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 "ref_counted_frame.h"
  40 #include "shared/timebase.h"
  41
  42 #ifdef HAVE_SRT
  43 #include <srt/srt.h>
  44 #endif
  45
  46 using namespace std;
  47 using namespace std::chrono;
  48 using namespace bmusb;
  49 using namespace movit;
  50 using namespace Eigen;
  51
  52 // Avoid deprecation warnings, but we don't want to drop FFmpeg 5.1 support just yet.
  53 #if LIBAVUTIL_VERSION_INT >= AV_VERSION_INT(57, 30, 100)
  54 #define pkt_duration duration
  55 #endif
  56
  57 namespace {
  58
  59 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)
  60 {
  61         const duration<double> pts((frame_pts - pts_origin) * double(video_timebase.num) / double(video_timebase.den));
  62         return origin + duration_cast<steady_clock::duration>(pts / rate);
  63 }
  64
  65 bool changed_since(const std::string &pathname, const timespec &ts)
  66 {
  67         if (ts.tv_sec < 0) {
  68                 return false;
  69         }
  70         struct stat buf;
  71         if (stat(pathname.c_str(), &buf) != 0) {
  72                 fprintf(stderr, "%s: Couldn't check for new version, leaving the old in place.\n", pathname.c_str());
  73                 return false;
  74         }
  75         return (buf.st_mtim.tv_sec != ts.tv_sec || buf.st_mtim.tv_nsec != ts.tv_nsec);
  76 }
  77
  78 bool is_full_range(const AVPixFmtDescriptor *desc)
  79 {
  80         // This is horrible, but there's no better way that I know of.
  81         return (strchr(desc->name, 'j') != nullptr);
  82 }
  83
  84 AVPixelFormat decide_dst_format(AVPixelFormat src_format, bmusb::PixelFormat dst_format_type)
  85 {
  86         if (dst_format_type == bmusb::PixelFormat_8BitBGRA) {
  87                 return AV_PIX_FMT_BGRA;
  88         }
  89         if (dst_format_type == FFmpegCapture::PixelFormat_NV12) {
  90                 return AV_PIX_FMT_NV12;
  91         }
  92
  93         assert(dst_format_type == bmusb::PixelFormat_8BitYCbCrPlanar);
  94
  95         // If this is a non-Y'CbCr format, just convert to 4:4:4 Y'CbCr
  96         // and be done with it. It's too strange to spend a lot of time on.
  97         // (Let's hope there's no alpha.)
  98         const AVPixFmtDescriptor *src_desc = av_pix_fmt_desc_get(src_format);
  99         if (src_desc == nullptr ||
 100             src_desc->nb_components != 3 ||
 101             (src_desc->flags & AV_PIX_FMT_FLAG_RGB)) {
 102                 return AV_PIX_FMT_YUV444P;
 103         }
 104
 105         // The best for us would be Cb and Cr together if possible,
 106         // but FFmpeg doesn't support that except in the special case of
 107         // NV12, so we need to go to planar even for the case of NV12.
 108         // Thus, look for the closest (but no worse) 8-bit planar Y'CbCr format
 109         // that matches in color range. (This will also include the case of
 110         // the source format already being acceptable.)
 111         bool src_full_range = is_full_range(src_desc);
 112         const char *best_format = "yuv444p";
 113         unsigned best_score = numeric_limits<unsigned>::max();
 114         for (const AVPixFmtDescriptor *desc = av_pix_fmt_desc_next(nullptr);
 115              desc;
 116              desc = av_pix_fmt_desc_next(desc)) {
 117                 // Find planar Y'CbCr formats only.
 118                 if (desc->nb_components != 3) continue;
 119                 if (desc->flags & AV_PIX_FMT_FLAG_RGB) continue;
 120                 if (!(desc->flags & AV_PIX_FMT_FLAG_PLANAR)) continue;
 121                 if (desc->comp[0].plane != 0 ||
 122                     desc->comp[1].plane != 1 ||
 123                     desc->comp[2].plane != 2) continue;
 124
 125                 // 8-bit formats only.
 126                 if (desc->flags & AV_PIX_FMT_FLAG_BE) continue;
 127                 if (desc->comp[0].depth != 8) continue;
 128
 129                 // Same or better chroma resolution only.
 130                 int chroma_w_diff = src_desc->log2_chroma_w - desc->log2_chroma_w;
 131                 int chroma_h_diff = src_desc->log2_chroma_h - desc->log2_chroma_h;
 132                 if (chroma_w_diff < 0 || chroma_h_diff < 0)
 133                         continue;
 134
 135                 // Matching full/limited range only.
 136                 if (is_full_range(desc) != src_full_range)
 137                         continue;
 138
 139                 // Pick something with as little excess chroma resolution as possible.
 140                 unsigned score = (1 << (chroma_w_diff)) << chroma_h_diff;
 141                 if (score < best_score) {
 142                         best_score = score;
 143                         best_format = desc->name;
 144                 }
 145         }
 146         return av_get_pix_fmt(best_format);
 147 }
 148
 149 YCbCrFormat decode_ycbcr_format(const AVPixFmtDescriptor *desc, const AVFrame *frame, bool is_mjpeg, AVColorSpace *last_colorspace, AVChromaLocation *last_chroma_location)
 150 {
 151         YCbCrFormat format;
 152         AVColorSpace colorspace = frame->colorspace;
 153         switch (colorspace) {
 154         case AVCOL_SPC_BT709:
 155                 format.luma_coefficients = YCBCR_REC_709;
 156                 break;
 157         case AVCOL_SPC_BT470BG:
 158         case AVCOL_SPC_SMPTE170M:
 159         case AVCOL_SPC_SMPTE240M:
 160                 format.luma_coefficients = YCBCR_REC_601;
 161                 break;
 162         case AVCOL_SPC_BT2020_NCL:
 163                 format.luma_coefficients = YCBCR_REC_2020;
 164                 break;
 165         case AVCOL_SPC_UNSPECIFIED:
 166                 format.luma_coefficients = (frame->height >= 720 ? YCBCR_REC_709 : YCBCR_REC_601);
 167                 break;
 168         default:
 169                 if (colorspace != *last_colorspace) {
 170                         fprintf(stderr, "Unknown Y'CbCr coefficient enum %d from FFmpeg; choosing Rec. 709.\n",
 171                                 colorspace);
 172                 }
 173                 format.luma_coefficients = YCBCR_REC_709;
 174                 break;
 175         }
 176         *last_colorspace = colorspace;
 177
 178         format.full_range = is_full_range(desc);
 179         format.num_levels = 1 << desc->comp[0].depth;
 180         format.chroma_subsampling_x = 1 << desc->log2_chroma_w;
 181         format.chroma_subsampling_y = 1 << desc->log2_chroma_h;
 182
 183         switch (frame->chroma_location) {
 184         case AVCHROMA_LOC_LEFT:
 185                 format.cb_x_position = 0.0;
 186                 format.cb_y_position = 0.5;
 187                 break;
 188         case AVCHROMA_LOC_CENTER:
 189                 format.cb_x_position = 0.5;
 190                 format.cb_y_position = 0.5;
 191                 break;
 192         case AVCHROMA_LOC_TOPLEFT:
 193                 format.cb_x_position = 0.0;
 194                 format.cb_y_position = 0.0;
 195                 break;
 196         case AVCHROMA_LOC_TOP:
 197                 format.cb_x_position = 0.5;
 198                 format.cb_y_position = 0.0;
 199                 break;
 200         case AVCHROMA_LOC_BOTTOMLEFT:
 201                 format.cb_x_position = 0.0;
 202                 format.cb_y_position = 1.0;
 203                 break;
 204         case AVCHROMA_LOC_BOTTOM:
 205                 format.cb_x_position = 0.5;
 206                 format.cb_y_position = 1.0;
 207                 break;
 208         default:
 209                 if (frame->chroma_location != *last_chroma_location) {
 210                         fprintf(stderr, "Unknown chroma location coefficient enum %d from FFmpeg; choosing center.\n",
 211                                 frame->chroma_location);
 212                 }
 213                 format.cb_x_position = 0.5;
 214                 format.cb_y_position = 0.5;
 215                 break;
 216         }
 217         *last_chroma_location = frame->chroma_location;
 218
 219         if (is_mjpeg && !format.full_range) {
 220                 // Limited-range MJPEG is only detected by FFmpeg whenever a special
 221                 // JPEG comment is set, which means that in practice, the stream is
 222                 // almost certainly generated by Futatabi. Override FFmpeg's forced
 223                 // MJPEG defaults (it disregards the values set in the mux) with what
 224                 // Futatabi sets.
