[FFmpeg-devel] [PATCH] QCLP wrong sampling rate

Michael Niedermayer michaelni
Wed Sep 24 20:08:15 CEST 2008


On Wed, Sep 24, 2008 at 10:44:28AM -0700, Baptiste Coudurier wrote:
> Michael Niedermayer wrote:
> > On Wed, Sep 24, 2008 at 10:10:02AM -0700, Baptiste Coudurier wrote:
> >> Michael Niedermayer wrote:
> >>> On Sat, Aug 16, 2008 at 09:58:08PM +0900, KO Myung-Hun wrote:
> >>>> Baptiste Coudurier wrote:
> >>>>> Hi,
> >>>>>
> >>>>> KO Myung-Hun wrote:
> >>>>>   
> >>>>>> Reynaldo H. Verdejo Pinochet wrote:
> >>>>>>     
> >>>>>>> Hi KO Myung-Hun
> >>>>>>>
> >>>>>>> KO Myung-Hun wrote:
> >>>>>>>  
> >>>>>>>       
> >>>>>>>> Hi/2.
> >>>>>>>>
> >>>>>>>> Sampling rate of QCLP audio is always set to 8000Hz. But it's wrong.
> >>>>>>>>
> >>>>>>>> Test clips : http://sketchup.google.com/gsu6vtvideos.html
> >>>>>>>>     
> >>>>>>>>         
> >>>>>>> I had problems with these kind of streams in the past
> >>>>>>>
> >>>>>>> If this QCLP tag identifies TIA/EIA/ISS-733 conforming
> >>>>>>> data then this is just wrong. See, these are sampled at
> >>>>>>> 8kHz -- period. this is no optional recomendation but
> >>>>>>> a requirement (You can take a look at section 2.4.1
> >>>>>>> of the all infamous C.S0020-0with3Gcover.pdf if you
> >>>>>>> feel like it) Now, if this patch works out decoding
> >>>>>>> for you I'd suggest adding a warning to state out-spec
> >>>>>>> data, at the very least.
> >>>>>>>   
> >>>>>>>       
> >>>>>> I've added a warning to the patch as your suggestion.
> >>>>>>     
> >>>>> Does this file decodes correctly with ffmpeg ?
> >>>>> With soc decoder or non redistributable one ?
> >>>>>
> >>>>>   
> >>>> Ah, MPlayer with QuickTime support.
> >>> baptiste?
> >>> IMHO the mov demuxer should not override the stored sampling rate for
> >>> qcelp & amr
> >> Well, I'm not disagreeing, the code was this way a long time ago, should
> >> be fixed.
> > 
> > thanks
> > 
> > Though iam realizing now that the overriding may be needed for .mp4, though
> > thats just a feeling based on the reliability of such fields for other
> > codecs like aac in .mp4 ...
> > 
> 
> Channels overriding is needed for mp4/3gp because it is commonly set to
> 2. Sample rate has to be set correctly in both formats, so I guess this

ok, i must have confused it with aac in flv ...


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Let us carefully observe those good qualities wherein our enemies excel us
and endeavor to excel them, by avoiding what is faulty, and imitating what
is excellent in them. -- Plutarch
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