private static void WriteScalingList(ref H264BitStreamWriter writer, IArray <byte> list)
{
ReadOnlySpan <byte> scan = list.Length == 16 ? ZigZagScan : ZigZagDirect;
int lastScale = 8;
for (int index = 0; index < list.Length; index++)
{
byte value = list[scan[index]];
int deltaScale = value - lastScale;
writer.WriteSe(deltaScale);
lastScale = value;
}
}
public static Span <byte> Reconstruct(ref H264PictureInfo pictureInfo, byte[] workBuffer)
{
H264BitStreamWriter writer = new H264BitStreamWriter(workBuffer);
// Sequence Parameter Set.
writer.WriteU(1, 24);
writer.WriteU(0, 1);
writer.WriteU(3, 2);
writer.WriteU(7, 5);
writer.WriteU(100, 8); // Profile idc
writer.WriteU(0, 8); // Reserved
writer.WriteU(31, 8); // Level idc
writer.WriteUe(0); // Seq parameter set id
writer.WriteUe(pictureInfo.ChromaFormatIdc);
if (pictureInfo.ChromaFormatIdc == 3)
{
writer.WriteBit(false); // Separate colour plane flag
}
writer.WriteUe(0); // Bit depth luma minus 8
writer.WriteUe(0); // Bit depth chroma minus 8
writer.WriteBit(pictureInfo.QpprimeYZeroTransformBypassFlag);
writer.WriteBit(false); // Scaling matrix present flag
writer.WriteUe(pictureInfo.Log2MaxFrameNumMinus4);
writer.WriteUe(pictureInfo.PicOrderCntType);
if (pictureInfo.PicOrderCntType == 0)
{
writer.WriteUe(pictureInfo.Log2MaxPicOrderCntLsbMinus4);
}
else if (pictureInfo.PicOrderCntType == 1)
{
writer.WriteBit(pictureInfo.DeltaPicOrderAlwaysZeroFlag);
writer.WriteSe(0); // Offset for non-ref pic
writer.WriteSe(0); // Offset for top to bottom field
writer.WriteUe(0); // Num ref frames in pic order cnt cycle
}
writer.WriteUe(16); // Max num ref frames
writer.WriteBit(false); // Gaps in frame num value allowed flag
writer.WriteUe(pictureInfo.PicWidthInMbsMinus1);
writer.WriteUe(pictureInfo.PicHeightInMapUnitsMinus1);
writer.WriteBit(pictureInfo.FrameMbsOnlyFlag);
if (!pictureInfo.FrameMbsOnlyFlag)
{
writer.WriteBit(pictureInfo.MbAdaptiveFrameFieldFlag);
}
writer.WriteBit(pictureInfo.Direct8x8InferenceFlag);
writer.WriteBit(false); // Frame cropping flag
writer.WriteBit(false); // VUI parameter present flag
writer.End();
// Picture Parameter Set.
writer.WriteU(1, 24);
writer.WriteU(0, 1);
writer.WriteU(3, 2);
writer.WriteU(8, 5);
writer.WriteUe(0); // Pic parameter set id
writer.WriteUe(0); // Seq parameter set id
writer.WriteBit(pictureInfo.EntropyCodingModeFlag);
writer.WriteBit(pictureInfo.PicOrderPresentFlag);
writer.WriteUe(0); // Num slice groups minus 1
writer.WriteUe(pictureInfo.NumRefIdxL0ActiveMinus1);
writer.WriteUe(pictureInfo.NumRefIdxL1ActiveMinus1);
writer.WriteBit(pictureInfo.WeightedPredFlag);
writer.WriteU(pictureInfo.WeightedBipredIdc, 2);
writer.WriteSe(pictureInfo.PicInitQpMinus26);
writer.WriteSe(0); // Pic init qs minus 26
writer.WriteSe(pictureInfo.ChromaQpIndexOffset);
writer.WriteBit(pictureInfo.DeblockingFilterControlPresentFlag);
writer.WriteBit(pictureInfo.ConstrainedIntraPredFlag);
writer.WriteBit(pictureInfo.RedundantPicCntPresentFlag);
writer.WriteBit(pictureInfo.Transform8x8ModeFlag);
writer.WriteBit(pictureInfo.ScalingMatrixPresent);
if (pictureInfo.ScalingMatrixPresent)
{
for (int index = 0; index < 6; index++)
{
writer.WriteBit(true);
WriteScalingList(ref writer, pictureInfo.ScalingLists4x4[index]);
}
if (pictureInfo.Transform8x8ModeFlag)
{
for (int index = 0; index < 2; index++)
{
writer.WriteBit(true);
WriteScalingList(ref writer, pictureInfo.ScalingLists8x8[index]);
}
}
}
writer.WriteSe(pictureInfo.SecondChromaQpIndexOffset);
writer.End();
return(writer.AsSpan());
}