 225                 format.luma_coefficients = YCBCR_REC_709;
 226                 format.cb_x_position = 0.0;
 227                 format.cb_y_position = 0.5;
 228         }
 229
 230         format.cr_x_position = format.cb_x_position;
 231         format.cr_y_position = format.cb_y_position;
 232         return format;
 233 }
 234
 235 RGBTriplet get_neutral_color(AVDictionary *metadata)
 236 {
 237         if (metadata == nullptr) {
 238                 return RGBTriplet(1.0f, 1.0f, 1.0f);
 239         }
 240         AVDictionaryEntry *entry = av_dict_get(metadata, "WhitePoint", nullptr, 0);
 241         if (entry == nullptr) {
 242                 return RGBTriplet(1.0f, 1.0f, 1.0f);
 243         }
 244
 245         unsigned x_nom, x_den, y_nom, y_den;
 246         if (sscanf(entry->value, " %u:%u , %u:%u", &x_nom, &x_den, &y_nom, &y_den) != 4) {
 247                 fprintf(stderr, "WARNING: Unable to parse white point '%s', using default white point\n", entry->value);
 248                 return RGBTriplet(1.0f, 1.0f, 1.0f);
 249         }
 250
 251         double x = double(x_nom) / x_den;
 252         double y = double(y_nom) / y_den;
 253         double z = 1.0 - x - y;
 254
 255         Matrix3d rgb_to_xyz_matrix = movit::ColorspaceConversionEffect::get_xyz_matrix(COLORSPACE_sRGB);
 256         Vector3d rgb = rgb_to_xyz_matrix.inverse() * Vector3d(x, y, z);
 257
 258         return RGBTriplet(rgb[0], rgb[1], rgb[2]);
 259 }
 260
 261 }  // namespace
 262
 263 FFmpegCapture::FFmpegCapture(const string &filename, unsigned width, unsigned height)
 264         : filename(filename), width(width), height(height), video_timebase{1, 1}
 265 {
 266         description = "Video: " + filename;
 267
 268         last_frame = steady_clock::now();
 269
 270         avformat_network_init();  // In case someone wants this.
 271 }
 272
 273 #ifdef HAVE_SRT
 274 FFmpegCapture::FFmpegCapture(int srt_sock, const string &stream_id)
 275         : srt_sock(srt_sock),
 276           width(0),  // Don't resize; SRT streams typically have stable resolution, and should behave much like regular cards in general.
 277           height(0),
 278           pixel_format(bmusb::PixelFormat_8BitYCbCrPlanar),
 279           video_timebase{1, 1}
 280 {
 281         if (stream_id.empty()) {
 282                 description = "SRT stream";
 283         } else {
 284                 description = stream_id;
 285         }
 286         play_as_fast_as_possible = true;
 287         play_once = true;
 288         last_frame = steady_clock::now();
 289 }
 290 #endif
 291
 292 FFmpegCapture::~FFmpegCapture()
 293 {
 294         if (has_dequeue_callbacks) {
 295                 dequeue_cleanup_callback();
 296         }
 297         swr_free(&resampler);
 298 #ifdef HAVE_SRT
 299         if (srt_sock != -1) {
 300                 srt_close(srt_sock);
 301         }
 302 #endif
 303 }
 304
 305 void FFmpegCapture::configure_card()
 306 {
 307         if (video_frame_allocator == nullptr) {
 308                 owned_video_frame_allocator.reset(new MallocFrameAllocator(FRAME_SIZE, NUM_QUEUED_VIDEO_FRAMES));
 309                 set_video_frame_allocator(owned_video_frame_allocator.get());
 310         }
 311         if (audio_frame_allocator == nullptr) {
 312                 // Audio can come out in pretty large chunks, so increase from the default 1 MB.
 313                 owned_audio_frame_allocator.reset(new MallocFrameAllocator(1 << 20, NUM_QUEUED_AUDIO_FRAMES));
 314                 set_audio_frame_allocator(owned_audio_frame_allocator.get());
 315         }
 316 }
 317
 318 void FFmpegCapture::start_bm_capture()
 319 {
 320         if (running) {
 321                 return;
 322         }
 323         running = true;
 324         producer_thread_should_quit.unquit();
 325         producer_thread = thread(&FFmpegCapture::producer_thread_func, this);
 326 }
 327
 328 void FFmpegCapture::stop_dequeue_thread()
 329 {
 330         if (!running) {
 331                 return;
 332         }
 333         running = false;
 334         producer_thread_should_quit.quit();
 335         producer_thread.join();
 336 }
 337
 338 std::map<uint32_t, VideoMode> FFmpegCapture::get_available_video_modes() const
 339 {
 340         // Note: This will never really be shown in the UI.
