## Troubleshooting

### Linux issues

#### mrViewer does not start up.

Whenever you try to start up image viewer, it crashes right away or it crashes as soon as an image is loaded.
Answer:
This can sometimes happen when your distro updates some kernel files that effect your OpenGL driver. Check other OpenGL programs to see if they exhibit similar behavior. If they do, recompile your linux graphics card driver or update it from your repository.

#### Some image formats load as 8-bit or 16-bit only or with incorrect alpha channel.

Whenever I try loading an image like a tiff file, it loads only as a 16-bit or 8-bit only file or an unpremult alpha channel even though it is a float file with alpha channel.
Answer:
This is usually a problem with your ImageMagick library. mrViewer expects ImageMagick to have been compiled with 32-bit float channel support, but most Linux distributions compile it with 16-bit only. The mrViewer shell wrapper script should set your LD_LIBRARY_PATH to point to its own local ImageMagick library to avoid problems, but perhaps you've changed it or have a different setup. Make sure to set up your LD_LIBRARY_PATH to point to mrViewer's ImageMagick library or compile your own version of ImageMagick but with 32-bit support.

#### Some avi or movie files do not play their audio.

Sometimes, when loading some movie or avi files, the video plays, but there's no audio.
Answer:
This often indicates the lack of an appropriate codec for playing the audio in the ffmpeg library. Open the image information window and check the audio track you are interested in. Check whether "Known Codec" says "Yes". If it says no, ffmpeg does not have the needed codec for playback. Check also the name of the codec and its fourcc id. Most codecs go by their name but others have become popular by their fourcc id (DIVX or XVID, for example).
Movie and avi files are just a format for storing a movie. However, the way the movie and audio is compressed is handled by what is referred as a codec (a codify - decodify routine or plugin). mrViewer ships with a library that handles almost every codec currently known. However, some of these codecs are proprietary and are patented.
In countries that accept software patents like the U.S., this requires the paying of license fees for distribution or for decoding them.