/// <summary>
/// Initializes a new instance of the <see cref="MediaComponent"/> class.
/// </summary>
/// <param name="container">The container.</param>
/// <param name="streamIndex">Index of the stream.</param>
/// <exception cref="System.ArgumentNullException">container</exception>
/// <exception cref="System.Exception"></exception>
protected MediaComponent(MediaContainer container, int streamIndex)
{
// NOTE: code largely based on stream_component_open
if (container == null)
{
throw new ArgumentNullException(nameof(container));
}
Container = container;
CodecContext = ffmpeg.avcodec_alloc_context3(null);
StreamIndex = streamIndex;
Stream = container.InputContext->streams[StreamIndex];
// Set codec options
var setCodecParamsResult = ffmpeg.avcodec_parameters_to_context(CodecContext, Stream->codecpar);
if (setCodecParamsResult < 0)
{
Container.Log(MediaLogMessageType.Warning, $"Could not set codec parameters. Error code: {setCodecParamsResult}");
}
// We set the packet timebase in the same timebase as the stream as opposed to the tpyical AV_TIME_BASE
ffmpeg.av_codec_set_pkt_timebase(CodecContext, Stream->time_base);
// Find the codec and set it.
var codec = ffmpeg.avcodec_find_decoder(Stream->codec->codec_id);
if (codec == null)
{
var errorMessage = $"Fatal error. Unable to find suitable decoder for {Stream->codec->codec_id.ToString()}";
Dispose();
throw new MediaContainerException(errorMessage);
}
CodecContext->codec_id = codec->id;
// Process the low res index option
var lowResIndex = ffmpeg.av_codec_get_max_lowres(codec);
if (Container.MediaOptions.EnableLowRes)
{
ffmpeg.av_codec_set_lowres(CodecContext, lowResIndex);
CodecContext->flags |= ffmpeg.CODEC_FLAG_EMU_EDGE;
}
else
{
lowResIndex = 0;
}
// Configure the codec context flags
if (Container.MediaOptions.EnableFastDecoding)
{
CodecContext->flags2 |= ffmpeg.AV_CODEC_FLAG2_FAST;
}
if ((codec->capabilities & ffmpeg.AV_CODEC_CAP_DR1) != 0)
{
CodecContext->flags |= ffmpeg.CODEC_FLAG_EMU_EDGE;
}
if ((codec->capabilities & ffmpeg.AV_CODEC_CAP_TRUNCATED) != 0)
{
CodecContext->flags |= ffmpeg.AV_CODEC_CAP_TRUNCATED;
}
if ((codec->capabilities & ffmpeg.CODEC_FLAG2_CHUNKS) != 0)
{
CodecContext->flags |= ffmpeg.CODEC_FLAG2_CHUNKS;
}
// Setup additional settings. The most important one is Threads -- Setting it to 1 decoding is very slow. Setting it to auto
// decoding is very fast in most scenarios.
var codecOptions = Container.MediaOptions.CodecOptions.FilterOptions(CodecContext->codec_id, Container.InputContext, Stream, codec);
if (codecOptions.HasKey(CodecOption.Threads) == false)
{
codecOptions[CodecOption.Threads] = "auto";
}
if (lowResIndex != 0)
{
codecOptions[CodecOption.LowRes] = lowResIndex.ToString(CultureInfo.InvariantCulture);
}
if (CodecContext->codec_type == AVMediaType.AVMEDIA_TYPE_VIDEO || CodecContext->codec_type == AVMediaType.AVMEDIA_TYPE_AUDIO)
{
codecOptions[CodecOption.RefCountedFrames] = 1.ToString(CultureInfo.InvariantCulture);
}
// Open the CodecContext
var codecOpenResult = 0;
fixed(AVDictionary **reference = &codecOptions.Pointer)
codecOpenResult = ffmpeg.avcodec_open2(CodecContext, codec, reference);
if (codecOpenResult < 0)
{
Dispose();
throw new MediaContainerException($"Unable to open codec. Error code {codecOpenResult}");
}
// If there are any codec options left over from passing them, it means they were not consumed
if (codecOptions.First() != null)
{
Container.Log(MediaLogMessageType.Warning, $"Codec Option '{codecOptions.First().Key}' not found.");
}
// Startup done. Set some options.
Stream->discard = AVDiscard.AVDISCARD_DEFAULT;
MediaType = (MediaType)CodecContext->codec_type;
// Compute the start time
if (Stream->start_time == Constants.AV_NOPTS)
{
StartTimeOffset = Container.MediaStartTimeOffset;
}
else
{
StartTimeOffset = Stream->start_time.ToTimeSpan(Stream->time_base);
}
// compute the duration
if (Stream->duration == Constants.AV_NOPTS || Stream->duration == 0)
{
Duration = Container.InputContext->duration.ToTimeSpan();
}
else
{
Duration = Stream->duration.ToTimeSpan(Stream->time_base);
}
CodecId = Stream->codec->codec_id;
CodecName = ffmpeg.avcodec_get_name(CodecId);
Bitrate = (int)Stream->codec->bit_rate;
Container.Log(MediaLogMessageType.Trace, $"{MediaType}: Start Offset: {StartTimeOffset.Debug()}; Duration: {Duration.Debug()}");
}