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 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);
}
