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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9760DC76190 for ; Thu, 25 Jul 2019 19:26:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 718A5218DA for ; Thu, 25 Jul 2019 19:26:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726690AbfGYT0O (ORCPT ); Thu, 25 Jul 2019 15:26:14 -0400 Received: from relay1-d.mail.gandi.net ([217.70.183.193]:56089 "EHLO relay1-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726597AbfGYT0O (ORCPT ); Thu, 25 Jul 2019 15:26:14 -0400 X-Originating-IP: 93.29.109.196 Received: from aptenodytes (196.109.29.93.rev.sfr.net [93.29.109.196]) (Authenticated sender: paul.kocialkowski@bootlin.com) by relay1-d.mail.gandi.net (Postfix) with ESMTPSA id 4692D240009; Thu, 25 Jul 2019 19:26:11 +0000 (UTC) Date: Thu, 25 Jul 2019 21:26:10 +0200 From: Paul Kocialkowski To: Boris Brezillon Cc: Mauro Carvalho Chehab , Hans Verkuil , Laurent Pinchart , Sakari Ailus , linux-media@vger.kernel.org, Tomasz Figa , Nicolas Dufresne , kernel@collabora.com, Maxime Ripard , Ezequiel Garcia , Jonas Karlman , Jernej Skrabec , Alexandre Courbot , Thierry Reding Subject: Re: [PATCH v3 1/3] media: uapi: h264: Clarify our expectations regarding NAL header format Message-ID: <20190725192610.GC14499@aptenodytes> References: <20190703122849.6316-1-boris.brezillon@collabora.com> <20190703122849.6316-2-boris.brezillon@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190703122849.6316-2-boris.brezillon@collabora.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi, On Wed 03 Jul 19, 14:28, Boris Brezillon wrote: > Looks like some stateless decoders expect slices to be prefixed with > ANNEX B start codes (they most likely do some kind of bitstream parsing > and/or need that to delimit slices when doing per frame decoding). > Since skipping those start codes for dummy stateless decoders (those > expecting all params to be passed through controls) should be pretty > easy, let's mandate that all slices be prepended with ANNEX B start > codes. > > If we ever need to support AVC headers, we can add a new menu control > to select the type of NAL header to use. After thinking a bit about this, I'd rather be in favor of having offsets in the control structures rather than forcing the start code type or having a dedicated control for that, as I've mentionned on the other patch. What do you think? Cheers, Paul > Signed-off-by: Boris Brezillon > Reviewed-by: Paul Kocialkowski > --- > Changes in v3: > * Add Paul's R-b > > Changes in v2: > * None > --- > Documentation/media/uapi/v4l/ext-ctrls-codec.rst | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst > index 7a1947f5be96..3ae1367806cf 100644 > --- a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst > +++ b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst > @@ -1726,6 +1726,7 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type - > :ref:`h264`, section 7.4.3 "Slice Header Semantics". For further > documentation, refer to the above specification, unless there is > an explicit comment stating otherwise. > + All slices should be prepended with an ANNEX B start code. > > .. note:: > > -- > 2.21.0 > -- Paul Kocialkowski, Bootlin Embedded Linux and kernel engineering https://bootlin.com