diff mbox series

[v3,2/3] media: uapi: h264: Add the concept of decoding mode

Message ID 20190703122849.6316-3-boris.brezillon@collabora.com (mailing list archive)
State New, archived
Headers show
Series media: uapi: h264: First batch of adjusments | expand

Commit Message

Boris Brezillon July 3, 2019, 12:28 p.m. UTC
Some stateless decoders don't support per-slice decoding (or at least
not in a way that would make them efficient or easy to use).
Let's expose a menu to control and expose the supported decoding modes.
Drivers are allowed to support only one decoding but they can support
both too.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
---
Changes in v3:
* s/per-{slice,frame} decoding/{slice,frame}-based decoding/
* Add Paul's R-b

Changes in v2:
* Allow decoding multiple slices in per-slice decoding mode
* Minor doc improvement/fixes
---
 .../media/uapi/v4l/ext-ctrls-codec.rst        | 47 ++++++++++++++++++-
 drivers/media/v4l2-core/v4l2-ctrls.c          |  9 ++++
 include/media/h264-ctrls.h                    | 13 +++++
 3 files changed, 68 insertions(+), 1 deletion(-)

Comments

Hans Verkuil July 22, 2019, 3:29 p.m. UTC | #1
On 7/3/19 2:28 PM, Boris Brezillon wrote:
> Some stateless decoders don't support per-slice decoding (or at least
> not in a way that would make them efficient or easy to use).
> Let's expose a menu to control and expose the supported decoding modes.
> Drivers are allowed to support only one decoding but they can support
> both too.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> ---
> Changes in v3:
> * s/per-{slice,frame} decoding/{slice,frame}-based decoding/
> * Add Paul's R-b
> 
> Changes in v2:
> * Allow decoding multiple slices in per-slice decoding mode
> * Minor doc improvement/fixes
> ---
>  .../media/uapi/v4l/ext-ctrls-codec.rst        | 47 ++++++++++++++++++-
>  drivers/media/v4l2-core/v4l2-ctrls.c          |  9 ++++
>  include/media/h264-ctrls.h                    | 13 +++++
>  3 files changed, 68 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
> index 3ae1367806cf..47ba2d057a92 100644
> --- a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
> +++ b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
> @@ -1748,6 +1748,14 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
>      * - __u32
>        - ``size``
>        -
> +    * - __u32
> +      - ``start_byte_offset``
> +      - Where the slice payload starts in the output buffer. Useful when
> +        operating in frame-based decoding mode and decoding multi-slice
> +        content. In this case, the output buffer will contain more than one
> +        slice and some codecs need to know where each slice starts. Note that
> +        this offsets points to the beginning of the slice which is supposed to

offsets -> offset

> +        contain an ANNEX B start code

Add . at the end of the sentence.

I think this is a bit awkward. How about:

"Note that the slice at this offset shall start with an ANNEX B start code."

I'm assuming it has to actually start with an ANNEX B code? Or should it
just 'contain' an ANNEX B code?

When in sliced-based decoding mode, what should be used here? I assume that in
that case start_byte_offset would be 0, and that the slice shall still begin
with an ANNEX B start code?

>      * - __u32
>        - ``header_bit_size``
>        -
> @@ -1931,7 +1939,10 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
>        -
>      * - __u16
>        - ``num_slices``
> -      - Number of slices needed to decode the current frame
> +      - Number of slices needed to decode the current frame/field. When
> +        operating in slice-based decoding mode (see
> +        :c:type:`v4l2_mpeg_video_h264_decoding_mode`), this field
> +        should always be set to one

Add . at the end of the sentence.

