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

[Paul B Mahol]

On 4/25/19, Nicolas George <george at nsup.org> wrote:
> Paul B Mahol (12019-04-25):
>> The filter does not take sample rate as argument, but integer factor
>> instead.
>> So that make it impossible to be used with lswr.
>
> No need for an argument: the filter knows the negotiated input and
> output sample rate.

Not really, it works with 2x/3x/4x/5x.. sample rate or 1/2 / 1/3 / 1/4 / 1/5
o sample rate in other direction.
It can not be done in aresample filter because of limitations of query_formats
code in libavfilter and doing it anyway for aresample filter would
cause many regressions.