 }  // namespace
 258
 259 FFmpegCapture::FFmpegCapture(const string &filename, unsigned width, unsigned height)
 260         : filename(filename), width(width), height(height), video_timebase{1, 1}
 261 {
 262         description = "Video: " + filename;
 263
 264         last_frame = steady_clock::now();
 265
 266         avformat_network_init();  // In case someone wants this.
 267 }
 268
 269 #ifdef HAVE_SRT
 270 FFmpegCapture::FFmpegCapture(int srt_sock, const string &stream_id)
 271         : srt_sock(srt_sock),
 272           width(0),  // Don't resize; SRT streams typically have stable resolution, and should behave much like regular cards in general.
 273           height(0),
 274           pixel_format(bmusb::PixelFormat_8BitYCbCrPlanar),
 275           video_timebase{1, 1}
 276 {
 277         if (stream_id.empty()) {
 278                 description = "SRT stream";
 279         } else {
 280                 description = stream_id;
 281         }
 282         play_as_fast_as_possible = true;
 283         play_once = true;
 284         last_frame = steady_clock::now();
 285 }
 286 #endif
 287
 288 FFmpegCapture::~FFmpegCapture()
 289 {
 290         if (has_dequeue_callbacks) {
 291                 dequeue_cleanup_callback();
 292         }
 293         swr_free(&resampler);
 294 #ifdef HAVE_SRT
 295         if (srt_sock != -1) {
 296                 srt_close(srt_sock);
 297         }
 298 #endif
 299 }
 300
 301 void FFmpegCapture::configure_card()
 302 {
 303         if (video_frame_allocator == nullptr) {
 304                 owned_video_frame_allocator.reset(new MallocFrameAllocator(FRAME_SIZE, NUM_QUEUED_VIDEO_FRAMES));
 305                 set_video_frame_allocator(owned_video_frame_allocator.get());
 306         }
 307         if (audio_frame_allocator == nullptr) {
 308                 // Audio can come out in pretty large chunks, so increase from the default 1 MB.
 309                 owned_audio_frame_allocator.reset(new MallocFrameAllocator(1 << 20, NUM_QUEUED_AUDIO_FRAMES));
 310                 set_audio_frame_allocator(owned_audio_frame_allocator.get());
 311         }
 312 }
 313
 314 void FFmpegCapture::start_bm_capture()
 315 {
 316         if (running) {
 317                 return;
 318         }
 319         running = true;
 320         producer_thread_should_quit.unquit();
 321         producer_thread = thread(&FFmpegCapture::producer_thread_func, this);
 322 }
 323
 324 void FFmpegCapture::stop_dequeue_thread()
 325 {
 326         if (!running) {
 327                 return;
 328         }
 329         running = false;
 330         producer_thread_should_quit.quit();
 331         producer_thread.join();
 332 }
 333
 334 std::map<uint32_t, VideoMode> FFmpegCapture::get_available_video_modes() const
 335 {
 336         // Note: This will never really be shown in the UI.
 337         VideoMode mode;
 338
 339         char buf[256];
 340         snprintf(buf, sizeof(buf), "%ux%u", sws_last_width, sws_last_height);
 341         mode.name = buf;
 342
 343         mode.autodetect = false;
 344         mode.width = sws_last_width;
 345         mode.height = sws_last_height;
 346         mode.frame_rate_num = 60;
 347         mode.frame_rate_den = 1;
 348         mode.interlaced = false;
 349
 350         return {{ 0, mode }};
 351 }
 352
 353 void FFmpegCapture::producer_thread_func()
 354 {
 355         char thread_name[16];
 356         snprintf(thread_name, sizeof(thread_name), "FFmpeg_C_%d", card_index);
 357         pthread_setname_np(pthread_self(), thread_name);
 358
 359         while (!producer_thread_should_quit.should_quit()) {
 360                 string filename_copy;
 361                 {
 362                         lock_guard<mutex> lock(filename_mu);
 363                         filename_copy = filename;
 364                 }
 365
 366                 string pathname;
 367                 if (srt_sock == -1) {
 368                         pathname = search_for_file(filename_copy);
 369                 } else {
 370                         pathname = description;
 371                 }
 372                 if (pathname.empty()) {
 373                         send_disconnected_frame();
 374                         if (play_once) {
 375                                 break;
 376                         }
 377                         producer_thread_should_quit.sleep_for(seconds(1));
 378                         fprintf(stderr, "%s not found, sleeping one second and trying again...\n", filename_copy.c_str());
 379                         continue;
 380                 }
 381                 should_interrupt = false;
 382                 if (!play_video(pathname)) {
 383                         // Error.
 384                         send_disconnected_frame();
 385                         if (play_once) {
 386                                 break;
 387                         }
 388                         fprintf(stderr, "Error when playing %s, sleeping one second and trying again...\n", pathname.c_str());
 389                         producer_thread_should_quit.sleep_for(seconds(1));
 390                         continue;
 391                 }
 392
 393                 if (play_once) {
 394                         send_disconnected_frame();
 395                         break;
 396                 }
 397
 398                 // Probably just EOF, will exit the loop above on next test.
 399         }
 400
 401         if (has_dequeue_callbacks) {
 402                 dequeue_cleanup_callback();
 403                 has_dequeue_callbacks = false;
 404         }
 405 }
 406
 407 void FFmpegCapture::send_disconnected_frame()
 408 {
 409         // Send an empty frame to signal that we have no signal anymore.
