FrameParserStatus_t FrameParser_VideoMjpeg_c::ReadHeaders( void )
{
FrameParserStatus_t Status = FrameParserNoError;
unsigned int Code;
bool StartOfImageSeen;
#if 0
unsigned int i;
report (severity_info, "First 40 bytes of %d :", BufferLength);
for (unsigned int i=0; i<40; i++)
report (severity_info, " %02x", BufferData[i]);
report (severity_info, "\n");
#endif
#if 0
report (severity_info, "Start codes (%d):", StartCodeList->NumberOfStartCodes);
for (unsigned int i=0; i<StartCodeList->NumberOfStartCodes; i++)
report (severity_info, " %02x(%d)", ExtractStartCodeCode(StartCodeList->StartCodes[i]), ExtractStartCodeOffset(StartCodeList->StartCodes[i]));
report (severity_info, "\n");
#endif
ParsedFrameParameters->DataOffset = 0;
StartOfImageSeen = false;
for (unsigned int i=0; i<StartCodeList->NumberOfStartCodes; i++)
{
Code = StartCodeList->StartCodes[i];
Bits.SetPointer (BufferData + ExtractStartCodeOffset(Code));
Bits.FlushUnseen(16);
Status = FrameParserNoError;
switch (ExtractStartCodeCode(Code))
{
case MJPEG_SOI:
ParsedFrameParameters->DataOffset = ExtractStartCodeOffset(Code);
StartOfImageSeen = true;
break;
case MJPEG_SOF_0: // Read the start of frame header
case MJPEG_SOF_1:
if (!StartOfImageSeen)
{
FRAME_ERROR("%s - No Start Of Image seen\n", __FUNCTION__);
return FrameParserError;
}
Status = ReadStartOfFrame();
if (Status == FrameParserNoError)
return CommitFrameForDecode();
break;
case MJPEG_APP_15:
Status = ReadStreamMetadata();
break;
default:
break;
}
}
return FrameParserNoError;
}
//
// ReadHeader()
//
void JLSInputStream::ReadHeader()
{
if (ReadByte() != 0xFF)
throw JlsException(InvalidCompressedData);
if (ReadByte() != JPEG_SOI)
throw JlsException(InvalidCompressedData);
for (;;)
{
if (ReadByte() != 0xFF)
throw JlsException(InvalidCompressedData);
BYTE marker = (BYTE)ReadByte();
size_t cbyteStart = _cbyteOffset;
LONG cbyteMarker = ReadWord();
switch (marker)
{
case JPEG_SOS: ReadStartOfScan(); break;
case JPEG_SOF: ReadStartOfFrame(); break;
case JPEG_COM: ReadComment(); break;
case JPEG_LSE: ReadPresetParameters(); break;
case JPEG_APP0: ReadJfif(); break;
case JPEG_APP7: ReadColorSpace(); break;
case JPEG_APP8: ReadColorXForm(); break;
// Other tags not supported (among which DNL DRI)
default: throw JlsException(ImageTypeNotSupported);
}
if (marker == JPEG_SOS)
{
_cbyteOffset = cbyteStart - 2;
return;
}
_cbyteOffset = cbyteStart + cbyteMarker;
}
}
