Re: [PATCH v8 01/17] media: uapi: HEVC: Add v4l2_ctrl_hevc_ext_sps_[ls]t_rps controls

[Nicolas Dufresne <nicolas.dufresne@collabora.com>]

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Le vendredi 09 janvier 2026 à 11:15 -0500, Detlev Casanova a écrit :
> Some hardware (e.g.: Rockchip's rk3588 hevc decoder) need to fully parse
> the slice header, which cannot be passed with the current controls.
> There is also no skip method similar as to what can be found in
> verisilicon HW.
> 
> The SPS is therefore extended through these 2 new controls, providing the
> long and short term reference information from the slice header for HEVC
> decoding.
> 
> These now controls are similar as what is passed in the Vulkan Video API
> with the StdVideoH265ShortTermRefPicSet and StdVideoH265LongTermRefPicsSps
> structures embedded in the SPS struct.
> 
> Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>

Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>

> ---
>  .../media/v4l/ext-ctrls-codec-stateless.rst   | 120 ++++++++++++++++++
>  .../media/v4l/videodev2.h.rst.exceptions      |   2 +
>  .../media/v4l/vidioc-queryctrl.rst            |  12 ++
>  3 files changed, 134 insertions(+)
> 
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst
> index 497ae74379f6..3b1e05c6eb13 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec-stateless.rst
> @@ -2959,6 +2959,126 @@ This structure contains all loop filter related parameters. See sections
>        - 0x00000004
>        -
>  
> +``V4L2_CID_STATELESS_HEVC_EXT_SPS_LT_RPS (struct)``
> +    Subset of the :c:type:`v4l2_ctrl_hevc_sps` control.
> +    It extends it with the list of Long-term reference sets parameters.
> +    These parameters are defined according to :ref:`hevc`.
> +    They are described in section 7.4.3.2.1 "General sequence parameter set
> +    RBSP semantics" of the specification.
> +    This control is a dynamically sized 1-dimensional array.
> +    The values in the array should be ignored when either
> +    num_long_term_ref_pics_sps is 0 or the
> +    V4L2_HEVC_SPS_FLAG_LONG_TERM_REF_PICS_PRESENT flag is not set in
> +    :c:type:`v4l2_ctrl_hevc_sps`.
> +
> +.. c:type:: v4l2_ctrl_hevc_ext_sps_lt_rps
> +
> +.. cssclass:: longtable
> +
> +.. flat-table:: struct v4l2_ctrl_hevc_ext_sps_lt_rps
> +    :header-rows:  0
> +    :stub-columns: 0
> +    :widths:       1 1 2
> +
> +    * - __u16
> +      - ``lt_ref_pic_poc_lsb_sps``
> +      - Long term reference picture order count as described in section 7.4.3.2.1
> +        "General sequence parameter set RBSP semantics" of the specification.
> +    * - __u16
> +      - ``flags``
> +      - See :ref:`Extended Long-Term RPS Flags <hevc_ext_sps_lt_rps_flags>`
> +
> +.. _hevc_ext_sps_lt_rps_flags:
> +
> +``Extended SPS Long-Term RPS Flags``
> +
> +.. cssclass:: longtable
> +
> +.. flat-table::
> +    :header-rows:  0
> +    :stub-columns: 0
> +    :widths:       1 1 2
> +
> +    * - ``V4L2_HEVC_EXT_SPS_LT_RPS_FLAG_USED_LT``
> +      - 0x00000001
> +      - Specifies if the long-term reference picture is used 7.4.3.2.1 "General sequence parameter
> +        set RBSP semantics" of the specification.
> +
> +``V4L2_CID_STATELESS_HEVC_EXT_SPS_ST_RPS (struct)``
> +    Subset of the :c:type:`v4l2_ctrl_hevc_sps` control.
> +    It extends it with the list of Short-term reference sets parameters.
> +    These parameters are defined according to :ref:`hevc`.
> +    They are described in section 7.4.8 "Short-term reference picture set
> +    semantics" of the specification.
> +    This control is a dynamically sized 1-dimensional array.
> +    The values in the array should be ignored when
> +    num_short_term_ref_pic_sets is 0.
> +
> +.. c:type:: v4l2_ctrl_hevc_ext_sps_st_rps
> +
> +.. cssclass:: longtable
> +
> +.. flat-table:: struct v4l2_ctrl_hevc_ext_sps_st_rps
> +    :header-rows:  0
> +    :stub-columns: 0
> +    :widths:       1 1 2
> +
> +    * - __u8
> +      - ``delta_idx_minus1``
> +      - Specifies the delta compare to the index. See details in section 7.4.8 "Short-term
> +        reference picture set semantics" of the specification.
> +    * - __u8
> +      - ``delta_rps_sign``
