[1/3] media: uapi: h264: update reference lists

When dealing with with interlaced frames, reference lists must tell if
each particular reference is meant for top or bottom field. This info
is currently not provided at all in the H264 related controls.

Make reference lists hold a structure which will also hold flags along
index into DPB array. Flags will tell if reference is meant for top or
bottom field.

Currently the only user of these lists is Cedrus which is just compile
fixed here. Actual usage of newly introduced flags will come in
following commit.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
---
 .../media/v4l/ext-ctrls-codec.rst             | 40 ++++++++++++++++++-
 .../staging/media/sunxi/cedrus/cedrus_h264.c  |  6 +--
 include/media/h264-ctrls.h                    | 12 +++++-
 3 files changed, 51 insertions(+), 7 deletions(-)
  

Le jeudi 04 juin 2020 à 20:57 +0200, Jernej Skrabec a écrit :
> When dealing with with interlaced frames, reference lists must tell if
> each particular reference is meant for top or bottom field. This info
> is currently not provided at all in the H264 related controls.
> 
> Make reference lists hold a structure which will also hold flags along
> index into DPB array. Flags will tell if reference is meant for top or
> bottom field.
> 
> Currently the only user of these lists is Cedrus which is just compile
> fixed here. Actual usage of newly introduced flags will come in
> following commit.
> 
> Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>

This looks like the right approach to me and is extensible if anything
else is needed for MVC and SVC special referencing (at least will be
enough for what H.264 actually supports in this regard).

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

> ---
>  .../media/v4l/ext-ctrls-codec.rst             | 40 ++++++++++++++++++-
>  .../staging/media/sunxi/cedrus/cedrus_h264.c  |  6 +--
>  include/media/h264-ctrls.h                    | 12 +++++-
>  3 files changed, 51 insertions(+), 7 deletions(-)
> 
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> index d0d506a444b1..6c36d298db20 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> @@ -1843,10 +1843,10 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
>      * - __u32
>        - ``slice_group_change_cycle``
>        -
> -    * - __u8
> +    * - struct :c:type:`v4l2_h264_reference`
>        - ``ref_pic_list0[32]``
>        - Reference picture list after applying the per-slice modifications
> -    * - __u8
> +    * - struct :c:type:`v4l2_h264_reference`
>        - ``ref_pic_list1[32]``
>        - Reference picture list after applying the per-slice modifications
>      * - __u32
> @@ -1926,6 +1926,42 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
>        - ``chroma_offset[32][2]``
>        -
>  
> +``Picture Reference``
> +
> +.. c:type:: v4l2_h264_reference
> +
> +.. cssclass:: longtable
> +
> +.. flat-table:: struct v4l2_h264_reference
> +    :header-rows:  0
> +    :stub-columns: 0
> +    :widths:       1 1 2
> +
> +    * - __u16
> +      - ``flags``
> +      - See :ref:`Picture Reference Flags <h264_reference_flags>`
> +    * - __u8
> +      - ``index``
> +      -
> +
> +.. _h264_reference_flags:
> +
> +``Picture Reference Flags``
> +
> +.. cssclass:: longtable
> +
> +.. flat-table::
> +    :header-rows:  0
> +    :stub-columns: 0
> +    :widths:       1 1 2
> +
> +    * - ``V4L2_H264_REFERENCE_FLAG_TOP_FIELD``
> +      - 0x00000001
> +      -
> +    * - ``V4L2_H264_REFERENCE_FLAG_BOTTOM_FIELD``
> +      - 0x00000002
> +      -
> +
>  ``V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS (struct)``
>      Specifies the decode parameters (as extracted from the bitstream)
>      for the associated H264 slice data. This includes the necessary
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> index 54ee2aa423e2..cce527bbdf86 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> @@ -166,8 +166,8 @@ static void cedrus_write_frame_list(struct cedrus_ctx *ctx,
>  
>  static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
>  				   struct cedrus_run *run,
> -				   const u8 *ref_list, u8 num_ref,
> -				   enum cedrus_h264_sram_off sram)
> +				   const struct v4l2_h264_reference *ref_list,
> +				   u8 num_ref, enum cedrus_h264_sram_off sram)
>  {
>  	const struct v4l2_ctrl_h264_decode_params *decode = run->h264.decode_params;
>  	struct vb2_queue *cap_q;
> @@ -188,7 +188,7 @@ static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
>  		int buf_idx;
>  		u8 dpb_idx;
>  
> -		dpb_idx = ref_list[i];
> +		dpb_idx = ref_list[i].index;
>  		dpb = &decode->dpb[dpb_idx];
>  
>  		if (!(dpb->flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE))
> diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
> index 080fd1293c42..9b1cbc9bc38e 100644
> --- a/include/media/h264-ctrls.h
> +++ b/include/media/h264-ctrls.h
> @@ -140,6 +140,14 @@ struct v4l2_h264_pred_weight_table {
>  #define V4L2_H264_SLICE_FLAG_DIRECT_SPATIAL_MV_PRED	0x04
>  #define V4L2_H264_SLICE_FLAG_SP_FOR_SWITCH		0x08
>  
> +#define V4L2_H264_REFERENCE_FLAG_TOP_FIELD		0x01
> +#define V4L2_H264_REFERENCE_FLAG_BOTTOM_FIELD		0x02
> +
> +struct v4l2_h264_reference {
> +	__u8 flags;
> +	__u8 index;
> +};
> +
>  struct v4l2_ctrl_h264_slice_params {
>  	/* Size in bytes, including header */
>  	__u32 size;
> @@ -182,8 +190,8 @@ struct v4l2_ctrl_h264_slice_params {
>  	 * Entries on each list are indices into
>  	 * v4l2_ctrl_h264_decode_params.dpb[].
>  	 */
> -	__u8 ref_pic_list0[32];
> -	__u8 ref_pic_list1[32];
> +	struct v4l2_h264_reference ref_pic_list0[32];
> +	struct v4l2_h264_reference ref_pic_list1[32];
>  
>  	__u32 flags;
>  };
  

