[FFmpeg-devel] [PATCH] avfilter: add apitch filter

[Paul B Mahol]

On 5/12/19, Paul B Mahol <onemda at gmail.com> wrote:
> On 5/12/19, Michael Niedermayer <michael at niedermayer.cc> wrote:
>> On Sun, May 12, 2019 at 11:00:51PM +0200, Nicolas George wrote:
>>> Marton Balint (12019-05-12):
>>> > Yeah, you are right, what I had in mind was this:
>>> >
>>> > apitch  ===  asetrate,aresample,atempo
>>>
>>> Exactly. And reciprocally, atempo = apitch+asetrate+aresample.
>>>
>>> Furthermore, since it works with the spectrum, the filter that does the
>>> hard work can probably easily output at any sample rate, at a cost much
>>> lower than resampling afterwards. Therefore, it makes most sense to have
>>> a single filter with all three parameters (sample rate, speed adjustment
>>> and pitch adjustment).
>>
>> and if thats done in our resampler than that can also be combined with
>> changing the channel order, layout, sample type and so on.
>> Iam not sure its a good idea but purely technically it should be more
>> efficient to do it all together.
>> Also swresample already supports an external FFT resampler so it might
>> actually fit in there nicely and it might even allow us to remove an
>> external
>> dependancy without loosing a feature. (assuming the new FFT resampler
>> would be equally good)
>>
>>
>
> To make it work dynamically, filter must resample audio internally.
>

Can I get testers?