[MPlayer-dev-eng] Re: How to play the raw mpeg4 bitstream

[swchen]

> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> swchen wrote:
> >    I have got a stream encoded with ffmpeg, with file name .m4v,
> > i can sure it is a raw bitstream without any avi header
> > i can decode it using ffmpeg, but how to play it using Mplayer??
> > 
> > ./mplayer movie.m4v
> > ========= sorry, this file format is not recognized/supported ====
> > 
> > but i can sure it can be understood by libavcodec, how to solve this
> > problem??
> 
> It may be understood by libavformat, but AFAIK, libavcodec does encoding 
> and decoding of video and audio at the frame or sample level; it doesn't 
> know about stream formats. MPlayer doesn't use libavformat, since it has 
> its own demuxers.

thank you, i am also sure ffmpeg use libavformat to find the correct codec to decode it.

Is is possible for Mplayer to support MPEG4-ES decoding, as i know, 
mpeg4 is the same mpeg1/mpeg2 bitstream, they don't need globe header, 
we can decode mpeg1/2 bitstream start from anywhere in the bitstream, it will search 
next frame start code and start to decode it. 

Why Mplayer can play a MPEG2 elementary stream, but can't play a MPEG4 
elementary stream?? If at this time, Mplayer can't decode a MPEG4-ES, we can submit
patches to it. But i must know is it true first??


>  You should be able to use ffmpeg itself to put the 
> video in the m4v into an AVI. Then, MPlayer can read it.
> 
> Jonathan Rogers

and if i use ffmpeg to convert the mpeg4-ES into avi, ffmpeg will decode it first then
encode it again with avi header . 
(command:--> ffmpeg -i movie.m4v movie.avi) of course, this command works fine.
But it is waste time and video quallity will be degraded!

someone tell me to use 
---> ffmpeg -i movie.m4v -vcodec copy movie.avi
but using this command, it can't played correctly using mplayer, even ffmpeg itself can't
decode the copyed movie.avi correclty.  It's strange!! I think the avi header and because
chunk length is fixed to 2048. 

I have asked this in ffmpeg, but it seems no one answer. 
other command usage ?? 

swchen
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