Sorry, missed one thing.

Le vendredi 05 juin 2020 à 13:08 -0400, Nicolas Dufresne a écrit :
> Le jeudi 04 juin 2020 à 20:57 +0200, Jernej Skrabec a écrit :
> > When dealing with with interlaced frames, reference lists must tell if
> > each particular reference is meant for top or bottom field. This info
> > is currently not provided at all in the H264 related controls.
> > 
> > Make reference lists hold a structure which will also hold flags along
> > index into DPB array. Flags will tell if reference is meant for top or
> > bottom field.
> > 
> > Currently the only user of these lists is Cedrus which is just compile
> > fixed here. Actual usage of newly introduced flags will come in
> > following commit.
> > 
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> 
> This looks like the right approach to me and is extensible if anything
> else is needed for MVC and SVC special referencing (at least will be
> enough for what H.264 actually supports in this regard).
> 
> Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
> 
> > ---
> >  .../media/v4l/ext-ctrls-codec.rst             | 40 ++++++++++++++++++-
> >  .../staging/media/sunxi/cedrus/cedrus_h264.c  |  6 +--
> >  include/media/h264-ctrls.h                    | 12 +++++-
> >  3 files changed, 51 insertions(+), 7 deletions(-)
> > 
> > diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > index d0d506a444b1..6c36d298db20 100644
> > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > @@ -1843,10 +1843,10 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
> >      * - __u32
> >        - ``slice_group_change_cycle``
> >        -
> > -    * - __u8
> > +    * - struct :c:type:`v4l2_h264_reference`
> >        - ``ref_pic_list0[32]``
> >        - Reference picture list after applying the per-slice modifications
> > -    * - __u8
> > +    * - struct :c:type:`v4l2_h264_reference`
> >        - ``ref_pic_list1[32]``
> >        - Reference picture list after applying the per-slice modifications
> >      * - __u32
> > @@ -1926,6 +1926,42 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
> >        - ``chroma_offset[32][2]``
> >        -
> >  
> > +``Picture Reference``
> > +
> > +.. c:type:: v4l2_h264_reference
> > +
> > +.. cssclass:: longtable
> > +
> > +.. flat-table:: struct v4l2_h264_reference
> > +    :header-rows:  0
> > +    :stub-columns: 0
> > +    :widths:       1 1 2
> > +
> > +    * - __u16
> > +      - ``flags``
> > +      - See :ref:`Picture Reference Flags <h264_reference_flags>`
> > +    * - __u8
> > +      - ``index``
> > +      -
> > +
> > +.. _h264_reference_flags:
> > +
> > +``Picture Reference Flags``
> > +
> > +.. cssclass:: longtable
> > +
> > +.. flat-table::
> > +    :header-rows:  0
> > +    :stub-columns: 0
> > +    :widths:       1 1 2
> > +
> > +    * - ``V4L2_H264_REFERENCE_FLAG_TOP_FIELD``
> > +      - 0x00000001
> > +      -
> > +    * - ``V4L2_H264_REFERENCE_FLAG_BOTTOM_FIELD``
> > +      - 0x00000002
> > +      -
> > +
> >  ``V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS (struct)``
> >      Specifies the decode parameters (as extracted from the bitstream)
> >      for the associated H264 slice data. This includes the necessary
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > index 54ee2aa423e2..cce527bbdf86 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > @@ -166,8 +166,8 @@ static void cedrus_write_frame_list(struct cedrus_ctx *ctx,
> >  
> >  static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
> >  				   struct cedrus_run *run,
> > -				   const u8 *ref_list, u8 num_ref,
> > -				   enum cedrus_h264_sram_off sram)
> > +				   const struct v4l2_h264_reference *ref_list,
> > +				   u8 num_ref, enum cedrus_h264_sram_off sram)
> >  {
> >  	const struct v4l2_ctrl_h264_decode_params *decode = run->h264.decode_params;
> >  	struct vb2_queue *cap_q;
> > @@ -188,7 +188,7 @@ static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
> >  		int buf_idx;
> >  		u8 dpb_idx;
> >  
> > -		dpb_idx = ref_list[i];
> > +		dpb_idx = ref_list[i].index;
> >  		dpb = &decode->dpb[dpb_idx];
> >  
> >  		if (!(dpb->flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE))
> > diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
> > index 080fd1293c42..9b1cbc9bc38e 100644
> > --- a/include/media/h264-ctrls.h
> > +++ b/include/media/h264-ctrls.h
> > @@ -140,6 +140,14 @@ struct v4l2_h264_pred_weight_table {
> >  #define V4L2_H264_SLICE_FLAG_DIRECT_SPATIAL_MV_PRED	0x04
> >  #define V4L2_H264_SLICE_FLAG_SP_FOR_SWITCH		0x08
> >  
> > +#define V4L2_H264_REFERENCE_FLAG_TOP_FIELD		0x01
> > +#define V4L2_H264_REFERENCE_FLAG_BOTTOM_FIELD		0x02
> > +
> > +struct v4l2_h264_reference {
> > +	__u8 flags;
> > +	__u8 index;
> > +};
> > +
> >  struct v4l2_ctrl_h264_slice_params {
> >  	/* Size in bytes, including header */
> >  	__u32 size;
> > @@ -182,8 +190,8 @@ struct v4l2_ctrl_h264_slice_params {
> >  	 * Entries on each list are indices into
> >  	 * v4l2_ctrl_h264_decode_params.dpb[].
> >  	 */

