2008.02.03 11:07 "Re: [Tiff] Problem with large tiff images", by

Jean-Michel,

   I am a developer in c# and c++ and i am working on tiff images. But i am a problem when i try to save image (22000x9000 pixels and 30000x10000 pixels) i have an error "No space to output buffer".
How to save a large tiff file with libtiff?
I use:

unsigned char* scanline_data = (unsigned char*)_TIFFmalloc(exportWidth*spp*sizeof(unsigned char));

if(scanline_data != NULL)
{
for(unsigned long row= 0 ; row < height ; row++)
{
memcpy(scanline_data,raster+row*exportWidth*spp,exportWidth*spp);
TIFFWriteScanline(output,scanline_data, row,0);
}

_TIFFfree(scanline_data);
}
TIFFFlush(output);
TIFFClose(output);
_TIFFfree(raster);

Since you use the Scanline interface, you're likely writing a strip TIFF or this wouldn't succeed at all. Bear in mind that some stages in LibTiff may require buffers as large as one complete strip, though that may depend on the compression mode selected. Though it's not clear if you do any error checking, what tags you set with what values, and at what point exactly the error occurs, this might very well be related to your problem as you might be writing this as a single strip image.

So make sure you set the RowsPerStrip tag to an appropriatelly small value. A good value might be 10 or so, as 10*30000*4, with 30000 being about the highest width you have in mind, and 4 being a typical average bytesize of a pixel depending on your colourspace setting, is 1200000, is roughly about a bit more then a megabyte. That's not too much so as to not get large stalls on buffering decoders, and in the first place it will not get you into unscalable trouble in buffering encoders, and it's not too little such that the overhead in various places that comes from the division into strips is still negligable. If you're using JPEG compression, you might want to select a value of 16 instead, as that'll likely correspond to the height of a JPEG MCU if you use default subsampling values and result in efficient compression.

Best regards,

Joris Van Damme
info@awaresystems.be
http://www.awaresystems.be/
Download your free TIFF tag viewer for windows here:
http://www.awaresystems.be/imaging/tiff/astifftagviewer.html