Breaking Eggs And Making Omelettes

Topics On Multimedia Technology and Reverse Engineering


Archives:

Of Filesystems and Codecs

April 9th, 2009 by Multimedia Mike

I have been hanging out at the Linux Foundation Collaboration Summit. One theme I have heard tossed around is the matter of filesystems– ongoing filesystem research, the need to upgrade standard filesystems in Linux, etc. I admit that I don’t spend a lot of time thinking about filesystems (except when I’m writing FUSE drivers for filesystems that lack wide appeal). The filesystem is something that’s just “there” and should just work. Indeed, I have never had a major problem with any filesystem I have used while it is still considered modern. It is only when the next generation comes along that I understand the faults in the previous generation (journaled filesystems helped me understand that extensive integrity checking at boot time doesn’t have to be necessary; anything beyond FAT16 helped me understand that 8.3 filenames didn’t have to be the standard).

But there is a category of obsessed individuals who spend a lot of time thinking about filesystems and measuring what they’re doing and figuring out how they could be doing things better. And it’s a good thing that we have these people around, even though most of us largely view filesystems as a transparent cog in the machine of daily computing.

This got me to thinking about how it’s probably very likely that most computer users view multimedia codecs the same way that I view filesystems. An AVI file might contain Cinepak or MPEG-4 part 2 video, or any of 100+ video codecs. Most users don’t have a reason to care about the difference. This may help to explain why some people (not particularly well-versed in multimedia technology) take it for granted that Theora could easily replace H.264 in all applications where the latter is in use today.

They’re both video codecs, right?

Posted in General | 8 Comments »

8 Responses

  1. Diego “Flameeyes” Pettenò Says:

    But xiph produces perfect software doesn’t it?

    Oh sorry I know it starts to be cheap to take a shot at them for me… I sincerely can’t get over the 21-bit sized fields in FLAC files…

  2. Alex Says:

    Presumably this is also they same syndrome that causes people to try to shoehorn everything under the sun into AVI?

  3. Diego “Flameeyes” Pettenò Says:

    No that’s just because for quite a while multimedia on Windows meant “.avi files” and most people expect that to be better supported than anything else in the world…

  4. Denver Gingerich Says:

    I think many in the open source community realize that Theora has shortcomings, but you’re right, probably many don’t.

    What is your opinion of Dirac ( http://diracvideo.org/ )? From what I’ve heard, it seems to compete with H.264 on size/quality much better than Theora.

    There is the issue of the installed base of hardware H.264 decoders as well when we consider a switch to Dirac. Switching would take time, but if Dirac is just as good as H.264, why not?

  5. Reimar Says:

    Well, at least in a few years ago AVI definitely _was_ better supported than anything else, e.g. indexes are completely optional and headers are small and in the front so partial files basically always could be played, there are many tools that will restore the index (even during runtime) so that even seeking works.
    In contrast, for all I know if mov/mp4 misses the index there’s basically nothing you can do, so minor damage -> whole file unusable.
    MKV probably is better, but I don’t know if there are any easy tools to restore the index to allow seeking, and at least FFmpeg and MPlayer are definitely no good in handling mkv files without index.

  6. Diego “Flameeyes” Pettenò Says:

    At least for xine I think there are better chances of QT to work than AVI; on the other hand you’re right, damaged files are probably better recovered with AVI right now and mkv needs love for most players.

  7. Pengvado Says:

    > MKV probably is better, but I don’t know if there are any easy tools to restore the index to allow seeking

    mkvmerge will do that as a side effect of remuxing.

  8. tam Says:

    Were you wondering why so many lambda users call any digital sound file, mp3 as well? Even when encoding and media library management software such as WMP and iTunes uses their own proprietary format? :p

    As far as users are concerned, you are right to point out that format standard should not be of any concern. :)