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 95E5C4B7A3 for ; Thu, 13 Jun 2024 07:37:04 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 8759A68D956; Thu, 13 Jun 2024 10:37:02 +0300 (EEST) Received: from relay4-d.mail.gandi.net (relay4-d.mail.gandi.net [217.70.183.196]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 2ACE968D872 for ; Thu, 13 Jun 2024 10:36:56 +0300 (EEST) Received: by mail.gandi.net (Postfix) with ESMTPSA id 5E2E9E0003 for ; Thu, 13 Jun 2024 07:36:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=niedermayer.cc; s=gm1; t=1718264215; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=SsTDdvis9gOlrmEuvbv31PfBkRuJ68gdGLVTYR2T6co=; b=GGi566BJQgQbmAcmO7mPPNCd5nmz5hFTG+zwkh/cggWq8i/COlvZhC5DA7f9dA1dEwAo/2 L6tEh1wQJ8tw+ted7DWGhOnj8DLGYgijbvUQ2oOvbJfrSqGslyzbsgkmogKC34QwvBHkZZ djckz8e4oF4Zq/z/IhDbr19cZLuuIZA5FibkURAstzOFufe6/UF0V6zpzYeRteN9YH6wgw VuYl7j3ACuxy7t+IF4qQAQhOJJJhmFXLkER1iYnDHKTezadEimsW0k8zqV/Xrp6b49SvfS m1AiZefeGDc5qS8caHNQsA6ImIz1lw7IJ4/4y96o951np5P41m4+3VWwXPGtCw== Date: Thu, 13 Jun 2024 09:36:54 +0200 From: Michael Niedermayer To: FFmpeg development discussions and patches Message-ID: <20240613073654.GB2821752@pb2> References: MIME-Version: 1.0 In-Reply-To: X-GND-Sasl: michael@niedermayer.cc Subject: Re: [FFmpeg-devel] [PATCH 33/57] avcodec/mpv_reconstruct_mb_template: Don't unnecessarily copy data 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="===============3806872865930745022==" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: --===============3806872865930745022== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="kghIAaLagGnE7NnV" Content-Disposition: inline --kghIAaLagGnE7NnV Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jun 12, 2024 at 03:48:29PM +0200, Andreas Rheinhardt wrote: > There is no reason to use a temporary buffer as destination > for the new macroblock before copying it into its proper place. >=20 > (History: 3994623df2efd2749631c3492184dd8d4ffa9d1b changed > the precursor of ff_mpv_reconstruct_mb() to always decode > to the first row of macroblocks for B pictures when > a draw_horiz_band callback is set (they are exported to the caller > via said callback and each row overwrites the previously decoded > row; this was probably intended as a cache-optimization). > Later b68ab2609c67d07b6f12ed65125d76bf9a054479 changed this > to the current form in which a scratchpad buffer is used when > decoding B-pictures without draw_horiz_band callback, followed > by copying the block from the scratchpad buffer to the actual > destination. I do not know what the aim of this was. When thinking > of it as a cache optimization, it makes sense to not use it > when the aforementioned draw_horiz_band optimization is in effect, > because then the destination row can be presumed to be hot > already. But then it makes no sense to restrict this optimization > to B-frames.) IIRC The B frames where directly placed in GPU memory, which is slow to read =66rom, so building up MC + IDCT (which could read depending on caches) was avoided by a a scratchpad but its really long ago so i might remember this only partly thx [...] --=20 Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB While the State exists there can be no freedom; when there is freedom there will be no State. -- Vladimir Lenin --kghIAaLagGnE7NnV Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABEKAB0WIQSf8hKLFH72cwut8TNhHseHBAsPqwUCZmqhlgAKCRBhHseHBAsP qwMiAJ9eZVaobfBGJj4p5QyA03OSymODGQCeLEyLl78oeuqxnN+sTtbpgaDunWM= =fJPX -----END PGP SIGNATURE----- --kghIAaLagGnE7NnV-- --===============3806872865930745022== 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". --===============3806872865930745022==--