[FFmpeg-devel] Patch review request: 10bit DNxHD decoding support

[Michael Niedermayer]

On Fri, Mar 11, 2011 at 09:11:04AM +0000, Joseph Artsimovich wrote:
> > @@ -39,8 +40,16 @@ typedef struct {
> >       int cur_field;                      ///< current interlaced field
> >       VLC ac_vlc, dc_vlc, run_vlc;
> >       int last_dc[3];
> > -    DSPContext dsp;
> > +
> > +    /* It easier to have both DSPs always initialized than initialize one
> > +       on demand. Note that these DSPs may have different permutation
> > tables. */
> > +    DSPContext dsp8;
> > +    DSPContext dsp10;
> > +    DSPContext* dsp;
> > 
> > I think you should avoid having DSPContext twice. If you really need 8bit and
> > 10bit decoding in the same file or stream, you could just add a second
> > permutation table within DSPContext, one for the 8bit IDCT as is and the
> > other for the 10bit IDCT.
> Any particular reason why not?  I mean they are reentrant and relatively lightweight. The reason I decided to have both is that bit depth is specified in frame header, and therefore it's theoretically possible for it to change on the fly.  I am also not a great fan of foo_is_initialized type of flags.

i dunno about having 2 but the *dsp means that there is an additional
pointer dereference on each call, this may result in a tiny performance drop

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

No human being will ever know the Truth, for even if they happen to say it
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