Files loaded into the sequencer uses the default render output of 1920x1080, but wanting to change to the input source native resolution, or something else, causes Blender to crash during playback or scrubbing. Sometimes using the "Strip -> Set Render Size" triggers the crash, but if not, changing render settings manually consistently assures a crash when attempting to playback/scrub.

Steps to reproduce:

1) Add a movie or image sequence into the sequencer. Playback works.
2) Change the render dimensions in the Properties editor (Presets/Manually). Start playback = crash.

Tested on:

Fedora 17 64bit
Intel i7-2600K
16 GB RAM
GeForce GTX 560