public void SetupAudio(int sampleRate, int channels, byte[] esdsData)
{
_audioTrack = new AudioTrack(
new AudioAttributes.Builder()
.SetUsage(AudioUsageKind.Media)
.SetContentType(AudioContentType.Music)
.SetFlags(AudioFlags.LowLatency)
.Build(),
new Android.Media.AudioFormat.Builder()
.SetEncoding(Encoding.Pcm16bit)
.SetSampleRate(44100)
.SetChannelMask(ChannelOut.Stereo)
.Build(),
4096,
AudioTrackMode.Stream,
AudioManager.AudioSessionIdGenerate);
MediaFormat audioFormat = MediaFormat.CreateAudioFormat(
mime: MediaFormat.MimetypeAudioAac,
sampleRate: sampleRate,
channelCount: channels);
audioFormat.SetInteger(MediaFormat.KeyIsAdts, 0);
audioFormat.SetInteger(MediaFormat.KeyAacProfile, (int)MediaCodecProfileType.Aacobjectlc);
_audioCodec = MediaCodec.CreateDecoderByType(
MediaFormat.MimetypeAudioAac);
// TODO: Remove hardcoding
byte profile = (byte)MediaCodecProfileType.Aacobjectlc;
byte sampleIndex = AacAdtsAssembler.GetSamplingFrequencyIndex(sampleRate);
byte[] csd0 = new byte[2];
csd0[0] = (byte)(((byte)profile << 3) | (sampleIndex >> 1));
csd0[1] = (byte)((byte)((sampleIndex << 7) & 0x80) | (channels << 3));
esdsData = csd0;
audioFormat.SetByteBuffer("csd-0", Java.Nio.ByteBuffer.Wrap(esdsData));
_audioCodec.SetCallback(this);
_audioCodec.Configure(
format: audioFormat,
surface: null,
crypto: null,
flags: MediaCodecConfigFlags.None);
_audioCodec.Start();
_audioTrack.Play();
}
public MediaFormat CreateAudioOutputFormat(MediaFormat inputFormat)
{
if (mAudioBitrate == AUDIO_BITRATE_AS_IS || mAudioChannels == AUDIO_CHANNELS_AS_IS)
{
return(null);
}
// Use original sample rate, as resampling is not supported yet.
MediaFormat format = MediaFormat.CreateAudioFormat(MediaFormatExtraConstants.MimetypeAudioAac,
inputFormat.GetInteger(MediaFormat.KeySampleRate),
mAudioChannels);
// this is obsolete: MediaCodecInfo.CodecProfileLevel.AACObjectLC, so using MediaCodecProfileType.Aacobjectlc instead
format.SetInteger(MediaFormat.KeyAacProfile, (int)MediaCodecProfileType.Aacobjectlc);
format.SetInteger(MediaFormat.KeyBitRate, mAudioBitrate);
return(format);
}
public static MediaFormat GetMediaFormat(string mimeType, int sampleRate, int channels)
{
var format = MediaFormat.CreateAudioFormat(
mime: MediaFormat.MimetypeAudioAac,
sampleRate: sampleRate,
channelCount: channels);
format.SetInteger(MediaFormat.KeyIsAdts, 0);
format.SetInteger(MediaFormat.KeyAacProfile, (int)MediaCodecProfileType.Aacobjectlc);
byte profile = (byte)MediaCodecProfileType.Aacobjectlc;
byte sampleIndex = AacAdtsAssembler.GetSamplingFrequencyIndex(sampleRate);
byte[] csd0 = new byte[2];
csd0[0] = (byte)(((byte)profile << 3) | (sampleIndex >> 1));
csd0[1] = (byte)((byte)((sampleIndex << 7) & 0x80) | (channels << 3));
format.SetByteBuffer("csd-0", Java.Nio.ByteBuffer.Wrap(csd0));
return(format);
}
// https://github.com/lanhq147/SampleMediaFrame/blob/e2f20ff9eef73318e5a9b4de15458c5c2eb0fd46/app/src/main/java/com/google/android/exoplayer2/video/av/HWRecorder.java
public bool BeginEncoding(int resX, int resY, int rateNumer, int rateDenom, int videoBitRate, int audioBitRate, string audioFile, string outputFile)
{
videoBufferInfo = new MediaCodec.BufferInfo();
audioBufferInfo = new MediaCodec.BufferInfo();
frameRateNumer = rateNumer;
frameRateDenom = rateDenom;
MediaFormat videoFormat = MediaFormat.CreateVideoFormat(VideoMimeType, resX, resY);
videoFormat.SetInteger(MediaFormat.KeyColorFormat, (int)MediaCodecCapabilities.Formatsurface);
videoFormat.SetInteger(MediaFormat.KeyBitRate, videoBitRate * 1000);
videoFormat.SetFloat(MediaFormat.KeyFrameRate, rateNumer / (float)rateDenom);
videoFormat.SetInteger(MediaFormat.KeyIFrameInterval, 4);
videoFormat.SetInteger(MediaFormat.KeyProfile, (int)MediaCodecProfileType.Avcprofilehigh);
videoFormat.SetInteger(MediaFormat.KeyLevel, (int)MediaCodecProfileLevel.Avclevel31);
videoEncoder = MediaCodec.CreateEncoderByType(VideoMimeType);
videoEncoder.Configure(videoFormat, null, null, MediaCodecConfigFlags.Encode);
surface = videoEncoder.CreateInputSurface();
videoEncoder.Start();
MediaFormat audioFormat = MediaFormat.CreateAudioFormat(AudioMimeType, 44100, 1);
audioFormat.SetInteger(MediaFormat.KeyAacProfile, (int)MediaCodecProfileType.Aacobjectlc);
audioFormat.SetInteger(MediaFormat.KeyBitRate, audioBitRate * 1000);
audioEncoder = MediaCodec.CreateEncoderByType(AudioMimeType);
audioEncoder.Configure(audioFormat, null, null, MediaCodecConfigFlags.Encode);
audioEncoder.Start();
try
{
muxer = new MediaMuxer(outputFile, MuxerOutputType.Mpeg4);
}
catch
{
return(false);
}
videoTrackIndex = -1;
audioTrackIndex = -1;
muxerStarted = false;
if (!ElgInitialize())
{
return(false);
}
audioData = File.ReadAllBytes(audioFile);
if (audioData == null)
{
return(false);
}
DrainEncoder(videoEncoder, videoBufferInfo, videoTrackIndex, false);
DrainEncoder(audioEncoder, audioBufferInfo, audioTrackIndex, false);
audioEncodingTask = Task.Factory.StartNew(AudioEncodeThread, TaskCreationOptions.LongRunning);
return(true);
}
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}");
}
}