>      * - __u16
>        - ``nal_ref_idc``
>        - NAL reference ID value coming from the NAL Unit header
> @@ -2022,6 +2033,40 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
>        - 0x00000004
>        - The DPB entry is a long term reference frame
>  
> +``V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE (enum)``
> +    Specifies the decoding mode to use. Currently exposes slice-based and
> +    frame-based decoding but new modes might be added later on.
> +
> +    .. note::
> +
> +       This menu control is not yet part of the public kernel API and
> +       it is expected to change.
> +
> +.. c:type:: v4l2_mpeg_video_h264_decoding_mode
> +
> +.. cssclass:: longtable
> +
> +.. flat-table::
> +    :header-rows:  0
> +    :stub-columns: 0
> +    :widths:       1 1 2
> +
> +    * - ``V4L2_MPEG_VIDEO_H264_SLICE_BASED_DECODING``
> +      - 0
> +      - The decoding is done at the slice granularity.
> +        v4l2_ctrl_h264_decode_params->num_slices can be set to anything between
> +        1 and then number of slices that remain to fully decode the

then -> the

> +        frame/field.
> +        The output buffer should contain
> +        v4l2_ctrl_h264_decode_params->num_slices slices.
> +    * - ``V4L2_MPEG_VIDEO_H264_FRAME_BASED_DECODING``
> +      - 1
> +      - The decoding is done at the frame granularity.
> +        v4l2_ctrl_h264_decode_params->num_slices should be set to the number of
> +        slices forming a frame.
> +        The output buffer should contain all slices needed to decode the
> +        frame/field.
> +
>  .. _v4l2-mpeg-mpeg2:
>  
>  ``V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS (struct)``
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 471ff5c91f43..70d994be27e1 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -394,6 +394,11 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
>  		"Explicit",
>  		NULL,
>  	};
> +	static const char * const h264_decoding_mode[] = {
> +		"Slice-based",
> +		"Frame-based",

based -> Based

> +		NULL,
> +	};
>  	static const char * const mpeg_mpeg2_level[] = {
>  		"Low",
>  		"Main",
> @@ -625,6 +630,8 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
>  		return h264_fp_arrangement_type;
>  	case V4L2_CID_MPEG_VIDEO_H264_FMO_MAP_TYPE:
>  		return h264_fmo_map_type;
> +	case V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE:
> +		return h264_decoding_mode;
>  	case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:
>  		return mpeg_mpeg2_level;
>  	case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:
> @@ -844,6 +851,7 @@ const char *v4l2_ctrl_get_name(u32 id)
>  	case V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX:		return "H264 Scaling Matrix";
>  	case V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS:		return "H264 Slice Parameters";
>  	case V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS:		return "H264 Decode Parameters";
> +	case V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE:		return "H264 Decoding Mode";
>  	case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:			return "MPEG2 Level";
>  	case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:			return "MPEG2 Profile";
>  	case V4L2_CID_MPEG_VIDEO_MPEG4_I_FRAME_QP:		return "MPEG4 I-Frame QP Value";
> @@ -1212,6 +1220,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
>  	case V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_IDC:
>  	case V4L2_CID_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE:
>  	case V4L2_CID_MPEG_VIDEO_H264_FMO_MAP_TYPE:
> +	case V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE:
>  	case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:
>  	case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:
>  	case V4L2_CID_MPEG_VIDEO_MPEG4_LEVEL:
> diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
> index e1404d78d6ff..206fd5ada620 100644
> --- a/include/media/h264-ctrls.h
> +++ b/include/media/h264-ctrls.h
> @@ -26,6 +26,7 @@
>  #define V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX	(V4L2_CID_MPEG_BASE+1002)
>  #define V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS	(V4L2_CID_MPEG_BASE+1003)
>  #define V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS	(V4L2_CID_MPEG_BASE+1004)
> +#define V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE	(V4L2_CID_MPEG_BASE+1005)
>  
>  /* enum v4l2_ctrl_type type values */
>  #define V4L2_CTRL_TYPE_H264_SPS			0x0110
> @@ -33,6 +34,12 @@
>  #define V4L2_CTRL_TYPE_H264_SCALING_MATRIX	0x0112
>  #define V4L2_CTRL_TYPE_H264_SLICE_PARAMS	0x0113
>  #define V4L2_CTRL_TYPE_H264_DECODE_PARAMS	0x0114
> +#define V4L2_CTRL_TYPE_H264_DECODING_MODE	0x0115
> +
> +enum v4l2_mpeg_video_h264_decoding_mode {
> +	V4L2_MPEG_VIDEO_H264_SLICE_BASED_DECODING,
> +	V4L2_MPEG_VIDEO_H264_FRAME_BASED_DECODING,
> +};
>  
>  #define V4L2_H264_SPS_CONSTRAINT_SET0_FLAG			0x01
>  #define V4L2_H264_SPS_CONSTRAINT_SET1_FLAG			0x02
> @@ -111,6 +118,8 @@ struct v4l2_h264_pred_weight_table {
>  	struct v4l2_h264_weight_factors weight_factors[2];
>  };
>  
> +#define V4L2_H264_MAX_SLICES_PER_FRAME			16

