[Ffmpeg-devel] [RFC] ZMBV encoder

[Michael Niedermayer]

Hi

On Wed, Dec 06, 2006 at 11:55:43PM +0000, M?ns Rullg?rd wrote:
> Diego Biurrun <diego at biurrun.de> writes:
> 
> > On Tue, Dec 05, 2006 at 06:32:50PM +0100, Michael Niedermayer wrote:
> >> 
> >> On Tue, Dec 05, 2006 at 05:11:35PM +0100, Benjamin Larsson wrote:
> >> > Michael Niedermayer skrev:
> >> > [..]
> >> > 
> >> > >>+#ifdef CONFIG_ZLIB
> >> > >>+    // Needed if zlib unused or init aborted before deflateInit
> >> > >>+    memset(&(c->zstream), 0, sizeof(z_stream));
> >> > >>+#else
> >> > >>+    av_log(avctx, AV_LOG_ERROR, "Zlib support not compiled.\n");
> >> > >>+    return 1;
> >> > >>+#endif
> >> > >
> >> > >hmm maybe the whole file shouldnt be compiled if zlib isnt available
> >> > 
> >> > Hi, can we get a policy for this? Currently we have both disabled 
> >> > compilation and runtime reporting like this.
> >> 
> >> yes, theres no sense to compile a codec which then cannot work but just
> >> says "oops" ...
> >
> > Agreed.  IMO we should disable codecs that need zlib when zlib is not
> > available.
> 
> Zlib compression is optional in ZMBV.  Stupidly enough, zlib
> compression is enabled or disabled per frame, and there is no global
> flag indicating if zlib is needed to decode the stream.  While it does
> make sense to support decoding of non-zlib videos when zlib is not
> available, there is no way to tell whether a stream is supported
> without decoding all the frames.

are there any zmbv files which dont depend on zlib? also even though such
files should be decodeable without zlib our decoder will not, it just prints
an error if zlib isnt available no matter if its actually needed or not


[...]

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