## Troubleshooting

### All Platforms

#### Movies do not play back smoothly in reverse.

Whenever I try to play back a movie in reverse, the playback is choppy.
Answer:
Smooth playback of movies in reverse is highly dependant on the speed of your computer as well as the resolution and codec used to encode the movie. A lot of codecs assume the playback is always done forwards and encode frames by taking advantage of frame differences.
Sometimes to decode even one frame it is needed to know up to a second of all the frames that came before it (and sometimes after it, too).
When playing back in reverse, it means mrViewer needs to work harder in decoding several back frames before the current frame is actually displayed. If your computer is not fast enough to decode those frames under the fps playback, you will see the playback stutter.
If your movie contains audio, you can often improve reverse playback by turning off the audio by going to the audio track selection button and selecting <no audio>.

#### Opening mrViewer reports another instance is running.

Whenever I try to open mrViewer, it fails telling me another instance is running.
Answer:
mrViewer supports a mode where only an instance of mrViewer is present so that if you try opening an image in another viewer, the image is redirected towards the first opened viewer. This feature is set in the preferences. This system works by creating a dummy mrViewer.lock.prefs file inside the preferences directory. Sometimes if the viewer was not closed properly, this dummy file is left behind and will incorrectly report that another instance of mrViewer is running. Under Linux that file is /home/@user@/.fltk/filmaura/ and under Windows, it is %APPDATA%/filmaura. Removing the file will allow you to open a new mrViewer.