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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no 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 04B72C0651F for ; Thu, 4 Jul 2019 13:06:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D2ACF2189E for ; Thu, 4 Jul 2019 13:06:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727056AbfGDNGH (ORCPT ); Thu, 4 Jul 2019 09:06:07 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:51250 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726994AbfGDNGH (ORCPT ); Thu, 4 Jul 2019 09:06:07 -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 E9D8F287FCD; Thu, 4 Jul 2019 14:06:04 +0100 (BST) Date: Thu, 4 Jul 2019 15:06:01 +0200 From: Boris Brezillon To: Ezequiel Garcia Cc: Nicolas Dufresne , linux-media@vger.kernel.org, Hans Verkuil , kernel@collabora.com, Tomasz Figa , linux-rockchip@lists.infradead.org, Heiko Stuebner , Jonas Karlman , Philipp Zabel , Paul Kocialkowski , Alexandre Courbot , fbuergisser@chromium.org, linux-kernel@vger.kernel.org, Pawel Osciak Subject: Re: [PATCH v2 1/2] media: uapi: Add VP8 stateless decoder API Message-ID: <20190704150601.05509027@collabora.com> In-Reply-To: References: <20190702170016.5210-1-ezequiel@collabora.com> <20190702170016.5210-2-ezequiel@collabora.com> <4206efe071473daee60cc330ae7934697110516f.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 Thu, 04 Jul 2019 10:00:33 -0300 Ezequiel Garcia wrote: > > Oops, this is just an internal note, it seems I forgot to remove this one. > > > I am right to think that this is basically the size in bits of the > > frame header ? Maybe it could be another way to formulate it ? I'm just > > trying to think of formulation that will better guide the developers > > implementing the parser feeding this. You basically need to parse the > > header to get this size (as everything is dynamically sized). > > > > Depending what you call "frame header", then yes, it's the size in bits. > > first_part_size parttion_sizes[0] > ^ ^ > | | > +--------+------+ +-----+-----+ > | control part | | | > +--------+----------------+------------------+-----------+-----+-----------+ > | tag 3B | extra 7B | hdr | mb_data | dct sz | dct part0 | ... | dct partn | > +--------+-----------------------------------+-----------+-----+-----------+ > > The above shows a VP8 frame, "macroblock_bit_offset" is the size in bits of > the "hdr" portion: i.e. the header of the first partition (aka control partition). > > Thinking about it, the current description is quite confusing. > > How about: > > "Size in bits of the frame header. In other words, this the size in bits of the header > portion of the first partition". How about having a similar diagram somewhere in the spec? It's usually much clearer than a sentence, at least that's my opinion.