[FFmpeg-devel] Fwd: parser vs. demuxer

Michael Niedermayer michaelni
Wed May 30 11:06:08 CEST 2007


On Wed, May 30, 2007 at 01:08:57PM +1000, mark cox wrote:
> I'm reposting this on the devel list, hope some-one can point me in the
> right direction.
> ---------- Forwarded message ----------
> From: mark cox <melbournemark+ffmpeg at gmail.com>
> Date: 29-May-2007 12:21
> Subject: parser vs. demuxer
> To: FFmpeg user questions and RTFMs <ffmpeg-user at mplayerhq.hu>
> I'm confused about when to use a parser and when to use a demuxer. I have
> been trying to study the img2 code, and i'm surprised that a simple image
> format like pnm has a parser, yet a complex one like gif does not. does
> anyone have any opinions on this, because it seems there is no clear line
> when to use one or the other, and the definitions of a parser i have found
> are much to general to be of use. I want an ffmpeg world view of this.
> Regards,
> mark

demuxer is the thing which takes a container (a single 1-D vector of bytes)
and splits (demuxes) these into several streams (1 or more audio streams,
1 or more video streams, ...)

a parser is the thing which takes a single stream as output by a demuxer and
splits it into proper frames (some demuxers already produce proper frames
so no parser is needed)

pnm itself doesnt need a parser, what needs a parser is something like

cat *.pnm | ffmpeg ...

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Democracy is the form of government in which you can choose your dictator
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