 410         FrameAllocator::Frame video_frame = video_frame_allocator->alloc_frame();
 411         size_t frame_width = width == 0 ? global_flags.width : width;
 412         size_t frame_height = height == 0 ? global_flags.height : height;
 413         if (video_frame.data) {
 414                 VideoFormat video_format;
 415                 video_format.width = frame_width;
 416                 video_format.height = frame_height;
 417                 video_format.frame_rate_nom = 60;
 418                 video_format.frame_rate_den = 1;
 419                 video_format.is_connected = false;
 420                 if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
 421                         video_format.stride = frame_width * 4;
 422                         video_frame.len = frame_width * frame_height * 4;
 423                         memset(video_frame.data, 0, video_frame.len);
 424                 } else {
 425                         video_format.stride = frame_width;
 426                         current_frame_ycbcr_format.luma_coefficients = YCBCR_REC_709;
 427                         current_frame_ycbcr_format.full_range = true;
 428                         current_frame_ycbcr_format.num_levels = 256;
 429                         current_frame_ycbcr_format.chroma_subsampling_x = 2;
 430                         current_frame_ycbcr_format.chroma_subsampling_y = 2;
 431                         current_frame_ycbcr_format.cb_x_position = 0.0f;
 432                         current_frame_ycbcr_format.cb_y_position = 0.0f;
 433                         current_frame_ycbcr_format.cr_x_position = 0.0f;
 434                         current_frame_ycbcr_format.cr_y_position = 0.0f;
 435                         video_frame.len = frame_width * frame_height * 2;
 436                         memset(video_frame.data, 0, frame_width * frame_height);
 437                         memset(video_frame.data + frame_width * frame_height, 128, frame_width * frame_height);  // Valid for both NV12 and planar.
 438                 }
 439
 440                 if (frame_callback != nullptr) {
 441                         frame_callback(-1, AVRational{1, TIMEBASE}, -1, AVRational{1, TIMEBASE}, timecode++,
 442                                 video_frame, /*video_offset=*/0, video_format,
 443                                 FrameAllocator::Frame(), /*audio_offset=*/0, AudioFormat());
 444                 }
 445                 last_frame_was_connected = false;
 446         }
 447
 448         if (play_once) {
 449                 disconnected = true;
 450                 if (card_disconnected_callback != nullptr) {
 451                         card_disconnected_callback();
 452                 }
 453         }
 454 }
 455
 456 template<AVHWDeviceType type>
 457 AVPixelFormat get_hw_format(AVCodecContext *ctx, const AVPixelFormat *fmt)
 458 {
 459         bool found_config_of_right_type = false;
 460         for (int i = 0;; ++i) {  // Termination condition inside loop.
 461                 const AVCodecHWConfig *config = avcodec_get_hw_config(ctx->codec, i);
 462                 if (config == nullptr) {  // End of list.
 463                         break;
 464                 }
 465                 if (!(config->methods & AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX) ||
 466                     config->device_type != type) {
 467                         // Not interesting for us.
 468                         continue;
 469                 }
 470
 471                 // We have a config of the right type, but does it actually support
 472                 // the pixel format we want? (Seemingly, FFmpeg's way of signaling errors
 473                 // is to just replace the pixel format with a software-decoded one,
 474                 // such as yuv420p.)
 475                 found_config_of_right_type = true;
 476                 for (const AVPixelFormat *fmt_ptr = fmt; *fmt_ptr != -1; ++fmt_ptr) {
 477                         if (config->pix_fmt == *fmt_ptr) {
 478                                 fprintf(stderr, "Initialized '%s' hardware decoding for codec '%s'.\n",
 479                                         av_hwdevice_get_type_name(type), ctx->codec->name);
 480                                 if (ctx->profile == FF_PROFILE_H264_BASELINE) {
 481                                         fprintf(stderr, "WARNING: Stream claims to be H.264 Baseline, which is generally poorly supported in hardware decoders.\n");
 482                                         fprintf(stderr, "         Consider encoding it as Constrained Baseline, Main or High instead.\n");
 483                                         fprintf(stderr, "         Decoding might fail and fall back to software.\n");
 484                                 }
 485                                 return config->pix_fmt;
 486                         }
 487                 }
 488                 fprintf(stderr, "Decoder '%s' supports only these pixel formats:", ctx->codec->name);
 489                 unordered_set<AVPixelFormat> seen;
 490                 for (const AVPixelFormat *fmt_ptr = fmt; *fmt_ptr != -1; ++fmt_ptr) {
 491                         if (!seen.count(*fmt_ptr)) {
 492                                 fprintf(stderr, " %s", av_get_pix_fmt_name(*fmt_ptr));
 493                                 seen.insert(*fmt_ptr);
 494                         }
 495                 }
 496                 fprintf(stderr, " (wanted %s for hardware acceleration)\n", av_get_pix_fmt_name(config->pix_fmt));
 497
 498         }
 499
 500         if (!found_config_of_right_type) {
 501                 fprintf(stderr, "Decoder '%s' does not support device type '%s'.\n", ctx->codec->name, av_hwdevice_get_type_name(type));
 502         }
 503
 504         // We found no VA-API formats, so take the first software format.
 505         for (const AVPixelFormat *fmt_ptr = fmt; *fmt_ptr != -1; ++fmt_ptr) {
 506                 if ((av_pix_fmt_desc_get(*fmt_ptr)->flags & AV_PIX_FMT_FLAG_HWACCEL) == 0) {
 507                         fprintf(stderr, "Falling back to software format %s.\n", av_get_pix_fmt_name(*fmt_ptr));
 508                         return *fmt_ptr;
 509                 }
 510         }
 511
 512         // Fallback: Just return anything. (Should never really happen.)
 513         return fmt[0];
 514 }
 515
 516 bool FFmpegCapture::play_video(const string &pathname)
 517 {
 518         // Note: Call before open, not after; otherwise, there's a race.
 519         // (There is now, too, but it tips the correct way. We could use fstat()
 520         // if we had the file descriptor.)
