public Stream ReadVideoFrame(TimeSpan seek, Size?size)
{
this.Dispose();
try
{
FFmpegArgsBuilder fFmpegArgsBuilder = new FFmpegArgsBuilder();
fFmpegArgsBuilder.GlobalOptionArgs
.SetThreadQueueSize(512)
;
fFmpegArgsBuilder.SetInputFile(this.filePath)
.SeekAccurate()
.ReadByNativeFrame()
.SetSeek(seek)
;
var outputOptionArgs = fFmpegArgsBuilder.SetOutputImagePipe(videoPipeName)
.SetPixFormat(Formats.FFmpegPixFormat.rgb24)
.SetOutputVideoFrame(1)
.SetVideoFormat(FFmpegVideoFormat.image2)
.SetFramerate(this.FPS)
;
if (size != null)
{
outputOptionArgs
.SetVideoSize(size.Value);
}
this.ffmpegProcess = FFmpegService.StartFFmpegStandardOutput(fFmpegArgsBuilder.Args);
return(this.ffmpegProcess.StandardOutput.BaseStream);
}
catch
{
}
return(null);
}
public IEnumerable <VideoFrameArgs> ReadVideoFrames(TimeSpan?seek = null, TimeSpan?seekEnd = null, Size?size = null, bool readByNativeFrame = true, CancellationToken?cancellationToken = null)
{
this.Dispose();
TimeSpan startSeek = seek ?? TimeSpan.FromSeconds(0);
FFmpegArgsBuilder fFmpegArgsBuilder = new FFmpegArgsBuilder();
fFmpegArgsBuilder.GlobalOptionArgs
.SetThreadQueueSize(512)
.SetNoStandardInput()
;
var inputOptionArgs = fFmpegArgsBuilder.SetInputFile(this.filePath)
.SeekAccurate()
.SetSeek(startSeek)
.ReadByNativeFrame(() => readByNativeFrame)
;
var outputOptionArgs = fFmpegArgsBuilder.SetOutputImagePipe(videoPipeName)
.SetVideoFormat(FFmpegVideoFormat.image2pipe)
.SetVideoCodec(FFmpegVideoCodec.rawvideo)
.SetPixFormat(Formats.FFmpegPixFormat.rgb24)
.SetFramerate(this.FPS)
.SetSeekEnd(seekEnd ?? TimeSpan.MinValue, () => seekEnd != null)
.SetVideoSize(this.GetSize(size))
;
this.ffmpegProcess = FFmpegService.StartFFmpegStandardOutput(fFmpegArgsBuilder.Args);
cancellationToken?.Register(() =>
{
this.Dispose();
});
int frameIndex = (int)(startSeek.TotalMilliseconds / (1000.0 / this.FPS));
Size bitmapSize = this.GetSize(size);
byte[] frameDataBuffer = new byte[bitmapSize.Width * bitmapSize.Height * 3];
byte[] buffer = new byte[32768]; //ffmpeg的缓冲区大小被限定在32k 32768 似乎没有办法修改？
int read;
int readed = 0;
while ((read = this.ffmpegProcess.StandardOutput.BaseStream.Read(buffer, 0, Math.Min(buffer.Length, frameDataBuffer.Length - readed))) > 0)
{
if (cancellationToken?.IsCancellationRequested ?? false)
{
this.Dispose();
yield break;
}
Array.Copy(buffer, 0, frameDataBuffer, readed, read);
readed += read;
if (readed == frameDataBuffer.Length)
{
//对每一个像素的颜色进行转化
for (int i = 0; i < frameDataBuffer.Length; i += 3)
{
byte temp = frameDataBuffer[i + 2];
frameDataBuffer[i + 2] = frameDataBuffer[i];
frameDataBuffer[i] = temp;
}
yield return(new VideoFrameArgs(frameIndex++, frameDataBuffer));
readed = 0;
}
}
}