Are there arrays in these compound control structs where this define can be used?
Is this define standards-based or a restriction of V4L2?

Regards,

	Hans

> +
>  #define V4L2_H264_SLICE_TYPE_P				0
>  #define V4L2_H264_SLICE_TYPE_B				1
>  #define V4L2_H264_SLICE_TYPE_I				2
> @@ -125,6 +134,10 @@ struct v4l2_h264_pred_weight_table {
>  struct v4l2_ctrl_h264_slice_params {
>  	/* Size in bytes, including header */
>  	__u32 size;
> +
> +	/* Where the slice starts in the output buffer (expressed in bytes). */
> +	__u32 start_byte_offset;
> +
>  	/* Offset in bits to slice_data() from the beginning of this slice. */
>  	__u32 header_bit_size;
>  
>
Boris Brezillon July 22, 2019, 5:54 p.m. UTC | #2
Hi Hans,

On Mon, 22 Jul 2019 17:29:21 +0200
Hans Verkuil <hverkuil@xs4all.nl> wrote:

> On 7/3/19 2:28 PM, Boris Brezillon wrote:
> > Some stateless decoders don't support per-slice decoding (or at least
> > not in a way that would make them efficient or easy to use).
> > Let's expose a menu to control and expose the supported decoding modes.
> > Drivers are allowed to support only one decoding but they can support
> > both too.
> > 
> > Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> > Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> > ---
> > Changes in v3:
> > * s/per-{slice,frame} decoding/{slice,frame}-based decoding/
> > * Add Paul's R-b
> > 
> > Changes in v2:
> > * Allow decoding multiple slices in per-slice decoding mode
> > * Minor doc improvement/fixes
> > ---
> >  .../media/uapi/v4l/ext-ctrls-codec.rst        | 47 ++++++++++++++++++-
> >  drivers/media/v4l2-core/v4l2-ctrls.c          |  9 ++++
> >  include/media/h264-ctrls.h                    | 13 +++++
> >  3 files changed, 68 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
> > index 3ae1367806cf..47ba2d057a92 100644
> > --- a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
> > +++ b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
> > @@ -1748,6 +1748,14 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
> >      * - __u32
> >        - ``size``
> >        -
> > +    * - __u32
> > +      - ``start_byte_offset``
> > +      - Where the slice payload starts in the output buffer. Useful when
> > +        operating in frame-based decoding mode and decoding multi-slice
> > +        content. In this case, the output buffer will contain more than one
> > +        slice and some codecs need to know where each slice starts. Note that
> > +        this offsets points to the beginning of the slice which is supposed to  
> 
> offsets -> offset
> 
> > +        contain an ANNEX B start code  
> 
> Add . at the end of the sentence.
> 
> I think this is a bit awkward. How about:
> 
> "Note that the slice at this offset shall start with an ANNEX B start code."

Definitely better.

> 
> I'm assuming it has to actually start with an ANNEX B code? Or should it
> just 'contain' an ANNEX B code?

It has to start with an ANNEX B code.

> 
> When in sliced-based decoding mode, what should be used here? I assume that in
> that case start_byte_offset would be 0, and that the slice shall still begin
> with an ANNEX B start code?

The first slice should have start_byte_offset set to 0 and should start
with an ANNEX B start code, but even in slice-based decoding mode, the
driver can be passed several slices in the same buffer, in which case,
the second slice will have start_byte_offset > 0.


