[Mplayer-cvslog] CVS: main/DOCS/tech formats.txt,NONE,1.1

[Arpi]

Hi,

> > --- NEW FILE ---
> > 1. Input layer, supported devices, methods:
> >   - plain file, with seeking
> >   - STDIN, without seeking backward
> without seeking forward in avis with index.
it's demuxer layer limitation. btw it's not too hard to implement :)

> >     Codecs: video is always mpeg video (mpeg1, mpeg2 or mpeg4).
> hmm, I've never seen raw mpeg4 stream...
i've seen one very small chunk, and it's possible.
but, as mpeg group recommends qt for mpeg4, most standard mpeg4 is mov

> >     - bps-based: it is baed on bitrate/samplerate of video/audio steram.
typo                       ^^^^

> >       this method is used by most players, including avifile and wmp.
> >       files with broken headers, and files created with VBR audio but not
> >       vbr-compliant encoder will result a-v desync with this method.
> >       (mostly at seeking).
> >     - interleaving-based: note: it can't be used togethwer with -ni
> >       it doesn't use bitrate stuff of header, it uses the relative position
> >       of interleaved audio and video chunks. makes some badly encoded file
> >       with vbr audio playable.
> usually with vbr audio -bps has better sync then -nobps, but it helps with 
but -bps only works for vbr if samplesize==0 and samplerate/frames/sec.
many bad files handles vbr as cbr, with average values.

> other badly interleaved avis.
> 
> >
> >     Headers: AVI files has a mandatory header at the begin of the file,
> >     describing video parameters (resolution, fps) and codecs. Optionally
> >     they have an INDEX block at the end of the file. It's optional, but
> >     most files has such block, because it REQUIRES for seeking.
> >     Btw usually it can be rebuild from file content, mplayer does it with
> >     the -idx switch. Mplayer can fix broken index blocks using -forceidx.
> should be recreate not fix.
yes.

> >     Codecs: video is mostly microsoft's mpeg4 variants, MP42, MP43 (aka
> > DivX), WMV1 and WMV2. but any codecs allowed.
> >             audio is usually wma or voxware, but any codecs allowed.
> maybe add mpeg1layer3 here, too.
is it common in asf/wmv ?

> >   - QuickTime / MOV files:
> >     They come from Mac users, usually with .mov or .qt extension, but as
> >     MPEG Group choose quicktime as recommended file format for MPEG4,
> >     sometimes you meet quicktime files with .mpg extension.
> they have .mp4 extension not .mpg
hmm. btw, do you have such files?
i lost the links :(

> >     Codecs: any codecs allowed, both CBR and VBR.
> >     Note: most new mov files use Sorenson video and audio, they are
> there's no sorenson  audio, they use QDesign Music codec by QDesign but it's 
> also patented to apple it seems.
ok


A'rpi / Astral & ESP-team

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mailto:arpi at thot.banki.hu
http://esp-team.scene.hu