This comment needs to be updated or moved inside the structure.

> > -	__u8 ref_pic_list0[32];
> > -	__u8 ref_pic_list1[32];
> > +	struct v4l2_h264_reference ref_pic_list0[32];
> > +	struct v4l2_h264_reference ref_pic_list1[32];
> >  
> >  	__u32 flags;
> >  };
  

Dne petek, 05. junij 2020 ob 19:13:24 CEST je Nicolas Dufresne napisal(a):
> Sorry, missed one thing.
> 
> Le vendredi 05 juin 2020 à 13:08 -0400, Nicolas Dufresne a écrit :
> > Le jeudi 04 juin 2020 à 20:57 +0200, Jernej Skrabec a écrit :
> > > When dealing with with interlaced frames, reference lists must tell if
> > > each particular reference is meant for top or bottom field. This info
> > > is currently not provided at all in the H264 related controls.
> > > 
> > > Make reference lists hold a structure which will also hold flags along
> > > index into DPB array. Flags will tell if reference is meant for top or
> > > bottom field.
> > > 
> > > Currently the only user of these lists is Cedrus which is just compile
> > > fixed here. Actual usage of newly introduced flags will come in
> > > following commit.
> > > 
> > > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> > 
> > This looks like the right approach to me and is extensible if anything
> > else is needed for MVC and SVC special referencing (at least will be
> > enough for what H.264 actually supports in this regard).
> > 
> > Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
> > 
> > > ---
> > > 
> > >  .../media/v4l/ext-ctrls-codec.rst             | 40 ++++++++++++++++++-
> > >  .../staging/media/sunxi/cedrus/cedrus_h264.c  |  6 +--
> > >  include/media/h264-ctrls.h                    | 12 +++++-
> > >  3 files changed, 51 insertions(+), 7 deletions(-)
> > > 
> > > diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > > b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst index
> > > d0d506a444b1..6c36d298db20 100644
> > > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > > @@ -1843,10 +1843,10 @@ enum
> > > v4l2_mpeg_video_h264_hierarchical_coding_type -> > 
> > >      * - __u32
> > >      
> > >        - ``slice_group_change_cycle``
> > >        -
> > > 
> > > -    * - __u8
> > > +    * - struct :c:type:`v4l2_h264_reference`
> > > 
> > >        - ``ref_pic_list0[32]``
> > >        - Reference picture list after applying the per-slice
> > >        modifications
> > > 
> > > -    * - __u8
> > > +    * - struct :c:type:`v4l2_h264_reference`
> > > 
> > >        - ``ref_pic_list1[32]``
> > >        - Reference picture list after applying the per-slice
> > >        modifications
> > >      
> > >      * - __u32
> > > 
> > > @@ -1926,6 +1926,42 @@ enum
> > > v4l2_mpeg_video_h264_hierarchical_coding_type -
> > > 
> > >        - ``chroma_offset[32][2]``
> > >        -
> > > 
> > > +``Picture Reference``
> > > +
> > > +.. c:type:: v4l2_h264_reference
> > > +
> > > +.. cssclass:: longtable
> > > +
> > > +.. flat-table:: struct v4l2_h264_reference
> > > +    :header-rows:  0
> > > +    :stub-columns: 0
> > > +    :widths:       1 1 2
> > > +
> > > +    * - __u16
> > > +      - ``flags``
> > > +      - See :ref:`Picture Reference Flags <h264_reference_flags>`
> > > +    * - __u8
> > > +      - ``index``
> > > +      -
> > > +
> > > +.. _h264_reference_flags:
> > > +
