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=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 54662C433E0 for ; Fri, 10 Jul 2020 12:05:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 33E70207BB for ; Fri, 10 Jul 2020 12:05:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727107AbgGJMFL (ORCPT ); Fri, 10 Jul 2020 08:05:11 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:41218 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726828AbgGJMFK (ORCPT ); Fri, 10 Jul 2020 08:05:10 -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 2C6AB2A694F; Fri, 10 Jul 2020 13:05:06 +0100 (BST) Date: Fri, 10 Jul 2020 14:05:02 +0200 From: Boris Brezillon To: Ezequiel Garcia Cc: Jonas Karlman , Mauro Carvalho Chehab , Hans Verkuil , Philipp Zabel , Paul Kocialkowski , "linux-media@vger.kernel.org" , "linux-rockchip@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [RFC 07/12] media: uapi: h264: Add DPB entry field reference flags Message-ID: <20200710140502.627b2b54@collabora.com> In-Reply-To: <6232d8475e169ee53b5864959af21d14bf0fc620.camel@collabora.com> References: <20190901124531.23645-1-jonas@kwiboo.se> <233509924f72d69824920d9312373eced68674c0.camel@collabora.com> <20200710101333.05077f18@collabora.com> <6232d8475e169ee53b5864959af21d14bf0fc620.camel@collabora.com> Organization: Collabora X-Mailer: Claws Mail 3.17.5 (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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 10 Jul 2020 08:50:28 -0300 Ezequiel Garcia wrote: > On Fri, 2020-07-10 at 10:13 +0200, Boris Brezillon wrote: > > On Fri, 10 Jul 2020 01:21:07 -0300 > > Ezequiel Garcia wrote: > > > > > Hello Jonas, > > > > > > In the context of the uAPI cleanup, > > > I'm revisiting this patch. > > > > > > On Sun, 2019-09-01 at 12:45 +0000, Jonas Karlman wrote: > > > > Add DPB entry flags to help indicate when a reference frame is a field picture > > > > and how the DPB entry is referenced, top or bottom field or full frame. > > > > > > > > Signed-off-by: Jonas Karlman > > > > --- > > > > Documentation/media/uapi/v4l/ext-ctrls-codec.rst | 12 ++++++++++++ > > > > include/media/h264-ctrls.h | 4 ++++ > > > > 2 files changed, 16 insertions(+) > > > > > > > > diff --git a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst > > > > index bc5dd8e76567..eb6c32668ad7 100644 > > > > --- a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst > > > > +++ b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst > > > > @@ -2022,6 +2022,18 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type - > > > > * - ``V4L2_H264_DPB_ENTRY_FLAG_LONG_TERM`` > > > > - 0x00000004 > > > > - The DPB entry is a long term reference frame > > > > + * - ``V4L2_H264_DPB_ENTRY_FLAG_FIELD_PICTURE`` > > > > + - 0x00000008 > > > > + - The DPB entry is a field picture > > > > + * - ``V4L2_H264_DPB_ENTRY_FLAG_REF_TOP`` > > > > + - 0x00000010 > > > > + - The DPB entry is a top field reference > > > > + * - ``V4L2_H264_DPB_ENTRY_FLAG_REF_BOTTOM`` > > > > + - 0x00000020 > > > > + - The DPB entry is a bottom field reference > > > > + * - ``V4L2_H264_DPB_ENTRY_FLAG_REF_FRAME`` > > > > + - 0x00000030 > > > > + - The DPB entry is a reference frame > > > > > > > > ``V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE (enum)`` > > > > Specifies the decoding mode to use. Currently exposes slice-based and > > > > diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h > > > > index e877bf1d537c..76020ebd1e6c 100644 > > > > --- a/include/media/h264-ctrls.h > > > > +++ b/include/media/h264-ctrls.h > > > > @@ -185,6 +185,10 @@ struct v4l2_ctrl_h264_slice_params { > > > > #define V4L2_H264_DPB_ENTRY_FLAG_VALID 0x01 > > > > #define V4L2_H264_DPB_ENTRY_FLAG_ACTIVE 0x02 > > > > #define V4L2_H264_DPB_ENTRY_FLAG_LONG_TERM 0x04 > > > > +#define V4L2_H264_DPB_ENTRY_FLAG_FIELD_PICTURE 0x08 > > > > +#define V4L2_H264_DPB_ENTRY_FLAG_REF_TOP 0x10 > > > > +#define V4L2_H264_DPB_ENTRY_FLAG_REF_BOTTOM 0x20 > > > > +#define V4L2_H264_DPB_ENTRY_FLAG_REF_FRAME 0x30 > > > > > > > > > > I've been going thru the H264 spec and I'm unsure, > > > are all these flags semantically needed? > > > > > > For instance, if one of REF_BOTTOM or REF_TOP (or both) > > > are set, doesn't that indicate it's a field picture? > > > > > > Or conversely, if neither REF_BOTTOM or REF_TOP are set, > > > then it's a frame picture? > > > > I think that's what I was trying to do here [1] > > > > [1]https://patchwork.kernel.org/patch/11392095/ > > Right. Aren't we missing a DPB_ENTRY_FLAG_TOP_FIELD? > > If I understand correctly, the DPB can contain: > > * frames (FLAG_FIELD not set) > * a field pair, with a single field (FLAG_FIELD and either TOP or BOTTOM). > * a field pair, with boths fields (FLAG_FIELD and both TOP or BOTTOM). Well, my understand is that, if the buffer contains both a TOP and BOTTOM field, it actually becomes a full frame, so you actually have those cases: * FLAG_FIELD not set: this a frame (note that a TOP/BOTTOM field decoded buffer can become of frame if it's complemented with the missing field later during the decoding) * FLAG_FIELD set + BOTTOM_FIELD not set: this is a TOP field * FLAG_FIELD set + BOTTOM_FIELD set: this is a BOTTOM field * FLAG_FIELD not set + BOTTOM_FIELD set: invalid combination but I might be wrong.