[FFmpeg-devel] dealing with tables in DV codec

[Diego Biurrun]

On Wed, Sep 10, 2008 at 07:59:47PM -0700, Roman V. Shaposhnik wrote:
> 
> On Thu, 2008-09-11 at 01:56 +0200, Diego Biurrun wrote:
> > On Wed, Sep 10, 2008 at 12:27:21PM -0700, Roman Shaposhnik wrote:
> > > On Wed, 2008-09-10 at 15:51 +0200, Diego Biurrun wrote:
> > > > On Tue, Sep 09, 2008 at 01:51:06PM -0700, Roman Shaposhnik wrote:
> > > > > 
> > > > > Now, on SPARC I see a stable speed loss of about ~3% or so.
> > > > 
> > > > While we're discussing performance: qdv still performs about 50% better
> > > > than FFmpeg on certain samples, do you know the reason?  An example is
> > > > 
> > > > http://samples.mplayerhq.hu/V-codecs/DVSD/henrich-weirdqt.mov
> > > 
> > > Wow! That's news to me. Thanks for bringing this up. I'm not familiar
> > > with qdv. What is it? How can I test with it?
> > 
> > It's a binary codec for DV that MPlayer can use.  It performs up to 50%
> > better than FFmpeg on some samples.  Not on all samples though, for a
> > few FFmpeg is slightly faster, but most of the time qdv wins by a
> > considerable and sometimes even huge margin.  Just try all DV samples
> > from the MPlayer collection.
> 
> Good info. Thanks. A couple of questions, though:
>    1. What other samples do you know of that exhibit this slowness?

Most of the samples in this directory:

http://samples.mplayerhq.hu/V-codecs/DVSD/

Most noticeably pond.dv, henrich-weirdqt.mov, sample2001.avi, but
basically all of the samples in that directory except for
v-2002.03.21_18-01-28.avi.

FFmpeg is considerably faster for the following sample:

http://samples.mplayerhq.hu/DV-raw/voxnews.dv

qdv cannot play the following samples:

http://samples.mplayerhq.hu/V-codecs/DV50/

>    2. How can I benchmark the qdv via MPlayer so that things
>       like I/O get factored out? Command line switched would be best...

I do not know what you really mean by factored-out I/O, but the way I
usually benchmark things with MPlayer is

mplayer -benchmark -nosound -vc qdv [-vo null]
mplayer -benchmark -nosound -vc ffdv [-vo null]

Diego