[FFmpeg-devel] patch for DCA "floating point output" option

[Michael Niedermayer]

On Sat, Jan 19, 2008 at 07:41:11PM +0000, M?ns Rullg?rd wrote:
> Michael Niedermayer <michaelni at gmx.at> writes:
> 
> > On Sat, Jan 19, 2008 at 05:10:01PM +0100, madshi wrote:
> >> M?ns Rullg?rd schrieb:
> >> > madshi <dear at madshi.net> writes:
> >> >
> >> >   
> >> >> M?ns Rullg?rd schrieb:
> >> >>     
> >> >>> madshi <dear at madshi.net> writes:
> >> >>>
> >> >>>   
> >> >>>       
> >> >>>> M?ns Rullg?rd schrieb:
> >> >>>>     
> >> >>>>         
> >> >>>>> madshi <dear at madshi.net> writes:
> >> >>>>>
> >> >>>>>   
> >> >>>>>       
> >> >>>>>           
> >> >>>>>> Not sure whether the DCA maintainers will like this patch. But maybe
> >> >>>>>> they will, so I'm posting it here just in case.
> >> >>>>>>
> >> >>>>>> This patch adds optional floating point output to the DCA
> >> >>>>>> decoder. This optional feature must be enabled at compile time by
> >> >>>>>> adding the following switch to config.h:
> >> >>>>>>
> >> >>>>>> #define CONFIG_AUDIO_NONSHORT 1
> >> >>>>>>
> >> >>>>>> I'm using this solution in my eac3to tool because 16bit PCM just
> >> >>>>>> doesn't cut it for a good audio transcoding tool. The idea for this
> >> >>>>>> option comes from the MLP/TrueHD decoder which offers a similar
> >> >>>>>> feature.
> >> >>>>>>
> >> >>>>>> +#ifdef CONFIG_AUDIO_NONSHORT
> >> >>>>>>     
> >> >>>>>>         
> >> >>>>>>             
> >> >>>>> That's a rather useless name.  Can't you think of anything better?
> >> >>>>>
> >> >>>>>   
> >> >>>>>       
> >> >>>>>           
> >> >>>> It was not my idea. The same constant is already used by the
> >> >>>> MLP/TrueHD decoder. I thought that it doesn't make sense to
> >> >>>> use a different name for every decoder...
> >> >>>>
> >> >>>> Besides, I don't think that the name is useless. Currently the decoders
> >> >>>> all output "short" samples (shorter than they should be). "non short"
> >> >>>> simply means that the decoders stop shorten the audio samples.
> >> >>>>     
> >> >>>>         
> >> >>> The name is equally non-descriptive for any decoder.  If the output is
> >> >>> not 'short', then what is it?
> >> >>>   
> >> >>>       
> >> >> Well, the point of the constant is to allow the decoder to output
> >> >> whatever sample format suits best. It may be floating point or
> >> >> 24 bit integer or even the usual 16 bit integer. Of course the
> >> >> decoder must set the "sample_fmt" field to the correct value.
> >> >> My patch does that. The MLP/TrueHD decoder does that, too.
> >> >>     
> >> >
> >> > I figured as much, but the name doesn't convey that very well.
> >> > Perhaps something like "native" would be better than "nonshort".
> >> >   
> >> 
> >> "native" sounds very good to me!
> >
> > Changing the name from CONFIG_AUDIO_NONSHORT will break applications using
> > it, also it is independant of this patch, that is
> > adding float output support vs. changing API.
> 
> How can renaming a CONFIG_ symbol break the API?  

just read the archives, its quite common that such changes break applications
useing their own system for setting CONFIG_*

ignoring that is BOFH attitude


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Republics decline into democracies and democracies degenerate into
despotisms. -- Aristotle
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