[FFmpeg-devel] [PATCH 2/3] avfilter: add audio upsample filter

Nicolas George george at nsup.org
Mon Apr 22 09:14:25 EEST 2019

Paul B Mahol (12019-04-21):
> https://dspguru.com/dsp/faqs/multirate/resampling/
> Resampling involves interpolation.
> If I do resampling with aresample and resampling with factor 2 from
> 44100 to 88200
> I can see there is still some spectrum data in highest frequencies.

Resampling MAY involve interpolation, to enhance the subjective quality
of the output.

> If you haven't noticed, this is just upsampling/downsampling without lowpass.
> And that is not resampling in any way.

No matter how many times you repeat it, saying that changing the sample
rate is not resampling will not make it true.

> That is just your opinion now, you need to provide technical terms
> to support your statements.

I have given technical considerations: we have automatic sample rate
negotiation. These filter would not fit with it.

What have you provided besides your opinion and links to generic
considerations that do not substantiate your views?

> Another option to aresample filter would just confuse users.

Less so than yet another pair of filters that do almost exactly the same
thing as others.


  Nicolas George
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