 341         VideoMode mode;
 342
 343         char buf[256];
 344         snprintf(buf, sizeof(buf), "%ux%u", sws_last_width, sws_last_height);
 345         mode.name = buf;
 346
 347         mode.autodetect = false;
 348         mode.width = sws_last_width;
 349         mode.height = sws_last_height;
 350         mode.frame_rate_num = 60;
 351         mode.frame_rate_den = 1;
 352         mode.interlaced = false;
 353
 354         return {{ 0, mode }};
 355 }
 356
 357 void FFmpegCapture::producer_thread_func()
 358 {
 359         char thread_name[16];
 360         snprintf(thread_name, sizeof(thread_name), "FFmpeg_C_%d", card_index);
 361         pthread_setname_np(pthread_self(), thread_name);
 362
 363         while (!producer_thread_should_quit.should_quit()) {
 364                 string filename_copy;
 365                 {
 366                         lock_guard<mutex> lock(filename_mu);
 367                         filename_copy = filename;
 368                 }
 369
 370                 string pathname;
 371                 if (srt_sock == -1) {
 372                         pathname = search_for_file(filename_copy);
 373                 } else {
 374                         pathname = description;
 375                 }
 376                 if (pathname.empty()) {
 377                         send_disconnected_frame();
 378                         if (play_once) {
 379                                 break;
 380                         }
 381                         producer_thread_should_quit.sleep_for(seconds(1));
 382                         fprintf(stderr, "%s not found, sleeping one second and trying again...\n", filename_copy.c_str());
 383                         continue;
 384                 }
 385                 should_interrupt = false;
 386                 if (!play_video(pathname)) {
 387                         // Error.
 388                         send_disconnected_frame();
 389                         if (play_once) {
 390                                 break;
 391                         }
 392                         fprintf(stderr, "Error when playing %s, sleeping one second and trying again...\n", pathname.c_str());
 393                         producer_thread_should_quit.sleep_for(seconds(1));
 394                         continue;
 395                 }
 396
 397                 if (play_once) {
 398                         send_disconnected_frame();
 399                         break;
 400                 }
 401
 402                 // Probably just EOF, will exit the loop above on next test.
 403         }
 404
 405         if (has_dequeue_callbacks) {
 406                 dequeue_cleanup_callback();
 407                 has_dequeue_callbacks = false;
 408         }
 409 }
 410
 411 void FFmpegCapture::send_disconnected_frame()
 412 {
 413         // Send an empty frame to signal that we have no signal anymore.
 414         FrameAllocator::Frame video_frame = video_frame_allocator->alloc_frame();
 415         size_t frame_width = width == 0 ? global_flags.width : width;
 416         size_t frame_height = height == 0 ? global_flags.height : height;
 417         if (video_frame.data) {
 418                 VideoFormat video_format;
 419                 video_format.width = frame_width;
 420                 video_format.height = frame_height;
 421                 video_format.frame_rate_nom = 60;
 422                 video_format.frame_rate_den = 1;
 423                 video_format.is_connected = false;
 424                 if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
 425                         video_format.stride = frame_width * 4;
 426                         video_frame.len = frame_width * frame_height * 4;
 427                         memset(video_frame.data, 0, video_frame.len);
 428                 } else {
 429                         video_format.stride = frame_width;
 430                         current_frame_ycbcr_format.luma_coefficients = YCBCR_REC_709;
 431                         current_frame_ycbcr_format.full_range = true;
 432                         current_frame_ycbcr_format.num_levels = 256;
 433                         current_frame_ycbcr_format.chroma_subsampling_x = 2;
 434                         current_frame_ycbcr_format.chroma_subsampling_y = 2;
 435                         current_frame_ycbcr_format.cb_x_position = 0.0f;
 436                         current_frame_ycbcr_format.cb_y_position = 0.0f;
 437                         current_frame_ycbcr_format.cr_x_position = 0.0f;
 438                         current_frame_ycbcr_format.cr_y_position = 0.0f;
 439                         video_frame.len = frame_width * frame_height * 2;
 440                         memset(video_frame.data, 0, frame_width * frame_height);
 441                         memset(video_frame.data + frame_width * frame_height, 128, frame_width * frame_height);  // Valid for both NV12 and planar.
 442                 }
 443
 444                 if (frame_callback != nullptr) {
 445                         frame_callback(-1, AVRational{1, TIMEBASE}, -1, AVRational{1, TIMEBASE}, timecode++,
 446                                 video_frame, /*video_offset=*/0, video_format,
 447                                 FrameAllocator::Frame(), /*audio_offset=*/0, AudioFormat());
 448                 }
 449                 last_frame_was_connected = false;
 450         }
 451
 452         if (play_once) {
 453                 disconnected = true;
 454                 if (card_disconnected_callback != nullptr) {
 455                         card_disconnected_callback();
 456                 }
 457         }
 458 }
 459
 460 template<AVHWDeviceType type>
 461 AVPixelFormat get_hw_format(AVCodecContext *ctx, const AVPixelFormat *fmt)
 462 {
 463         bool found_config_of_right_type = false;
 464         for (int i = 0;; ++i) {  // Termination condition inside loop.
 465                 const AVCodecHWConfig *config = avcodec_get_hw_config(ctx->codec, i);
 466                 if (config == nullptr) {  // End of list.
 467                         break;
 468                 }
 469                 if (!(config->methods & AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX) ||
 470                     config->device_type != type) {
 471                         // Not interesting for us.
 472                         continue;
 473                 }
 474
 475                 // We have a config of the right type, but does it actually support
 476                 // the pixel format we want? (Seemingly, FFmpeg's way of signaling errors
 477                 // is to just replace the pixel format with a software-decoded one,
 478                 // such as yuv420p.)
 479                 found_config_of_right_type = true;
 480                 for (const AVPixelFormat *fmt_ptr = fmt; *fmt_ptr != -1; ++fmt_ptr) {
 481                         if (config->pix_fmt == *fmt_ptr) {
 482                                 fprintf(stderr, "Initialized '%s' hardware decoding for codec '%s'.\n",
 483                                         av_hwdevice_get_type_name(type), ctx->codec->name);
 484                                 if (ctx->profile == FF_PROFILE_H264_BASELINE) {
 485                                         fprintf(stderr, "WARNING: Stream claims to be H.264 Baseline, which is generally poorly supported in hardware decoders.\n");
 486                                         fprintf(stderr, "         Consider encoding it as Constrained Baseline, Main or High instead.\n");
 487                                         fprintf(stderr, "         Decoding might fail and fall back to software.\n");
 488                                 }
 489                                 return config->pix_fmt;
 490                         }
 491                 }
 492                 fprintf(stderr, "Decoder '%s' supports only these pixel formats:", ctx->codec->name);
 493                 unordered_set<AVPixelFormat> seen;
 494                 for (const AVPixelFormat *fmt_ptr = fmt; *fmt_ptr != -1; ++fmt_ptr) {
 495                         if (!seen.count(*fmt_ptr)) {
 496                                 fprintf(stderr, " %s", av_get_pix_fmt_name(*fmt_ptr));
 497                                 seen.insert(*fmt_ptr);
 498                         }
 499                 }
 500                 fprintf(stderr, " (wanted %s for hardware acceleration)\n", av_get_pix_fmt_name(config->pix_fmt));
 501
 502         }
 503
 504         if (!found_config_of_right_type) {
 505                 fprintf(stderr, "Decoder '%s' does not support device type '%s'.\n", ctx->codec->name, av_hwdevice_get_type_name(type));
 506         }
 507
 508         // We found no VA-API formats, so take the first software format.
