/// <summary>
/// transcode audio
/// </summary>
/// <param name="input">input audio file</param>
/// <param name="output">output audio file</param>
/// <param name="outChannels">output audio file channels</param>
/// <param name="outSampleRate">output audio file sample rate</param>
public AudioTranscode(string input, string output, int outChannels = 2, int outSampleRate = 44100)
{
using (MediaWriter writer = new MediaWriter(output))
using (MediaReader reader = new MediaReader(input))
{
int audioIndex = reader.First(_ => _.Codec.Type == AVMediaType.AVMEDIA_TYPE_AUDIO).Index;
writer.AddStream(MediaEncoder.CreateAudioEncode(writer.Format, outChannels, outSampleRate));
writer.Initialize();
AudioFrame dst = AudioFrame.CreateFrameByCodec(writer[0].Codec);
SampleConverter converter = new SampleConverter(dst);
long pts = 0;
foreach (var packet in reader.ReadPacket())
{
foreach (var srcframe in reader[audioIndex].ReadFrame(packet))
{
foreach (var dstframe in converter.Convert(srcframe))
{
pts += dstframe.AVFrame.nb_samples;
dstframe.Pts = pts; // audio's pts is total samples, pts can only increase.
foreach (var outpacket in writer[0].WriteFrame(dstframe))
{
writer.WritePacket(outpacket);
}
}
}
}
writer.FlushMuxer();
}
}
public EncodeAudioByMat(string output)
{
using (MediaWriter writer = new MediaWriter(output))
{
writer.AddStream(MediaEncoder.CreateAudioEncode(writer.Format, 2, 44100));
writer.Initialize();
AudioFrame dstFrame = AudioFrame.CreateFrameByCodec(writer[0].Codec);
SampleConverter converter = new SampleConverter(dstFrame);
using (Mat mat = CreateMat(writer[0].Codec.AVCodecContext.channels))
{
long pts = 0;
for (int i = 0; i < 1000; i++)
{
foreach (var item in converter.Convert(mat.ToAudioFrame(dstSampleRate: writer[0].Codec.AVCodecContext.sample_rate)))
{
pts += item.NbSamples;
item.Pts = pts;
foreach (var packet in writer[0].WriteFrame(item))
{
writer.WritePacket(packet);
}
}
}
}
writer.FlushMuxer();
}
}
public Mp4VideoWriter AddAudio(int dstChannels, int dstSampleRate)
{
if (writer.Where(_ => _.Codec.Type == AVMediaType.AVMEDIA_TYPE_AUDIO).Count() == 0)
{
Channels = dstChannels;
SampleRate = dstSampleRate;
var stream = writer.AddStream(MediaEncoder.CreateAudioEncode(writer.Format, dstChannels, dstSampleRate));
audioIndex = writer.Count - 1;
sampleConverter = new SampleConverter(stream.Codec);
}
return(this);
}
/// <summary>
/// recording audio.
/// <para>
/// first set inputDeviceName = null, you will get inputDeviceName list in vs output,
/// </para>
/// <para>
/// then set inputDeviceName to your real device name and run again,you will get a audio output.
/// </para>
/// <para>
/// if you want stop record, exit console;
/// </para>
/// <para>ffmpeg </para>
/// </summary>
/// <param name="outputFile"></param>
/// <param name="inputDeviceName"></param>
public RecordingAudio(string outputFile, string inputDeviceName = null)
{
// console output
FFmpegHelper.SetupLogging(logWrite: _ => Console.Write(_));
// register all device
FFmpegHelper.RegisterDevice();
var dshowInput = InFormat.Get("dshow");
// list all "dshow" device at console output, ffmpeg does not support direct reading of device names
MediaDevice.PrintDeviceInfos(dshowInput, "list", MediaDevice.ListDevicesOptions);
if (string.IsNullOrWhiteSpace(inputDeviceName))
{
return;
}
// get your audio input device name from console output
// NOTE: DO NOT delete "audio="
using (MediaReader reader = new MediaReader($"audio={inputDeviceName}", dshowInput))
using (MediaWriter writer = new MediaWriter(outputFile))
{
var stream = reader.Where(_ => _.Codec.Type == AVMediaType.AVMEDIA_TYPE_AUDIO).First();
writer.AddStream(MediaEncoder.CreateAudioEncode(writer.Format, stream.Codec.AVCodecContext.channels, stream.Codec.AVCodecContext.sample_rate));
writer.Initialize();
AudioFrame dstFrame = AudioFrame.CreateFrameByCodec(writer[0].Codec);
SampleConverter converter = new SampleConverter(dstFrame);
long pts = 0;
foreach (var packet in reader.ReadPacket())
{
foreach (var frame in stream.ReadFrame(packet))
{
foreach (var dstframe in converter.Convert(frame))
{
pts += dstFrame.AVFrame.nb_samples;
dstFrame.Pts = pts;
foreach (var dstpacket in writer[0].WriteFrame(dstFrame))
{
writer.WritePacket(dstpacket);
}
}
}
}
writer.FlushMuxer();
}
}
