Function make_avcodec_encode_session

src/video.cpp:1511–1881

  }

  std::unique_ptr<avcodec_encode_session_t> make_avcodec_encode_session(
    platf::display_t *disp,
    const encoder_t &encoder,
    const config_t &config,
    int width,
    int height,
    std::unique_ptr<platf::avcodec_encode_device_t> encode_device
  ) {
    auto platform_formats = dynamic_cast<const encoder_platform_formats_avcodec *>(encoder.platform_formats.get());
    if (!platform_formats) {
      return nullptr;
    }

    bool hardware = platform_formats->avcodec_base_dev_type != AV_HWDEVICE_TYPE_NONE;

    auto &video_format = encoder.codec_from_config(config);
    if (!video_format[encoder_t::PASSED] || !disp->is_codec_supported(video_format.name, config)) {
      BOOST_LOG(error) << encoder.name << ": "sv << video_format.name << " mode not supported"sv;
      return nullptr;
    }

    if (config.dynamicRange && !video_format[encoder_t::DYNAMIC_RANGE]) {
      BOOST_LOG(error) << video_format.name << ": dynamic range not supported"sv;
      return nullptr;
    }

    if (config.chromaSamplingType == 1 && !video_format[encoder_t::YUV444]) {
      BOOST_LOG(error) << video_format.name << ": YUV 4:4:4 not supported"sv;
      return nullptr;
    }

    auto codec = avcodec_find_encoder_by_name(video_format.name.c_str());
    if (!codec) {
      BOOST_LOG(error) << "Couldn't open ["sv << video_format.name << ']';

      return nullptr;
    }

    auto colorspace = encode_device->colorspace;
    auto sw_fmt = (colorspace.bit_depth == 8 && config.chromaSamplingType == 0)  ? platform_formats->avcodec_pix_fmt_8bit :
                  (colorspace.bit_depth == 8 && config.chromaSamplingType == 1)  ? platform_formats->avcodec_pix_fmt_yuv444_8bit :
                  (colorspace.bit_depth == 10 && config.chromaSamplingType == 0) ? platform_formats->avcodec_pix_fmt_10bit :
                  (colorspace.bit_depth == 10 && config.chromaSamplingType == 1) ? platform_formats->avcodec_pix_fmt_yuv444_10bit :
                                                                                   AV_PIX_FMT_NONE;

    // Allow up to 1 retry to apply the set of fallback options.
    //
    // Note: If we later end up needing multiple sets of
    // fallback options, we may need to allow more retries
    // to try applying each set.
    avcodec_ctx_t ctx;
    for (int retries = 0; retries < 2; retries++) {
      ctx.reset(avcodec_alloc_context3(codec));
      ctx->width = config.width;
      ctx->height = config.height;
      ctx->time_base = AVRational {1, config.framerate};
      ctx->framerate = AVRational {config.framerate, 1};