> > > +``Picture Reference Flags``
> > > +
> > > +.. cssclass:: longtable
> > > +
> > > +.. flat-table::
> > > +    :header-rows:  0
> > > +    :stub-columns: 0
> > > +    :widths:       1 1 2
> > > +
> > > +    * - ``V4L2_H264_REFERENCE_FLAG_TOP_FIELD``
> > > +      - 0x00000001
> > > +      -
> > > +    * - ``V4L2_H264_REFERENCE_FLAG_BOTTOM_FIELD``
> > > +      - 0x00000002
> > > +      -
> > > +
> > > 
> > >  ``V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS (struct)``
> > >  
> > >      Specifies the decode parameters (as extracted from the bitstream)
> > >      for the associated H264 slice data. This includes the necessary
> > > 
> > > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > > b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c index
> > > 54ee2aa423e2..cce527bbdf86 100644
> > > --- a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > > @@ -166,8 +166,8 @@ static void cedrus_write_frame_list(struct
> > > cedrus_ctx *ctx,> > 
> > >  static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
> > >  
> > >  				   struct cedrus_run *run,
> > > 
> > > -				   const u8 *ref_list, u8 
num_ref,
> > > -				   enum cedrus_h264_sram_off 
sram)
> > > +				   const struct 
v4l2_h264_reference *ref_list,
> > > +				   u8 num_ref, enum 
cedrus_h264_sram_off sram)
> > > 
> > >  {
> > >  
> > >  	const struct v4l2_ctrl_h264_decode_params *decode =
> > >  	run->h264.decode_params; struct vb2_queue *cap_q;
> > > 
> > > @@ -188,7 +188,7 @@ static void _cedrus_write_ref_list(struct cedrus_ctx
> > > *ctx,> > 
> > >  		int buf_idx;
> > >  		u8 dpb_idx;
> > > 
> > > -		dpb_idx = ref_list[i];
> > > +		dpb_idx = ref_list[i].index;
> > > 
> > >  		dpb = &decode->dpb[dpb_idx];
> > >  		
> > >  		if (!(dpb->flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE))
> > > 
> > > diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
> > > index 080fd1293c42..9b1cbc9bc38e 100644
> > > --- a/include/media/h264-ctrls.h
> > > +++ b/include/media/h264-ctrls.h
> > > @@ -140,6 +140,14 @@ struct v4l2_h264_pred_weight_table {
> > > 
> > >  #define V4L2_H264_SLICE_FLAG_DIRECT_SPATIAL_MV_PRED	0x04
> > >  #define V4L2_H264_SLICE_FLAG_SP_FOR_SWITCH		0x08
> > > 
> > > +#define V4L2_H264_REFERENCE_FLAG_TOP_FIELD		0x01
> > > +#define V4L2_H264_REFERENCE_FLAG_BOTTOM_FIELD		0x02
> > > +
> > > +struct v4l2_h264_reference {
> > > +	__u8 flags;
> > > +	__u8 index;
> > > +};
> > > +
> > > 
> > >  struct v4l2_ctrl_h264_slice_params {
> > >  
> > >  	/* Size in bytes, including header */
> > >  	__u32 size;
> > > 
> > > @@ -182,8 +190,8 @@ struct v4l2_ctrl_h264_slice_params {
> > > 
> > >  	 * Entries on each list are indices into
> > >  	 * v4l2_ctrl_h264_decode_params.dpb[].
> > >  	 */
> 
> This comment needs to be updated or moved inside the structure.

I'll move it in v2.

Best regards,
Jernej

> 
> > > -	__u8 ref_pic_list0[32];
> > > -	__u8 ref_pic_list1[32];
> > > +	struct v4l2_h264_reference ref_pic_list0[32];
> > > +	struct v4l2_h264_reference ref_pic_list1[32];
> > > 
> > >  	__u32 flags;
> > >  
> > >  };
  

Hello Jernej,

I'd like to post a new H264 uAPI cleanup series soon,
would you mind resending this, or otherwise do you
mind if I include this patch in the series?

See below for a tiny comment.

