From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [PATCH v2 1/2] media: uapi: Add VP8 stateless decoder API Date: Thu, 4 Jul 2019 15:06:01 +0200 Message-ID: <20190704150601.05509027@collabora.com> References: <20190702170016.5210-1-ezequiel@collabora.com> <20190702170016.5210-2-ezequiel@collabora.com> <4206efe071473daee60cc330ae7934697110516f.camel@collabora.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-rockchip.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.