 521         timespec last_modified;
 522         struct stat buf;
 523         if (stat(pathname.c_str(), &buf) != 0) {
 524                 // Probably some sort of protocol, so can't stat.
 525                 last_modified.tv_sec = -1;
 526         } else {
 527                 last_modified = buf.st_mtim;
 528         }
 529         last_colorspace = static_cast<AVColorSpace>(-1);
 530         last_chroma_location = static_cast<AVChromaLocation>(-1);
 531
 532         AVFormatContextWithCloser format_ctx;
 533         if (srt_sock == -1) {
 534                 // Regular file (or stream).
 535                 frame_timeout_started = steady_clock::now();
 536                 frame_timeout_valid = true;
 537                 format_ctx = avformat_open_input_unique(pathname.c_str(), /*fmt=*/nullptr,
 538                         /*options=*/nullptr,
 539                         AVIOInterruptCB{ &FFmpegCapture::interrupt_cb_thunk, this });
 540                 frame_timeout_valid = false;
 541         } else {
 542 #ifdef HAVE_SRT
 543                 // SRT socket, already opened.
 544                 const AVInputFormat *mpegts_fmt = av_find_input_format("mpegts");
 545                 format_ctx = avformat_open_input_unique(&FFmpegCapture::read_srt_thunk, this,
 546                         mpegts_fmt, /*options=*/nullptr,
 547                         AVIOInterruptCB{ &FFmpegCapture::interrupt_cb_thunk, this });
 548 #else
 549                 assert(false);
 550 #endif
 551         }
 552         if (format_ctx == nullptr) {
 553                 fprintf(stderr, "%s: Error opening file\n", pathname.c_str());
 554                 return false;
 555         }
 556
 557         if (avformat_find_stream_info(format_ctx.get(), nullptr) < 0) {
 558                 fprintf(stderr, "%s: Error finding stream info\n", pathname.c_str());
 559                 return false;
 560         }
 561
 562         int video_stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_VIDEO);
 563         if (video_stream_index == -1) {
 564                 fprintf(stderr, "%s: No video stream found\n", pathname.c_str());
 565                 return false;
 566         }
 567
 568         int audio_stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_AUDIO);
 569         int subtitle_stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_SUBTITLE);
 570         has_last_subtitle = false;
 571
 572         // Open video decoder.
 573         const AVCodecParameters *video_codecpar = format_ctx->streams[video_stream_index]->codecpar;
 574         const AVCodec *video_codec = avcodec_find_decoder(video_codecpar->codec_id);
 575
 576         video_timebase = format_ctx->streams[video_stream_index]->time_base;
 577         AVCodecContextWithDeleter video_codec_ctx = avcodec_alloc_context3_unique(nullptr);
 578         if (avcodec_parameters_to_context(video_codec_ctx.get(), video_codecpar) < 0) {
 579                 fprintf(stderr, "%s: Cannot fill video codec parameters\n", pathname.c_str());
 580                 return false;
 581         }
 582         if (video_codec == nullptr) {
 583                 fprintf(stderr, "%s: Cannot find video decoder\n", pathname.c_str());
 584                 return false;
 585         }
 586
 587         // Seemingly, it's not too easy to make something that just initializes
 588         // “whatever goes”, so we don't get CUDA or VULKAN or whatever here
 589         // without enumerating through several different types.
 590         // VA-API and VDPAU will do for now. We prioritize VDPAU for the
 591         // simple reason that there's a VA-API-via-VDPAU emulation for NVidia
 592         // cards that seems to work, but just hangs when trying to transfer the frame.
 593         //
 594         // Note that we don't actually check codec support beforehand,
 595         // so if you have a low-end VDPAU device but a high-end VA-API device,
 596         // you lose out on the extra codec support from the latter.
 597         AVBufferRef *hw_device_ctx = nullptr;
 598         if (av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VDPAU, nullptr, nullptr, 0) >= 0) {
 599                 video_codec_ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
 600                 video_codec_ctx->get_format = get_hw_format<AV_HWDEVICE_TYPE_VDPAU>;
 601         } else if (av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VAAPI, nullptr, nullptr, 0) >= 0) {
 602                 video_codec_ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
 603                 video_codec_ctx->get_format = get_hw_format<AV_HWDEVICE_TYPE_VAAPI>;
 604         } else {
 605                 fprintf(stderr, "Failed to initialize VA-API or VDPAU for FFmpeg acceleration. Decoding video in software.\n");
 606         }
 607
 608         if (avcodec_open2(video_codec_ctx.get(), video_codec, nullptr) < 0) {
 609                 fprintf(stderr, "%s: Cannot open video decoder\n", pathname.c_str());
 610                 return false;
 611         }
 612         unique_ptr<AVCodecContext, decltype(avcodec_close)*> video_codec_ctx_cleanup(
 613                 video_codec_ctx.get(), avcodec_close);
 614
 615         // Used in decode_ycbcr_format().
 616         is_mjpeg = video_codecpar->codec_id == AV_CODEC_ID_MJPEG;
 617
 618         // Open audio decoder, if we have audio.
 619         AVCodecContextWithDeleter audio_codec_ctx;
 620         if (audio_stream_index != -1) {
 621                 audio_codec_ctx = avcodec_alloc_context3_unique(nullptr);
 622                 const AVCodecParameters *audio_codecpar = format_ctx->streams[audio_stream_index]->codecpar;
 623                 audio_timebase = format_ctx->streams[audio_stream_index]->time_base;
 624                 if (avcodec_parameters_to_context(audio_codec_ctx.get(), audio_codecpar) < 0) {
 625                         fprintf(stderr, "%s: Cannot fill audio codec parameters\n", pathname.c_str());
 626                         return false;
 627                 }
 628                 const AVCodec *audio_codec = avcodec_find_decoder(audio_codecpar->codec_id);
 629                 if (audio_codec == nullptr) {
 630                         fprintf(stderr, "%s: Cannot find audio decoder\n", pathname.c_str());
 631                         return false;
 632                 }
 633                 if (avcodec_open2(audio_codec_ctx.get(), audio_codec, nullptr) < 0) {
 634                         fprintf(stderr, "%s: Cannot open audio decoder\n", pathname.c_str());
 635                         return false;
 636                 }
 637         }
 638         unique_ptr<AVCodecContext, decltype(avcodec_close)*> audio_codec_ctx_cleanup(
 639                 audio_codec_ctx.get(), avcodec_close);
 640
 641         internal_rewind();
 642
 643         // Main loop.
