/// <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);
}
}
}
private static void WriteImageTo(Frame frame, FormatContext fc)
{
Codec codec = Codec.FindEncoder(fc.OutputFormat.VideoCodec);
var mediaStream = new MediaStream(fc);
using CodecContext codecContext = new CodecContext(codec)
{
PixelFormat = codec.PixelFormats.First(),
Width = frame.Width,
Height = frame.Height,
TimeBase = new MediaRational(1, 25),
Flags = fc.OutputFormat.Flags.HasFlag(FormatOutputFlag.Globalheader) ? CodecFlag.GlobalHeader : CodecFlag.None,
};
codecContext.Open(codec);
mediaStream.Codecpar.CopyFrom(codecContext);
if ((PixelFormat)frame.Format == codecContext.PixelFormat)
{
WriteAction(frame, fc, codecContext);
}
else
{
using var tempFrame = Frame.CreateWritableVideo(frame.Width, frame.Height, codecContext.PixelFormat);
using var frameConverter = new FrameConverter();
frameConverter.ConvertFrame(frame, tempFrame);
WriteAction(tempFrame, fc, codecContext);
}
}