Martin Samuelsson wrote: > On Sun, 18 Mar 2007 08:38:08 +0100 > Andrea Giuliano <[EMAIL PROTECTED]> wrote: > > > AVI files are files containing data contained in the RIFF container format > (which in turn is a ripoff of IFF, just with different endianness and chunk > naming authority). > > Lavrec, or rather avilib, create a file with an empty RIFF header, which is > filled in when the file is closed. Why, I do not know, but that's the way > it's done. Thus, if lavrec crashes, there'll be a file without RIFF header, a > lot of RIFF data and no index chunk, as the index is written last, too. > > http://en.wikipedia.org/wiki/RIFF gives some background, and > http://en.wikipedia.org/wiki/Audio_Video_Interleave gives a little more > in-depth information. > > http://msdn2.microsoft.com/en-us/library/ms779636.aspx (linked to fromn the > latter) explains the really gory parts of RIFF, and with this information, in > combination with head, cat, a good text editor and a certain amount of > creativity, you should be able to transplant a header from one of the working > files. With any luck, you should be able to feed this file to mencoder, using > -oac copy -ovc copy, and recreating the index with -forceindex, giving you a > working file. > > I've done it once, but I'm not sure it was worth the effort. > > /Sam
Many thanks for your hint! It was not easy, but at least I got to fix my last, corrupted AVI file. Completely! Here is what I did: a) dd bs=2048 count=1 if=good.avi of=good-header (to get a good RIFF header from another AVI output by lavrec) b) dd bs=2048 skip=1 if=bad.avi of=bad-noheader.avi (to get a copy of the bad AVI file without the empty header) c) cat good-header bad-noheader.avi > fixed.avi (to get a correct AVI file, still without index) d) aviindex -i fixed.avi -o idx (to create an index file for fixed.avi) e) avimerge -i fixed.avi -o perfect.avi -x idx (to create a copy of fixed.avi with the index from the idx file) It took some time to tune the receipt, but it worked. I hope it works in general, but it should indeed, because the RIFF header really seems to be the same for every file produced by lavrec. Best regards. > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > Mjpeg-users mailing list > Mjpeg-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/mjpeg-users -- Andrea ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Mjpeg-users mailing list Mjpeg-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mjpeg-users
