public Picture decodePicture(Context context, PictureHeader ph, MemoryStream buffer, int[][] buf, int vertOff,
int vertStep)
{
int planeSize = context.codedWidth * context.codedHeight;
if (buf.Length < 3 || buf[0].Length < planeSize || buf[1].Length < planeSize || buf[2].Length < planeSize)
{
throw new Exception("ByteBuffer too small to hold output picture [" + context.codedWidth + "x"
+ context.codedHeight + "]");
}
try
{
MemoryStream segment;
while ((segment = MPEGUtil.nextSegment(buffer)) != null)
{
if (segment.get(3) >= MPEGConst.SLICE_START_CODE_FIRST && segment.get(3) <= MPEGConst.SLICE_START_CODE_LAST)
{
segment.position(4);
try
{
decodeSlice(ph, segment.get(3) & 0xff, context, buf, new BitReader(segment), vertOff, vertStep);
}
catch (Exception e)
{
//e.printStackTrace();
}
}
else if (segment.get(3) >= 0xB3 && segment.get(3) != 0xB6 && segment.get(3) != 0xB7)
{
throw new Exception("Unexpected start code " + segment.get(3));
}
else if (segment.get(3) == 0x0)
{
//buffer.reset();
break;
}
}
Picture pic = new Picture(context.codedWidth, context.codedHeight, buf, context.color);
if ((ph.picture_coding_type == PictureHeader.IntraCoded || ph.picture_coding_type == PictureHeader.PredictiveCoded) &&
ph.pictureCodingExtension != null && ph.pictureCodingExtension.picture_structure != PictureCodingExtension.Frame)
{
refFields[ph.pictureCodingExtension.picture_structure - 1] = copyAndCreateIfNeeded(pic,
refFields[ph.pictureCodingExtension.picture_structure - 1]);
}
return(pic);
}
catch (IOException e)
{
throw e;
}
}
private PictureHeader readHeader(MemoryStream buffer)
{
PictureHeader ph = null;
MemoryStream segment;
MemoryStream fork = buffer.duplicate();
while ((segment = MPEGUtil.nextSegment(fork)) != null)
{
int code = segment.getInt() & 0xff;
if (code == MPEGConst.SEQUENCE_HEADER_CODE)
{
SequenceHeader newSh = SequenceHeader.read(segment);
if (sh != null)
{
newSh.copyExtensions(sh);
}
sh = newSh;
}
else if (code == MPEGConst.GROUP_START_CODE)
{
gh = GOPHeader.read(segment);
}
else if (code == MPEGConst.PICTURE_START_CODE)
{
ph = PictureHeader.read(segment);
}
else if (code == MPEGConst.EXTENSION_START_CODE)
{
int extType = segment.get(4) >> 4;
if (extType == SequenceHeader.Sequence_Extension || extType == SequenceHeader.Sequence_Scalable_Extension ||
extType == SequenceHeader.Sequence_Display_Extension)
{
SequenceHeader.readExtension(segment, sh);
}
else
{
PictureHeader.readExtension(segment, ph, sh);
}
}
else if (code == MPEGConst.USER_DATA_START_CODE)
{
// do nothing
}
else
{
break;
}
buffer.position(fork.position());
}
return(ph);
}
private static SequenceHeader getSequenceHeader(MemoryStream data)
{
MemoryStream segment = MPEGUtil.nextSegment(data);
while (segment != null)
{
int marker = segment.getInt();
if (marker == (0x100 | MPEGConst.SEQUENCE_HEADER_CODE))
{
return(SequenceHeader.read(segment));
}
segment = MPEGUtil.nextSegment(data);
}
return(null);
}