On Wed, 2015-03-11 at 20:27 +0200, Tanu Kaskinen wrote: > On Wed, 2014-11-12 at 23:16 +0300, Andrey Semashev wrote: > > On Wednesday 12 November 2014 20:03:48 Alexander E. Patrakov wrote: > > > 12.11.2014 14:26, Alexander E. Patrakov пиÑ?еÑ?: > > > > I will recheck the quality separately later today, in order to verify > > > > that it is still as good as in the previous tests. Please don't merge > > > > the patches until this is done. > > > > > > Done. The -mq, -hq and -vhq variants of the resampler never produce > > > audible distortions. The -lq variant sometimes does, by means of > > > suppressing very high frequencies, but this is relevant to artificial > > > tests only, and only if the listener knows that these frequencies are > > > supposed to be there. Thus, quality is on par with speex-float-5, the > > > CPU consumption is even better than with speex-float-1. Conclusion: > > > > > > *** the patches are generally acceptable *** > > > > Great! And thanks a lot for the quality data and information. I will send v2 > > patches in a day or two. > > > > > However, because the low-quality and high-quality versions eat very > > > similar amount of CPU time, I'd just expose a single (high or very high) > > > quality setting. > > > > Given that -lq is actually slower than -mq in some cases and has worse > > quality, I agree there is no point in keeping it. > > > > However, the other three presets do have different performance and quality. In > > my test results [1] -mq is about 2 times faster than -vhq, and -hq is > > somewhere in between. Performance wise, there should be no problem with -vhq > > on modern CPUs, but maybe the little extra would be desired in embedded domain > > to conserve battery. Do you think we could keep the three presets: -mq, -hq > > and -vhq? > > > > [1]: http://lastique.github.io/src_test/ > > I'm writing release notes for 7.0, and I'm wondering how to describe the > three soxr resampler variants. Alexander says that all variants are > perfect quality-wise (no audible distortions). Alexander also says that > each variant takes about the same amount of CPU time, but Andrey says > that there's 2x difference between mq and vhq. Who's right? > > To me it sounds like the hq and vhq variants are redundant, since mq is > at least as fast (and on some hardware significantly faster) as the > other variants, and there's no meaningful difference in quality. I now wrote something to the notes, feel free to comment if you'd like to change something: http://www.freedesktop.org/wiki/Software/PulseAudio/Notes/7.0/ By the way, the fact that I'm writing the release notes already now doesn't mean that the release is going to happen any time soon... I'm just experimenting with a different approach to writing the notes; I'm trying to avoid a situation where I have to go through the whole commit history in one go when the release is about to happen. -- Tanu