 644         bool first_frame = true;
 645         int consecutive_errors = 0;
 646         while (!producer_thread_should_quit.should_quit()) {
 647                 if (process_queued_commands(format_ctx.get(), pathname, last_modified, /*rewound=*/nullptr)) {
 648                         return true;
 649                 }
 650                 if (should_interrupt.load()) {
 651                         // Check as a failsafe, so that we don't need to rely on avio if we don't have to.
 652                         return false;
 653                 }
 654                 UniqueFrame audio_frame = audio_frame_allocator->alloc_frame();
 655                 AudioFormat audio_format;
 656
 657                 int64_t audio_pts;
 658                 bool error;
 659                 frame_timeout_started = steady_clock::now();
 660                 frame_timeout_valid = true;
 661                 AVFrameWithDeleter frame = decode_frame(format_ctx.get(), video_codec_ctx.get(), audio_codec_ctx.get(),
 662                         pathname, video_stream_index, audio_stream_index, subtitle_stream_index, audio_frame.get(), &audio_format, &audio_pts, &error);
 663                 frame_timeout_valid = false;
 664                 if (should_interrupt.load()) {
 665                         // Abort no matter whether we got a frame or not.
 666                         return false;
 667                 }
 668                 if (error) {
 669                         if (++consecutive_errors >= 100) {
 670                                 fprintf(stderr, "More than 100 consecutive error video frames, aborting playback.\n");
 671                                 return false;
 672                         } else {
 673                                 continue;
 674                         }
 675                 } else {
 676                         consecutive_errors = 0;
 677                 }
 678                 if (frame == nullptr) {
 679                         // EOF. Loop back to the start if we can.
 680                         if (format_ctx->pb != nullptr && format_ctx->pb->seekable == 0) {
 681                                 // Not seekable (but seemingly, sometimes av_seek_frame() would return 0 anyway,
 682                                 // so don't try).
 683                                 return true;
 684                         }
 685                         if (av_seek_frame(format_ctx.get(), /*stream_index=*/-1, /*timestamp=*/0, /*flags=*/0) < 0) {
 686                                 fprintf(stderr, "%s: Rewind failed, not looping.\n", pathname.c_str());
 687                                 return true;
 688                         }
 689                         if (video_codec_ctx != nullptr) {
 690                                 avcodec_flush_buffers(video_codec_ctx.get());
 691                         }
 692                         if (audio_codec_ctx != nullptr) {
 693                                 avcodec_flush_buffers(audio_codec_ctx.get());
 694                         }
 695                         // If the file has changed since last time, return to get it reloaded.
 696                         // Note that depending on how you move the file into place, you might
 697                         // end up corrupting the one you're already playing, so this path
 698                         // might not trigger.
 699                         if (changed_since(pathname, last_modified)) {
 700                                 return true;
 701                         }
 702                         internal_rewind();
 703                         continue;
 704                 }
 705
 706                 VideoFormat video_format = construct_video_format(frame.get(), video_timebase);
 707                 if (video_format.frame_rate_nom == 0 || video_format.frame_rate_den == 0) {
 708                         // Invalid frame rate; try constructing it from the previous frame length.
 709                         // (This is especially important if we are the master card, for SRT,
 710                         // since it affects audio. Not all senders have good timebases
 711                         // (e.g., Larix rounds first to timebase 1000 and then multiplies by
 712                         // 90 from there, it seems), but it's much better to have an oscillating
 713                         // value than just locking at 60.
 714                         if (last_pts != 0 && frame->pts > last_pts) {
 715                                 int64_t pts_diff = frame->pts - last_pts;
 716                                 video_format.frame_rate_nom = video_timebase.den;
 717                                 video_format.frame_rate_den = video_timebase.num * pts_diff;
 718                         } else {
 719                                 video_format.frame_rate_nom = 60;
 720                                 video_format.frame_rate_den = 1;
 721                         }
 722                 }
 723                 UniqueFrame video_frame = make_video_frame(frame.get(), pathname, &error);
 724                 if (error) {
 725                         return false;
 726                 }
 727
 728                 for ( ;; ) {
 729                         if (last_pts == 0 && pts_origin == 0) {
 730                                 pts_origin = frame->pts;
 731                         }
 732                         steady_clock::time_point now = steady_clock::now();
 733                         if (play_as_fast_as_possible) {
 734                                 video_frame->received_timestamp = now;
 735                                 audio_frame->received_timestamp = now;
 736                                 next_frame_start = now;
 737                         } else {
 738                                 next_frame_start = compute_frame_start(frame->pts, pts_origin, video_timebase, start, rate);
 739                                 if (first_frame && last_frame_was_connected) {
 740                                         // If reconnect took more than one second, this is probably a live feed,
 741                                         // and we should reset the resampler. (Or the rate is really, really low,
 742                                         // in which case a reset on the first frame is fine anyway.)
 743                                         if (duration<double>(next_frame_start - last_frame).count() >= 1.0) {
 744                                                 last_frame_was_connected = false;
 745                                         }
 746                                 }
 747                                 video_frame->received_timestamp = next_frame_start;
 748
 749                                 // The easiest way to get all the rate conversions etc. right is to move the
 750                                 // audio PTS into the video PTS timebase and go from there. (We'll get some
 751                                 // rounding issues, but they should not be a big problem.)
