public AudioTranscoder(AudioEncoder audioEncoder, AudioDecoder audioDecoder = null)
{
decoder = audioDecoder;
encoder = audioEncoder;
if (audioDecoder != null)
{
resampler = new Resampler(audioDecoder, audioEncoder);
}
buffer = new AudioFifoBuffer(audioEncoder.SampleFormat, audioEncoder.Channels);
}
public static void InitOutputFrame(AVFrame **frame, AudioEncoder encoder, int maxFrameSize)
{
if ((*frame = ffmpeg.av_frame_alloc()) == null)
{
throw new FFmpegException(ffmpeg.AVERROR(ffmpeg.ENOMEM), "Failed to allocate output frame.");
}
(*frame)->nb_samples = Math.Min(maxFrameSize, encoder.FrameSize);
(*frame)->channel_layout = encoder.ChannelLayout;
(*frame)->format = (int)encoder.SampleFormat;
(*frame)->sample_rate = encoder.SampleRate;
int ret;
if ((ret = ffmpeg.av_frame_get_buffer(*frame, 0)) < 0)
{
ffmpeg.av_frame_free(frame);
throw new FFmpegException(ret, "Failed to allocate output frame samples.");
}
}
public void WriteFrameToEncoder(AudioEncoder encoder)
{
AVFrame *outputFrame = null;
Util.InitOutputFrame(&outputFrame, encoder, GetBufferSize());
try
{
byte *[] outputDataArray = outputFrame->data;
fixed(byte **dataPtr = &outputDataArray[0])
{
if (ffmpeg.av_audio_fifo_read(audioFifo, (void **)dataPtr, outputFrame->nb_samples) < outputFrame->nb_samples)
{
throw new FFmpegException(ffmpeg.AVERROR_UNKNOWN, "Failed to read data from fifo buffer.");
}
}
encoder.WriteNextAudioFrame(outputFrame);
}
finally
{
ffmpeg.av_frame_free(&outputFrame);
}
}