> +      - Sign of the delta as specified in section 7.4.8 "Short-term reference picture set
> +        semantics" of the specification.
> +    * - __u8
> +      - ``num_negative_pics``
> +      - Number of short-term RPS entries that have picture order count values less than the
> +        picture order count value of the current picture.
> +    * - __u8
> +      - ``num_positive_pics``
> +      - Number of short-term RPS entries that have picture order count values greater than the
> +        picture order count value of the current picture.
> +    * - __u32
> +      - ``used_by_curr_pic``
> +      - Bit i specifies if short-term RPS i is used by the current picture.
> +    * - __u32
> +      - ``use_delta_flag``
> +      - Bit i specifies if short-term RPS i is included in the short-term RPS entries.
> +    * - __u16
> +      - ``abs_delta_rps_minus1``
> +      - Absolute delta RPS as specified in section 7.4.8 "Short-term reference picture set
> +        semantics" of the specification.
> +    * - __u16
> +      - ``delta_poc_s0_minus1[16]``
> +      - Specifies the negative picture order count delta for the i-th entry in the short-term RPS.
> +        See details in section 7.4.8 "Short-term reference picture set semantics" of the
> +        specification.
> +    * - __u16
> +      - ``delta_poc_s1_minus1[16]``
> +      - Specifies the positive picture order count delta for the i-th entry in the short-term RPS.
> +        See details in section 7.4.8 "Short-term reference picture set semantics" of the
> +        specification.
> +    * - __u16
> +      - ``flags``
> +      - See :ref:`Extended Short-Term RPS Flags <hevc_ext_sps_st_rps_flags>`
> +
> +.. _hevc_ext_sps_st_rps_flags:
> +
> +``Extended SPS Short-Term RPS Flags``
> +
> +.. cssclass:: longtable
> +
> +.. flat-table::
> +    :header-rows:  0
> +    :stub-columns: 0
> +    :widths:       1 1 2
> +
> +    * - ``V4L2_HEVC_EXT_SPS_ST_RPS_FLAG_INTER_REF_PIC_SET_PRED``
> +      - 0x00000001
> +      - Specifies if the short-term RPS is predicted from another short term RPS. See details in
> +        section 7.4.8 "Short-term reference picture set semantics" of the specification.
> +
>  .. _v4l2-codec-stateless-av1:
>  
>  ``V4L2_CID_STATELESS_AV1_SEQUENCE (struct)``
> diff --git a/Documentation/userspace-api/media/v4l/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/v4l/videodev2.h.rst.exceptions
> index c41693115db6..6182b4e2d2ee 100644
> --- a/Documentation/userspace-api/media/v4l/videodev2.h.rst.exceptions
> +++ b/Documentation/userspace-api/media/v4l/videodev2.h.rst.exceptions
> @@ -150,6 +150,8 @@ replace symbol V4L2_CTRL_TYPE_H264_SCALING_MATRIX :c:type:`V4L.v4l2_ctrl_type`
>  replace symbol V4L2_CTRL_TYPE_H264_PRED_WEIGHTS :c:type:`V4L.v4l2_ctrl_type`
>  replace symbol V4L2_CTRL_TYPE_H264_SLICE_PARAMS :c:type:`V4L.v4l2_ctrl_type`
>  replace symbol V4L2_CTRL_TYPE_H264_DECODE_PARAMS :c:type:`V4L.v4l2_ctrl_type`
> +replace symbol V4L2_CTRL_TYPE_HEVC_EXT_SPS_ST_RPS :c:type:`V4L.v4l2_ctrl_type`
> +replace symbol V4L2_CTRL_TYPE_HEVC_EXT_SPS_LT_RPS :c:type:`V4L.v4l2_ctrl_type`
>  replace symbol V4L2_CTRL_TYPE_HEVC_SPS :c:type:`V4L.v4l2_ctrl_type`
>  replace symbol V4L2_CTRL_TYPE_HEVC_PPS :c:type:`V4L.v4l2_ctrl_type`
>  replace symbol V4L2_CTRL_TYPE_HEVC_SLICE_PARAMS :c:type:`V4L.v4l2_ctrl_type`
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> index c8baa9430c14..82c8b52e771c 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> @@ -531,6 +531,18 @@ See also the examples in :ref:`control`.
>        - n/a
>        - A struct :c:type:`v4l2_ctrl_hevc_decode_params`, containing HEVC
>  	decoding parameters for stateless video decoders.
> +    * - ``V4L2_CTRL_TYPE_HEVC_EXT_SPS_LT_RPS``
> +      - n/a
> +      - n/a
> +      - n/a
> +      - A struct :c:type:`v4l2_ctrl_hevc_ext_sps_lt_rps`, containing HEVC
> +	extended Long-Term RPS for stateless video decoders.
> +    * - ``V4L2_CTRL_TYPE_HEVC_EXT_SPS_ST_RPS``
> +      - n/a
> +      - n/a
> +      - n/a
> +      - A struct :c:type:`v4l2_ctrl_hevc_ext_sps_st_rps`, containing HEVC
> +	extended Short-Term RPS for stateless video decoders.
>      * - ``V4L2_CTRL_TYPE_VP9_COMPRESSED_HDR``
>        - n/a
>        - n/a

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