Changing AVI Aspect Ratio

logifuse · **10th March 2008, 01:42 PM**

Leaving aside MC's ability to adjust aspect ratio via the zoom settings, & leaving aside FFDShow's ability for force an aspect ratio for playback, can an AVI's aspect ratio be altered after it has been created?

With an MPEG2, you can change the header, but there doesn't seem to be the same option for an AVI, so when you view something in the wrong aspect on a device that can't adjust it, it's stuffed.

I've tried a few tools, but any changes seem to be ignored by the player - I assume then that the aspect ratio is set purely by numbers of pixels & therefore rectangular pixels aren't catered for?

Any ideas?

Justin

AdrianW · **10th March 2008, 02:29 PM**

MPEG4Modifier can change the aspect ratio of avi files. Some players take notice of it and others don't (VLC usually does). My Pioneer DivX/XviD capable DVD player does take notice and I've fixed some 4:3 avi's so they actually display at 4:3 instead of 3:2.

The mkv container has it's own aspect information, and I've successfully altered this to correctly display some anamorphic encodes properly (using the mkvmerge).

You could stick your avi inside an mkv container and set the aspect there - most players should take notice of that (including Media Centre).

mkvmerge is included with the mkvtoolnix utilities which are available for free.

Note: MPEG4Modifier is also a great tool for "unpacking" packed bitstream avi's which can cause playback stuttering on some standalone players (like my Pioneer DVD player).

logifuse · **10th March 2008, 02:40 PM**

Quote:

Originally Posted by AdrianW

MPEG4Modifier can change the aspect ratio of avi files. Some players take notice of it and others don't (VLC usually does). My Pioneer DivX/XviD capable DVD player does take notice and I've fixed some 4:3 avi's so they actually display at 4:3 instead of 3:2.

Yeah, that's one of the programs I tested. Unfortunately my crapola video playing hard drive (called a DXmini 400) doesn't do aspect ratio changing & it ignored any changes. I've been trying to find a firmware update for it, but have had no joy.

Quote:

The mkv container has it's own aspect information, and I've successfully altered this to correctly display some anamorphic encodes properly (using the mkvmerge).

You could stick your avi inside an mkv container and set the aspect there - most players should take notice of that (including Media Centre).

Unfortunately the DXmini is MKV incapable.

Quote:

mkvmerge is included with the mkvtoolnix utilities which are available for free.

I've played with them - great tools!

Justin