 752                                 int64_t audio_pts_as_video_pts = av_rescale_q(audio_pts, audio_timebase, video_timebase);
 753                                 audio_frame->received_timestamp = compute_frame_start(audio_pts_as_video_pts, pts_origin, video_timebase, start, rate);
 754
 755                                 if (audio_frame->len != 0) {
 756                                         // The received timestamps in Nageru are measured after we've just received the frame.
 757                                         // However, pts (especially audio pts) is at the _beginning_ of the frame.
 758                                         // If we have locked audio, the distinction doesn't really matter, as pts is
 759                                         // on a relative scale and a fixed offset is fine. But if we don't, we will have
 760                                         // a different number of samples each time, which will cause huge audio jitter
 761                                         // and throw off the resampler.
 762                                         //
 763                                         // In a sense, we should have compensated by adding the frame and audio lengths
 764                                         // to video_frame->received_timestamp and audio_frame->received_timestamp respectively,
 765                                         // but that would mean extra waiting in sleep_until(). All we need is that they
 766                                         // are correct relative to each other, though (and to the other frames we send),
 767                                         // so just align the end of the audio frame, and we're fine.
 768                                         size_t num_samples = (audio_frame->len * 8) / audio_format.bits_per_sample / audio_format.num_channels;
 769                                         double offset = double(num_samples) / OUTPUT_FREQUENCY -
 770                                                 double(video_format.frame_rate_den) / video_format.frame_rate_nom;
 771                                         audio_frame->received_timestamp += duration_cast<steady_clock::duration>(duration<double>(offset));
 772                                 }
 773
 774                                 if (duration<double>(now - next_frame_start).count() >= 0.1) {
 775                                         // If we don't have enough CPU to keep up, or if we have a live stream
 776                                         // where the initial origin was somehow wrong, we could be behind indefinitely.
 777                                         // In particular, this will give the audio resampler problems as it tries
 778                                         // to speed up to reduce the delay, hitting the low end of the buffer every time.
 779                                         fprintf(stderr, "%s: Playback %.0f ms behind, resetting time scale\n",
 780                                                 pathname.c_str(),
 781                                                 1e3 * duration<double>(now - next_frame_start).count());
 782                                         pts_origin = frame->pts;
 783                                         start = next_frame_start = now;
 784                                         timecode += TYPICAL_FPS * 2 + 1;
 785                                 }
 786                         }
 787                         bool finished_wakeup;
 788                         if (play_as_fast_as_possible) {
 789                                 finished_wakeup = !producer_thread_should_quit.should_quit();
 790                         } else {
 791                                 finished_wakeup = producer_thread_should_quit.sleep_until(next_frame_start);
 792                         }
 793                         if (finished_wakeup) {
 794                                 if (audio_frame->len > 0) {
 795                                         assert(audio_pts != -1);
 796                                 }
 797                                 if (!last_frame_was_connected) {
 798                                         // We're recovering from an error (or really slow load, see above).
 799                                         // Make sure to get the audio resampler reset. (This is a hack;
 800                                         // ideally, the frame callback should just accept a way to signal
 801                                         // audio discontinuity.)
 802                                         timecode += TYPICAL_FPS * 2 + 1;
 803                                 }
 804                                 last_neutral_color = get_neutral_color(frame->metadata);
 805                                 if (frame_callback != nullptr) {
 806                                         frame_callback(frame->pts, video_timebase, audio_pts, audio_timebase, timecode++,
 807                                                 video_frame.get_and_release(), 0, video_format,
 808                                                 audio_frame.get_and_release(), 0, audio_format);
 809                                 }
 810                                 first_frame = false;
 811                                 last_frame = steady_clock::now();
 812                                 last_frame_was_connected = true;
 813                                 break;
 814                         } else {
 815                                 if (producer_thread_should_quit.should_quit()) break;
 816
 817                                 bool rewound = false;
 818                                 if (process_queued_commands(format_ctx.get(), pathname, last_modified, &rewound)) {
 819                                         return true;
 820                                 }
 821                                 // If we just rewound, drop this frame on the floor and be done.
 822                                 if (rewound) {
 823                                         break;
 824                                 }
 825                                 // OK, we didn't, so probably a rate change. Recalculate next_frame_start,
 826                                 // but if it's now in the past, we'll reset the origin, so that we don't
 827                                 // generate a huge backlog of frames that we need to run through quickly.
 828                                 next_frame_start = compute_frame_start(frame->pts, pts_origin, video_timebase, start, rate);
 829                                 steady_clock::time_point now = steady_clock::now();
 830                                 if (next_frame_start < now) {
 831                                         pts_origin = frame->pts;
 832                                         start = next_frame_start = now;
 833                                 }
 834                         }
 835                 }
 836                 last_pts = frame->pts;
 837         }
 838         return true;
 839 }
 840
 841 void FFmpegCapture::internal_rewind()
 842 {
 843         pts_origin = last_pts = 0;
 844         start = next_frame_start = steady_clock::now();
 845 }
 846
 847 bool FFmpegCapture::process_queued_commands(AVFormatContext *format_ctx, const std::string &pathname, timespec last_modified, bool *rewound)
 848 {
 849         // Process any queued commands from other threads.
 850         vector<QueuedCommand> commands;
 851         {
 852                 lock_guard<mutex> lock(queue_mu);
 853                 swap(commands, command_queue);
 854         }
 855         for (const QueuedCommand &cmd : commands) {
 856                 switch (cmd.command) {
 857                 case QueuedCommand::REWIND:
 858                         if (av_seek_frame(format_ctx, /*stream_index=*/-1, /*timestamp=*/0, /*flags=*/0) < 0) {
 859                                 fprintf(stderr, "%s: Rewind failed, stopping play.\n", pathname.c_str());
 860                         }
 861                         // If the file has changed since last time, return to get it reloaded.