> 
> >      * - __u32
> >        - ``header_bit_size``
> >        -
> > @@ -1931,7 +1939,10 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
> >        -
> >      * - __u16
> >        - ``num_slices``
> > -      - Number of slices needed to decode the current frame
> > +      - Number of slices needed to decode the current frame/field. When
> > +        operating in slice-based decoding mode (see
> > +        :c:type:`v4l2_mpeg_video_h264_decoding_mode`), this field
> > +        should always be set to one  
> 
> Add . at the end of the sentence.
> 
> >      * - __u16
> >        - ``nal_ref_idc``
> >        - NAL reference ID value coming from the NAL Unit header
> > @@ -2022,6 +2033,40 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
> >        - 0x00000004
> >        - The DPB entry is a long term reference frame
> >  
> > +``V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE (enum)``
> > +    Specifies the decoding mode to use. Currently exposes slice-based and
> > +    frame-based decoding but new modes might be added later on.
> > +
> > +    .. note::
> > +
> > +       This menu control is not yet part of the public kernel API and
> > +       it is expected to change.
> > +
> > +.. c:type:: v4l2_mpeg_video_h264_decoding_mode
> > +
> > +.. cssclass:: longtable
> > +
> > +.. flat-table::
> > +    :header-rows:  0
> > +    :stub-columns: 0
> > +    :widths:       1 1 2
> > +
> > +    * - ``V4L2_MPEG_VIDEO_H264_SLICE_BASED_DECODING``
> > +      - 0
> > +      - The decoding is done at the slice granularity.
> > +        v4l2_ctrl_h264_decode_params->num_slices can be set to anything between
> > +        1 and then number of slices that remain to fully decode the  
> 
> then -> the
> 
> > +        frame/field.
> > +        The output buffer should contain
> > +        v4l2_ctrl_h264_decode_params->num_slices slices.
> > +    * - ``V4L2_MPEG_VIDEO_H264_FRAME_BASED_DECODING``
> > +      - 1
> > +      - The decoding is done at the frame granularity.
> > +        v4l2_ctrl_h264_decode_params->num_slices should be set to the number of
> > +        slices forming a frame.
> > +        The output buffer should contain all slices needed to decode the
> > +        frame/field.
> > +
> >  .. _v4l2-mpeg-mpeg2:
> >  
> >  ``V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS (struct)``
> > diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> > index 471ff5c91f43..70d994be27e1 100644
> > --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> > +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> > @@ -394,6 +394,11 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
> >  		"Explicit",
> >  		NULL,
> >  	};
> > +	static const char * const h264_decoding_mode[] = {
> > +		"Slice-based",
> > +		"Frame-based",  
> 
> based -> Based
> 
> > +		NULL,
> > +	};
> >  	static const char * const mpeg_mpeg2_level[] = {
> >  		"Low",
> >  		"Main",
> > @@ -625,6 +630,8 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
> >  		return h264_fp_arrangement_type;
