[FFmpeg-devel] [PATCH] miscelleneous NUT fixes

[Michael Niedermayer]

On Sun, Feb 03, 2008 at 01:28:03PM -0500, Rich Felker wrote:
> On Sun, Feb 03, 2008 at 12:55:39PM +0100, Michael Niedermayer wrote:
> > On Sun, Feb 03, 2008 at 01:11:33AM -0500, Rich Felker wrote:
> > > On Sun, Feb 03, 2008 at 12:34:46AM +0100, Michael Niedermayer wrote:
> > > > On Sat, Feb 02, 2008 at 02:19:25PM -0500, Rich Felker wrote:
> > > > > On Sat, Feb 02, 2008 at 06:41:20PM +0100, Michael Niedermayer wrote:
> > > > > > > 1. "Bleh, libnut muxed this ;)\n" please, I fixed this bug over a year ago :)
> > > > > > 
> > > > > > rejected, we do not remove workarounds needed for demuxing/decoding
> > > > > 
> > > > > While I agree with this principle, I don't think it applies to
> > > > > under-development formats. The snow decoder does not support every
> > > > > random historical version of snow, and likewise the nut demuxer should
> > > > 
> > > > I would support them if it is easy to do and would not cause a slowdown.
> > > 
> > > I reviewed the code in question and it's actually a bug. Samplerate
> > > num=2 den=3 means 2 samples every 3 seconds, but with the bogus code
> > > in place, it will be interpreted as 3 samples per second. Apparently
> > > lavf does not support non-integer values for samples-per-second so it
> > > should drop an "unsupported format" error in any case rather than
> > > misinterpreting the data.
> > 
> > Maybe we should have disallowed non integer samplerates in nut ...
> 
> No, that creates a fundamental dependency on a physical unit
> (seconds). Also what if one has a stream sampled at 44100 Hz but wants
> to retime the video from NTSC to PAL or film to NTSC?? The conversion
> factor does not divide 44100 evenly so a noninteger samplerate is
> needed.
> 
> > > I stand by Oded's patch to remove the incorrect interpretation and
> > 
> > We have files which need this interpretation, we do not have ones which
> > break due to it. Feel free to add a big comment to the code saying its
> > not spec compliant if you like.
> 
> We have invalid files which should be patched or deleted.

Its ffmpegs philosophy to play as many files as possible, broken or not.


> 
> > > hope lavf will eventually support non-integer samplerates.
> > 
> > Right after we add mpeg4 scalability, multiple object and most important so
> > called face and body animation objects support. That also would make all
> > the profile counters happy.
> 
> Um, all that's required for noninteger samplerates is converting the
> samplerate field to a rational type instead of an integer type. This
> is hardly comparable to implementing major high-complexity features.

No, you have to at least add a flag to indicate which muxers support
non integer samplerates, and deal with the additional case in the user
applications, which with near certainity will not support non integer
samplerates. And audio in/out hardware which again with near certainity
wont support it, nor will even have +-1 sample/second accuracy.

Anyway a patch is welcome, if its simple and works.

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

The worst form of inequality is to try to make unequal things equal.
-- Aristotle
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