Re: [RFC v2 5/8] media: uapi: Add fields needed for RKVDEC driver

[Benjamin Gaignard <benjamin.gaignard@collabora.com>]

Le 18/02/2022 à 12:32, Hans Verkuil a écrit :
> On 15/02/2022 12:01, Benjamin Gaignard wrote:
>> RKVDEC driver requires additional fields to perform HEVC decoding.
>> Even if the driver isn't mainlined yet WIP patches could be find here:
>> https://github.com/LibreELEC/LibreELEC.tv/blob/master/projects/Rockchip/patches/linux/default/linux-2000-v4l2-wip-rkvdec-hevc.patch
>>
>> This patch only include the change in HEVC uAPI.
>>
>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
>> ---
>>   .../userspace-api/media/v4l/ext-ctrls-codec.rst  | 16 ++++++++++++++++
>>   include/uapi/linux/v4l2-controls.h               |  5 +++++
>>   2 files changed, 21 insertions(+)
>>
>> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>> index 4f3b3ba8319f..3296ac3b9fca 100644
>> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>> @@ -2661,6 +2661,13 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
>>       :stub-columns: 0
>>       :widths:       1 1 2
>>   
>> +    * - __u8
>> +      - ``video_parameter_set_id``
>> +      - Identifies the VPS for reference by other syntax elements.
>> +    * - __u8
>> +      - ``seq_parameter_set_id``
>> +      - Provides an identifier for the SPS for reference by other syntax
>> +        elements.
>>       * - __u16
>>         - ``pic_width_in_luma_samples``
>>         -
>> @@ -2800,6 +2807,9 @@ 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 +3036,12 @@ 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``
>> +      -
>> +    * - __u16
>> +      - ``long_term_ref_pic_set_size``
>> +      -
>>       * - __u8
>>         - ``padding``
>>         - Applications and drivers must set this to zero.
> Just to confirm: these additional fields are all from the H.265 spec, right?
> They are not rkvdec specific.

They are in H.265 spec section "7.4.3.2.2 Sequence parameter set range extension semantics":
- num_short_term_ref_pic_sets specifies the number of st_ref_pic_set( ) syntax structures included in the SPS. The value
of num_short_term_ref_pic_sets shall be in the range of 0 to 64, inclusive.

- num_long_term_ref_pics_sps specifies the number of candidate long-term reference pictures that are specified in the
SPS. The value of num_long_term_ref_pics_sps shall be in the range of 0 to 32, inclusive.

I mention rkvdec because that it is the only driver to use they (as far I knows)

Regards,
Benjamin

>
> Regards,
>
> 	Hans
>
>> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
>> index 0e0ec2c61b80..b1a3dc05f02f 100644
>> --- a/include/uapi/linux/v4l2-controls.h
>> +++ b/include/uapi/linux/v4l2-controls.h
>> @@ -2341,6 +2341,8 @@ enum v4l2_stateless_hevc_start_code {
>>   
>>   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;
>> @@ -2393,6 +2395,7 @@ 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;
>> @@ -2487,6 +2490,8 @@ 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;
>>   
>>   	/* ISO/IEC 23008-2, ITU-T Rec. H.265: Weighted prediction parameter */
>>   	struct v4l2_hevc_pred_weight_table pred_weight_table;