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Message-ID: <20220426090015.4xhl5ubkptnvqjr2@basti-XPS-13-9310>
Date: Tue, 26 Apr 2022 11:00:15 +0200
From: Sebastian Fricke <sebastian.fricke@...labora.com>
To: Benjamin Gaignard <benjamin.gaignard@...labora.com>
Cc: mchehab@...nel.org, hverkuil@...all.nl,
ezequiel@...guardiasur.com.ar, p.zabel@...gutronix.de,
gregkh@...uxfoundation.org, mripard@...nel.org,
paul.kocialkowski@...tlin.com, wens@...e.org,
jernej.skrabec@...il.com, samuel@...lland.org,
nicolas.dufresne@...labora.com, linux-media@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-rockchip@...ts.infradead.org,
linux-staging@...ts.linux.dev,
linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev
Subject: Re: [PATCH v5 04/17] media: uapi: HEVC: Add missing fields in HEVC
controls
On 26.04.2022 10:50, Benjamin Gaignard wrote:
>
>Le 26/04/2022 à 09:52, Sebastian Fricke a écrit :
>>Hey Benjamin,
>>
>>On 25.04.2022 18:16, Benjamin Gaignard wrote:
>>>
>>>Le 25/04/2022 à 15:54, Sebastian Fricke a écrit :
>>>>On 07.04.2022 17:29, Benjamin Gaignard wrote:
>>>>>Complete the HEVC controls with missing fields from H.265
>>>>>specifications.
>>>>>Even if these fields aren't used by the current mainlined drivers
>>>>>they will be need for (at least) rkvdec driver.
>>>>
>>>>s/be need/be required/
>>>>or
>>>>s/be need/be needed/
>>>>
>>>>s/rkvdec/the rkvdec/
>>>>
>>>>>
>>>>>Signed-off-by: Benjamin Gaignard <benjamin.gaignard@...labora.com>
>>>>>---
>>>>>.../media/v4l/ext-ctrls-codec.rst | 19 +++++++++++++++++++
>>>>>include/media/hevc-ctrls.h | 6 +++++-
>>>>>2 files changed, 24 insertions(+), 1 deletion(-)
>>>>>
>>>>>diff --git
>>>>>a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>>>>>b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>>>>>index 4cd7c541fc30..dbb08603217b 100644
>>>>>--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>>>>>+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>>>>>@@ -2661,6 +2661,16 @@ enum
>>>>>v4l2_mpeg_video_hevc_size_of_length_field -
>>>>> :stub-columns: 0
>>>>> :widths: 1 1 2
>>>>>
>>>>>+ * - __u8
>>>>>+ - ``video_parameter_set_id``
>>>>>+ - Specifies the value of the vps_video_parameter_set_id
>>>>>of the active VPS
>>>>>+ as descibed in section "7.4.3.2.1 General sequence
>>>>>parameter set RBSP semantics"
>>>>>+ of H.265 specifications.
>>>>>+ * - __u8
>>>>>+ - ``seq_parameter_set_id``
>>>>>+ - Provides an identifier for the SPS for reference by
>>>>>other syntax elements
>>>>>+ as descibed in section "7.4.3.2.1 General sequence
>>>>>parameter set RBSP semantics"
>>>>>+ of H.265 specifications.
>>>>> * - __u16
>>>>> - ``pic_width_in_luma_samples``
>>>>> -
>>>>>@@ -2800,6 +2810,9 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
>>>>> :stub-columns: 0
>>>>> :widths: 1 1 2
>>>>>
>>>>>+ * - __u8
>>>>>+ - ``pic_parameter_set_id``
>>>>>+ - Identifies the PPS for reference by other syntax elements.
>>>>> * - __u8
>>>>> - ``num_extra_slice_header_bits``
>>>>> -
>>>>>@@ -3026,6 +3039,12 @@ enum
>>>>>v4l2_mpeg_video_hevc_size_of_length_field -
>>>>> * - __u8
>>>>> - ``ref_idx_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX]``
>>>>> - The list of L1 reference elements as indices in the DPB.
>>>>>+ * - __u16
>>>>>+ - ``short_term_ref_pic_set_size``
>>>>>+ - Specifies the size of short-term reference pictures
>>>>>set included in the SPS.
>>>>
>>>>s/size of/size of the/
>>>>
>>>>Section 7.4.8 depicts that the st_ref_pic_set syntax
>>>>structure can be part of the SPS or the slice header.
>>>>
>>>>I think we should mention that we talk about the size of the
>>>>st_ref_pic_set
>>>>syntax structure from section 7.4.8 of the specification.
>>>>>+ * - __u16
>>>>>+ - ``long_term_ref_pic_set_size``
>>>>>+ - Specifies the size of long-term reference pictures
>>>>>set include in the SPS.
