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Subject: Re: [PATCH v2 0/4] media: HEVC: RPS clean up
To:     =?UTF-8?Q?Jernej_=c5=a0krabec?= <jernej.skrabec@gmail.com>,
        mchehab@kernel.org, p.zabel@pengutronix.de,
        gregkh@linuxfoundation.org, mripard@kernel.org,
        paul.kocialkowski@bootlin.com, wens@csie.org,
        hverkuil-cisco@xs4all.nl, jc@kynesim.co.uk,
        ezequiel@vanguardiasur.com.ar,
        Benjamin Gaignard <benjamin.gaignard@collabora.com>
Cc:     linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-rockchip@lists.infradead.org, linux-staging@lists.linux.dev,
        linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev
References: <20211012143552.661751-1-benjamin.gaignard@collabora.com>
 <21222555.EfDdHjke4D@kista>
 <3c5851ac-3b8a-decc-93c1-01a65b1f8611@collabora.com>
 <1705005.VLH7GnMWUR@kista>
From:   Alex Bee <knaerzche@gmail.com>
Message-ID: <4f8f6da3-70b1-5dd8-27b7-c9f9fd37920b@gmail.com>
Date:   Fri, 15 Oct 2021 12:33:26 +0200
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Hi Benjamin, Jernej
Am 12.10.21 um 18:08 schrieb Jernej Škrabec:
> CC: Alex Bee
> 
> Alex, please take a look to these patches too.
These patches don't remove anything that would be need for rkvdec hevc - 
but indeed - we need some more:
https://github.com/LibreELEC/LibreELEC.tv/blob/master/projects/Rockchip/patches/linux/default/linux-2001-v4l-wip-rkvdec-hevc.patch#L242-L305

v4l2_ctrl_hevc_sps:
__u8	video_parameter_set_id
__u8	seq_parameter_set_id

v4l2_ctrl_hevc_pps:
__u8	pic_parameter_set_id
__u16	short_term_ref_pic_set_size
__u16	long_term_ref_pic_set_size

As far as I can see, they are all part of the spec and should be 
therefore good to go in the uapi.

As you might now, even rkvdec is a frame-based decoder, it doesn't fully 
parse slice headers in HW for HEVC and we need to set references in SW 
which requires looping over the slices. Downstream we have a hack to 
give num_slices in v4l2_ctrl_hevc_sps for doing that.
That could fully go away, if V4L2_CID_MPEG_VIDEO_HEVC_SLICE_PARAMS could 
get dynamic array control support and would make upstreaming this a lot 
easier - as far as I'm concered this would be required for RPi HEVC 
decoder as well.
As a last resort we could also implement a HW specifc control à la
V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP - but I'd like to avoid that, 
knowing it would certainly be better from performance pov.

Alex.
> 
> Dne torek, 12. oktober 2021 ob 17:57:50 CEST je Benjamin Gaignard napisal(a):
>>
>> Le 12/10/2021 à 17:34, Jernej Škrabec a écrit :
>>> Hi Benjamin!
>>>
>>> Dne torek, 12. oktober 2021 ob 16:35:48 CEST je Benjamin Gaignard
> napisal(a):
>>>> This series aims to clean up Reference Picture Set usage and flags.
>>>>
>>>> Long term flag was named with RPS prefix while it is not used for RPS
>>>> but for mark long term references in DBP. Remane it and remove the two
>>>> other useless RPS flags.
>>>>
>>>> Clarify documentation about RPS lists content and make sure that Hantro
>>>> driver use them correctly (i.e without look up in DBP).
>>>>
>>>> These patches are the last in my backlog impacting HEVC uAPI.
>>>>   From my point of view, once they get merged, you could start talking
>>>> about how move HEVC uAPI to stable.
>>> With your changes, HEVC uAPI controls still won't be complete. Cedrus
> needs
>>> entry point control, which in turn needs dynamic array support. I'm a bit
> lazy
>>> implementing that control, but I guess I can take a look in a month or so.
>>> rkvdec also needs more fields for HEVC. With patches collected here:
>>> https://github.com/LibreELEC/LibreELEC.tv/blob/master/projects/Rockchip/
>>> patches/linux/default/linux-2001-v4l-wip-rkvdec-hevc.patch
>>> fluster HEVC test score is reportedly 121/135 (8-bit tests only).
>>
>> Hi Jernej,
>>
>> Thanks for your feedback, getting a list of missing items in HEVC uAPI
>> will definitively help to fill the hope.
>> The patch you mention for rkvdec are already merged in mainline kernel (at
>> least for uAPI part).
> 
> Are they? What about:
> video_parameter_set_id
> seq_parameter_set_id
> pic_parameter_set_id
> short_term_ref_pic_set_size
> long_term_ref_pic_set_size
> 
> At least I don't see them in linux-next. Maybe that information can be
> obtained in some other way?
> 
>> Cedrus needs are about num_entry_point_offsets, offset_len_minus1 and
> entry_point_offset_minus1[ i ]
>> in HEVC specifications ?
> 
> Yes, Cedrus needs to know whole list of entry points. I don't think we need to
> worry about offset_len_minus1, list could be pre-processed - just number of
> entry points and their values.
> 
> Best regards,
> Jernej
> 
>>
>> Regards,
>> Benjamin
>>
>>>
>>> I would certainly wait with moving HEVC uAPI to stable.
>>>
>>> Best regards,
>>> Jernej
>>>
>>>> version 2:
>>>> - change DPB field name from rps to flags
>>>>
>>>> Please note that the only purpose of commits 3 and 4 is to allow to test
>>>> G2 hardware block for IMX8MQ until a proper solution isuing power domain
>>>> can be found. Do not merge them.
>>>>
>>>> GStreamer HEVC plugin merge request can be found here:
>>>> https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1079
>>>>
>>>> With those piece of code fluster score is 77/147.
>>>>
>>>> Benjamin
>>>>
>>>> Benjamin Gaignard (4):
>>>>     media: hevc: Remove RPS named flags
>>>>     media: hevc: Embedded indexes in RPS
>>>>     media: hantro: Use syscon instead of 'ctrl' register
>>>>     arm64: dts: imx8mq: Add node to G2 hardware
>>>>
>>>>    .../media/v4l/ext-ctrls-codec.rst             | 14 +++---
>>>>    arch/arm64/boot/dts/freescale/imx8mq.dtsi     | 43 +++++++++++++----
>>>>    drivers/staging/media/hantro/hantro.h         |  5 +-
>>>>    .../staging/media/hantro/hantro_g2_hevc_dec.c | 27 +++--------
>>>>    drivers/staging/media/hantro/imx8m_vpu_hw.c   | 48 ++++++++++++-------
>>>>    .../staging/media/sunxi/cedrus/cedrus_h265.c  |  2 +-
>>>>    include/media/hevc-ctrls.h                    |  6 +--
>>>>    7 files changed, 84 insertions(+), 61 deletions(-)
>>>>
>>>> -- 
>>>> 2.30.2
>>>>
>>>>
>>>
>>
> 
>