On Thu, 4 Jun 2020 at 15:55, Jernej Skrabec <jernej.skrabec@siol.net> wrote:
>
> When dealing with with interlaced frames, reference lists must tell if
> each particular reference is meant for top or bottom field. This info
> is currently not provided at all in the H264 related controls.
>
> Make reference lists hold a structure which will also hold flags along
> index into DPB array. Flags will tell if reference is meant for top or
> bottom field.
>
> Currently the only user of these lists is Cedrus which is just compile
> fixed here. Actual usage of newly introduced flags will come in
> following commit.
>
> Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> ---
>  .../media/v4l/ext-ctrls-codec.rst             | 40 ++++++++++++++++++-
>  .../staging/media/sunxi/cedrus/cedrus_h264.c  |  6 +--
>  include/media/h264-ctrls.h                    | 12 +++++-
>  3 files changed, 51 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> index d0d506a444b1..6c36d298db20 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> @@ -1843,10 +1843,10 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
>      * - __u32
>        - ``slice_group_change_cycle``
>        -
> -    * - __u8
> +    * - struct :c:type:`v4l2_h264_reference`
>        - ``ref_pic_list0[32]``
>        - Reference picture list after applying the per-slice modifications
> -    * - __u8
> +    * - struct :c:type:`v4l2_h264_reference`
>        - ``ref_pic_list1[32]``
>        - Reference picture list after applying the per-slice modifications
>      * - __u32
> @@ -1926,6 +1926,42 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
>        - ``chroma_offset[32][2]``
>        -
>
> +``Picture Reference``
> +
> +.. c:type:: v4l2_h264_reference
> +
> +.. cssclass:: longtable
> +
> +.. flat-table:: struct v4l2_h264_reference
> +    :header-rows:  0
> +    :stub-columns: 0
> +    :widths:       1 1 2
> +
> +    * - __u16
> +      - ``flags``
> +      - See :ref:`Picture Reference Flags <h264_reference_flags>`
> +    * - __u8
> +      - ``index``
> +      -
> +
> +.. _h264_reference_flags:
> +
> +``Picture Reference Flags``
> +
> +.. cssclass:: longtable
> +
> +.. flat-table::
> +    :header-rows:  0
> +    :stub-columns: 0
> +    :widths:       1 1 2
> +
> +    * - ``V4L2_H264_REFERENCE_FLAG_TOP_FIELD``
> +      - 0x00000001
> +      -
> +    * - ``V4L2_H264_REFERENCE_FLAG_BOTTOM_FIELD``
> +      - 0x00000002
> +      -
> +
>  ``V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS (struct)``
>      Specifies the decode parameters (as extracted from the bitstream)
>      for the associated H264 slice data. This includes the necessary
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> index 54ee2aa423e2..cce527bbdf86 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> @@ -166,8 +166,8 @@ static void cedrus_write_frame_list(struct cedrus_ctx *ctx,
>
>  static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
>                                    struct cedrus_run *run,
> -                                  const u8 *ref_list, u8 num_ref,
> -                                  enum cedrus_h264_sram_off sram)
> +                                  const struct v4l2_h264_reference *ref_list,
> +                                  u8 num_ref, enum cedrus_h264_sram_off sram)
>  {
>         const struct v4l2_ctrl_h264_decode_params *decode = run->h264.decode_params;
>         struct vb2_queue *cap_q;
> @@ -188,7 +188,7 @@ static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
>                 int buf_idx;
>                 u8 dpb_idx;
>
> -               dpb_idx = ref_list[i];
> +               dpb_idx = ref_list[i].index;
>                 dpb = &decode->dpb[dpb_idx];
>
>                 if (!(dpb->flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE))
> diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
> index 080fd1293c42..9b1cbc9bc38e 100644
> --- a/include/media/h264-ctrls.h
> +++ b/include/media/h264-ctrls.h
> @@ -140,6 +140,14 @@ struct v4l2_h264_pred_weight_table {
>  #define V4L2_H264_SLICE_FLAG_DIRECT_SPATIAL_MV_PRED    0x04
>  #define V4L2_H264_SLICE_FLAG_SP_FOR_SWITCH             0x08
>
> +#define V4L2_H264_REFERENCE_FLAG_TOP_FIELD             0x01
> +#define V4L2_H264_REFERENCE_FLAG_BOTTOM_FIELD          0x02
> +
> +struct v4l2_h264_reference {
> +       __u8 flags;
> +       __u8 index;
> +};
> +
>  struct v4l2_ctrl_h264_slice_params {
>         /* Size in bytes, including header */
>         __u32 size;
> @@ -182,8 +190,8 @@ struct v4l2_ctrl_h264_slice_params {
>          * Entries on each list are indices into
>          * v4l2_ctrl_h264_decode_params.dpb[].
>          */
> -       __u8 ref_pic_list0[32];
> -       __u8 ref_pic_list1[32];
> +       struct v4l2_h264_reference ref_pic_list0[32];
> +       struct v4l2_h264_reference ref_pic_list1[32];
>

Could we use a macro for "32" here? Something like:

#define V4L2_H264_REF_PIC_LIST_LEN (V4L2_H264_NUM_DPB_ENTRIES * 2).

Does it make sense to add a comment as well?

I was thinking something along these lines:

"""
Pictures in the DPB can be a frame, a complementary field pair or a
single field.
Therefore, reference pictures lists need twice as much entries, so it
can reference
either field of a field pair.
"""

While it doesn't replace proper H264 specification reading,
it would add some clarity.

Thanks,
Ezequiel
  

Hi!

Dne sreda, 08. julij 2020 ob 15:28:52 CEST je Ezequiel Garcia napisal(a):
> Hello Jernej,
> 
> I'd like to post a new H264 uAPI cleanup series soon,
> would you mind resending this, or otherwise do you
> mind if I include this patch in the series?

I don't mind at all. Currently my focus was elsewhere...

