[Ffmpeg-devel] [PATCH] allow ffmpeg to read mp3s beginning with partial frames

[Victor Voros]

Updated patch as per suggestions...

> Hi
> 
> On Fri, Sep 08, 2006 at 09:59:30AM +0100, Victor Voros wrote:
> > Michael - thank you for the feedback. I will post a revised patch
today
> > or tomorrow with the suggestions. I assume you're in agreement with
the
> > cosmetic changes. (constants bad!). 
> 
> yes, ive no objections to replacing 1234 constants by named constants
like 
> FOOBAR but that should ideally be a seperate patch

Taken cosmetic out as mp3_init_read doesn't need to be changed moreover
id3_parser is worse! Ideally id3 should be struct based, however a bit
too
much effort for something that is actually working 

> > 
> > I believe the false positive issue can be resolved with
> > 
> > -if (mp3_is_frame_header(p->buf+d)) return AVPROBE_SCORE_MAX;
> > +if (ff_mpa_check_header(p->buf+d/*or however its called*/)) return
> > d==0?AVPROBE_SCORE_MAX:SOME_SMALL_NON_ZERO_NUMBER;
> 
> yes
> 
>

Now utilises ff_mpa_check_header and returns 1 (safest to match if
nothing else does)

[snip ffmpeg doesn't handle it if av_probe changed w/o av_init_header]

> yes thats why i am so much against doing it in lavf/mp3.c, it belongs
> to the mp3 parser (libavcodec/parser.c)
> 
> 

Turns out im wrong it does. libavcodec/parser.c handles initial partial
frame and files work fine with just the change to mp3_read_probe as
supplied. 

Ps this is the only e-mail I can use 24x7 for complicated reasons. Sorry
about the s**t at the bottom obviously auto-gened - will try and find
alternative


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