 509         for (const AVPixelFormat *fmt_ptr = fmt; *fmt_ptr != -1; ++fmt_ptr) {
 510                 if ((av_pix_fmt_desc_get(*fmt_ptr)->flags & AV_PIX_FMT_FLAG_HWACCEL) == 0) {
 511                         fprintf(stderr, "Falling back to software format %s.\n", av_get_pix_fmt_name(*fmt_ptr));
 512                         return *fmt_ptr;
 513                 }
 514         }
 515
 516         // Fallback: Just return anything. (Should never really happen.)
 517         return fmt[0];
 518 }
 519
 520 bool FFmpegCapture::play_video(const string &pathname)
 521 {
 522         // Note: Call before open, not after; otherwise, there's a race.
 523         // (There is now, too, but it tips the correct way. We could use fstat()
 524         // if we had the file descriptor.)
 525         timespec last_modified;
 526         struct stat buf;
 527         if (stat(pathname.c_str(), &buf) != 0) {
 528                 // Probably some sort of protocol, so can't stat.
 529                 last_modified.tv_sec = -1;
 530         } else {
 531                 last_modified = buf.st_mtim;
 532         }
 533         last_colorspace = static_cast<AVColorSpace>(-1);
 534         last_chroma_location = static_cast<AVChromaLocation>(-1);
 535
 536         AVFormatContextWithCloser format_ctx;
 537         if (srt_sock == -1) {
 538                 // Regular file (or stream).
 539                 frame_timeout_started = steady_clock::now();
 540                 frame_timeout_valid = true;
 541                 format_ctx = avformat_open_input_unique(pathname.c_str(), /*fmt=*/nullptr,
 542                         /*options=*/nullptr,
 543                         AVIOInterruptCB{ &FFmpegCapture::interrupt_cb_thunk, this });
 544                 frame_timeout_valid = false;
 545         } else {
 546 #ifdef HAVE_SRT
 547                 // SRT socket, already opened.
 548                 const AVInputFormat *mpegts_fmt = av_find_input_format("mpegts");
 549                 format_ctx = avformat_open_input_unique(&FFmpegCapture::read_srt_thunk, this,
 550                         mpegts_fmt, /*options=*/nullptr,
 551                         AVIOInterruptCB{ &FFmpegCapture::interrupt_cb_thunk, this });
 552 #else
 553                 assert(false);
 554 #endif
 555         }
 556         if (format_ctx == nullptr) {
 557                 fprintf(stderr, "%s: Error opening file\n", pathname.c_str());
 558                 return false;
 559         }
 560
 561         if (avformat_find_stream_info(format_ctx.get(), nullptr) < 0) {
 562                 fprintf(stderr, "%s: Error finding stream info\n", pathname.c_str());
 563                 return false;
 564         }
 565
 566         int video_stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_VIDEO);
 567         if (video_stream_index == -1) {
 568                 fprintf(stderr, "%s: No video stream found\n", pathname.c_str());
 569                 return false;
 570         }
 571
 572         int audio_stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_AUDIO);
 573         int subtitle_stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_SUBTITLE);
 574         has_last_subtitle = false;
 575
 576         // Open video decoder.
 577         const AVCodecParameters *video_codecpar = format_ctx->streams[video_stream_index]->codecpar;
 578         const AVCodec *video_codec = avcodec_find_decoder(video_codecpar->codec_id);
 579
 580         video_timebase = format_ctx->streams[video_stream_index]->time_base;
 581         AVCodecContextWithDeleter video_codec_ctx = avcodec_alloc_context3_unique(nullptr);
 582         if (avcodec_parameters_to_context(video_codec_ctx.get(), video_codecpar) < 0) {
 583                 fprintf(stderr, "%s: Cannot fill video codec parameters\n", pathname.c_str());
 584                 return false;
 585         }
 586         if (video_codec == nullptr) {
 587                 fprintf(stderr, "%s: Cannot find video decoder\n", pathname.c_str());
 588                 return false;
 589         }
 590
 591         // Seemingly, it's not too easy to make something that just initializes
 592         // “whatever goes”, so we don't get CUDA or VULKAN or whatever here
 593         // without enumerating through several different types.
 594         // VA-API and VDPAU will do for now. We prioritize VDPAU for the
 595         // simple reason that there's a VA-API-via-VDPAU emulation for NVidia
 596         // cards that seems to work, but just hangs when trying to transfer the frame.
 597         //
 598         // Note that we don't actually check codec support beforehand,
 599         // so if you have a low-end VDPAU device but a high-end VA-API device,
 600         // you lose out on the extra codec support from the latter.
 601         AVBufferRef *hw_device_ctx = nullptr;
 602         if (av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VDPAU, nullptr, nullptr, 0) >= 0) {
 603                 video_codec_ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
 604                 video_codec_ctx->get_format = get_hw_format<AV_HWDEVICE_TYPE_VDPAU>;
 605         } else if (av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VAAPI, nullptr, nullptr, 0) >= 0) {
 606                 video_codec_ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
 607                 video_codec_ctx->get_format = get_hw_format<AV_HWDEVICE_TYPE_VAAPI>;
 608         } else {
 609                 fprintf(stderr, "Failed to initialize VA-API or VDPAU for FFmpeg acceleration. Decoding video in software.\n");
 610         }
 611
 612         if (avcodec_open2(video_codec_ctx.get(), video_codec, nullptr) < 0) {
 613                 fprintf(stderr, "%s: Cannot open video decoder\n", pathname.c_str());
 614                 return false;
 615         }
 616         unique_ptr<AVCodecContext, decltype(avcodec_close)*> video_codec_ctx_cleanup(
 617                 video_codec_ctx.get(), avcodec_close);
 618
 619         // Used in decode_ycbcr_format().
 620         is_mjpeg = video_codecpar->codec_id == AV_CODEC_ID_MJPEG;
 621
 622         // Open audio decoder, if we have audio.
 623         AVCodecContextWithDeleter audio_codec_ctx;
 624         if (audio_stream_index != -1) {
 625                 audio_codec_ctx = avcodec_alloc_context3_unique(nullptr);
 626                 const AVCodecParameters *audio_codecpar = format_ctx->streams[audio_stream_index]->codecpar;
 627                 audio_timebase = format_ctx->streams[audio_stream_index]->time_base;
 628                 if (avcodec_parameters_to_context(audio_codec_ctx.get(), audio_codecpar) < 0) {
 629                         fprintf(stderr, "%s: Cannot fill audio codec parameters\n", pathname.c_str());
 630                         return false;
 631                 }
 632                 const AVCodec *audio_codec = avcodec_find_decoder(audio_codecpar->codec_id);
 633                 if (audio_codec == nullptr) {
 634                         fprintf(stderr, "%s: Cannot find audio decoder\n", pathname.c_str());
 635                         return false;
 636                 }
 637                 if (avcodec_open2(audio_codec_ctx.get(), audio_codec, nullptr) < 0) {
 638                         fprintf(stderr, "%s: Cannot open audio decoder\n", pathname.c_str());
 639                         return false;
 640                 }
 641         }
 642         unique_ptr<AVCodecContext, decltype(avcodec_close)*> audio_codec_ctx_cleanup(
 643                 audio_codec_ctx.get(), avcodec_close);
 644
 645         internal_rewind();
 646
 647         // Main loop.