>>>>
>>>>s/size of/size of the/
>>>>
>>>>Can we make this a bit more helpful? The specification doesn't contain
>>>>a similar structure to `st_ref_pic_set` for long term pictures.
>>>>So, as a
>>>>programmer this leaves me guessing:
>>>>- Which syntax structure's size are we talking about?
>>>>- Does this correlate to any of the existing sections of the
>>>>specification?
>>>>Because in the end, I feel like this documentation should be able to
>>>>help a programmer to provide the correct data for the uABI.
>>>
>>>I will reword it like that:
>>>
>>> * - __u16
>>> - ``short_term_ref_pic_set_size``
>>> - Specifies the size, in bits, of the short-term reference
>>>pictures set, described as st_ref_pic_set()
>>
>>Just ...
>>
>>s/reference pictures set/reference picture set/
>>
>>> in the specification, included in the slice header (section
>>>7.3.6.1).
>>
>>s/slice header/slice header or SPS/
>>
>>
>>>
>>>* - __u16
>>> - ``long_term_ref_pic_set_size``
>>> - Specifies the size, in bits, of the long-term reference
>>>pictures set include in the slice header.
>>
>>s/reference pictures set/reference picture set/
>>
>>Looking at the documentation it looks like: s/slice header/slice
>>header or SPS/
>>(For example in section 7.3.6.1:
>>```
>>if( long_term_ref_pics_present_flag ) {
>> if( num_long_term_ref_pics_sps > 0 )
>> num_long_term_sps
>> num_long_term_pics
>> for( i = 0; i < num_long_term_sps + num_long_term_pics; i++ ) {
>> ...
>>```
>>)
>>
>>... and then it looks very good!
>
>I don't know the syntax to insert this kind of comment inside an array in the documentation
>so it will remain as before :-)
Ah, no I didn't mean the pseudo code, I only gave that as an *example*
why just `slice header` seems incorrect to me.
The changes I suggest for that line are only:
s/reference pictures set/reference picture set/ (grammatical error)
s/slice header/slice header or SPS/ (correct statement)
>
>Benjamin
Greetings,
Sebastian
>
>>
>>Greetings,
>>Sebastian
>>
>>> It is the number of bits in the conditional block if(
>>>long_term_ref_pics_present_flag ) {...}
>>> in section 7.3.6.1 of the specification.
>>>
>>>Benjamin
>>>
>>>
>>>>
>>>>Greetings,
>>>>Sebastian
>>>>
>>>>> * - __u8
>>>>> - ``padding``
>>>>> - Applications and drivers must set this to zero.
>>>>>diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
>>>>>index 01ccda48d8c5..a329e086a89a 100644
>>>>>--- a/include/media/hevc-ctrls.h
>>>>>+++ b/include/media/hevc-ctrls.h
>>>>>@@ -58,6 +58,8 @@ enum v4l2_mpeg_video_hevc_start_code {
>>>>>/* The controls are not stable at the moment and will likely
>>>>>be reworked. */
>>>>>struct v4l2_ctrl_hevc_sps {
>>>>> /* ISO/IEC 23008-2, ITU-T Rec. H.265: Sequence parameter set */
>>>>>+ __u8 video_parameter_set_id;
>>>>>+ __u8 seq_parameter_set_id;
>>>>> __u16 pic_width_in_luma_samples;
>>>>> __u16 pic_height_in_luma_samples;
>>>>> __u8 bit_depth_luma_minus8;
>>>>>@@ -108,6 +110,7 @@ struct v4l2_ctrl_hevc_sps {
>>>>>
>>>>>struct v4l2_ctrl_hevc_pps {
>>>>> /* ISO/IEC 23008-2, ITU-T Rec. H.265: Picture parameter set */
>>>>>+ __u8 pic_parameter_set_id;
>>>>> __u8 num_extra_slice_header_bits;
>>>>> __u8 num_ref_idx_l0_default_active_minus1;
>>>>> __u8 num_ref_idx_l1_default_active_minus1;
>>>>>@@ -199,7 +202,8 @@ struct v4l2_ctrl_hevc_slice_params {
>>>>> __u32 slice_segment_addr;
>>>>> __u8 ref_idx_l0[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
>>>>> __u8 ref_idx_l1[V4L2_HEVC_DPB_ENTRIES_NUM_MAX];
>>>>>-
>>>>>+ __u16 short_term_ref_pic_set_size;
>>>>>+ __u16 long_term_ref_pic_set_size;
>>>>> __u8 padding;
>>>>>
>>>>> /* ISO/IEC 23008-2, ITU-T Rec. H.265: Weighted prediction
>>>>>parameter */
>>>>>--
>>>>>2.32.0
>>>>>
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