> >  	case V4L2_CID_MPEG_VIDEO_H264_FMO_MAP_TYPE:
> >  		return h264_fmo_map_type;
> > +	case V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE:
> > +		return h264_decoding_mode;
> >  	case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:
> >  		return mpeg_mpeg2_level;
> >  	case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:
> > @@ -844,6 +851,7 @@ const char *v4l2_ctrl_get_name(u32 id)
> >  	case V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX:		return "H264 Scaling Matrix";
> >  	case V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS:		return "H264 Slice Parameters";
> >  	case V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS:		return "H264 Decode Parameters";
> > +	case V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE:		return "H264 Decoding Mode";
> >  	case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:			return "MPEG2 Level";
> >  	case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:			return "MPEG2 Profile";
> >  	case V4L2_CID_MPEG_VIDEO_MPEG4_I_FRAME_QP:		return "MPEG4 I-Frame QP Value";
> > @@ -1212,6 +1220,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
> >  	case V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_IDC:
> >  	case V4L2_CID_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE:
> >  	case V4L2_CID_MPEG_VIDEO_H264_FMO_MAP_TYPE:
> > +	case V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE:
> >  	case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:
> >  	case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:
> >  	case V4L2_CID_MPEG_VIDEO_MPEG4_LEVEL:
> > diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
> > index e1404d78d6ff..206fd5ada620 100644
> > --- a/include/media/h264-ctrls.h
> > +++ b/include/media/h264-ctrls.h
> > @@ -26,6 +26,7 @@
> >  #define V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX	(V4L2_CID_MPEG_BASE+1002)
> >  #define V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS	(V4L2_CID_MPEG_BASE+1003)
> >  #define V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS	(V4L2_CID_MPEG_BASE+1004)
> > +#define V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE	(V4L2_CID_MPEG_BASE+1005)
> >  
> >  /* enum v4l2_ctrl_type type values */
> >  #define V4L2_CTRL_TYPE_H264_SPS			0x0110
> > @@ -33,6 +34,12 @@
> >  #define V4L2_CTRL_TYPE_H264_SCALING_MATRIX	0x0112
> >  #define V4L2_CTRL_TYPE_H264_SLICE_PARAMS	0x0113
> >  #define V4L2_CTRL_TYPE_H264_DECODE_PARAMS	0x0114
> > +#define V4L2_CTRL_TYPE_H264_DECODING_MODE	0x0115
> > +
> > +enum v4l2_mpeg_video_h264_decoding_mode {
> > +	V4L2_MPEG_VIDEO_H264_SLICE_BASED_DECODING,
> > +	V4L2_MPEG_VIDEO_H264_FRAME_BASED_DECODING,
> > +};
> >  
> >  #define V4L2_H264_SPS_CONSTRAINT_SET0_FLAG			0x01
> >  #define V4L2_H264_SPS_CONSTRAINT_SET1_FLAG			0x02
> > @@ -111,6 +118,8 @@ struct v4l2_h264_pred_weight_table {
> >  	struct v4l2_h264_weight_factors weight_factors[2];
> >  };
> >  
> > +#define V4L2_H264_MAX_SLICES_PER_FRAME			16  
> 
> Are there arrays in these compound control structs where this define can be used?