 648         bool first_frame = true;
 649         int consecutive_errors = 0;
 650         while (!producer_thread_should_quit.should_quit()) {
 651                 if (process_queued_commands(format_ctx.get(), pathname, last_modified, /*rewound=*/nullptr)) {
 652                         return true;
 653                 }
 654                 if (should_interrupt.load()) {
 655                         // Check as a failsafe, so that we don't need to rely on avio if we don't have to.
 656                         return false;
 657                 }
 658                 UniqueFrame audio_frame = audio_frame_allocator->alloc_frame();
 659                 AudioFormat audio_format;
 660
 661                 int64_t audio_pts;
 662                 bool error;
 663                 frame_timeout_started = steady_clock::now();
 664                 frame_timeout_valid = true;
 665                 AVFrameWithDeleter frame = decode_frame(format_ctx.get(), video_codec_ctx.get(), audio_codec_ctx.get(),
 666                         pathname, video_stream_index, audio_stream_index, subtitle_stream_index, audio_frame.get(), &audio_format, &audio_pts, &error);
 667                 frame_timeout_valid = false;
 668                 if (should_interrupt.load()) {
 669                         // Abort no matter whether we got a frame or not.
 670                         return false;
 671                 }
 672                 if (error) {
 673                         if (++consecutive_errors >= 100) {
 674                                 fprintf(stderr, "More than 100 consecutive error video frames, aborting playback.\n");
 675                                 return false;
 676                         } else {
 677                                 continue;
 678                         }
 679                 } else {
 680                         consecutive_errors = 0;
 681                 }
 682                 if (frame == nullptr) {
 683                         // EOF. Loop back to the start if we can.
 684                         if (format_ctx->pb != nullptr && format_ctx->pb->seekable == 0) {
 685                                 // Not seekable (but seemingly, sometimes av_seek_frame() would return 0 anyway,
 686                                 // so don't try).
 687                                 return true;
 688                         }
 689                         if (av_seek_frame(format_ctx.get(), /*stream_index=*/-1, /*timestamp=*/0, /*flags=*/0) < 0) {
 690                                 fprintf(stderr, "%s: Rewind failed, not looping.\n", pathname.c_str());
 691                                 return true;
 692                         }
 693                         if (video_codec_ctx != nullptr) {
 694                                 avcodec_flush_buffers(video_codec_ctx.get());
 695                         }
 696                         if (audio_codec_ctx != nullptr) {
 697                                 avcodec_flush_buffers(audio_codec_ctx.get());
 698                         }
 699                         // If the file has changed since last time, return to get it reloaded.
 700                         // Note that depending on how you move the file into place, you might
 701                         // end up corrupting the one you're already playing, so this path
 702                         // might not trigger.
 703                         if (changed_since(pathname, last_modified)) {
 704                                 return true;
 705                         }
 706                         internal_rewind();
 707                         continue;
 708                 }
 709
 710                 VideoFormat video_format = construct_video_format(frame.get(), video_timebase);
 711                 if (video_format.frame_rate_nom == 0 || video_format.frame_rate_den == 0) {
 712                         // Invalid frame rate; try constructing it from the previous frame length.
 713                         // (This is especially important if we are the master card, for SRT,
 714                         // since it affects audio. Not all senders have good timebases
 715                         // (e.g., Larix rounds first to timebase 1000 and then multiplies by
 716                         // 90 from there, it seems), but it's much better to have an oscillating
 717                         // value than just locking at 60.
 718                         if (last_pts != 0 && frame->pts > last_pts) {
 719                                 int64_t pts_diff = frame->pts - last_pts;
 720                                 video_format.frame_rate_nom = video_timebase.den;
 721                                 video_format.frame_rate_den = video_timebase.num * pts_diff;
 722                         } else {
 723                                 video_format.frame_rate_nom = 60;
 724                                 video_format.frame_rate_den = 1;
 725                         }
 726                 }
 727                 UniqueFrame video_frame = make_video_frame(frame.get(), pathname, &error);
 728                 if (error) {
 729                         return false;
 730                 }
 731
 732                 for ( ;; ) {
 733                         if (last_pts == 0 && pts_origin == 0) {
 734                                 pts_origin = frame->pts;
 735                         }
 736                         steady_clock::time_point now = steady_clock::now();
 737                         if (play_as_fast_as_possible) {
 738                                 video_frame->received_timestamp = now;
 739                                 audio_frame->received_timestamp = now;
 740                                 next_frame_start = now;
 741                         } else {
 742                                 next_frame_start = compute_frame_start(frame->pts, pts_origin, video_timebase, start, rate);
 743                                 if (first_frame && last_frame_was_connected) {
 744                                         // If reconnect took more than one second, this is probably a live feed,
 745                                         // and we should reset the resampler. (Or the rate is really, really low,
 746                                         // in which case a reset on the first frame is fine anyway.)
 747                                         if (duration<double>(next_frame_start - last_frame).count() >= 1.0) {
 748                                                 last_frame_was_connected = false;
 749                                         }
 750                                 }
 751                                 video_frame->received_timestamp = next_frame_start;
 752
 753                                 // The easiest way to get all the rate conversions etc. right is to move the
 754                                 // audio PTS into the video PTS timebase and go from there. (We'll get some
 755                                 // rounding issues, but they should not be a big problem.)
 756                                 int64_t audio_pts_as_video_pts = av_rescale_q(audio_pts, audio_timebase, video_timebase);
 757                                 audio_frame->received_timestamp = compute_frame_start(audio_pts_as_video_pts, pts_origin, video_timebase, start, rate);
 758
 759                                 if (audio_frame->len != 0) {
 760                                         // The received timestamps in Nageru are measured after we've just received the frame.
 761                                         // However, pts (especially audio pts) is at the _beginning_ of the frame.
 762                                         // If we have locked audio, the distinction doesn't really matter, as pts is
 763                                         // on a relative scale and a fixed offset is fine. But if we don't, we will have
 764                                         // a different number of samples each time, which will cause huge audio jitter
 765                                         // and throw off the resampler.
 766                                         //
 767                                         // In a sense, we should have compensated by adding the frame and audio lengths
 768                                         // to video_frame->received_timestamp and audio_frame->received_timestamp respectively,
 769                                         // but that would mean extra waiting in sleep_until(). All we need is that they
 770                                         // are correct relative to each other, though (and to the other frames we send),
 771                                         // so just align the end of the audio frame, and we're fine.
 772                                         size_t num_samples = (audio_frame->len * 8) / audio_format.bits_per_sample / audio_format.num_channels;
 773                                         double offset = double(num_samples) / OUTPUT_FREQUENCY -
 774                                                 double(video_format.frame_rate_den) / video_format.frame_rate_nom;
 775                                         audio_frame->received_timestamp += duration_cast<steady_clock::duration>(duration<double>(offset));
 776                                 }
 777
 778                                 if (duration<double>(now - next_frame_start).count() >= 0.1) {
 779                                         // If we don't have enough CPU to keep up, or if we have a live stream
 780                                         // where the initial origin was somehow wrong, we could be behind indefinitely.