 862                         // Note that depending on how you move the file into place, you might
 863                         // end up corrupting the one you're already playing, so this path
 864                         // might not trigger.
 865                         if (changed_since(pathname, last_modified)) {
 866                                 return true;
 867                         }
 868                         internal_rewind();
 869                         if (rewound != nullptr) {
 870                                 *rewound = true;
 871                         }
 872                         break;
 873
 874                 case QueuedCommand::CHANGE_RATE:
 875                         // Change the origin to the last played frame.
 876                         start = compute_frame_start(last_pts, pts_origin, video_timebase, start, rate);
 877                         pts_origin = last_pts;
 878                         rate = cmd.new_rate;
 879                         play_as_fast_as_possible = (rate >= 10.0);
 880                         break;
 881                 }
 882         }
 883         return false;
 884 }
 885
 886 namespace {
 887
 888 }  // namespace
 889
 890 AVFrameWithDeleter FFmpegCapture::decode_frame(AVFormatContext *format_ctx, AVCodecContext *video_codec_ctx, AVCodecContext *audio_codec_ctx,
 891         const std::string &pathname, int video_stream_index, int audio_stream_index, int subtitle_stream_index,
 892         FrameAllocator::Frame *audio_frame, AudioFormat *audio_format, int64_t *audio_pts, bool *error)
 893 {
 894         *error = false;
 895
 896         // Read packets until we have a frame or there are none left.
 897         bool frame_finished = false;
 898         AVFrameWithDeleter audio_avframe = av_frame_alloc_unique();
 899         AVFrameWithDeleter video_avframe = av_frame_alloc_unique();
 900         bool eof = false;
 901         *audio_pts = -1;
 902         bool has_audio = false;
 903         do {
 904                 AVPacket pkt;
 905                 unique_ptr<AVPacket, decltype(av_packet_unref)*> pkt_cleanup(
 906                         &pkt, av_packet_unref);
 907                 av_init_packet(&pkt);
 908                 pkt.data = nullptr;
 909                 pkt.size = 0;
 910                 if (av_read_frame(format_ctx, &pkt) == 0) {
 911                         if (pkt.stream_index == audio_stream_index && audio_callback != nullptr) {
 912                                 audio_callback(&pkt, format_ctx->streams[audio_stream_index]->time_base);
 913                         }
 914                         if (pkt.stream_index == video_stream_index && video_callback != nullptr) {
 915                                 video_callback(&pkt, format_ctx->streams[video_stream_index]->time_base);
 916                         }
 917                         if (pkt.stream_index == video_stream_index && global_flags.transcode_video) {
 918                                 if (avcodec_send_packet(video_codec_ctx, &pkt) < 0) {
 919                                         fprintf(stderr, "%s: Cannot send packet to video codec.\n", pathname.c_str());
 920                                         *error = true;
 921                                         return AVFrameWithDeleter(nullptr);
 922                                 }
 923                         } else if (pkt.stream_index == audio_stream_index && global_flags.transcode_audio) {
 924                                 has_audio = true;
 925                                 if (avcodec_send_packet(audio_codec_ctx, &pkt) < 0) {
 926                                         fprintf(stderr, "%s: Cannot send packet to audio codec.\n", pathname.c_str());
 927                                         *error = true;
 928                                         return AVFrameWithDeleter(nullptr);
 929                                 }
 930                         } else if (pkt.stream_index == subtitle_stream_index) {
 931                                 last_subtitle = string(reinterpret_cast<const char *>(pkt.data), pkt.size);
 932                                 has_last_subtitle = true;
 933                         }
 934                 } else {
 935                         eof = true;  // Or error, but ignore that for the time being.
 936                 }
 937
 938                 // Decode audio, if any.
 939                 if (has_audio) {
 940                         for ( ;; ) {
 941                                 int err = avcodec_receive_frame(audio_codec_ctx, audio_avframe.get());
 942                                 if (err == 0) {
 943                                         if (*audio_pts == -1) {
 944                                                 *audio_pts = audio_avframe->pts;
 945                                         }
 946                                         convert_audio(audio_avframe.get(), audio_frame, audio_format);
 947                                 } else if (err == AVERROR(EAGAIN)) {
 948                                         break;
 949                                 } else {
 950                                         fprintf(stderr, "%s: Cannot receive frame from audio codec.\n", pathname.c_str());
 951                                         *error = true;
 952                                         return AVFrameWithDeleter(nullptr);
 953                                 }
 954                         }
 955                 }
 956
 957                 // Decode video, if we have a frame.
 958                 int err = avcodec_receive_frame(video_codec_ctx, video_avframe.get());
 959                 if (err == 0) {
 960                         if (video_avframe->format == AV_PIX_FMT_VAAPI ||
 961                             video_avframe->format == AV_PIX_FMT_VDPAU) {
 962                                 // Get the frame down to the CPU. (TODO: See if we can keep it
 963                                 // on the GPU all the way, since it will be going up again later.
 964                                 // However, this only works if the OpenGL GPU is the same one.)
