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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 04AF5C46499 for ; Fri, 5 Jul 2019 17:16:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D85B52147A for ; Fri, 5 Jul 2019 17:16:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727742AbfGERQX (ORCPT ); Fri, 5 Jul 2019 13:16:23 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:37394 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727217AbfGERQX (ORCPT ); Fri, 5 Jul 2019 13:16:23 -0400 Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 7F37A28B61B; Fri, 5 Jul 2019 18:16:21 +0100 (BST) Date: Fri, 5 Jul 2019 19:16:18 +0200 From: Boris Brezillon To: Ezequiel Garcia Cc: Mauro Carvalho Chehab , Hans Verkuil , Laurent Pinchart , Sakari Ailus , linux-media@vger.kernel.org, Tomasz Figa , Nicolas Dufresne , kernel@collabora.com, Paul Kocialkowski , Maxime Ripard , 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: <20190705191618.3467c417@collabora.com> In-Reply-To: <2f836ff0ce9ea68329a81e83109e53e24f7783c6.camel@collabora.com> References: <20190703122849.6316-1-boris.brezillon@collabora.com> <20190703122849.6316-2-boris.brezillon@collabora.com> <2f836ff0ce9ea68329a81e83109e53e24f7783c6.camel@collabora.com> Organization: Collabora X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Fri, 05 Jul 2019 13:40:03 -0300 Ezequiel Garcia wrote: > Hi Boris, Paul, > > On Wed, 2019-07-03 at 14:28 +0200, 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. > > > > 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. > > > > Currently, the H264 slice V4L2_PIX_FMT_H264_SLICE_RAW, > is specified to _not_ contain the ANNEX B start code. Yep, we should provably rename the format. > > As you know, this is used in the cedrus driver, which is not > expecting the start code. > > What's the plan regarding that? I had a few patches modifying the cedrus driver accordingly, but I dropped them in v2. I guess we can fix the driver once we've settled on the uAPI changes.