[Ffmpeg-cvslog] Re: ffmpeg-cvslog Digest, Vol 20, Issue 22

[Måns Rullgård]

Steve Lhomme <steve.lhomme at free.fr> writes:

>> From: M?ns Rullg?rd <mru at inprovide.com>
>> Steve Lhomme <steve.lhomme at free.fr> writes:
>>
>>> Alex Beregszaszi <alex at fsn.hu> writes:
>>>
>>>  > Hi,
>>>  >
>>>  >> Log:
>>>  >> add support for AAC in matroska
>>>  >
>>>  > Why matroska has to be so complicated? :)
>>>
>>>  > I think it was one of the design goals.
>>>  >
>>>  > --
>>>  > M?ns Rullg?rd
>>>
>>>  > From: Nico Sabbi <nicola_sabbi at fastwebnet.it>
>>>  > indeed: in every single mmedia program I've seen so far
>>>  > the demuxer for matroska is by far the largest and most
>>>  > full of special cases to handle separately
>>>
>>> Oh boy. Not again...
>>>
>>> Let me see, Matroska handles more formats than any other format,
>>> handles attachment, chapters, VFR, compressed data, subtitles,
>>> index-less playback, fast seeking, gaps, tags, interactive playback
>>> (DVD menus), seamless file linking and recently 3D/stereo files, all
>>> that with the lowest overhead. So yes, it may take some code to
>>> achieve that.
>> Oh boy.  So much fluff from someone who can't even quote an email
>> properly...
>
> Personal attack... (blame Thunderbird for not being able to quote with
> signatures, which happen a lot in Digest MLs)

And who should be blamed for you using thunderbird?

>>> It can take very little code to actually handle basic matroska files,
>>> once you have the EBML layer working. (MOV and AVI hide this code in
>>> riff.c in lavf).
>> The rather large size of all known matroska demuxers seems to
>> contradict that statement.
>
> Can you give examples instead of just waving things in the air ?

Sure:

$ cd ~/src/tcvp/src/demuxer
$ wc -l avi/*.c
1094 avi/avi.c

$ wc -l matroska/*.c
  285 matroska/ebml.c
 1269 matroska/matroska.c
 1554 total

$ wc -l mpeg/mpegps.c
697 mpeg/mpegps.c

$ wc -l mpeg/mpegts.c
842 mpeg/mpegts.c

$ wc -l ogg/*.c
   66 ogg/flac.c
  603 ogg/oggread.c
  162 ogg/ogm.c
  111 ogg/theora.c
  146 ogg/vorbis.c
 1088 total

$ cd ~/src/ffmpeg/libavformat
$ wc -l avidec.c gxf.c matroska.c mov.c mpeg.c mpegts.c mxf.c 
   984 avidec.c
   516 gxf.c
  2720 matroska.c
  1794 mov.c
  1824 mpeg.c      # includes muxer
  1527 mpegts.c
  1078 mxf.c

>>> And yes, the AAC codec was a mess so far in matroska as some codec
>>> "information" were given by the codec ID. Now "A_AAC" alone should be
>>> used with setting the common MPEG4 extradata (3 or 5 bytes).
>> The spec on the web fails to mention this.
>
> The codec page on the site was never up to date. Only Mosu and Haali
> know exactly about all the ones used (and looking in their OSS code,
> of course), but they aren't willing to update the specs. They are free
> to answer questions though.

ROTFL

-- 
M?ns Rullg?rd
mru at inprovide.com