 965                                 AVFrameWithDeleter sw_frame = av_frame_alloc_unique();
 966                                 int err = av_hwframe_transfer_data(sw_frame.get(), video_avframe.get(), 0);
 967                                 if (err != 0) {
 968                                         fprintf(stderr, "%s: Cannot transfer hardware video frame to software.\n", pathname.c_str());
 969                                         *error = true;
 970                                         return AVFrameWithDeleter(nullptr);
 971                                 }
 972                                 sw_frame->pts = video_avframe->pts;
 973                                 sw_frame->pkt_duration = video_avframe->pkt_duration;
 974                                 video_avframe = move(sw_frame);
 975                         }
 976                         frame_finished = true;
 977                         break;
 978                 } else if (err != AVERROR(EAGAIN)) {
 979                         fprintf(stderr, "%s: Cannot receive frame from video codec.\n", pathname.c_str());
 980                         *error = true;
 981                         return AVFrameWithDeleter(nullptr);
 982                 }
 983         } while (!eof);
 984
 985         if (frame_finished)
 986                 return video_avframe;
 987         else
 988                 return AVFrameWithDeleter(nullptr);
 989 }
 990
 991 void FFmpegCapture::convert_audio(const AVFrame *audio_avframe, FrameAllocator::Frame *audio_frame, AudioFormat *audio_format)
 992 {
 993         // Decide on a format. If there already is one in this audio frame,
 994         // we're pretty much forced to use it. If not, we try to find an exact match.
 995         // If that still doesn't work, we default to 32-bit signed chunked
 996         // (float would be nice, but there's really no way to signal that yet).
 997         AVSampleFormat dst_format;
 998         if (audio_format->bits_per_sample == 0) {
 999                 switch (audio_avframe->format) {
1000                 case AV_SAMPLE_FMT_S16:
1001                 case AV_SAMPLE_FMT_S16P:
1002                         audio_format->bits_per_sample = 16;
1003                         dst_format = AV_SAMPLE_FMT_S16;
1004                         break;
1005                 case AV_SAMPLE_FMT_S32:
1006                 case AV_SAMPLE_FMT_S32P:
1007                 default:
1008                         audio_format->bits_per_sample = 32;
1009                         dst_format = AV_SAMPLE_FMT_S32;
1010                         break;
1011                 }
1012         } else if (audio_format->bits_per_sample == 16) {
1013                 dst_format = AV_SAMPLE_FMT_S16;
1014         } else if (audio_format->bits_per_sample == 32) {
1015                 dst_format = AV_SAMPLE_FMT_S32;
1016         } else {
1017                 assert(false);
1018         }
1019         audio_format->num_channels = 2;
1020
1021         int64_t channel_layout = audio_avframe->channel_layout;
1022         if (channel_layout == 0) {
1023                 channel_layout = av_get_default_channel_layout(audio_avframe->channels);
1024         }
1025
1026         if (resampler == nullptr ||
1027             audio_avframe->format != last_src_format ||
1028             dst_format != last_dst_format ||
1029             channel_layout != last_channel_layout ||
1030             audio_avframe->sample_rate != last_sample_rate) {
1031                 swr_free(&resampler);
1032                 resampler = swr_alloc_set_opts(nullptr,
1033                                                /*out_ch_layout=*/AV_CH_LAYOUT_STEREO_DOWNMIX,
1034                                                /*out_sample_fmt=*/dst_format,
1035                                                /*out_sample_rate=*/OUTPUT_FREQUENCY,
1036                                                /*in_ch_layout=*/channel_layout,
1037                                                /*in_sample_fmt=*/AVSampleFormat(audio_avframe->format),
1038                                                /*in_sample_rate=*/audio_avframe->sample_rate,
1039                                                /*log_offset=*/0,
1040                                                /*log_ctx=*/nullptr);
1041
1042                 if (resampler == nullptr) {
1043                         fprintf(stderr, "Allocating resampler failed.\n");
1044                         abort();
1045                 }
1046
1047                 if (swr_init(resampler) < 0) {
1048                         fprintf(stderr, "Could not open resample context.\n");
1049                         abort();
1050                 }
1051
1052                 last_src_format = AVSampleFormat(audio_avframe->format);
1053                 last_dst_format = dst_format;
1054                 last_channel_layout = channel_layout;
1055                 last_sample_rate = audio_avframe->sample_rate;
1056         }
1057
1058         size_t bytes_per_sample = (audio_format->bits_per_sample / 8) * 2;
1059         size_t num_samples_room = (audio_frame->size - audio_frame->len) / bytes_per_sample;
1060
1061         uint8_t *data = audio_frame->data + audio_frame->len;
1062         int out_samples = swr_convert(resampler, &data, num_samples_room,
1063                 const_cast<const uint8_t **>(audio_avframe->data), audio_avframe->nb_samples);
1064         if (out_samples < 0) {
1065                 fprintf(stderr, "Audio conversion failed.\n");
1066                 abort();
1067         }
1068
1069         audio_frame->len += out_samples * bytes_per_sample;
1070 }
1071
1072 VideoFormat FFmpegCapture::construct_video_format(const AVFrame *frame, AVRational video_timebase)
1073 {
1074         VideoFormat video_format;
1075         video_format.width = frame_width(frame);
1076         video_format.height = frame_height(frame);
1077         if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
1078                 video_format.stride = frame_width(frame) * 4;
1079         } else if (pixel_format == FFmpegCapture::PixelFormat_NV12) {
1080                 video_format.stride = frame_width(frame);
1081         } else {
1082                 assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
1083                 video_format.stride = frame_width(frame);
1084         }
1085         video_format.frame_rate_nom = video_timebase.den;
1086         video_format.frame_rate_den = frame->pkt_duration * video_timebase.num;