 781                                         // In particular, this will give the audio resampler problems as it tries
 782                                         // to speed up to reduce the delay, hitting the low end of the buffer every time.
 783                                         fprintf(stderr, "%s: Playback %.0f ms behind, resetting time scale\n",
 784                                                 pathname.c_str(),
 785                                                 1e3 * duration<double>(now - next_frame_start).count());
 786                                         pts_origin = frame->pts;
 787                                         start = next_frame_start = now;
 788                                         timecode += TYPICAL_FPS * 2 + 1;
 789                                 }
 790                         }
 791                         bool finished_wakeup;
 792                         if (play_as_fast_as_possible) {
 793                                 finished_wakeup = !producer_thread_should_quit.should_quit();
 794                         } else {
 795                                 finished_wakeup = producer_thread_should_quit.sleep_until(next_frame_start);
 796                         }
 797                         if (finished_wakeup) {
 798                                 if (audio_frame->len > 0) {
 799                                         assert(audio_pts != -1);
 800                                 }
 801                                 if (!last_frame_was_connected) {
 802                                         // We're recovering from an error (or really slow load, see above).
 803                                         // Make sure to get the audio resampler reset. (This is a hack;
 804                                         // ideally, the frame callback should just accept a way to signal
 805                                         // audio discontinuity.)
 806                                         timecode += TYPICAL_FPS * 2 + 1;
 807                                 }
 808                                 last_neutral_color = get_neutral_color(frame->metadata);
 809                                 if (frame_callback != nullptr) {
 810                                         frame_callback(frame->pts, video_timebase, audio_pts, audio_timebase, timecode++,
 811                                                 video_frame.get_and_release(), 0, video_format,
 812                                                 audio_frame.get_and_release(), 0, audio_format);
 813                                 }
 814                                 first_frame = false;
 815                                 last_frame = steady_clock::now();
 816                                 last_frame_was_connected = true;
 817                                 break;
 818                         } else {
 819                                 if (producer_thread_should_quit.should_quit()) break;
 820
 821                                 bool rewound = false;
 822                                 if (process_queued_commands(format_ctx.get(), pathname, last_modified, &rewound)) {
 823                                         return true;
 824                                 }
 825                                 // If we just rewound, drop this frame on the floor and be done.
 826                                 if (rewound) {
 827                                         break;
 828                                 }
 829                                 // OK, we didn't, so probably a rate change. Recalculate next_frame_start,
 830                                 // but if it's now in the past, we'll reset the origin, so that we don't
 831                                 // generate a huge backlog of frames that we need to run through quickly.
 832                                 next_frame_start = compute_frame_start(frame->pts, pts_origin, video_timebase, start, rate);
 833                                 steady_clock::time_point now = steady_clock::now();
 834                                 if (next_frame_start < now) {
 835                                         pts_origin = frame->pts;
 836                                         start = next_frame_start = now;
 837                                 }
 838                         }
 839                 }
 840                 last_pts = frame->pts;
 841         }
 842         return true;
 843 }
 844
 845 void FFmpegCapture::internal_rewind()
 846 {
 847         pts_origin = last_pts = 0;
 848         start = next_frame_start = steady_clock::now();
 849 }
 850
 851 bool FFmpegCapture::process_queued_commands(AVFormatContext *format_ctx, const std::string &pathname, timespec last_modified, bool *rewound)
 852 {
 853         // Process any queued commands from other threads.
 854         vector<QueuedCommand> commands;
 855         {
 856                 lock_guard<mutex> lock(queue_mu);
 857                 swap(commands, command_queue);
 858         }
 859         for (const QueuedCommand &cmd : commands) {
 860                 switch (cmd.command) {
 861                 case QueuedCommand::REWIND:
 862                         if (av_seek_frame(format_ctx, /*stream_index=*/-1, /*timestamp=*/0, /*flags=*/0) < 0) {
 863                                 fprintf(stderr, "%s: Rewind failed, stopping play.\n", pathname.c_str());
 864                         }
 865                         // If the file has changed since last time, return to get it reloaded.
 866                         // Note that depending on how you move the file into place, you might
 867                         // end up corrupting the one you're already playing, so this path
 868                         // might not trigger.
 869                         if (changed_since(pathname, last_modified)) {
 870                                 return true;
 871                         }
 872                         internal_rewind();
 873                         if (rewound != nullptr) {
 874                                 *rewound = true;
 875                         }
 876                         break;
 877
 878                 case QueuedCommand::CHANGE_RATE:
 879                         // Change the origin to the last played frame.
 880                         start = compute_frame_start(last_pts, pts_origin, video_timebase, start, rate);
 881                         pts_origin = last_pts;
 882                         rate = cmd.new_rate;
 883                         play_as_fast_as_possible = (rate >= 10.0);
 884                         break;
 885                 }
 886         }
 887         return false;
 888 }
 889
 890 namespace {
 891
 892 }  // namespace
 893
 894 AVFrameWithDeleter FFmpegCapture::decode_frame(AVFormatContext *format_ctx, AVCodecContext *video_codec_ctx, AVCodecContext *audio_codec_ctx,
 895         const std::string &pathname, int video_stream_index, int audio_stream_index, int subtitle_stream_index,
 896         FrameAllocator::Frame *audio_frame, AudioFormat *audio_format, int64_t *audio_pts, bool *error)
 897 {
 898         *error = false;
 899
 900         // Read packets until we have a frame or there are none left.
 901         bool frame_finished = false;
 902         AVFrameWithDeleter audio_avframe = av_frame_alloc_unique();
 903         AVFrameWithDeleter video_avframe = av_frame_alloc_unique();
 904         bool eof = false;
 905         *audio_pts = -1;
 906         bool has_audio = false;
 907         do {
 908                 AVPacketWithDeleter pkt = av_packet_alloc_unique();
 909                 pkt->data = nullptr;
 910                 pkt->size = 0;
 911                 if (av_read_frame(format_ctx, pkt.get()) == 0) {
 912                         if (pkt->stream_index == audio_stream_index && audio_callback != nullptr) {
 913                                 audio_callback(pkt.get(), format_ctx->streams[audio_stream_index]->time_base);
 914                         }
 915                         if (pkt->stream_index == video_stream_index && video_callback != nullptr) {
 916                                 video_callback(pkt.get(), format_ctx->streams[video_stream_index]->time_base);
 917                         }
 918                         if (pkt->stream_index == video_stream_index && global_flags.transcode_video) {
 919                                 if (avcodec_send_packet(video_codec_ctx, pkt.get()) < 0) {
 920                                         fprintf(stderr, "%s: Cannot send packet to video codec.\n", pathname.c_str());
 921                                         *error = true;
 922                                         return AVFrameWithDeleter(nullptr);
 923                                 }
 924                         } else if (pkt->stream_index == audio_stream_index && global_flags.transcode_audio) {
 925                                 has_audio = true;
 926                                 if (avcodec_send_packet(audio_codec_ctx, pkt.get()) < 0) {
 927                                         fprintf(stderr, "%s: Cannot send packet to audio codec.\n", pathname.c_str());
 928                                         *error = true;
 929                                         return AVFrameWithDeleter(nullptr);
 930                                 }
 931                         } else if (pkt->stream_index == subtitle_stream_index) {
 932                                 last_subtitle = string(reinterpret_cast<const char *>(pkt->data), pkt->size);
 933                                 has_last_subtitle = true;
 934                         }
 935                 } else {
 936                         eof = true;  // Or error, but ignore that for the time being.
