gstreamer-ffmpeg package - incorrect description

Jakub Misak jmisak at
Fri Mar 9 07:02:38 GMT 2007


There's incorrect description displayed for the gstreamer-ffmpeg package 
(FFmpeg plugin for GSstreamer). It says it can be used for encoding/decoding 
the DivX format (or even "play divx"). This is wrong, and in case you don't 
know why (most people don't understand what DivX is, there's a lot of 
confusion and intentional misinformation about this topic), I'd like to 
explain it in more detail.

DivX is:

1. A company name - DivX, Inc. is a company.

2. Brand name - the DivX company makes various software products and uses the 
DivX brand name for naming products such as DivX Pro Codec, DivX Player etc.

3. Trademark - that is, DivX is not a generic word and you cannot say that 
FFmpeg or the plugin supports DivX. Because it doesn't.

For more info, I recommend the Wikipedia article about DivX:

Now, this common confusion stems from the fact that most people don't know 
that DivX is not a format - the DivX codec (which is what most people 
call "DivX", along with video encoded with this piece of software) is a 
proprietary software product that encodes and decodes standard MPEG-4 ASP 
video. That is, video encoded with this codec is not "DivX video" or "DivX", 
it is standard MPEG-4 ASP video.

FFmpeg includes many codecs, and an MPEG-4 ASP implementation is one of them. 
So what the FFmpeg codec can decode and encode is MPEG-4 ASP video, 
not "DivX". It can decode MPEG-4 ASP video encoded with any MPEG-4 ASP 
encoder (such as DivX Pro Codec, Xvid, FFmpeg MPEG-4 or 3ivx) and video 
encoded with it can be decoded with any MPEG-4 ASP decoder (such as DivX Pro 
Codec, Xvid, FFmpeg MPEG-4 or 3ivx).

Another confusion is that while the MPEG-4 ASP video must be stored in a 
container format (usually AVI or MP4), some time ago, the DivX company 
introduced their own container format which they called "DivX Media Format" 
(i.e., not "DivX"). But firstly, FFmpeg does not support it, secondly, 
containers are not handled at the codec level (and the description mentions 
encoding and decoding, which is handled at the codec level) and thirdly, 
MPEG-4 ASP video (even encoded with DivX) is mostly saved in AVI or MP4 
containers anyway.

So, there is no way the description could be considered correct. FFmeg has 
nothing to do with DivX. That's why I would like to ask you to correct it, 
because wrong descriptions like that confuse a lot of people, make a lot of 
damage (even to FFmpeg itself) and the trademark issue itself is quite clear. 
If DivX absolutely must be mentioned in the description for some reason (it 
is a popular buzzword and a very widespread myth), then I suggest you mention 
it in a way that's used in the Ubuntu wiki, Multimedia section: "MPEG-4 ASP 
video (for example, encoded with DivX, Xvid or FFmpeg MPEG-4"). It's longer, 
but it's the only correct and acceptable way of mentioning it.

(Also, correct spelling is MPEG-4, MPEG-1 etc.)

Thanks for listening,
Jakub Misak

More information about the Ubuntu-motu mailing list