From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id 77BD742A71 for ; Sun, 8 Jan 2023 14:52:22 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id C2BAE68BC1B; Sun, 8 Jan 2023 16:52:18 +0200 (EET) Received: from relay8-d.mail.gandi.net (relay8-d.mail.gandi.net [217.70.183.201]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 2305268B068 for ; Sun, 8 Jan 2023 16:52:12 +0200 (EET) Received: (Authenticated sender: michael@niedermayer.cc) by mail.gandi.net (Postfix) with ESMTPSA id 487EB1BF207 for ; Sun, 8 Jan 2023 14:52:10 +0000 (UTC) Date: Sun, 8 Jan 2023 15:52:10 +0100 From: Michael Niedermayer To: FFmpeg development discussions and patches Message-ID: <20230108145210.GD35806@pb2> References: <20230105205342.GE4028235@pb2> <20230106172506.GG4028235@pb2> MIME-Version: 1.0 In-Reply-To: Subject: Re: [FFmpeg-devel] [PATCH] libswresample: avoid s16p internal processing format X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Type: multipart/mixed; boundary="===============4764125832634682365==" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: --===============4764125832634682365== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="ytoMbUMiTKPMT3hY" Content-Disposition: inline --ytoMbUMiTKPMT3hY Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jan 06, 2023 at 07:04:59PM +0100, Paul B Mahol wrote: > On Fri, Jan 6, 2023 at 7:01 PM Paul B Mahol wrote: >=20 > > > > > > On Fri, Jan 6, 2023 at 6:25 PM Michael Niedermayer > > 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 < > >> michael@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 > >> > > > 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/dou= ble. > >> > 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. > > > > Also for others and reports for swr its is lower than exact -120dB > > > > > > 2. Reflection and attenuation at the transition frequency > >> With linear filters there is a tradeof between attenuation of the > >> passband, reflection of frequencies beyond, latency and so on > >> You can have a perfect sharp cutoff with no attenuation and no refelec= tion > >> that requires a infinitly long filter. And while this looks best in th= is > >> frequency plot, does it actually sound best ? If you can hear -120db > >> signals you surely would then also hear the ringing long before a guns= hot > >> from such long filter. > >> > > > One can always change linear FIR to be min phase FIR kernel. I certainly would welcome a wider range of filters in swr, if you want to a= dd any low delay sinc approximation or in fact i would welcome any filter you want to add. thx [...] --=20 Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB The real ebay dictionary, page 1 "Used only once" - "Some unspecified defect prevented a second use" "In good condition" - "Can be repaird by experienced expert" "As is" - "You wouldnt want it even if you were payed for it, if you knew .= =2E." --ytoMbUMiTKPMT3hY Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iFwEABEIAB0WIQSf8hKLFH72cwut8TNhHseHBAsPqwUCY7rYmgAKCRBhHseHBAsP q1VSAJwIXN17w+9v8v1Fvi1BF8UV1c/SxwCXUlMo64nBpI33WHGoOyX4ouVNiA== =efC2 -----END PGP SIGNATURE----- --ytoMbUMiTKPMT3hY-- --===============4764125832634682365== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe". --===============4764125832634682365==--