design problem for the snapshot hotkey with some vouts (sdl, aa, caca, ...)
For some vout outputs (for instance, sdl, aa, caca), hotkeys are directly detected and processed by the vout thread.
This is a problem for the snapshot hotkey (shift-'S'), that fails with "main video output error: Failed to grab a snapshot"
Actually, the snapshot api design makes it mandatory to use it in any thread but the vout thread, (otherwise vlc_cond_timedwait line 84 of src/video_output/snapshot.c always deadlocks till the deadline is reached)
Note that when snapshot is triggered from the qt4 menu, there is no problem since the qt4 thread is the one using the snapshot api.