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

[Michael Niedermayer]

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


> 
> 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


> 
> Wrt to the posted mp3s if there is no change to mp3_read_header but
> mp3_read_probe is changed, then ffmpeg goes seriously pear-shaped (ie
> codec thinks the random first few bytes of the file as valid sampling
> frequencies etc).
> 
> It would make sense to move the partial frame skipping code (factored!)
> from mp3_read_header to the libavcodec as presumably if something is
> generating dodgy mp3 files it stands to reason something is able to mux
> said dodgy files into a dodgy .mpg. 

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


[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
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