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

[Paul B Mahol]

On 5/15/19, Paul B Mahol <onemda at gmail.com> wrote:
> 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?
>

Because lack of testers, I will apply this patch as is.