[pulseaudio-discuss] [PATCH 2/3] resampler: Add optional soxr resampler

[Alexander E. Patrakov]

24.08.2014 23:55, Peter Meerwald wrote:
>
>> 04.08.2014 18:40, Peter Meerwald wrote:
>>> +    quality_spec = soxr_quality_spec(SOXR_QQ, 0);
>>
>> SOXR_QQ means "quick cubic interpolation" - i.e. the worst quality level
>> provided by the library. It is worse than speex-float-1 (but the message with
>> the relevant plots exceeded the maximum tolerable size for the list). I think
>> that it makes sense to expose other quality settings provided in soxr.h.
>
> probably we need to let the user decide, but default to some reasonable
> quality

Yes, even SOXR_LQ would be good enough for the definition of "good" that 
doesn't take limited bandwidth into account. However, I would like to 
raise one peculiar property of soxr that needs to be discussed further.

As described in the README, the soxr resampler is FFT-based (unlike, 
e.g., libsamplerate, ffmpeg and speex). Therefore, it introduces more 
latency than traditional resamplers - 20ms for the HQ variant vs less 
than 1ms for a traditional resampler. Should PulseAudio be aware of it? 
How can we make it aware?

-- 
Alexander E. Patrakov