private void EncodePredictedFrame(Stream outStream, BitmapData inputData, BitmapData previousData, int pixelBytes)
{
outStream.WriteByte((byte)FrameType.Predicted);
int xBlocksCount = DivideRoundUp(frameWidth, MCBlockSize);
int yBlocksCount = DivideRoundUp(frameHeight, MCBlockSize);
int identicalBlocksCount = 0;
int translatedBlocksCount = 0;
int fullBlocksCount = 0;
for (int yBlock = 0; yBlock < yBlocksCount; yBlock++)
{
for (int xBlock = 0; xBlock < xBlocksCount; xBlock++)
{
// absolute position of the block start
int yStart = yBlock * MCBlockSize;
int xStart = xBlock * MCBlockSize;
MotionVector motionVector;
bool motionVectorFound = SearchMotionVector(inputData,
previousData, pixelBytes, yStart, xStart, out motionVector);
if (motionVectorFound)
{
if ((motionVector.x == 0) && (motionVector.y == 0))
{
outStream.WriteByte((byte)MCRecordType.Identical);
identicalBlocksCount++;
}
else
{
// store a record type being a motion vector
outStream.WriteByte((byte)MCRecordType.MotionVector);
// store the motion vector itself
// TODO: store only a difference to the previous motion vector
// TODO: it could be possible to store only an index to the vector of
// possible motion vectors
outStream.WriteSShort(motionVector.x);
outStream.WriteSShort(motionVector.y);
translatedBlocksCount++;
}
}
else
{
// store a record type being a full block
outStream.WriteByte((byte)MCRecordType.FullBlock);
// store the full block contents
EncodeFullBlock(outStream, inputData, previousData, pixelBytes, yStart, xStart);
fullBlocksCount++;
}
}
}
Log("Block counts - identical: {0}, translated: {1}, full: {2}", identicalBlocksCount, translatedBlocksCount, fullBlocksCount);
}
public void EncodeFrame(int frameIndex, Bitmap inputFrame, Stream outStream)
{
if ((inputFrame == null) || (outStream == null)) return;
int width = inputFrame.Width;
int height = inputFrame.Height;
if ((width != frameWidth) || (height != frameHeight)) return;
// frame header: [ MAGIC_FRAME, frameIndex, frameType ]
outStream.WriteUInt(MAGIC_FRAME);
outStream.WriteSShort((short)frameIndex);
BitmapData inputData = inputFrame.LockBits(
new Rectangle(0, 0, width, height),
ImageLockMode.ReadOnly, inputFrame.PixelFormat);
BitmapData previousData = previousFrame.LockBits(
new Rectangle(0, 0, width, height),
ImageLockMode.ReadOnly, previousFrame.PixelFormat);
int pixelBytes = GetBytesPerPixel(inputFrame.PixelFormat);
if ((frameIndex % IntraFrameFrequency) == 0)
{
EncodeIntraFrame(outStream, inputData, pixelBytes);
}
else
{
EncodePredictedFrame(outStream, inputData, previousData, pixelBytes);
}
inputFrame.UnlockBits(inputData);
previousFrame.UnlockBits(previousData);
previousFrame.Dispose();
previousFrame = inputFrame;
}