public void TranscodeAudio(SourceMedia sourceMedia,
TargetMedia targetMedia,
TrimConfig trimConfig,
TransformationState transformationState)
{
if (targetMedia.targetFile.Exists())
{
targetMedia.targetFile.Delete();
}
transformationState.requestId = UUID.RandomUUID().ToString();
/*
MediaTransformationListener transformationListener = new MediaTransformationListener(context,
transformationState.requestId,
transformationState,
targetMedia);
*/
MediaRange mediaRange = trimConfig.enabled
? new MediaRange(
TimeUnit.Milliseconds.ToMicros((long)(trimConfig.range[0] * 1000)),
TimeUnit.Milliseconds.ToMicros((long)(trimConfig.range[1] * 1000)))
: new MediaRange(0, long.MaxValue);
try
{
var targetMimeType = targetMedia.writeToWav ? "audio/raw" : "audio/mp4a-latm";
IMediaTarget mediaTarget;
if (targetMedia.writeToWav)
{
mediaTarget = new WavMediaTarget(targetMedia.targetFile.Path);
}
else
{
mediaTarget = new MediaMuxerMediaTarget(targetMedia.targetFile.Path, 1, 0, (int)MuxerOutputType.Mpeg4);
}
var mediaSource = new MediaExtractorMediaSource(context, sourceMedia.uri, mediaRange);
List<TrackTransform> trackTransforms = new List<TrackTransform>(1);
foreach (TargetTrack targetTrack in targetMedia.tracks)
{
if (targetTrack.format is AudioTrackFormat trackFormat)
{
MediaFormat mediaFormat = MediaFormat.CreateAudioFormat(
targetMimeType,
trackFormat.samplingRate,
trackFormat.channelCount);
mediaFormat.SetInteger(MediaFormat.KeyBitRate, trackFormat.bitrate);
mediaFormat.SetLong(MediaFormat.KeyDuration, trackFormat.duration);
IEncoder encoder;
if (targetMedia.writeToWav)
{
encoder = new PassthroughBufferEncoder(8192);
}
else
{
encoder = new MediaCodecEncoder();
}
//IEncoder encoder = targetMedia.writeToWav ? new PassthroughBufferEncoder(8192) : new MediaCodecEncoder();
TrackTransform trackTransform = new TrackTransform.Builder(mediaSource, targetTrack.sourceTrackIndex, mediaTarget)
.SetTargetTrack(0)
.SetDecoder(new MediaCodecDecoder())
.SetEncoder(encoder)
.SetRenderer(new AudioRenderer(encoder))
.SetTargetFormat(mediaFormat)
.Build();
trackTransforms.Add(trackTransform);
break;
}
}
_mediaTransformer.Transform(
transformationState.requestId,
trackTransforms,
this,
MediaTransformer.GranularityDefault);
}
catch (System.Exception err)
{
System.Diagnostics.Debug.WriteLine($"Exception when trying to transcode audio: {err.Message}");
}
}