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 B3B4B47B06 for ; Mon, 2 Oct 2023 10:24:02 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id EF85368CD79; Mon, 2 Oct 2023 13:23:58 +0300 (EEST) Received: from mail0.khirnov.net (red.khirnov.net [176.97.15.12]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 5F38168CD73 for ; Mon, 2 Oct 2023 13:23:52 +0300 (EEST) Received: from localhost (localhost [IPv6:::1]) by mail0.khirnov.net (Postfix) with ESMTP id 1E5F6240490; Mon, 2 Oct 2023 12:23:52 +0200 (CEST) Received: from mail0.khirnov.net ([IPv6:::1]) by localhost (mail0.khirnov.net [IPv6:::1]) (amavis, port 10024) with ESMTP id 3BeA9itN35m6; Mon, 2 Oct 2023 12:23:51 +0200 (CEST) Received: from lain.khirnov.net (lain.khirnov.net [IPv6:2001:67c:1138:4306::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "lain.khirnov.net", Issuer "smtp.khirnov.net SMTP CA" (verified OK)) by mail0.khirnov.net (Postfix) with ESMTPS id 74B0E240445; Mon, 2 Oct 2023 12:23:51 +0200 (CEST) Received: by lain.khirnov.net (Postfix, from userid 1000) id 4DC5E1601B9; Mon, 2 Oct 2023 12:23:51 +0200 (CEST) From: Anton Khirnov To: FFmpeg development discussions and patches In-Reply-To: <20230929-v4l2-strides-v1-1-26c10bf10726@asahilina.net> References: <20230929-v4l2-strides-v1-1-26c10bf10726@asahilina.net> Mail-Followup-To: FFmpeg development discussions and patches , Asahi Lina Date: Mon, 02 Oct 2023 12:23:51 +0200 Message-ID: <169624223128.6638.14929681328366750242@lain.khirnov.net> User-Agent: alot/0.8.1 MIME-Version: 1.0 Subject: Re: [FFmpeg-devel] [PATCH] avdevice/v4l2: Switch to wrapped AVFrames and implement strides 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 Cc: Asahi Lina Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: Quoting Asahi Lina via ffmpeg-devel (2023-09-29 09:52:23) > V4L2 provides a line stride to the client for hardware that has > alignment requirements. rawvideo cannot represent this, so switch to > wrapped_avframe for raw video formats and calculate the plane strides > manually. > > This is slightly messy because the existing helper APIs expect > dimensions and an alignment value, while v4l2 provides the stride of > plane 0 and the subsequent plane strides are implied, so we need to > open-code the logic to calculate the plane strides. > > This makes vertical video work properly on Apple Macs with "1080p" > cameras, which are actually square and can support resolutions like > 1080x1920, which require stride padding to a multiple of 64 bytes. > > In principle, this could be extended to support the V4L2 multiplanar > API, though there seem to be practically no capture (not M2M) drivers > that support this, so it's not terribly useful right now. > > Signed-off-by: Asahi Lina > --- > libavdevice/v4l2-common.c | 68 +++++++++++------------ > libavdevice/v4l2.c | 138 +++++++++++++++++++++++++++++++++++++++------- > 2 files changed, 151 insertions(+), 55 deletions(-) Wrapped AVFrames is an abominable hack that should be going away, not spread to new places. The correct approach is move v4l2 rawvideo to a lavfi source filter, then none of these hacks are needed. -- Anton Khirnov _______________________________________________ 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".