[Ffmpeg-devel] versions, ABIs and sonames

Michael Niedermayer michaelni
Sat Jul 23 22:28:53 CEST 2005


On Saturday 23 July 2005 10:59, matthieu castet wrote:
> Hi,
> Michael Niedermayer wrote:
> > Hi
> >
> > if theres some interrest then ill change the meaning of the current
> > LIBAV*_BUILD number from integer to aabbcc 3 element version vector or do
> > we need more then 100 of each?
> why not aaabbbccc ?

well, the build number is stored in many encoded files at every keyframe, so 
its better if its shorter
the bitrate waste is 0.24kbit/sec for each byte for 30fps intra only (worst 
realistic case)

we could also certainly use a more compact and complicated format, iam just 
not sure if its worth it
our goals are:
1. easy to convert to a single number so bug workaround code just needs a 
2. short as its stored in files
3. large range for each version component
4. easy to parse
5. no occurance of 0x00 0x00 0x01 (would need escaping for mpeg*)
6. preferably a ascii string
7. preferably compatible with the current build number

and just to clarify it in case its not obvious, yes the "external" user 
vissible version will be 1.2.3 style

various ideas for the ident+build string

and yes all of these except maybe the last 2 would break compatibility with 
the current thing we store, which is "FFmpegCVSb4758" which actually isnt 
parsed correctly by h263.c and the string we stored before 
("FFmpeg0.4.9pre1b47??") wasnt parsed correctly either due to the "pre1"


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