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