// ######################################################################
unsigned int getFrameSize(const VideoFormat vidformat,
const Dims& imgdims)
{
const unsigned int sz = imgdims.sz();
unsigned int numer=0, denom=0;
getBytesPerPixelForMode(vidformat, &numer, &denom);
ASSERT(numer > 0);
ASSERT(denom > 0);
return (sz * numer) / denom;
}
// ######################################################################
GenericFrame MgzJDecoder::readFrame()
{
// Grab the journal entry for this frame and allocate an appropriate GenericFrame
MgzJEncoder::journalEntry entry = itsJournal.at(itsFrameNum);
const Dims dims(entry.width, entry.height);
const GenericFrame::NativeType pix_type = GenericFrame::NativeType(entry.pix_type);
const int num_pix = dims.sz();
GenericFrame frame;
//Read in the compressed image to a buffer
uint64 comp_image_buf_size = entry.end_byte - entry.start_byte;
byte * comp_image_buf = new byte[comp_image_buf_size];
itsFile.seekg(entry.start_byte, std::ios::beg);
itsFile.read((char*)comp_image_buf, comp_image_buf_size);
//Prepare zlib to do the decompression
z_stream strm;
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
strm.avail_in = 0;
strm.next_in = Z_NULL;
int ret = inflateInit(&strm);
if(ret != Z_OK)
LFATAL("Could not initialize zlib!");
strm.avail_in = comp_image_buf_size;
strm.next_in = comp_image_buf;
switch(pix_type)
{
case GenericFrame::GRAY_U8:
{
Image<byte> img(dims, NO_INIT);
strm.avail_out = num_pix * sizeof(byte);
strm.next_out = (unsigned char*)img.getArrayPtr();
ret = inflate(&strm, Z_FINISH);
if(ret != Z_STREAM_END)
{ LFATAL("Could Not Inflate Frame! %d, %s", ret, strm.msg); }
frame = GenericFrame(img);
break;
}
case GenericFrame::GRAY_U16:
{
Image<uint16> img(dims, NO_INIT);
strm.avail_out = num_pix * sizeof(uint16);
strm.next_out = (unsigned char*)img.getArrayPtr();
ret = inflate(&strm, Z_FINISH);
if(ret != Z_STREAM_END)
{ LFATAL("Could Not Inflate Frame! %d, %s", ret, strm.msg); }
frame = GenericFrame(img);
break;
}
case GenericFrame::GRAY_F32:
{
Image<float> img(dims, NO_INIT);
strm.avail_out = num_pix * sizeof(float);
strm.next_out = (unsigned char*)img.getArrayPtr();
ret = inflate(&strm, Z_FINISH);
if(ret != Z_STREAM_END)
{ LFATAL("Could Not Inflate Frame! %d, %s", ret, strm.msg); }
frame = GenericFrame(img, entry.flags);
break;
}
case GenericFrame::RGB_U8:
{
Image<PixRGB<byte> > img(dims, NO_INIT);
strm.avail_out = num_pix * sizeof(PixRGB<byte>);
strm.next_out = (unsigned char*)img.getArrayPtr();
ret = inflate(&strm, Z_FINISH);
if(ret != Z_STREAM_END)
{ LFATAL("Could Not Inflate Frame! %d, %s", ret, strm.msg); }
frame = GenericFrame(img);
break;
}
case GenericFrame::RGB_U16:
{
Image<PixRGB<uint16> > img(dims, NO_INIT);
strm.avail_out = num_pix * sizeof(PixRGB<uint16>);
strm.next_out = (unsigned char*)img.getArrayPtr();
ret = inflate(&strm, Z_FINISH);
if(ret != Z_STREAM_END)
{ LFATAL("Could Not Inflate Frame! %d, %s", ret, strm.msg); }
frame = GenericFrame(img);
break;
}
case GenericFrame::RGB_F32:
{
Image<PixRGB<float> > img(dims, NO_INIT);
strm.avail_out = num_pix * sizeof(PixRGB<float>);
strm.next_out = (unsigned char*)img.getArrayPtr();
ret = inflate(&strm, Z_FINISH);
if(ret != Z_STREAM_END)
{ LFATAL("Could Not Inflate Frame! %d, %s", ret, strm.msg); }
frame = GenericFrame(img, entry.flags);
break;
}
case GenericFrame::VIDEO:
{
const size_t vidSize = getFrameSize(VideoFormat(entry.flags), dims);
ArrayHandle<byte> vidBuffer(new ArrayData<byte>(Dims(vidSize,1), NO_INIT));
strm.avail_out = vidSize;
strm.next_out = (unsigned char*)vidBuffer.uniq().dataw();
ret = inflate(&strm, Z_FINISH);
if(ret != Z_STREAM_END)
{ LFATAL("Could Not Inflate Frame! %d, %s", ret, strm.msg); }
frame = GenericFrame(VideoFrame(vidBuffer, dims, VideoFormat(entry.flags), bool(entry.byte_swap)));
break;
}
default:
LFATAL("Could Not Open Frame Of Type: %d!", pix_type);
}
inflateEnd(&strm);
delete [] comp_image_buf;
return frame;
}