1087         video_format.has_signal = true;
1088         video_format.is_connected = true;
1089         return video_format;
1090 }
1091
1092 UniqueFrame FFmpegCapture::make_video_frame(const AVFrame *frame, const string &pathname, bool *error)
1093 {
1094         *error = false;
1095
1096         UniqueFrame video_frame(video_frame_allocator->alloc_frame());
1097         if (video_frame->data == nullptr) {
1098                 return video_frame;
1099         }
1100
1101         if (sws_ctx == nullptr ||
1102             sws_last_width != frame->width ||
1103             sws_last_height != frame->height ||
1104             sws_last_src_format != frame->format) {
1105                 sws_dst_format = decide_dst_format(AVPixelFormat(frame->format), pixel_format);
1106                 sws_ctx.reset(
1107                         sws_getContext(frame->width, frame->height, AVPixelFormat(frame->format),
1108                                 frame_width(frame), frame_height(frame), sws_dst_format,
1109                                 SWS_BICUBIC, nullptr, nullptr, nullptr));
1110                 sws_last_width = frame->width;
1111                 sws_last_height = frame->height;
1112                 sws_last_src_format = frame->format;
1113         }
1114         if (sws_ctx == nullptr) {
1115                 fprintf(stderr, "%s: Could not create scaler context\n", pathname.c_str());
1116                 *error = true;
1117                 return video_frame;
1118         }
1119
1120         uint8_t *pic_data[4] = { nullptr, nullptr, nullptr, nullptr };
1121         int linesizes[4] = { 0, 0, 0, 0 };
1122         if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
1123                 pic_data[0] = video_frame->data;
1124                 linesizes[0] = frame_width(frame) * 4;
1125                 video_frame->len = (frame_width(frame) * 4) * frame_height(frame);
1126         } else if (pixel_format == PixelFormat_NV12) {
1127                 pic_data[0] = video_frame->data;
1128                 linesizes[0] = frame_width(frame);
1129
1130                 pic_data[1] = pic_data[0] + frame_width(frame) * frame_height(frame);
1131                 linesizes[1] = frame_width(frame);
1132
1133                 video_frame->len = (frame_width(frame) * 2) * frame_height(frame);
1134
1135                 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(sws_dst_format);
1136                 current_frame_ycbcr_format = decode_ycbcr_format(desc, frame, is_mjpeg, &last_colorspace, &last_chroma_location);
1137         } else {
1138                 assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
1139                 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(sws_dst_format);
1140
1141                 int chroma_width = AV_CEIL_RSHIFT(int(frame_width(frame)), desc->log2_chroma_w);
1142                 int chroma_height = AV_CEIL_RSHIFT(int(frame_height(frame)), desc->log2_chroma_h);
1143
1144                 pic_data[0] = video_frame->data;
1145                 linesizes[0] = frame_width(frame);
1146
1147                 pic_data[1] = pic_data[0] + frame_width(frame) * frame_height(frame);
1148                 linesizes[1] = chroma_width;
1149
1150                 pic_data[2] = pic_data[1] + chroma_width * chroma_height;
1151                 linesizes[2] = chroma_width;
1152
1153                 video_frame->len = frame_width(frame) * frame_height(frame) + 2 * chroma_width * chroma_height;
1154
1155                 current_frame_ycbcr_format = decode_ycbcr_format(desc, frame, is_mjpeg, &last_colorspace, &last_chroma_location);
1156         }
1157
1158         // FIXME: Currently, if the video is too high-res for one of the allocated
1159         // frames, we simply refuse to scale it here to avoid crashes. It would be better
1160         // if we could somehow signal getting larger frames, especially as 4K is a thing now.
1161         if (video_frame->len > FRAME_SIZE) {
1162                 fprintf(stderr, "%s: Decoded frame would be larger than supported FRAME_SIZE (%zu > %u), not decoding.\n", pathname.c_str(), video_frame->len, FRAME_SIZE);
1163                 *error = true;
1164                 return video_frame;
1165         }
1166
1167         sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
1168
1169         return video_frame;
1170 }
1171
1172 int FFmpegCapture::interrupt_cb_thunk(void *opaque)
1173 {
1174         return reinterpret_cast<FFmpegCapture *>(opaque)->interrupt_cb();
1175 }
1176
1177 int FFmpegCapture::interrupt_cb()
1178 {
1179         // If ten seconds is gone without anything happening, we assume that
1180         // we are in a network stream that died and FFmpeg just didn't
1181         // pick it up (or perhaps it just hung, keeping the connection open).
1182         // Called back approximately every 100 ms if something is hanging,
1183         // so we get more than enough accuracy for our purposes.
1184         if (!should_interrupt && frame_timeout_valid &&
1185             duration<double>(steady_clock::now() - frame_timeout_started).count() >= 10.0) {
1186                 string filename_copy;
1187                 {
1188                         lock_guard<mutex> lock(filename_mu);
1189                         filename_copy = filename;
1190                 }
1191                 fprintf(stderr, "%s: No frame for more than 10 seconds, restarting stream.\n", filename.c_str());
1192                 should_interrupt = true;
1193         }
1194         return should_interrupt.load();
1195 }
1196
1197 unsigned FFmpegCapture::frame_width(const AVFrame *frame) const
1198 {
1199         if (width == 0) {
1200                 return frame->width;
1201         } else {
1202                 return width;
1203         }
1204 }
1205
1206 unsigned FFmpegCapture::frame_height(const AVFrame *frame) const
1207 {
1208         if (height == 0) {
1209                 return frame->height;
1210         } else {
1211                 return height;
1212         }
1213 }
1214
1215 #ifdef HAVE_SRT
1216 int FFmpegCapture::read_srt_thunk(void *opaque, uint8_t *buf, int buf_size)
1217 {
1218         return reinterpret_cast<FFmpegCapture *>(opaque)->read_srt(buf, buf_size);
1219 }
1220
1221 int FFmpegCapture::read_srt(uint8_t *buf, int buf_size)
1222 {
1223         SRT_MSGCTRL mc = srt_msgctrl_default;
1224         return srt_recvmsg2(srt_sock, reinterpret_cast<char *>(buf), buf_size, &mc);
1225 }
1226 #endif