 937                 }
 938
 939                 // Decode audio, if any.
 940                 if (has_audio) {
 941                         for ( ;; ) {
 942                                 int err = avcodec_receive_frame(audio_codec_ctx, audio_avframe.get());
 943                                 if (err == 0) {
 944                                         if (*audio_pts == -1) {
 945                                                 *audio_pts = audio_avframe->pts;
 946                                         }
 947                                         convert_audio(audio_avframe.get(), audio_frame, audio_format);
 948                                 } else if (err == AVERROR(EAGAIN)) {
 949                                         break;
 950                                 } else {
 951                                         fprintf(stderr, "%s: Cannot receive frame from audio codec.\n", pathname.c_str());
 952                                         *error = true;
 953                                         return AVFrameWithDeleter(nullptr);
 954                                 }
 955                         }
 956                 }
 957
 958                 // Decode video, if we have a frame.
 959                 int err = avcodec_receive_frame(video_codec_ctx, video_avframe.get());
 960                 if (err == 0) {
 961                         if (video_avframe->format == AV_PIX_FMT_VAAPI ||
 962                             video_avframe->format == AV_PIX_FMT_VDPAU) {
 963                                 // Get the frame down to the CPU. (TODO: See if we can keep it
 964                                 // on the GPU all the way, since it will be going up again later.
 965                                 // However, this only works if the OpenGL GPU is the same one.)
 966                                 AVFrameWithDeleter sw_frame = av_frame_alloc_unique();
 967                                 int err = av_hwframe_transfer_data(sw_frame.get(), video_avframe.get(), 0);
 968                                 if (err != 0) {
 969                                         fprintf(stderr, "%s: Cannot transfer hardware video frame to software.\n", pathname.c_str());
 970                                         *error = true;
 971                                         return AVFrameWithDeleter(nullptr);
 972                                 }
 973                                 sw_frame->pts = video_avframe->pts;
 974                                 sw_frame->pkt_duration = video_avframe->pkt_duration;
 975                                 video_avframe = move(sw_frame);
 976                         }
 977                         frame_finished = true;
 978                         break;
 979                 } else if (err != AVERROR(EAGAIN)) {
 980                         fprintf(stderr, "%s: Cannot receive frame from video codec.\n", pathname.c_str());
 981                         *error = true;
 982                         return AVFrameWithDeleter(nullptr);
 983                 }
 984         } while (!eof);
 985
 986         if (frame_finished)
 987                 return video_avframe;
 988         else
 989                 return AVFrameWithDeleter(nullptr);
 990 }
 991
 992 void FFmpegCapture::convert_audio(const AVFrame *audio_avframe, FrameAllocator::Frame *audio_frame, AudioFormat *audio_format)
 993 {
 994         // Decide on a format. If there already is one in this audio frame,
 995         // we're pretty much forced to use it. If not, we try to find an exact match.
 996         // If that still doesn't work, we default to 32-bit signed chunked
 997         // (float would be nice, but there's really no way to signal that yet).
 998         AVSampleFormat dst_format;
 999         if (audio_format->bits_per_sample == 0) {
1000                 switch (audio_avframe->format) {
1001                 case AV_SAMPLE_FMT_S16:
1002                 case AV_SAMPLE_FMT_S16P:
1003                         audio_format->bits_per_sample = 16;
1004                         dst_format = AV_SAMPLE_FMT_S16;
1005                         break;
1006                 case AV_SAMPLE_FMT_S32:
1007                 case AV_SAMPLE_FMT_S32P:
1008                 default:
1009                         audio_format->bits_per_sample = 32;
1010                         dst_format = AV_SAMPLE_FMT_S32;
1011                         break;
1012                 }
1013         } else if (audio_format->bits_per_sample == 16) {
1014                 dst_format = AV_SAMPLE_FMT_S16;
1015         } else if (audio_format->bits_per_sample == 32) {
1016                 dst_format = AV_SAMPLE_FMT_S32;
1017         } else {
1018                 assert(false);
1019         }
1020         audio_format->num_channels = 2;
1021
1022         AVChannelLayout channel_layout = audio_avframe->ch_layout;
1023         if (!av_channel_layout_check(&channel_layout) ||
1024             channel_layout.order == AV_CHANNEL_ORDER_UNSPEC) {
1025                 av_channel_layout_default(&channel_layout, audio_avframe->ch_layout.nb_channels);
1026         }
1027
1028         if (resampler == nullptr ||
1029             audio_avframe->format != last_src_format ||
1030             dst_format != last_dst_format ||
1031             av_channel_layout_compare(&channel_layout, &last_channel_layout) !=  0||
1032             audio_avframe->sample_rate != last_sample_rate) {
1033                 // TODO: When we get C++20, use AV_CHANNEL_LAYOUT_STEREO_DOWNMIX.
