private bool ReadNextSequence()
{
bufferLength = 0;
Frames.Clear();
SequenceExtensionPresent = false;
SequenceFrames = 0;
SequenceStartFrame = CurrentFrame;
if (!FindNextSequenceStart())
{
LastError = ErrorCode.MPEG_ERROR_NOSEQUENCE;
return(false);
}
int picture = 0;
MPEGFrame newFrame = new MPEGFrame();
newFrame.StartIndex = bufferLength - 4; // -4 compensates for sequence start code
newFrame.FrameNumber = CurrentFrame++;
if (!ConsumeSequenceHeader())
{
return(false);
}
if (!ConsumeExtensions(0))
{
return(false);
}
int pictures = 0;
bool done = false;
while (!done)
{
uint startCode = reader.Peek32();
if (startCode == MPEG_CODE_GROUP_START)
{
newFrame.StartOfGOP = true;
ConsumeGroupOfPicturesHeader();
ConsumeExtensions(1);
}
else if (startCode >= MPEG_CODE_SLICE_START_LOW && startCode <= MPEG_CODE_SLICE_START_HIGH)
{
ConsumeSlice();
}
else if (startCode == MPEG_CODE_PICTURE_START)
{
picture++;
if (picture > 1)
{
newFrame.EndIndex = bufferLength - 1;
Frames.Add(newFrame);
newFrame = new MPEGFrame();
newFrame.StartIndex = bufferLength;
newFrame.FrameNumber = CurrentFrame++;
}
pictures++;
ConsumePictureHeader();
if (PictureCodingType == 1)
{
newFrame.FrameType = 'I';
}
else if (PictureCodingType == 2)
{
newFrame.FrameType = 'P';
}
else if (PictureCodingType == 3)
{
newFrame.FrameType = 'B';
}
newFrame.TemporalReference = TemporalReference;
newFrame.PresentationNumber = SequenceStartFrame + TemporalReference;
newFrame.VBVDelay = PictureVBVDelay;
}
else if (startCode == MPEG_CODE_EXTENSION_START)
{
ConsumeExtensions(2);
}
else if (startCode == MPEG_CODE_SEQUENCE_END)
{
// consume sequence_end_code
ReadAndBuffer32();
done = true;
}
else
{
done = true;
}
}
newFrame.EndIndex = bufferLength - 1;
Frames.Add(newFrame);
return(true);
}
private ByteArray PesForFrame(int mpegStream, int index, double initialDTS)
{
ByteArray result = new ByteArray();
MPEGFrame frame = Frames[index];
result.Append((uint)(0x000001E0 + mpegStream));
result.Append((ushort)0x0000); // Transport stream PES packets don't need lengths if they're video
// '10' (2 bits) 02 = 0x80
// PES_scrambling_control = '00' (2 bits) 04 = 0x00
// PES_priority = '0' (1 bit) 05 = 0x00
// data_alignment indicator = '1' (1 bit) 06 = 0x04
// copyright = '0' (1 bit) 07 = 0x00
// original_or_copy = '1' (1 bit) 08 = 0x01
// = 0x85
result.Append((byte)0x85);
if (frame.FrameNumber == 0)
{
VBVDelay = frame.VBVDelay;
}
double frameDuration = 1.0 / SequenceFrameRate;
double dts = (double)frame.FrameNumber * frameDuration + VBVDelay; // initialDTS;
double pts = (double)(frame.PresentationNumber + 1) * frameDuration + VBVDelay; // initialDTS;
if (frame.PresentationNumber == 0)
{
InitialPTS = pts;
}
ulong intDts = (ulong)Math.Round(90000.0 * dts);
ulong intPts = (ulong)Math.Round(90000.0 * pts);
//if ((double)intDts / 90000.0 != dts)
// System.Diagnostics.Debugger.Break();
if (dts == pts)
{
// PTS_DTS_flags = '10' (2 bits) 02 = 0x80
// ESCR_flag = '0' (1 bit) 03 = 0x00
// ES_rate_flag = '0' (1 bit) 04 = 0x00
// DSM_trick_mode_flag = '0' (1 bit) 05 = 0x00
// additional_copy_info_flag = '0' (1 bit) 06 = 0x00
// PES_CRC_flag = '0' (1 bit) 07 = 0x00
// PES_extension_flag (1 bit) 08 = 0x00
// = 0x80
result.Append((byte)0x80);
// if(PTS_DTS_flags == '10')
// '0010' (4 bits) 04
// PTS[32..30] (3 bits) 07
// marker_bit = '1' (1 bit) 08
// PTS[29..15] (15 bits) 23
// marker_bit = '1' (1 bit) 24
// PTS[14..0] (15 bits) 39
// marker_bit = '1' (1 bit) 40
// PES_header_data_length = 40 bits or 5 bytes
result.Append((byte)5);
result.EnterBitMode();
result.AppendBits((byte)0x2, 3, 0);
result.AppendBits(intPts, 32, 30);
result.AppendBit(1);
result.AppendBits(intPts, 29, 15);
result.AppendBit(1);
result.AppendBits(intPts, 14, 0);
result.AppendBit(1);
result.LeaveBitMode();
}
else
{
// PTS_DTS_flags = '11' (2 bits) 02 = 0xC0
// ESCR_flag = '0' (1 bit) 03 = 0x00
// ES_rate_flag = '0' (1 bit) 04 = 0x00
// DSM_trick_mode_flag = '0' (1 bit) 05 = 0x00
// additional_copy_info_flag = '0' (1 bit) 06 = 0x00
// PES_CRC_flag = '0' (1 bit) 07 = 0x00
// PES_extension_flag (1 bit) 08 = 0x00
// = 0xC0
result.Append((byte)0xC0);
// if(PTS_DTS_flags == '11')
// '0011' (4 bits) 04
// PTS[32..30] (3 bits) 07
// marker_bit = '1' (1 bit) 08
// PTS[29..15] (15 bits) 23
// marker_bit = '1' (1 bit) 24
// PTS[14..0] (15 bits) 39
// marker_bit = '1' (1 bit) 40
// '0001' (4 bits) 44
// DTS[32..30] (3 bits) 47
// marker_bit = '1' (1 bit) 48
// DTS[29..15] (15 bits) 63
// marker_bit = '1' (1 bit) 64
// DTS[14..0] (15 bits) 79
// marker_bit = '1' (1 bit) 80
// PES_header_data_length = 80 bits or 10 bytes
result.Append((byte)10);
result.EnterBitMode();
result.AppendBits((byte)0x3, 3, 0);
result.AppendBits(intPts, 32, 30);
result.AppendBit(1);
result.AppendBits(intPts, 29, 15);
result.AppendBit(1);
result.AppendBits(intPts, 14, 0);
result.AppendBit(1);
result.AppendBits((byte)0x1, 3, 0);
result.AppendBits(intDts, 32, 30);
result.AppendBit(1);
result.AppendBits(intDts, 29, 15);
result.AppendBit(1);
result.AppendBits(intDts, 14, 0);
result.AppendBit(1);
result.LeaveBitMode();
}
// Append the frame data
result.Append(buffer, frame.StartIndex, frame.Length);
// TODO : figure out what the heck the quad-byte alignment thing is in Cablelabs VoD
/*int pesHeaderSize = 14; // just pts
* if (pts != dts)
* pesHeaderSize += 5; // adjust for dts
*
* while (((result.length - pesHeaderSize) % 4) != 0)
* result.append((byte)0x00);*/
frame.PESPacket = result;
frame.DTS = dts;
frame.PTS = pts;
return(result);
}
