/// <summary>
/// <see cref="sws_getCachedContext(SwsContext*, int, int, AVPixelFormat, int, int, AVPixelFormat, int, SwsFilter*, SwsFilter*, double*)"/>
/// <see cref="sws_scale(SwsContext*, byte*[], int[], int, int, byte*[], int[])"/>
/// </summary>
public static IEnumerable <Frame> ConvertFrames(this CodecContext c, IEnumerable <Frame> sourceFrames, ScaleFlag flags = ScaleFlag.Bilinear)
{
using var destFrame = c.CreateFrame();
int pts = 0;
if (c.Codec.Type == MediaType.Video)
{
using var frameConverter = new FrameConverter();
foreach (var sourceFrame in sourceFrames)
{
frameConverter.ConvertFrame(sourceFrame, destFrame, flags);
destFrame.Pts = pts++;
yield return(destFrame);
}
}
else if (c.Codec.Type == MediaType.Audio)
{
using var frameConverter = new SampleConverter();
foreach (var sourceFrame in sourceFrames)
{
frameConverter.ConvertFrame(destFrame, sourceFrame);
destFrame.Pts = pts += c.FrameSize;
yield return(destFrame);
}
}
}
/// <summary>
/// Convert to audio frame to <paramref name="dstFotmat"/>
/// <para><see cref="DepthType"/> to <see cref="AVSampleFormat"/> mapping table.
/// if <see cref="Mat.NumberOfChannels"/> > 1, use packet format, otherwise planar</para>
/// <list type="table" >
/// <item>
/// <term><see cref="DepthType.Cv8U"/></term>
/// <description1><see cref="AVSampleFormat.AV_SAMPLE_FMT_U8"/>/<see cref="AVSampleFormat.AV_SAMPLE_FMT_U8P"/></description1>
/// </item>
/// <item>
/// <term><see cref="DepthType.Cv16S"/></term>
/// <description1><see cref="AVSampleFormat.AV_SAMPLE_FMT_S16"/>/<see cref="AVSampleFormat.AV_SAMPLE_FMT_S16P"/></description1>
/// </item>
/// <item>
/// <term><see cref="DepthType.Cv32S"/></term>
/// <description1><see cref="AVSampleFormat.AV_SAMPLE_FMT_S32"/>/<see cref="AVSampleFormat.AV_SAMPLE_FMT_S32P"/></description1>
/// </item>
/// <item>
/// <term><see cref="DepthType.Cv32F"/></term>
/// <description1><see cref="AVSampleFormat.AV_SAMPLE_FMT_FLT"/>/<see cref="AVSampleFormat.AV_SAMPLE_FMT_FLTP"/></description1>
/// </item>
/// <item>
/// <term><see cref="DepthType.Cv64F"/></term>
/// <description1><see cref="AVSampleFormat.AV_SAMPLE_FMT_DBL"/>/<see cref="AVSampleFormat.AV_SAMPLE_FMT_DBLP"/></description1>
/// </item>
/// <item>
/// <term><see cref="DepthType.Cv64F"/></term>
/// <description1><see cref="AVSampleFormat.AV_SAMPLE_FMT_S64"/>/<see cref="AVSampleFormat.AV_SAMPLE_FMT_S64P"/></description1>
/// </item>
/// <item>NOTE: Emgucv not supported int64, mapping Cv64F to int64,
/// so set Mat with int64 if <paramref name="dstFotmat"/> is <see cref="AVSampleFormat.AV_SAMPLE_FMT_S64"/> or <see cref="AVSampleFormat.AV_SAMPLE_FMT_S64P"/>
/// </item>
/// </list>
/// </summary>
/// <param name="mat"></param>
/// <param name="dstFotmat">Default is auto format by <see cref="Mat.Depth"/> and <see cref="Mat.NumberOfChannels"/> use mapping table</param>
/// <param name="dstSampleRate">Mat not have sample rate, set value here or later</param>
/// <returns></returns>
public static AudioFrame ToAudioFrame(this Mat mat, AVSampleFormat dstFotmat = AVSampleFormat.AV_SAMPLE_FMT_NONE, int dstSampleRate = 0)
{
AVSampleFormat srcformat;
switch (mat.Depth)
{
case DepthType.Default:
case DepthType.Cv8U:
case DepthType.Cv8S:
srcformat = mat.NumberOfChannels > 1 ? AVSampleFormat.AV_SAMPLE_FMT_U8 : AVSampleFormat.AV_SAMPLE_FMT_U8P;
break;
case DepthType.Cv16U:
case DepthType.Cv16S:
srcformat = mat.NumberOfChannels > 1 ? AVSampleFormat.AV_SAMPLE_FMT_S16 : AVSampleFormat.AV_SAMPLE_FMT_S16P;
break;
case DepthType.Cv32S:
srcformat = mat.NumberOfChannels > 1 ? AVSampleFormat.AV_SAMPLE_FMT_S32 : AVSampleFormat.AV_SAMPLE_FMT_S32P;
break;
case DepthType.Cv32F:
srcformat = mat.NumberOfChannels > 1 ? AVSampleFormat.AV_SAMPLE_FMT_FLT : AVSampleFormat.AV_SAMPLE_FMT_FLTP;
break;
case DepthType.Cv64F:
srcformat = mat.NumberOfChannels > 1 ? AVSampleFormat.AV_SAMPLE_FMT_DBL : AVSampleFormat.AV_SAMPLE_FMT_DBLP;
break;
default:
throw new FFmpegException(FFmpegException.NotSupportFormat);
}
if (dstFotmat != AVSampleFormat.AV_SAMPLE_FMT_NONE && dstFotmat != srcformat)
{
// converter must need set sample rate
using (SampleConverter converter = new SampleConverter(dstFotmat, mat.NumberOfChannels > 1 ? mat.NumberOfChannels : mat.Height, mat.Width, Math.Min(1, dstSampleRate)))
{
AudioFrame frame = converter.ConvertFrame(MatToAudioFrame(mat, srcformat, Math.Min(1, dstSampleRate)), out int a, out int b);
unsafe
{
// set real sample rate after convert
((AVFrame *)frame)->sample_rate = dstSampleRate;
}
}
}
return(MatToAudioFrame(mat, srcformat, dstSampleRate));
}
