Sorry for barging in on this, but is there a way to run a benchmark on all the resamplers included in PulseAudio? For me, both speex-float-6 and speex-fixed-6 eat around 40% CPU. Laurentiu Nicola On Sat, May 10, 2014, at 20:29, Alexander E. Patrakov wrote: > 10.05.2014 23:12, Peter Meerwald wrote: > > Hi, > > > >>>> When Speex is compiled with FIXED_POINT defined, it scales float input > >>>> to ?32768 instead of ?1. In order to make floating point resampler > >>>> work with speex compiled with FIXED_POINT, we need to rescale the input > >>>> to speex. This rescaling does not hurt normal speex, so we do it > >>>> unconditionally. > >>> > >>> floating point multiplication is quite costly on some platforms, I'd > >>> rather not force everyone to scale every sample twice for no good reason > >> > >> Well, on such platforms (*cough* ARM *cough*) I'd call it a bug to use > >> speex-float-* resamplers by default, or even to provide them at all. If we fix > >> that, then the extra multiplication in an already-very-slow path would no > >> longer be relevant. > > > > speex-float resampler is actually faster than speex-fixed when using the > > NEON patch, or at least on par -- so it depends > > > > but floating point math really sucks on Cortex-A8, doing the same > > operation with NEON is quite fast > > Do I understand correctly that the above is a consideration on how one > should build speex on various ARM platforms? > > > so how about overriding PA's speex-float choice to speex-fixed when we > > find that speex-float is compiled as FIXED_POINT (and educate the user?) > > Good idea, but it would be really nice to see the numbers. Especially > the following comparison. > > Compile Speex as appropriate for the target platform. Start from s16 > samples, as found on a CD. > > Variant A: convert them to floating point in PulseAudio, feed to > speex_resampler_process_float(), convert back to s16. > > Variant B: feed directly to speex_resampler_process_int(). > > I.e. do not compare the two variants of speex, but two ways of using the > optimally-compiled speex. > > I am going to extend this thought in another e-mail. > > -- > Alexander E. Patrakov > _______________________________________________ > pulseaudio-discuss mailing list > pulseaudio-discuss at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
