private FFmpegFrame ensureFramePixelFormat(FFmpegFrame frame, AVPixelFormat targetPixelFormat)
{
if (frame.PixelFormat == targetPixelFormat)
{
return(frame);
}
int width = frame.Pointer->width;
int height = frame.Pointer->height;
swsContext = ffmpeg.sws_getCachedContext(
swsContext,
width, height, frame.PixelFormat,
width, height, targetPixelFormat,
1, null, null, null);
if (!scalerFrames.TryDequeue(out var scalerFrame))
{
scalerFrame = new FFmpegFrame(ffmpeg, returnScalerFrame);
}
// (re)initialize the scaler frame if needed.
if (scalerFrame.PixelFormat != targetPixelFormat || scalerFrame.Pointer->width != width || scalerFrame.Pointer->height != height)
{
ffmpeg.av_frame_unref(scalerFrame.Pointer);
// Note: this field determines the scaler's output pix format.
scalerFrame.PixelFormat = targetPixelFormat;
scalerFrame.Pointer->width = width;
scalerFrame.Pointer->height = height;
int getBufferResult = ffmpeg.av_frame_get_buffer(scalerFrame.Pointer, 0);
if (getBufferResult < 0)
{
Logger.Log($"Failed to allocate SWS frame buffer: {getErrorMessage(getBufferResult)}");
scalerFrame.Dispose();
frame.Return();
return(null);
}
}
int scalerResult = ffmpeg.sws_scale(
swsContext,
frame.Pointer->data, frame.Pointer->linesize, 0, height,
scalerFrame.Pointer->data, scalerFrame.Pointer->linesize);
// return the original frame regardless of the scaler result.
frame.Return();
if (scalerResult < 0)
{
Logger.Log($"Failed to scale frame: {getErrorMessage(scalerResult)}");
scalerFrame.Dispose();
return(null);
}
return(scalerFrame);
}