[PATCH v2 0/4] media: HEVC: RPS clean up

Benjamin Gaignard benjamin.gaignard at collabora.com
Fri Oct 15 07:53:18 PDT 2021 

Le 15/10/2021 à 16:14, Alex Bee a écrit :
>
> Am 15.10.21 um 16:06 schrieb Benjamin Gaignard:
>>
>> Le 15/10/2021 à 12:33, Alex Bee a écrit :
>>> 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.
>>
>> Do you have any plan to upstream these fields in HEVC uAPI ?
>
> I might be upstreaming them at some point, yes.
>
> With this I just wanted to underline Jernej said: HEVC uapi is NOT ready
> to get unstaged yet.

Ok but the question is how to get it unstaged ?
Should we continue to do changes in staged uAPI ?
or send a RFC to move it to stable and review all the missing parts at that time ?

Regards,
Benjamin

>
>>
>> Regards,
>> Benjamin
>>
>>>
>>> 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
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>

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