[gdal-dev] What happens by default when writing RGBA into jpeg?

2014-06-10 Thread Jukka Rahkonen
Hi, I would like to know what happens if I convert an original RGBA tiff image into jpeg as gdal_translate -of jpeg rgba_in.tif jpeg_out.jpg I know that for getting a good result I can add -b 1 -b 2 -b 3 but I am curious to know what happens and how GDAL computes sort of a transparent sepia

Re: [gdal-dev] What happens by default when writing RGBA into jpeg?

2014-06-10 Thread Even Rouault
Selon Jukka Rahkonen jukka.rahko...@mmmtike.fi: Hi, I would like to know what happens if I convert an original RGBA tiff image into jpeg as gdal_translate -of jpeg rgba_in.tif jpeg_out.jpg I know that for getting a good result I can add -b 1 -b 2 -b 3 but I am curious to know what

Re: [gdal-dev] What happens by default when writing RGBA into jpeg?

2014-06-10 Thread Jukka Rahkonen
Even Rouault even.rouault at mines-paris.org writes: Selon Jukka Rahkonen jukka.rahkonen at mmmtike.fi: Hi, I would like to know what happens if I convert an original RGBA tiff image into jpeg as gdal_translate -of jpeg rgba_in.tif jpeg_out.jpg I know that for getting a good

Re: [gdal-dev] What happens by default when writing RGBA into jpeg?

2014-06-10 Thread Even Rouault
Selon Jukka Rahkonen jukka.rahko...@mmmtike.fi: Even Rouault even.rouault at mines-paris.org writes: Selon Jukka Rahkonen jukka.rahkonen at mmmtike.fi: Hi, I would like to know what happens if I convert an original RGBA tiff image into jpeg as gdal_translate -of jpeg

Re: [gdal-dev] What happens by default when writing RGBA into jpeg?

2014-06-10 Thread Jukka Rahkonen
Even Rouault even.rouault at mines-paris.org writes: Hi Even, Sorry, I must have been unclear. The question was about writing out a real JPEG file, not JPEG compressed TIFF Ah my fault. I read too fast. The command gdal_translate -of jpeg rgba_in.tif jpeg_out.jpg creates a jpeg

Re: [gdal-dev] What happens by default when writing RGBA into jpeg?

2014-06-10 Thread Even Rouault
Thanks, that makes sense. However, the result is somehow surprising and I guess that in most cases unusable for the user. I wonder if it would be good to print something like WARNING. Encountered 4 source bands, assuming CMYC color space. Behaviour is not very easy to understand by reading

Re: [gdal-dev] What happens by default when writing RGBA into jpeg?

2014-06-10 Thread Eli Adam
On Tue, Jun 10, 2014 at 6:28 AM, Even Rouault even.roua...@mines-paris.org wrote: Thanks, that makes sense. However, the result is somehow surprising and I guess that in most cases unusable for the user. I wonder if it would be good to print something like WARNING. Encountered 4 source bands,