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 DC74E44F8F for ; Thu, 12 Jan 2023 19:49:35 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 2886968BBF3; Thu, 12 Jan 2023 21:49:32 +0200 (EET) Received: from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net [217.70.183.195]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 8A7B068B26F for ; Thu, 12 Jan 2023 21:49:25 +0200 (EET) Received: (Authenticated sender: michael@niedermayer.cc) by mail.gandi.net (Postfix) with ESMTPSA id 6D33960004 for ; Thu, 12 Jan 2023 19:49:24 +0000 (UTC) Date: Thu, 12 Jan 2023 20:49:22 +0100 From: Michael Niedermayer To: FFmpeg development discussions and patches Message-ID: <20230112194922.GN1949656@pb2> References: <20230105205342.GE4028235@pb2> <20230106172506.GG4028235@pb2> <20230108145210.GD35806@pb2> <20230112154136.GM1949656@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="===============9112987632137326686==" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: --===============9112987632137326686== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="D9sZ58tf58331Q5M" Content-Disposition: inline --D9sZ58tf58331Q5M Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jan 12, 2023 at 05:09:18PM +0100, Paul B Mahol wrote: > On 1/12/23, Michael Niedermayer wrote: > > On Thu, Jan 12, 2023 at 03:20:06PM +0100, Paul B Mahol wrote: > >> On 1/8/23, Michael Niedermayer wrote: > >> > 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 wrot= e: > >> >> > >> >> > > >> >> > > >> >> > 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.pa= tch > >> >> >> > > > 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 conversio= ns. > >> >> >> > > > 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. > >> >> > > >> >> > 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 > >> >> >> refelection > >> >> >> that requires a infinitly long filter. And while this looks best= in > >> >> >> this > >> >> >> frequency plot, does it actually sound best ? If you can hear > >> >> >> -120db > >> >> >> signals you surely would then also hear the ringing long before a > >> >> >> gunshot > >> >> >> 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 wa= nt > >> > to > >> > add > >> > any low delay sinc approximation or in fact i would welcome any filt= er > >> > you want to add. > >> > >> There is that afdelaysrc filter patch on ML to add FIR coefficient > >> generation for fractional delay audio filter that can be also used as > >> a interpolation FIR filter. And to me it seems better at same number > >> of taps than already used/available ones in soxr and swr. > > > > Please add improvments into swr, if you have any! > > > > > >> > >> Also I have done prototype of resampling filter using afir filter via > >> custom filters in filtergraph and it operates at similar speeds like > >> soxr (in these very non optimized approach) and providing better/wider > >> frequency output at highest band. > > > > Can it be added into swr ? >=20 > It will use libavutil/tx.h for convolution. ok of course >=20 > But I need first to research more and write actual code that does > out/in sample rate ratio factorization and do lot of benchmarks > comparing normal ratios with very big ones and make sure that approach > is always faster than swr/soxr and at same time providing better/same > quality. > Also need to add min phase version of filter and compare what > performance/latency it can bring at all. thx [...] --=20 Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Its not that you shouldnt use gotos but rather that you should write readable code and code with gotos often but not always is less readable --D9sZ58tf58331Q5M Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABEIAB0WIQSf8hKLFH72cwut8TNhHseHBAsPqwUCY8BkOQAKCRBhHseHBAsP q2/pAJ4m/ItY1L3F7Kg9RHOizsyFeMoUQgCdFNCZjjMb1dxPhRp+SFUiZDlH8Ns= =d+QG -----END PGP SIGNATURE----- --D9sZ58tf58331Q5M-- --===============9112987632137326686== 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". --===============9112987632137326686==--