Archive for the ‘Video’ Category

PAE kernel breaks NVidia Drivers (Ubuntu)

Thursday, May 19th, 2011

I’m running on a ThinkPad T410 with 4GB RAM. I need to stay on 32-bit as I have some dependency on 32-bit applications that I couldn’t get running on 64-bit. Thus I’ve installed the PAE kernel to access all the RAM. Problem is, this broke the graphics.

After booting up the first time, I was presented with the option of running Ubuntu in low graphics mode – great.

Anyway, the fix is nice and quick. Go into the Hardware Drivers tool and disable the NVidia driver. Reboot – you should now be back to normal resolution, just no acceleration. Re-enable the NVidia drivers and reboot again and everything should be back to normal.

Fixing the aspect ratio on Canon camcorder *.MOD files

Saturday, April 2nd, 2011

I have a Canon FS200 digital video camera which creates MOD files.  These are playable on Linux by simply changing the file extension to “mpg”.  The only issue is that the video displays in 4:3 aspect ratio, whereas it should be 16:9.

On many players, you can override the display aspect ratio during playback and then the files display correctly.  The problem is when you want to edit these files or create overlay text/graphics, as the editing program will process them in 4:3 ratio, and then when displayed in 16:9, the overlays will look stretched (while the video looks correct).

Although I have tried to solve this a number of ways, the actual fix is remarkably simple and fast.  The clue to this fix was in the error message “ODML: Aspect information not (yet?) available or unspecified, not writing vprp header.“.  Searching in the mencoder man page for “vprp” provided the solution.  Mencoder has a command line option “-force-avi-aspect” that can be used with the “-ovc copy” option, so you don’t need to re-encode (and potentially loose quality).  As this is only updating the meta data in the file, the fix is almost instantaneous.

The following command will perform the fix:

mencoder -oac copy -ovc copy -force-avi-aspect 1.777 input-4_3.mpg -o output-16_9.mpg