1034                 AVChannelLayout stereo_downmix;
1035                 stereo_downmix.order = AV_CHANNEL_ORDER_NATIVE;
1036                 stereo_downmix.nb_channels = 2;
1037                 stereo_downmix.u.mask = AV_CH_LAYOUT_STEREO_DOWNMIX;
1038
1039                 swr_free(&resampler);
1040                 resampler = nullptr;
1041                 int err = swr_alloc_set_opts2(&resampler,
1042                                               /*out_ch_layout=*/&stereo_downmix,
1043                                               /*out_sample_fmt=*/dst_format,
1044                                               /*out_sample_rate=*/OUTPUT_FREQUENCY,
1045                                               /*in_ch_layout=*/&channel_layout,
1046                                               /*in_sample_fmt=*/AVSampleFormat(audio_avframe->format),
1047                                               /*in_sample_rate=*/audio_avframe->sample_rate,
1048                                               /*log_offset=*/0,
1049                                               /*log_ctx=*/nullptr);
1050
1051                 if (err != 0 || resampler == nullptr) {
1052                         fprintf(stderr, "Allocating resampler failed.\n");
1053                         abort();
1054                 }
1055
1056                 if (swr_init(resampler) < 0) {
1057                         fprintf(stderr, "Could not open resample context.\n");
1058                         abort();
1059                 }
1060
1061                 last_src_format = AVSampleFormat(audio_avframe->format);
1062                 last_dst_format = dst_format;
1063                 last_channel_layout = channel_layout;
1064                 last_sample_rate = audio_avframe->sample_rate;
1065         }
1066
1067         size_t bytes_per_sample = (audio_format->bits_per_sample / 8) * 2;
1068         size_t num_samples_room = (audio_frame->size - audio_frame->len) / bytes_per_sample;
1069
1070         uint8_t *data = audio_frame->data + audio_frame->len;
1071         int out_samples = swr_convert(resampler, &data, num_samples_room,
1072                 const_cast<const uint8_t **>(audio_avframe->data), audio_avframe->nb_samples);
1073         if (out_samples < 0) {
1074                 fprintf(stderr, "Audio conversion failed.\n");
1075                 abort();
1076         }
1077
1078         audio_frame->len += out_samples * bytes_per_sample;
1079 }
1080
1081 VideoFormat FFmpegCapture::construct_video_format(const AVFrame *frame, AVRational video_timebase)
1082 {
1083         VideoFormat video_format;
1084         video_format.width = frame_width(frame);
1085         video_format.height = frame_height(frame);
1086         if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
1087                 video_format.stride = frame_width(frame) * 4;
1088         } else if (pixel_format == FFmpegCapture::PixelFormat_NV12) {
1089                 video_format.stride = frame_width(frame);
1090         } else {
1091                 assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
1092                 video_format.stride = frame_width(frame);
1093         }
1094         video_format.frame_rate_nom = video_timebase.den;
1095         video_format.frame_rate_den = frame->pkt_duration * video_timebase.num;
1096         video_format.has_signal = true;
1097         video_format.is_connected = true;
1098         return video_format;
1099 }
1100
1101 UniqueFrame FFmpegCapture::make_video_frame(const AVFrame *frame, const string &pathname, bool *error)
1102 {
1103         *error = false;
1104
1105         UniqueFrame video_frame(video_frame_allocator->alloc_frame());
1106         if (video_frame->data == nullptr) {
1107                 return video_frame;
1108         }
1109
1110         if (sws_ctx == nullptr ||
1111             sws_last_width != frame->width ||
1112             sws_last_height != frame->height ||
1113             sws_last_src_format != frame->format) {
1114                 sws_dst_format = decide_dst_format(AVPixelFormat(frame->format), pixel_format);
1115                 sws_ctx.reset(
1116                         sws_getContext(frame->width, frame->height, AVPixelFormat(frame->format),
1117                                 frame_width(frame), frame_height(frame), sws_dst_format,
1118                                 SWS_BICUBIC, nullptr, nullptr, nullptr));
1119                 sws_last_width = frame->width;
1120                 sws_last_height = frame->height;
1121                 sws_last_src_format = frame->format;
1122         }
1123         if (sws_ctx == nullptr) {
1124                 fprintf(stderr, "%s: Could not create scaler context\n", pathname.c_str());
1125                 *error = true;
1126                 return video_frame;
1127         }
1128
1129         uint8_t *pic_data[4] = { nullptr, nullptr, nullptr, nullptr };
1130         int linesizes[4] = { 0, 0, 0, 0 };
1131         if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
1132                 pic_data[0] = video_frame->data;
1133                 linesizes[0] = frame_width(frame) * 4;
1134                 video_frame->len = (frame_width(frame) * 4) * frame_height(frame);
1135         } else if (pixel_format == PixelFormat_NV12) {
1136                 pic_data[0] = video_frame->data;
1137                 linesizes[0] = frame_width(frame);
1138
1139                 pic_data[1] = pic_data[0] + frame_width(frame) * frame_height(frame);
1140                 linesizes[1] = frame_width(frame);
1141
1142                 video_frame->len = (frame_width(frame) * 2) * frame_height(frame);
1143
1144                 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(sws_dst_format);
1145                 current_frame_ycbcr_format = decode_ycbcr_format(desc, frame, is_mjpeg, &last_colorspace, &last_chroma_location);
1146         } else {
1147                 assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
1148                 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(sws_dst_format);
1149
1150                 int chroma_width = AV_CEIL_RSHIFT(int(frame_width(frame)), desc->log2_chroma_w);
1151                 int chroma_height = AV_CEIL_RSHIFT(int(frame_height(frame)), desc->log2_chroma_h);
1152
1153                 pic_data[0] = video_frame->data;
1154                 linesizes[0] = frame_width(frame);
1155
1156                 pic_data[1] = pic_data[0] + frame_width(frame) * frame_height(frame);
1157                 linesizes[1] = chroma_width;
1158
1159                 pic_data[2] = pic_data[1] + chroma_width * chroma_height;
1160                 linesizes[2] = chroma_width;
1161
1162                 video_frame->len = frame_width(frame) * frame_height(frame) + 2 * chroma_width * chroma_height;
1163
1164                 current_frame_ycbcr_format = decode_ycbcr_format(desc, frame, is_mjpeg, &last_colorspace, &last_chroma_location);
1165         }
1166
1167         // FIXME: Currently, if the video is too high-res for one of the allocated
1168         // frames, we simply refuse to scale it here to avoid crashes. It would be better
1169         // if we could somehow signal getting larger frames, especially as 4K is a thing now.
1170         if (video_frame->len > FRAME_SIZE) {
1171                 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);
1172                 *error = true;
1173                 return video_frame;
1174         }
1175
1176         sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
1177
1178         return video_frame;
1179 }
1180
1181 int FFmpegCapture::interrupt_cb_thunk(void *opaque)
1182 {
1183         return reinterpret_cast<FFmpegCapture *>(opaque)->interrupt_cb();
1184 }
1185
1186 int FFmpegCapture::interrupt_cb()
1187 {
1188         // If ten seconds is gone without anything happening, we assume that
1189         // we are in a network stream that died and FFmpeg just didn't
1190         // pick it up (or perhaps it just hung, keeping the connection open).
1191         // Called back approximately every 100 ms if something is hanging,
1192         // so we get more than enough accuracy for our purposes.
1193         if (!should_interrupt && frame_timeout_valid &&
1194             duration<double>(steady_clock::now() - frame_timeout_started).count() >= 10.0) {
1195                 string filename_copy;
1196                 {
1197                         lock_guard<mutex> lock(filename_mu);
1198                         filename_copy = filename;
1199                 }
1200                 fprintf(stderr, "%s: No frame for more than 10 seconds, restarting stream.\n", filename.c_str());
1201                 should_interrupt = true;
1202         }
1203         return should_interrupt.load();
1204 }
1205
1206 unsigned FFmpegCapture::frame_width(const AVFrame *frame) const
1207 {
1208         if (width == 0) {
1209                 return frame->width;
1210         } else {
1211                 return width;
1212         }
1213 }
1214
1215 unsigned FFmpegCapture::frame_height(const AVFrame *frame) const
1216 {
1217         if (height == 0) {
1218                 return frame->height;
1219         } else {
1220                 return height;
1221         }
1222 }
1223
1224 #ifdef HAVE_SRT
1225 int FFmpegCapture::read_srt_thunk(void *opaque, uint8_t *buf, int buf_size)
1226 {
1227         return reinterpret_cast<FFmpegCapture *>(opaque)->read_srt(buf, buf_size);
1228 }
1229
1230 int FFmpegCapture::read_srt(uint8_t *buf, int buf_size)
1231 {
1232         SRT_MSGCTRL mc = srt_msgctrl_default;
1233         return srt_recvmsg2(srt_sock, reinterpret_cast<char *>(buf), buf_size, &mc);
1234 }
1235 #endif