> 
> See below for a tiny comment.
> 
> On Thu, 4 Jun 2020 at 15:55, Jernej Skrabec <jernej.skrabec@siol.net> wrote:
> > When dealing with with interlaced frames, reference lists must tell if
> > each particular reference is meant for top or bottom field. This info
> > is currently not provided at all in the H264 related controls.
> > 
> > Make reference lists hold a structure which will also hold flags along
> > index into DPB array. Flags will tell if reference is meant for top or
> > bottom field.
> > 
> > Currently the only user of these lists is Cedrus which is just compile
> > fixed here. Actual usage of newly introduced flags will come in
> > following commit.
> > 
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> > ---
> > 
> >  .../media/v4l/ext-ctrls-codec.rst             | 40 ++++++++++++++++++-
> >  .../staging/media/sunxi/cedrus/cedrus_h264.c  |  6 +--
> >  include/media/h264-ctrls.h                    | 12 +++++-
> >  3 files changed, 51 insertions(+), 7 deletions(-)
> > 
> > diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst index
> > d0d506a444b1..6c36d298db20 100644
> > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > @@ -1843,10 +1843,10 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type
> > -> 
> >      * - __u32
> >      
> >        - ``slice_group_change_cycle``
> >        -
> > 
> > -    * - __u8
> > +    * - struct :c:type:`v4l2_h264_reference`
> > 
> >        - ``ref_pic_list0[32]``
> >        - Reference picture list after applying the per-slice modifications
> > 
> > -    * - __u8
> > +    * - struct :c:type:`v4l2_h264_reference`
> > 
> >        - ``ref_pic_list1[32]``
> >        - Reference picture list after applying the per-slice modifications
> >      
> >      * - __u32
> > 
> > @@ -1926,6 +1926,42 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type
> > -
> > 
> >        - ``chroma_offset[32][2]``
> >        -
> > 
> > +``Picture Reference``
> > +
> > +.. c:type:: v4l2_h264_reference
> > +
> > +.. cssclass:: longtable
> > +
> > +.. flat-table:: struct v4l2_h264_reference
> > +    :header-rows:  0
> > +    :stub-columns: 0
> > +    :widths:       1 1 2
> > +
> > +    * - __u16
> > +      - ``flags``
> > +      - See :ref:`Picture Reference Flags <h264_reference_flags>`
> > +    * - __u8
> > +      - ``index``
> > +      -
> > +
> > +.. _h264_reference_flags:
> > +
> > +``Picture Reference Flags``
> > +
> > +.. cssclass:: longtable
> > +
> > +.. flat-table::
> > +    :header-rows:  0
> > +    :stub-columns: 0
> > +    :widths:       1 1 2
> > +
> > +    * - ``V4L2_H264_REFERENCE_FLAG_TOP_FIELD``
> > +      - 0x00000001
> > +      -
> > +    * - ``V4L2_H264_REFERENCE_FLAG_BOTTOM_FIELD``
> > +      - 0x00000002
> > +      -
> > +
> > 
> >  ``V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS (struct)``
> >  
> >      Specifies the decode parameters (as extracted from the bitstream)
> >      for the associated H264 slice data. This includes the necessary
> > 
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c index
> > 54ee2aa423e2..cce527bbdf86 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > @@ -166,8 +166,8 @@ static void cedrus_write_frame_list(struct cedrus_ctx
> > *ctx,> 
> >  static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
> >  
> >                                    struct cedrus_run *run,
> > 
> > -                                  const u8 *ref_list, u8 num_ref,
> > -                                  enum cedrus_h264_sram_off sram)
> > +                                  const struct v4l2_h264_reference
> > *ref_list, +                                  u8 num_ref, enum
> > cedrus_h264_sram_off sram)> 
> >  {
> >  
> >         const struct v4l2_ctrl_h264_decode_params *decode =
> >         run->h264.decode_params; struct vb2_queue *cap_q;
> > 
> > @@ -188,7 +188,7 @@ static void _cedrus_write_ref_list(struct cedrus_ctx
> > *ctx,> 
> >                 int buf_idx;
> >                 u8 dpb_idx;
> > 
> > -               dpb_idx = ref_list[i];
> > +               dpb_idx = ref_list[i].index;
> > 
> >                 dpb = &decode->dpb[dpb_idx];
> >                 
> >                 if (!(dpb->flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE))
> > 
> > diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
> > index 080fd1293c42..9b1cbc9bc38e 100644
> > --- a/include/media/h264-ctrls.h
> > +++ b/include/media/h264-ctrls.h
> > @@ -140,6 +140,14 @@ struct v4l2_h264_pred_weight_table {
> > 
> >  #define V4L2_H264_SLICE_FLAG_DIRECT_SPATIAL_MV_PRED    0x04
> >  #define V4L2_H264_SLICE_FLAG_SP_FOR_SWITCH             0x08
> > 
> > +#define V4L2_H264_REFERENCE_FLAG_TOP_FIELD             0x01
> > +#define V4L2_H264_REFERENCE_FLAG_BOTTOM_FIELD          0x02
> > +
> > +struct v4l2_h264_reference {
> > +       __u8 flags;
> > +       __u8 index;
> > +};
> > +
> > 
> >  struct v4l2_ctrl_h264_slice_params {
> >  
> >         /* Size in bytes, including header */
> >         __u32 size;
> > 
> > @@ -182,8 +190,8 @@ struct v4l2_ctrl_h264_slice_params {
> > 
> >          * Entries on each list are indices into
> >          * v4l2_ctrl_h264_decode_params.dpb[].
> >          */
> > 
> > -       __u8 ref_pic_list0[32];
> > -       __u8 ref_pic_list1[32];
> > +       struct v4l2_h264_reference ref_pic_list0[32];
> > +       struct v4l2_h264_reference ref_pic_list1[32];
> 
> Could we use a macro for "32" here? Something like:
> 
> #define V4L2_H264_REF_PIC_LIST_LEN (V4L2_H264_NUM_DPB_ENTRIES * 2).
> 
> Does it make sense to add a comment as well?
> 
> I was thinking something along these lines:
> 
> """
> Pictures in the DPB can be a frame, a complementary field pair or a
> single field.

