From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7EB5C83F18 for ; Wed, 30 Aug 2023 18:29:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231341AbjH3S3Y (ORCPT ); Wed, 30 Aug 2023 14:29:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34450 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245486AbjH3PTH (ORCPT ); Wed, 30 Aug 2023 11:19:07 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [46.235.227.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E92DAE8; Wed, 30 Aug 2023 08:19:03 -0700 (PDT) Received: from nicolas-tpx395.localdomain (unknown [IPv6:2606:6d00:15:bae9::7a9]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) (Authenticated sender: nicolas) by madras.collabora.co.uk (Postfix) with ESMTPSA id 7C8EB66071BE; Wed, 30 Aug 2023 16:19:01 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1693408742; bh=zp4dOKYj5P2tbc9SOBi3zKYc8MACLC/blDAk7LSJAeU=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=ixeFWC8byNhVcaT8civxVnZbjC3jmIwMDdi5VCHpDwpEJ3oRDENR8qLz5DeCOhFOs Lp1mFL2VzQ99Hw+ATRij+Ne41vFsV9nFpeHcEKzDD0I5cKTzWtbC1hc9Gzljrwemta JR0hc2u/GJaJ1bozL7o8xH4fcHYe1OszsVpAZDSiO9tx/XwOqWbfTDtI6nuLttR6PY oY494YhspwrH8KFmb+HjeKHFF0CrU5logWvPI9kbaTckVsBrjr7/aciPgESqu0+kZJ zwO9o3sRf9DcFcz27ZXaeCXbu/UN6ptg6zyuccJnyom0OjURDwbN3IlVrr+l1aNj+p nkz2AZFeQCqiA== Message-ID: Subject: Re: Stateless Encoding uAPI Discussion and Proposal From: Nicolas Dufresne To: Hsia-Jun Li , Paul Kocialkowski Cc: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, Hans Verkuil , Sakari Ailus , Andrzej Pietrasiewicz , Michael Tretter , Jernej =?UTF-8?Q?=C5=A0krabec?= , Chen-Yu Tsai , Samuel Holland , Thomas Petazzoni Date: Wed, 30 Aug 2023 11:18:52 -0400 In-Reply-To: <52e9b710-5011-656b-aebf-8d57e6496ddd@synaptics.com> References: <720c476189552596cbd61dd74d6fa12818718036.camel@collabora.com> <39270c5e-24ab-8ff6-d925-7718b1fef3c4@synaptics.com> <52e9b710-5011-656b-aebf-8d57e6496ddd@synaptics.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Le mercredi 23 ao=C3=BBt 2023 =C3=A0 11:04 +0800, Hsia-Jun Li a =C3=A9crit= =C2=A0: > > It was suggested so far to leave h264 slice headers writing to the driv= er. This > > is motivated by H264 slice header not being byte aligned in size, so th= e > H.264, H.265 has the byte_alignment() in nalu. You don't need skip bits= =20 > feature which could be found in H1. As you said so, I rechecked the H.264 grammar. ... slice_header( ) slice_data( ) ... There is lot of variable size items in the slice_header() syntax and no pad= ding bits. And no padding at the start of any of the slice_data types. So no, th= e slice_header() syntax in H.264 is not byte aligned like you are claiming he= re. Its important to be super accurate about these things, as it will cause err= ors to be made. Please always double check. Nicolas