[FFmpeg-devel] [PATCH] Add documentation for the CRC muxer.

Stefano Sabatini stefano.sabatini-lala
Tue Feb 1 11:41:05 CET 2011


On date Tuesday 2011-02-01 00:23:42 +0000, M?ns Rullg?rd encoded:
> Stefano Sabatini <stefano.sabatini-lala at poste.it> writes:
> 
> > ---
> >  doc/muxers.texi |   33 +++++++++++++++++++++++++++++++++
> >  1 files changed, 33 insertions(+), 0 deletions(-)
> >
> > diff --git a/doc/muxers.texi b/doc/muxers.texi
> > index 7076959..f097753 100644
> > --- a/doc/muxers.texi
> > +++ b/doc/muxers.texi
> > @@ -18,6 +18,39 @@ enabled muxers.
> >
> >  A description of some of the currently available muxers follows.
> >
> > + at section crc
> > +
> > +CRC (Cyclic Redundancy Check) testing format.
> > +
> > +This muxer computes and prints the CRC of all the input audio and
> > +video frames. By default the CRC is computed on the decoded input
> > +audio and video frames converted respectively to rawvideo and signed
> > +16-bit rawaudio.
> 
> Just one problem, which is not your fault: it's not actually a CRC,
> but an adler32 checksum.

Mentioned Adler-32.

> > +The output of the muxer consists of a single line of the form:
> > +CRC=0x at var{CRC}, where @var{CRC} is an hexadecimal number 0-padded to
> > +8 digits containing the CRC for all the decoded input frames.
> > +
> > +For example to compute the CRC of the input, and store it in the file
> > + at file{out.crc}:
> > + at example
> > +ffmpeg -i INPUT -f crc out.crc
> > + at end example
> > +
> > +You can print the CRC to stdout with the command (using the
> > + at file{sh} shell syntax):
> > + at example
> > +ffmpeg -i INPUT -f crc - 2&> /dev/null
> > + at end example
> 
> That redirection is not standard shell syntax, and I don't think it's
> bash either.

Removed.

Updated.
-- 
FFmpeg = Fantastic Funny Murdering Peaceless Elastic Gymnast



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