To be honest, I don't know if user has a free choice to select same or 
different destination (capture) buffer for another field. I never tested it and 
I'm not sure how to test it with ffmpeg. HW deinterlacing cores on Allwinner 
SoCs support only interleaved fields as a input, that's why I never though 
about separate fields.

Best regards,
Jernej

> Therefore, reference pictures lists need twice as much entries, so it
> can reference
> either field of a field pair.
> """
> 
> While it doesn't replace proper H264 specification reading,
> it would add some clarity.
> 
> Thanks,
> Ezequiel
  

Le mercredi 08 juillet 2020 à 17:57 +0200, Jernej Škrabec a écrit :
> Hi!
> 
> Dne sreda, 08. julij 2020 ob 15:28:52 CEST je Ezequiel Garcia napisal(a):
> > Hello Jernej,
> > 
> > I'd like to post a new H264 uAPI cleanup series soon,
> > would you mind resending this, or otherwise do you
> > mind if I include this patch in the series?
> 
> I don't mind at all. Currently my focus was elsewhere...
> 
> > See below for a tiny comment.
> > 
> > On Thu, 4 Jun 2020 at 15:55, Jernej Skrabec <jernej.skrabec@siol.net> wrote:
> > > When dealing with with interlaced frames, reference lists must tell if
> > > each particular reference is meant for top or bottom field. This info
> > > is currently not provided at all in the H264 related controls.
> > > 
> > > Make reference lists hold a structure which will also hold flags along
> > > index into DPB array. Flags will tell if reference is meant for top or
> > > bottom field.
> > > 
> > > Currently the only user of these lists is Cedrus which is just compile
> > > fixed here. Actual usage of newly introduced flags will come in
> > > following commit.
> > > 
> > > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> > > ---
> > > 
> > >  .../media/v4l/ext-ctrls-codec.rst             | 40 ++++++++++++++++++-
> > >  .../staging/media/sunxi/cedrus/cedrus_h264.c  |  6 +--
> > >  include/media/h264-ctrls.h                    | 12 +++++-
> > >  3 files changed, 51 insertions(+), 7 deletions(-)
> > > 
> > > diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > > b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst index
> > > d0d506a444b1..6c36d298db20 100644
> > > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > > @@ -1843,10 +1843,10 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type
> > > -> 
> > >      * - __u32
> > >      
> > >        - ``slice_group_change_cycle``
> > >        -
> > > 
> > > -    * - __u8
> > > +    * - struct :c:type:`v4l2_h264_reference`
> > > 
> > >        - ``ref_pic_list0[32]``
> > >        - Reference picture list after applying the per-slice modifications
> > > 
> > > -    * - __u8
> > > +    * - struct :c:type:`v4l2_h264_reference`
> > > 
> > >        - ``ref_pic_list1[32]``
> > >        - Reference picture list after applying the per-slice modifications
> > >      
> > >      * - __u32
> > > 
> > > @@ -1926,6 +1926,42 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type
> > > -
> > > 
> > >        - ``chroma_offset[32][2]``
> > >        -
> > > 
> > > +``Picture Reference``
> > > +
> > > +.. c:type:: v4l2_h264_reference
> > > +
> > > +.. cssclass:: longtable
> > > +
> > > +.. flat-table:: struct v4l2_h264_reference
> > > +    :header-rows:  0
> > > +    :stub-columns: 0
> > > +    :widths:       1 1 2
> > > +
> > > +    * - __u16
> > > +      - ``flags``
> > > +      - See :ref:`Picture Reference Flags <h264_reference_flags>`
> > > +    * - __u8
> > > +      - ``index``
> > > +      -
> > > +
> > > +.. _h264_reference_flags:
> > > +
> > > +``Picture Reference Flags``
> > > +
> > > +.. cssclass:: longtable
> > > +
> > > +.. flat-table::
> > > +    :header-rows:  0
> > > +    :stub-columns: 0
> > > +    :widths:       1 1 2
> > > +
> > > +    * - ``V4L2_H264_REFERENCE_FLAG_TOP_FIELD``
> > > +      - 0x00000001
> > > +      -
> > > +    * - ``V4L2_H264_REFERENCE_FLAG_BOTTOM_FIELD``
> > > +      - 0x00000002
> > > +      -
> > > +
> > > 
> > >  ``V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS (struct)``
> > >  
> > >      Specifies the decode parameters (as extracted from the bitstream)
> > >      for the associated H264 slice data. This includes the necessary
> > > 
> > > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > > b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c index
> > > 54ee2aa423e2..cce527bbdf86 100644
> > > --- a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > > @@ -166,8 +166,8 @@ static void cedrus_write_frame_list(struct cedrus_ctx
> > > *ctx,> 
> > >  static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
> > >  
> > >                                    struct cedrus_run *run,
> > > 
> > > -                                  const u8 *ref_list, u8 num_ref,
> > > -                                  enum cedrus_h264_sram_off sram)
> > > +                                  const struct v4l2_h264_reference
> > > *ref_list, +                                  u8 num_ref, enum
> > > cedrus_h264_sram_off sram)> 
> > >  {
> > >  
> > >         const struct v4l2_ctrl_h264_decode_params *decode =
> > >         run->h264.decode_params; struct vb2_queue *cap_q;
> > > 
> > > @@ -188,7 +188,7 @@ static void _cedrus_write_ref_list(struct cedrus_ctx
> > > *ctx,> 
> > >                 int buf_idx;
> > >                 u8 dpb_idx;
> > > 
> > > -               dpb_idx = ref_list[i];
> > > +               dpb_idx = ref_list[i].index;
> > > 
> > >                 dpb = &decode->dpb[dpb_idx];
> > >                 
> > >                 if (!(dpb->flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE))
> > > 
> > > diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
> > > index 080fd1293c42..9b1cbc9bc38e 100644
> > > --- a/include/media/h264-ctrls.h
> > > +++ b/include/media/h264-ctrls.h
> > > @@ -140,6 +140,14 @@ struct v4l2_h264_pred_weight_table {
> > > 
> > >  #define V4L2_H264_SLICE_FLAG_DIRECT_SPATIAL_MV_PRED    0x04
> > >  #define V4L2_H264_SLICE_FLAG_SP_FOR_SWITCH             0x08
> > > 
> > > +#define V4L2_H264_REFERENCE_FLAG_TOP_FIELD             0x01
> > > +#define V4L2_H264_REFERENCE_FLAG_BOTTOM_FIELD          0x02
> > > +
> > > +struct v4l2_h264_reference {
> > > +       __u8 flags;
> > > +       __u8 index;
> > > +};
> > > +
> > > 
> > >  struct v4l2_ctrl_h264_slice_params {
> > >  
> > >         /* Size in bytes, including header */
> > >         __u32 size;
> > > 
> > > @@ -182,8 +190,8 @@ struct v4l2_ctrl_h264_slice_params {
> > > 
> > >          * Entries on each list are indices into
> > >          * v4l2_ctrl_h264_decode_params.dpb[].
> > >          */
> > > 
> > > -       __u8 ref_pic_list0[32];
> > > -       __u8 ref_pic_list1[32];
> > > +       struct v4l2_h264_reference ref_pic_list0[32];
> > > +       struct v4l2_h264_reference ref_pic_list1[32];
> > 
> > Could we use a macro for "32" here? Something like:
> > 
> > #define V4L2_H264_REF_PIC_LIST_LEN (V4L2_H264_NUM_DPB_ENTRIES * 2).
> > 
> > Does it make sense to add a comment as well?
> > 
> > I was thinking something along these lines:
> > 
> > """
> > Pictures in the DPB can be a frame, a complementary field pair or a
> > single field.
> 
> To be honest, I don't know if user has a free choice to select same or 
> different destination (capture) buffer for another field. I never tested it and 
> I'm not sure how to test it with ffmpeg. HW deinterlacing cores on Allwinner 
> SoCs support only interleaved fields as a input, that's why I never though 
> about separate fields.

When setting the format, one will choose V4L2_FIELD_INTERLACED_TB/BT.
Most driver will support that, but if not, they can update field in the
structure. Interlaced being very common, I think it's fine to only
support that, but the drive must enforce this field value.

But I know the Xilinx ZynqMP will do ALTERNATE instead, which would be
each field get decoded in it's own buffer. That, to be honest, I
haven't though about. The tricky part is for H264, since it means 1
slice may populate two capture buffers and I don't know if we can
support this right now.

For now I'd say we should just ensure that whatever userspace ask, we
enforce V4L2_FIELD_INTERLACED_TB/BT appropriately. That is likely not
complete, just look at how interlacing is signal in the bitstream.

> 
> Best regards,
> Jernej
> 
> > Therefore, reference pictures lists need twice as much entries, so it
> > can reference
> > either field of a field pair.
> > """
> > 
> > While it doesn't replace proper H264 specification reading,
> > it would add some clarity.
> > 
> > Thanks,
> > Ezequiel
> 
> 
>