[FFmpeg-devel] [PATCH] Implement pixdesc.h:write_line()

Stefano Sabatini stefano.sabatini-lala
Thu Apr 2 23:31:45 CEST 2009


On date Thursday 2009-04-02 23:03:04 +0200, Michael Niedermayer encoded:
> On Thu, Apr 02, 2009 at 10:53:25PM +0200, Stefano Sabatini wrote:
> > On date Thursday 2009-04-02 22:40:50 +0200, Michael Niedermayer encoded:
[...]
> > > [...]
> > > > +        while (w--) {
> > > > +            int val = *src++;
> > > > +            put_bits(&pb, depth, val);
> > > > +            if (step - depth)
> > > 
> > > > +                skip_put_bits(&pb, step - depth);
> > > 
> > > i suspect this will randomize the bits
> > 
> > That's why I added the if (step - depth) check (yes without that it
> > was broken).
> > Am I missing something?
> /**
>  * Skips the given number of bits.
>  * Must only be used if the actual values in the bitstream do not matter.
>     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Well I read it as "the actual values in the bitstream do not matter,
that is the skipped bits are simply discarded".

Now I can't say if the various put_bits() optimized implementation
randomize the skipped bits or not.

So I cannot say if we have to simply update the documentation or we
have somehow to extend the API to support such a functionality (which
looks to me - preserving the skipped bits - such a basic requirement
that I'm puzzled discovering that it isn't supported).

Regards.
-- 
FFmpeg = Foolish and Freak Mythic Portentous Excellent Game



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