Is there anyway to change comments in an OGM without remuxing?

[BluDChyLD]

Hi,
I want to change the LWING_GAIN value on the audio tracks in some already muxed OGM files. Is there program that can adjust the comments in an OGM without having to remux the original audio and video files again?
Thanks

[Joe Fenton]

You could always use a hex editor like XVI32.
http://www.chmaas.handshake.de/delphi/freeware/xvi32/xvi32.htm

If the video file is checksummed, you would have to then fix it with some form of video fixing utility like DivFix. Otherwise, I don't see a problem.

[Suiryc]

I don't know tools that would allow that (maybe there are, but not that I know).
Unless you know what you are doing (i.e. you know the Ogg bitstream format by heart) I highly recommand you to not manually edit an OGM file. As you may know an Ogg bitstream uses Pages (generally of 4kB, or less for headers and comments), and each Page is checksummed. Meaning that if you edit your file manually you need to update yourself the checksum of the Page(s) you modified.

Moreover I doubt that DivFix (an AVI 'repairing' utility) will help you with an OGM file.

[Joe Fenton]

I know DivFix doesn't work on OGMs. That's why I said "like" DivFix. I'm not aware of a utility that recalculates OGM checksums, but that doesn't mean there isn't one. Also, I wouldn't use a hexeditor to change a bunch of things in a file, but changing one comment tag should be safe enough. Going in and changing "1.0" to "1.5" doesn't have any danger to it at all. The only thing that stops you is recalculating the checksum. Check various OGM sites that have commandline tools. You might find something.