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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 CEA12C48BD6 for ; Wed, 26 Jun 2019 11:48:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A458E20656 for ; Wed, 26 Jun 2019 11:48:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726347AbfFZLsq (ORCPT ); Wed, 26 Jun 2019 07:48:46 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:36318 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726104AbfFZLsp (ORCPT ); Wed, 26 Jun 2019 07:48:45 -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 3B822260641; Wed, 26 Jun 2019 12:48:44 +0100 (BST) Date: Wed, 26 Jun 2019 13:48:39 +0200 From: Boris Brezillon To: Paul Kocialkowski 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 v2 3/3] media: uapi: h264: Get rid of the p0/b0/b1 ref-lists Message-ID: <20190626134839.709be189@collabora.com> In-Reply-To: <4dec37e985d160d2fe5b3b5e28eff0e081a860fa.camel@bootlin.com> References: <20190610085250.3255-1-boris.brezillon@collabora.com> <20190610085250.3255-4-boris.brezillon@collabora.com> <4dec37e985d160d2fe5b3b5e28eff0e081a860fa.camel@bootlin.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 Wed, 26 Jun 2019 13:33:41 +0200 Paul Kocialkowski wrote: > Hi, > > On Mon, 2019-06-10 at 10:52 +0200, Boris Brezillon wrote: > > Those lists can be extracted from the dpb, let's simplify userspace > > life and build that list kernel-side (generic helpers will be provided > > for drivers that need this list). > > I don't really have any clear idea about that, but there was a > discussion about DPB vs reference picture lists some weeks ago. What we call DPB right now is actually a list of reference pictures (each entry being flagged long or short term). When reading the spec, you said DPB was referring to something that's more implementation specific, and I think that's what motivated your initial suggestion to rename this field into something more appropriate (ref_pics?). TBH, I'm just guessing here, since you were the one initially proposing this change, and I must say that having to explain what you had in mind at that time is a bit weird :P. > > Is there some mail thread with a rationale about it, some IRC logs I > could look at or could the people involved in the discussion provide > some additional background at this point? Well, you were part of the discussion, and I think most of it happened in the "Proposed updates and guidelines for MPEG-2, H.264 and H.265 stateless support" thread you started. > > IIRC we also talked about removing the DPB or at least renaming it, but > I don't have a clear idea of the outcome as well. The list of long/short refs has to be passed, and that's actually what we currently call "DPB", so we're just talking about a rename here, nothing more. The ordered P/B0/B1 reflists can easily be built from the un-ordered list of ref pics, so I'm just proposing to get rid of these fields and have a generic implementation kernel-side so that drivers that need it don't have to re-implement it.