[MPlayer-users] Re: Free audio codec for .AVI files ?
alexander.noe at s2001.tu-chemnitz.de
Tue Jan 27 20:24:45 CET 2004
D Richard Felker III wrote:
>On Tue, Jan 27, 2004 at 06:58:57PM +0100, Alexander Noé wrote:
>>OK, I'll only comment on statements which are obviously nonsense:
>>>3. OGM reportedly lacks support for variable-fps video, but I'm not
>>> sure this is true.
>>It could be done using one page per frame, but the overhead would be
>>hilarious (about 30 bytes per frame = twice as much as AVI)
>Eh? One page per frame should decrease overhead, since all the
>overhead comes from the page headers... I guess I don't follow what
LOL. The read the specs (you need to read OGG, because OGM doesn't have any)
The page header is 28 bytes, the size per packet is then coded. If you
put k packets
into one page (which is typically done, unless you frames are larger
than 4 kb), you
have 28+(about [1..2]*k) bytes per k frames.
For audio streams, it is 28+k*(packet size/255+1) bytes per page with k
Currently, a page is about 4 kb, so that 28 bytes per 4 kB is the least
>>The OGM overhead is, assuming 4 kb pages, at least 0,6% (real life file
>>usually have 1%), for AVI, it is 16 bytes per frame/chunk
>>uses 24 bytes), for MKV, it is currently 13 (will be 16 for real B-frames)
>For NUT it's something like 6-8.
When lacing 2 frames into one block for a CFR file, it would be the
same, and should be less
for larger laces.
>No, I can judge it directly by the size of your code, which seems to
>be about 100k.
> That's about 5x as big as a demuxer should be. If you
>want to argue that it's not overcomplicated, write a 20k demuxer.
LOL. You judge the complexity of a demuxer from its size? Just using
shorter identifiers or
moving some convenience out of the demuxer (down to a level as the
libmatroska), it would be *seriously* smaller. But why should I? Just to
make you happy?
Maybe look at Gabest's code. I'm sure it is smaller than mine...
>Before you cry about your overhead again, here are some numbers. The test
>file is muxed from 36 MP3 source files, which last about 150 mins
>Not interested in your stupid test cases. Try a movie.
Ah, you don't like the numbers, so they are stupid. Good.
If you knew a single line of the specs, you could easily extrapolate the
overhead for a movie
file from those numbers. Anyway, since you are too lazy to read or
understand them, here
BTW, the test files were all around 1,5 GB, or a few hundred MBs more.
The used versions
were more or less old, but I did not change significant stuff (causing
in overhead) so far.
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