private void WritePendingFrame(bool forceKeyFrame)
{
if (!framePending)
{
return;
}
framePending = false;
bool keyFrame = forceKeyFrame || frameCount % keyFramePeriodInFrames == 0;
FlvWriter.FlvVideoFrameFlags frameFlags = FlvWriter.FlvVideoFrameFlags.Codec_ScreenVideo
| (keyFrame ? FlvWriter.FlvVideoFrameFlags.Type_KeyFrame : FlvWriter.FlvVideoFrameFlags.Type_InterFrame);
flvWriter.WriteFlvVideoFrame(frameFlags,
(int)(frameCount * 1000.0 / framesPerSecond),
reserveBytesPerFrame,
delegate(byte[] buffer, ref int bufferOffset)
{
// write frame header
buffer[bufferOffset++] = (byte)(((nominalBlockWidth / 16 - 1) << 4) | (width >> 8));
buffer[bufferOffset++] = (byte)width;
buffer[bufferOffset++] = (byte)(((nominalBlockHeight / 16 - 1) << 4) | (height >> 8));
buffer[bufferOffset++] = (byte)height;
// proceed from bottom-left to top-right row by row
for (int blockYOrigin = height; blockYOrigin >= 0; blockYOrigin -= nominalBlockHeight)
{
int blockHeight = Math.Min(blockYOrigin, nominalBlockHeight);
for (int blockXOrigin = 0; blockXOrigin < width; blockXOrigin += nominalBlockWidth)
{
int blockWidth = Math.Min(width - blockXOrigin, nominalBlockWidth);
bool diff = false;
int blockBufferOffset = 0;
int frameOffset = blockYOrigin * width + blockXOrigin;
for (int y = 0; y < blockHeight; y++)
{
frameOffset -= width;
for (int x = 0; x < blockWidth; x++)
{
int color = currentFramePixels[frameOffset];
blockBuffer[blockBufferOffset++] = (byte)color; // B
blockBuffer[blockBufferOffset++] = (byte)(color >> 8); // G
blockBuffer[blockBufferOffset++] = (byte)(color >> 16); // R
if (previousFramePixels[frameOffset++] != color)
{
diff = true;
}
}
frameOffset -= blockWidth;
}
if (keyFrame || diff)
{
deflater.Reset();
deflater.SetInput(blockBuffer, 0, blockBufferOffset);
deflater.Finish();
int blockLength = deflater.Deflate(buffer, bufferOffset + 2, buffer.Length - bufferOffset - 2);
Debug.Assert(deflater.IsFinished, "Deflater should be finished.");
buffer[bufferOffset++] = (byte)(blockLength >> 8);
buffer[bufferOffset++] = (byte)blockLength;
bufferOffset += blockLength;
}
else
{
buffer[bufferOffset++] = 0;
buffer[bufferOffset++] = 0;
}
}
}
});
frameCount += 1;
}
