[ scummvm-Feature Requests-766391 ] TOOLS: extract with high quality resampling

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Feature Requests item #766391, was opened at 2003-07-05 18:33
Message generated for change (Comment added) made by fingolfin
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Category: None
Group: None
>Status: Closed
>Resolution: Out of Date
Priority: 5
Submitted By: Marek Roth (logicdeluxe)
>Assigned to: Max Horn (fingolfin)
Summary: TOOLS: extract with high quality resampling

Initial Comment:
Ogg Vorbis is a very nice codec in deed and the OGGENC
does a very good job as well. But when it comes to
resampling the input sample the results are very bad.
The build in low-pass-filter is very simple and heavily
reduces the frequency response in the resulting encoded
file. (The optional low-pass option does not change
this, as I tried it already.) So it would be very nice,
if EXTRACT could do the resampling with an external
tool like sr-convert (see here:
https://sourceforge.net/projects/sr-convert/ ) before
encoding with OGGENC.
This should of course not be forced, but an option,
since this high quality resampling takes a lot time.

Alternatively, since sr-convert also is open-source,
you could include that high-quality resampling into
extract itself.

However, there is one little catch: sr-convert does not
read 11111 Hz, but this should be implemented easily.
Or EXTRACT could make it 11025 instead as an approximation.

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>Comment By: Max Horn (fingolfin)
Date: 2003-10-08 21:46

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The extract tool in CVS doesn't do any resampling anymore - it 
encodes with the "native" rate of the sound (be it 11025 or 
22050Hz). Any resampling is done by scummvm.

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Comment By: Max Horn (fingolfin)
Date: 2003-07-17 02:30

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That said, my dream always has been to take the excellent (GPL) 
resample code from sox, and use it for the mixer in ScummVM. 
The only concern I had and have is that slower devices might have 
a problem. OTOH, one could easily revert to a linear filter for 
those machines, or to the cubic interpolator we use right now... 
The key to this simply is a "clean" design. Of course any 
implementation would have to deal with various combinations of 
mono/stereo. 8/16bits, signed/unsigned data...

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Comment By: Max Horn (fingolfin)
Date: 2003-07-17 02:26

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An excellent sample rater converte (for arbitrary src/dst rates) is 
implemented in sox (http://sox.sourceforge.net/). Since it can 
also handle MP3 and OGG already, that would seem to be a more 
likely candidate...

However in either case, I don't think we should duplicate code; 
rather, if at all, include the ability to call one of these external 
tools.

That said, I am not going to implement this :-)

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