On 1/9/23, Tobias Rapp <t.r...@noa-archive.com> wrote: > On 08/01/2023 15:45, Michael Niedermayer wrote: > >> On Fri, Jan 06, 2023 at 07:01:06PM +0100, Paul B Mahol wrote: >>> On Fri, Jan 6, 2023 at 6:25 PM Michael Niedermayer >>> <mich...@niedermayer.cc> >>> wrote: >>> >>>> On Thu, Jan 05, 2023 at 11:08:25PM +0100, Paul B Mahol wrote: >>>>> On Thu, Jan 5, 2023 at 9:53 PM Michael Niedermayer < >>>> mich...@niedermayer.cc> >>>>> wrote: >>>>> >>>>>> On Thu, Jan 05, 2023 at 01:44:10PM +0100, Paul B Mahol wrote: >>>>>>> Patch attached. >>>>>>> swresample.c | 3 ++- >>>>>>> 1 file changed, 2 insertions(+), 1 deletion(-) >>>>>>> eee7a0685b44aa867562138a2e2437ecb8844612 >>>>>> 0001-libswresample-swresample-avoid-s16p-internal-transfe.patch >>>>>>> From 9c4cd60e2dd41cf98d693c8251f4cfade0807073 Mon Sep 17 00:00:00 >>>> 2001 >>>>>>> From: Paul B Mahol <one...@gmail.com> >>>>>>> Date: Thu, 5 Jan 2023 13:40:12 +0100 >>>>>>> Subject: [PATCH] libswresample/swresample: avoid s16p internal >>>> transfer >>>>>> format >>>>>>> Instead use float one by default for sample rate conversions. >>>>>>> The s16p internal transfer format produces visible and hearable >>>>>>> quantization artifacts. >>>>>> When does this occur and why? >>>>>> >>>>> It occurs always. Just compare output with 16bit and >>>>> int32/float/double. >>>>> Look at other people report on internet. >>>>> Look at src.infinitewave.ca >>>> src.infinitewave.ca uses 32bit none of what it shows should touch the >>>> codepath >>>> you change. >>>> >>>> if we look at src.infinitewave.ca for swr we see 2 types of artifacts >>>> 1. Aliassing which is at maybe -120db with the actual signal at 0db >>>> i would like to see some evidence that a human can hear this >>>> >>> For s16p<->s16p it is much lower, around -78dB thus this patch. >> ok but you pointed to the website that apparently uses >=32bit if i trust >> what they write. >> And even if they test this i cannot use that website to replicate the >> issue >> and the fix >> >> I just wanted to know how i can test this. You are testing it too ... >> so i can see what you see >> Id like to make sure this is the correct fix for the problem and >> Id like to make sure its used when it makes sense and not when not. > > IIRC a similar sweep graph can be created with "Spek" from > http://spek.cc/ but haven't used that application for a while. The SRC
Spek is both slow and limited in range of dB, so it should never be used by pro users. > comparison website apparently provides the input files for testing, see > the instructions at http://src.infinitewave.ca/faq.html. > > Regards, Tobias > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
