[FFmpeg-devel] [PATCH] mp3 muxer: write all metadata

Michael Niedermayer michaelni
Fri Sep 25 15:18:23 CEST 2009


On Fri, Sep 25, 2009 at 06:03:19AM -0400, Justin Ruggles wrote:
> Anton Khirnov wrote:
> 
> > Hi,
> > with attached patch the mp3 muxer will write all available metadata, not
> > just a few selected as it does now.
> > 
> > btw shouldn't there be a list of standard ffmpeg tag names somewhere?
> 
> 
> I agree that we should have a list of generic tag names (and their
> formats if applicable).
> 
> > From ced4fae2478201b70b417f8a10c6be5d6d4404b6 Mon Sep 17 00:00:00 2001
> 
> > From: Anton Khirnov <wyskas at gmail.com>
> > Date: Fri, 25 Sep 2009 09:04:42 +0200
> > Subject: [PATCH] mp3 muxer: write all metadata
> > 
> > ---
> >  libavformat/mp3.c |   86 ++++++++++++++++++++++++++++++++---------------------
> >  1 files changed, 52 insertions(+), 34 deletions(-)
> > 
> > [...]
> > +        if      (!strcmp(t->key, "album"))    tag = MKBETAG('T', 'A', 'L', 'B');
> > +        else if (!strcmp(t->key, "composer")) tag = MKBETAG('T', 'C', 'O', 'M');
> > +        else if (!strcmp(t->key, "genre"))    tag = MKBETAG('T', 'C', 'O', 'N');
> > +        else if (!strcmp(t->key, "copyright"))tag = MKBETAG('T', 'C', 'O', 'P');
> > +        else if (!strcmp(t->key, "date"))     tag = MKBETAG('T', 'D', 'R', 'L');
> 
> 
> Using "date" is not compatible with other metadata readers/writers,
> which all use "year".  Personally I think that all the readers/writers
> should be changed to use "date" instead, in ISO format so that the year
> would be the first 4 chars.  That way it would be usable for those
> formats that only support the year.  An alternative would be to have a
> fallback to use "year" for TDRL if "date" does not exist.

is either of you aware of AVMetadataConv ?
what can we do to make it more clear how the metadata api works?
that is demuxers export the metadata that is stored in the file,
muxers store it as it is provided to the muxer. There are some
specific rules how trees and multiple tags are exportet but i dont
see why one would rename all tag keys explixitly or reformat values in
the demuxer
That is what AVMetadataConv is for ...

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I hate to see young programmers poisoned by the kind of thinking
Ulrich Drepper puts forward since it is simply too narrow -- Roman Shaposhnik
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