[Vorbis] Oggenc producing a different file every time

[Joost van Dongen]

We are using the Ogg file format in our game Awesomenauts. Now whenever I
rebuild our compressed music files from our uncompressed sources (WAV to
OGG), oggenc.exe produces different files. They sound the same, but there
are differences in the file. I did a checksum on the hex, and it turns out
there are small pieces of similar differences throughout the file.

This is a serious problem for us: whenever I run our complete build process
and produce a patch for Awesomenauts (which happens almost every week), all
audio files are different, and thus all our Steam users will have to
download 120mb of music that has not actually changed. (We also regularly
make real changes to the soundtrack in patches, so I want to keep a
complete rebuild of the soundtrack in our build process to avoid
accidentally missing things when building.)

I thought oggenc.exe might add the current date if I don't set one myself,
so I tried setting the date through "-d 1-1-2012", but that did not help.

So, what changes every time, and how can I prevent this from happening?

Thanks in advance!

With kind regards,
Joost

-
Joost van Dongen
Lead programmer / co-founder
Ronimo Gameswww.ronimo-games.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.xiph.org/pipermail/vorbis/attachments/20121129/51ce41c5/attachment.htm