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
comparison website apparently provides the input files for testing, see
the instructions at http://src.infinitewave.ca/faq.html.
Regards, Tobias
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