[FFmpeg-devel] [RFC] scenechange_score in AVCodecContext?

[Michael Niedermayer]

On Thu, Nov 15, 2007 at 03:07:47PM +0100, Stefano Sabatini wrote:
> On date Thursday 2007-11-15 03:11:54 +0100, Michael Niedermayer encoded:
> > Hi
> > 
> > On Wed, Nov 14, 2007 at 03:00:55PM +0100, Stefano Sabatini wrote:
> [...]
> > > But this is also going astray from the original issue of the thread,
> > > so please could you comment about the attached patch?
> > 
> > 
> > [...]
> > > Index: libavcodec/avcodec.h
> > > ===================================================================
> > > --- libavcodec/avcodec.h	(revision 11020)
> > > +++ libavcodec/avcodec.h	(working copy)
> > > @@ -33,8 +33,8 @@
> > >  #define AV_STRINGIFY(s)         AV_TOSTRING(s)
> > >  #define AV_TOSTRING(s) #s
> > >  
> > > -#define LIBAVCODEC_VERSION_INT  ((51<<16)+(48<<8)+0)
> > > -#define LIBAVCODEC_VERSION      51.48.0
> > > +#define LIBAVCODEC_VERSION_INT  ((51<<16)+(49<<8)+0)
> > > +#define LIBAVCODEC_VERSION      51.49.0
> > >  #define LIBAVCODEC_BUILD        LIBAVCODEC_VERSION_INT
> > >  
> > >  #define LIBAVCODEC_IDENT        "Lavc" AV_STRINGIFY(LIBAVCODEC_VERSION)
> > > @@ -1671,6 +1671,15 @@
> > >      unsigned int stream_codec_tag;
> > >  
> > >      /**
> > > +     * scene change score.
> > > +     * Measures the degree of change between the current and the
> > > +     * previous encoded frame.
> > > +     * - encoding: Set by libavcodec.
> > > +     * - decoding: unused
> > > +     */
> > > +    int scenechange_score;
> > > +
> > > +    /**
> > >       * scene change detection threshold
> > >       * 0 is default, larger means fewer detected scene changes.
> > >       * - encoding: Set by user.
> > 
> > you cannot add anything in the middle it breaks the ABI
> > also id like to see some examples where this is usefull/needed
> > iam not in favor of exporting stuff just because it can be exportet
> > there should be some sense in it
> 
> Consider this scenario: real-time streaming of impredictable
> application dependant video content. It would be useful to change the
> encoding parameters (rate control, frame rate, etc.) in function of
> the *features* of the video streamed (I'm not sure if is possible to
> change the parameteres of the avcodec context on the fly at all).

this belongs into libavcodec not in the application, other applications
could benefit from such things as well
also we already export motion vectors, macroblock types and the picture
type
and scenechange_score does not belong in AVCodecContext but AVFrame

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

If you really think that XML is the answer, then you definitly missunderstood
the question -- Attila Kinali
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