private void AddOutputStreams(Uri source, MediaMuxer muxer, out AVStream *vidOutStream,
out AVStream *audioOutStream, out IDictionary <MediaStreamType, int> streamMap)
{
vidOutStream = audioOutStream = null;
using var audioDecoder = new MediaDecoder(source, HardwareDevice);
using var videoDecoder = new MediaDecoder(source, HardwareDevice);
var hasAudio = audioDecoder.SelectStream(AVMediaType.AVMEDIA_TYPE_AUDIO);
var hasVideo = videoDecoder.SelectStream(AVMediaType.AVMEDIA_TYPE_VIDEO);
var streamIndex = 0;
streamMap = new Dictionary <MediaStreamType, int>();
var decoders = new List <MediaDecoder>();
if (hasVideo)
{
decoders.Add(videoDecoder);
}
if (hasAudio)
{
decoders.Add(audioDecoder);
}
foreach (var decoder in decoders)
{
var targetCodec = decoder.CodecId;
var decoderCodec = decoder.CodecContext;
AVStream *stream;
var encoder = ffmpeg.avcodec_find_encoder(targetCodec);
stream = muxer.AddStream(encoder);
if (decoder == videoDecoder)
{
vidOutStream = stream;
streamMap.Add(MediaStreamType.Video, streamIndex);
}
else if (decoder == audioDecoder)
{
audioOutStream = stream;
streamMap.Add(MediaStreamType.Audio, streamIndex);
}
else
{
throw new NotImplementedException("Unknown decoder type.");
}
streamIndex++;
//streams[streamIndex] = stream;
var param = stream->codecpar;
ffmpeg.avcodec_parameters_from_context(param, decoder.GetStream()->codec).ThrowOnError();
stream->codecpar->codec_tag = 0;
}
}
public void Build()
{
var streams = new AVStream *[2];
var stream_dic = new Dictionary <MediaStreamType, int>();
ValidateArguments();
// open output iocontext
using var output = new IOContext(OutputPath, ffmpeg.AVIO_FLAG_WRITE);
// open muxer
using var muxer = new MediaMuxer(output, OutputExtension, OutputMimeType);
// create output streams
var firstSource = _sources.First();
AddOutputStreams(firstSource, muxer, out var vidOutStream, out var audioOutStream, out var streamMap);
// write headers
muxer.WriteHeader();
// concat media files
var context = new ConcatContext
{
Output = output,
Muxer = muxer,
VideoOutStream = vidOutStream,
AudioOutStream = audioOutStream,
StreamMap = streamMap,
};
foreach (var source in _sources)
{
ConcatFile(source, context);
}
// write trailer
muxer.WriteTrailer();
}
public void Build()
{
var streams = new AVStream *[2];
var stream_dic = new Dictionary <MediaStreamType, int>();
ValidateArguments();
// create decoders
var decoders = MakeDecoders();
try
{
// open output iocontext
using (var output = new IOContext(OutputPath, ffmpeg.AVIO_FLAG_WRITE))
// open muxer
using (var muxer = new MediaMuxer(output, OutputShortName, OutputMimeType))
{
// add streams
var index = 0;
foreach (var decoderPair in decoders)
{
var decoder = decoderPair.Value;
var targetCodec = decoder.CodecId;
var decoderCodec = decoder.CodecContext;
switch (decoderPair.Key)
{
case MediaStreamType.Audio:
if (TargetAudioCodec != null)
{
targetCodec = TargetAudioCodec.Value;
}
break;
case MediaStreamType.Video:
if (TargetVideoCodec != null)
{
targetCodec = TargetVideoCodec.Value;
}
break;
}
var encoder = ffmpeg.avcodec_find_encoder(targetCodec);
var outStream = muxer.AddStream(encoder);
var param = outStream->codecpar;
streams[index] = outStream;
stream_dic.Add(decoderPair.Key, index++);
if (decoder.CodecId == targetCodec)
{
// converting to the same codec
ffmpeg.avcodec_parameters_from_context(param, decoder.GetStream()->codec).ThrowOnError();
}
else
{
// converting to another codec
switch (decoderPair.Key)
{
case MediaStreamType.Audio:
param->codec_id = targetCodec;
param->codec_type = AVMediaType.AVMEDIA_TYPE_AUDIO;
param->sample_rate = decoderCodec->sample_rate;
param->channels = decoderCodec->channels;
param->channel_layout = decoderCodec->channel_layout;
outStream->time_base = decoderCodec->time_base;
break;
case MediaStreamType.Video:
throw new NotSupportedException();
}
}
outStream->codecpar->codec_tag = 0;
}
// write headers
muxer.WriteHeader();
// write packets
long audio_dts = ffmpeg.AV_NOPTS_VALUE, video_dts = ffmpeg.AV_NOPTS_VALUE;
long audio_pts = 0, video_pts = 0;
var audio_stream = decoders.Where(pair => pair.Key == MediaStreamType.Audio).First();
var video_stream = decoders.Where(pair => pair.Key == MediaStreamType.Video).First();
bool any_audio = true, any_video = true;
while (true)
{
bool anyPacket = false;
while (any_audio || any_video)
{
KeyValuePair <MediaStreamType, MediaDecoder> decoderPair;
// choose a decoder pair
if (!any_audio)
{
decoderPair = video_stream;
}
else if (!any_video)
{
decoderPair = audio_stream;
}
else
{
// choose between audio and video
decoderPair = video_dts < audio_dts ? video_stream : audio_stream;
}
// decoder is chosen now,
// let's read and encode
var decoder = decoderPair.Value;
var stream_index = stream_dic[decoderPair.Key];
var outputStream = streams[stream_index];
if (decoder.CodecId == outputStream->codec->codec_id)
{
// simply copy to target stream
using (var inputFrame = decoder.ReadPacket())
{
if (inputFrame == null)
{
if (decoder == audio_stream.Value)
{
any_audio = false;
}
else
{
any_video = false;
}
continue;
}
var pck = inputFrame.Pointer;
ffmpeg.av_packet_rescale_ts(pck, decoder.TimeBase, outputStream->time_base);
pck->stream_index = stream_index;
long *last_dts, last_pts;
switch (decoder.CodecContext->codec_type)
{
case AVMediaType.AVMEDIA_TYPE_AUDIO:
last_dts = &audio_dts;
last_pts = &audio_pts;
break;
case AVMediaType.AVMEDIA_TYPE_VIDEO:
last_dts = &video_dts;
last_pts = &video_pts;
break;
default:
throw new NotSupportedException();
}
if (pck->dts < (*last_dts + ((muxer.FormatContextPtr->oformat->flags & ffmpeg.AVFMT_TS_NONSTRICT) > 0 ? 0 : 1)) && pck->dts != ffmpeg.AV_NOPTS_VALUE && *last_dts != ffmpeg.AV_NOPTS_VALUE)
{
var next_dts = (*last_dts) + 1;
if (pck->pts >= pck->dts && pck->pts != ffmpeg.AV_NOPTS_VALUE)
{
pck->pts = Math.Max(pck->pts, next_dts);
}
if (pck->pts == ffmpeg.AV_NOPTS_VALUE)
{
pck->pts = next_dts;
}
pck->dts = next_dts;
}
(*last_dts) = pck->dts;
muxer.WritePacket(pck);
anyPacket = true;
}
}
else
{
throw new NotSupportedException("Format conversion is not supported.");
}
}
if (!anyPacket)
{
break;
}
}
// write trailer
muxer.WriteTrailer();
}
}
finally
{
// dispose decoders
foreach (var decoder in decoders.Values)
{
decoder.Dispose();
}
}
}
