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From: Nicolas Dufresne <nicolas.dufresne@collabora.com>
To: Alexandre Courbot <acourbot@chromium.org>,
	Ezequiel Garcia <ezequiel@collabora.com>
Cc: Linux Media Mailing List <linux-media@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Tomasz Figa <tfiga@chromium.org>,
	kernel@collabora.com, Jonas Karlman <jonas@kwiboo.se>,
	Hans Verkuil <hverkuil@xs4all.nl>,
	Jeffrey Kardatzke <jkardatzke@chromium.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Maxime Ripard <mripard@kernel.org>,
	Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Subject: Re: [PATCH 03/10] media: uapi: h264: Split prediction weight parameters
Date: Thu, 30 Jul 2020 09:48:01 -0400	[thread overview]
Message-ID: <74dbf137d8838967c6e1433463b2af708be4da03.camel@collabora.com> (raw)
In-Reply-To: <CAPBb6MVJ+baQshWRJJrwKJ6bKss_KqHoC1xP9kvGtDqC0iFZWw@mail.gmail.com>

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Le samedi 25 juillet 2020 à 22:30 +0900, Alexandre Courbot a écrit :
> On Thu, Jul 16, 2020 at 5:23 AM Ezequiel Garcia <ezequiel@collabora.com> wrote:
> > The prediction weight parameters are only required under
> > certain conditions, which depend on slice header parameters.
> > 
> > The slice header syntax specifies that the prediction
> > weight table is present if:
> > 
> > ((weighted_pred_flag && (slice_type == P || slice_type == SP)) || \
> > (weighted_bipred_idc == 1 && slice_type == B))
> 
> This is a pretty important bit - how about mentioning in the documentation when
> this new control is expected to be present, so both drivers and
> userspace submit it
> or omit it in a consistent manner?

This is copy paste from the spec. We can add a reference to the syntax
chapter in the spec that express exactly this if condition (syntax is
express in pseudo code). The bitstream works exactly the same. Note
that it's not a fault to provide the control even if not needed,
drivers will kindly ignore it.

Reference: 7.3.3 Slice header syntax

Nicolas

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  reply	other threads:[~2020-07-30 13:48 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-15 20:22 [PATCH 0/7] media: Clean H264 stateless uAPI Ezequiel Garcia
2020-07-15 20:22 ` [PATCH 01/10] media: uapi: h264: Update reference lists Ezequiel Garcia
2020-07-22 21:43   ` Jonas Karlman
2020-07-15 20:22 ` [PATCH 02/10] media: uapi: h264: Further clarify scaling lists order Ezequiel Garcia
2020-07-16  7:23   ` Hans Verkuil
2020-07-16 11:43     ` Ezequiel Garcia
2020-07-16 11:44       ` Hans Verkuil
2020-07-15 20:22 ` [PATCH 03/10] media: uapi: h264: Split prediction weight parameters Ezequiel Garcia
2020-07-16  7:26   ` Hans Verkuil
2020-07-16 11:14     ` Ezequiel Garcia
2020-07-22 16:03   ` Jernej Škrabec
2020-07-25 13:30   ` Alexandre Courbot
2020-07-30 13:48     ` Nicolas Dufresne [this message]
2020-07-15 20:22 ` [PATCH 04/10] media: uapi: h264: Clarify pic_order_cnt_bit_size field Ezequiel Garcia
2020-07-15 20:22 ` [PATCH 05/10] media: uapi: h264: Increase size of 'first_mb_in_slice' field Ezequiel Garcia
2020-07-15 20:22 ` [PATCH 06/10] media: uapi: h264: Cleanup DPB entry interface Ezequiel Garcia
2020-07-22 16:09   ` Jernej Škrabec
2020-07-22 17:11     ` Ezequiel Garcia
2020-07-22 21:52   ` Jonas Karlman
2020-07-24 19:08     ` Ezequiel Garcia
2020-07-27 23:39       ` Jonas Karlman
2020-07-31 12:49         ` Ezequiel Garcia
2020-07-15 20:22 ` [PATCH 07/10] media: uapi: h264: Increase size of DPB entry pic_num Ezequiel Garcia
2020-07-15 20:22 ` [PATCH 08/10] media: uapi: h264: Clean slice invariants syntax elements Ezequiel Garcia
2020-07-25 14:34   ` Alexandre Courbot
2020-07-27 14:39     ` Ezequiel Garcia
2020-07-27 14:52       ` Tomasz Figa
2020-07-27 16:18         ` Ezequiel Garcia
2020-07-27 18:10           ` Tomasz Figa
2020-07-27 19:43             ` Nicolas Dufresne
2020-08-04 13:35               ` Tomasz Figa
2020-08-05 16:41                 ` Ezequiel Garcia
2020-07-28 12:44       ` Maxime Ripard
2020-07-28 21:09         ` Nicolas Dufresne
2020-07-15 20:22 ` [PATCH 09/10] media: hantro: Don't require unneeded H264_SLICE_PARAMS Ezequiel Garcia
2020-07-25 14:45   ` Alexandre Courbot
2020-07-26 13:34     ` Alexandre Courbot
2020-07-27 14:44     ` Ezequiel Garcia
2020-07-15 20:22 ` [PATCH 10/10] media: rkvdec: " Ezequiel Garcia
2020-07-27 22:03   ` Jonas Karlman

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