No, slices_params is a separate control, but I initialize
slices_params_ctrl_cfg.dims[0] to this value.

> Is this define standards-based or a restriction of V4L2?

It's defined by the standard.

Will fix the other typos you reported.

Thanks for the review.

Boris
Hans Verkuil July 22, 2019, 7 p.m. UTC | #3
On 7/22/19 7:54 PM, Boris Brezillon wrote:
> Hi Hans,
> 
> On Mon, 22 Jul 2019 17:29:21 +0200
> Hans Verkuil <hverkuil@xs4all.nl> wrote:
> 
>> On 7/3/19 2:28 PM, Boris Brezillon wrote:
>>> Some stateless decoders don't support per-slice decoding (or at least
>>> not in a way that would make them efficient or easy to use).
>>> Let's expose a menu to control and expose the supported decoding modes.
>>> Drivers are allowed to support only one decoding but they can support
>>> both too.
>>>
>>> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
>>> Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
>>> ---
>>> Changes in v3:
>>> * s/per-{slice,frame} decoding/{slice,frame}-based decoding/
>>> * Add Paul's R-b
>>>
>>> Changes in v2:
>>> * Allow decoding multiple slices in per-slice decoding mode
>>> * Minor doc improvement/fixes
>>> ---
>>>  .../media/uapi/v4l/ext-ctrls-codec.rst        | 47 ++++++++++++++++++-
>>>  drivers/media/v4l2-core/v4l2-ctrls.c          |  9 ++++
>>>  include/media/h264-ctrls.h                    | 13 +++++
>>>  3 files changed, 68 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
>>> index 3ae1367806cf..47ba2d057a92 100644
>>> --- a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
>>> +++ b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
>>> @@ -1748,6 +1748,14 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
>>>      * - __u32
>>>        - ``size``
>>>        -
>>> +    * - __u32
>>> +      - ``start_byte_offset``
>>> +      - Where the slice payload starts in the output buffer. Useful when
>>> +        operating in frame-based decoding mode and decoding multi-slice
>>> +        content. In this case, the output buffer will contain more than one
>>> +        slice and some codecs need to know where each slice starts. Note that
>>> +        this offsets points to the beginning of the slice which is supposed to  
>>
>> offsets -> offset
>>
>>> +        contain an ANNEX B start code  
>>
>> Add . at the end of the sentence.
>>
>> I think this is a bit awkward. How about:
>>
>> "Note that the slice at this offset shall start with an ANNEX B start code."
> 
> Definitely better.
> 
>>
>> I'm assuming it has to actually start with an ANNEX B code? Or should it
>> just 'contain' an ANNEX B code?
> 
> It has to start with an ANNEX B code.
> 
>>
>> When in sliced-based decoding mode, what should be used here? I assume that in
>> that case start_byte_offset would be 0, and that the slice shall still begin
>> with an ANNEX B start code?
> 
> The first slice should have start_byte_offset set to 0 and should start
> with an ANNEX B start code, but even in slice-based decoding mode, the
> driver can be passed several slices in the same buffer, in which case,
> the second slice will have start_byte_offset > 0.
> 
> 
>>
>>>      * - __u32
>>>        - ``header_bit_size``
>>>        -
>>> @@ -1931,7 +1939,10 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
>>>        -
>>>      * - __u16
>>>        - ``num_slices``
>>> -      - Number of slices needed to decode the current frame
>>> +      - Number of slices needed to decode the current frame/field. When
>>> +        operating in slice-based decoding mode (see
>>> +        :c:type:`v4l2_mpeg_video_h264_decoding_mode`), this field
>>> +        should always be set to one  
>>
>> Add . at the end of the sentence.
>>
>>>      * - __u16
>>>        - ``nal_ref_idc``
>>>        - NAL reference ID value coming from the NAL Unit header
>>> @@ -2022,6 +2033,40 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
>>>        - 0x00000004
>>>        - The DPB entry is a long term reference frame
>>>  
>>> +``V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE (enum)``
>>> +    Specifies the decoding mode to use. Currently exposes slice-based and
>>> +    frame-based decoding but new modes might be added later on.
>>> +
>>> +    .. note::
>>> +
>>> +       This menu control is not yet part of the public kernel API and
>>> +       it is expected to change.
>>> +
>>> +.. c:type:: v4l2_mpeg_video_h264_decoding_mode
>>> +
>>> +.. cssclass:: longtable
>>> +
>>> +.. flat-table::
>>> +    :header-rows:  0
>>> +    :stub-columns: 0
>>> +    :widths:       1 1 2
>>> +
>>> +    * - ``V4L2_MPEG_VIDEO_H264_SLICE_BASED_DECODING``
>>> +      - 0
>>> +      - The decoding is done at the slice granularity.
>>> +        v4l2_ctrl_h264_decode_params->num_slices can be set to anything between
>>> +        1 and then number of slices that remain to fully decode the  
>>
>> then -> the
>>
>>> +        frame/field.
>>> +        The output buffer should contain
>>> +        v4l2_ctrl_h264_decode_params->num_slices slices.
>>> +    * - ``V4L2_MPEG_VIDEO_H264_FRAME_BASED_DECODING``
>>> +      - 1
>>> +      - The decoding is done at the frame granularity.
>>> +        v4l2_ctrl_h264_decode_params->num_slices should be set to the number of
>>> +        slices forming a frame.
>>> +        The output buffer should contain all slices needed to decode the
>>> +        frame/field.
>>> +
>>>  .. _v4l2-mpeg-mpeg2:
>>>  
>>>  ``V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS (struct)``
>>> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
>>> index 471ff5c91f43..70d994be27e1 100644
>>> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
>>> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
>>> @@ -394,6 +394,11 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
>>>  		"Explicit",
>>>  		NULL,
>>>  	};
>>> +	static const char * const h264_decoding_mode[] = {
>>> +		"Slice-based",
>>> +		"Frame-based",  
>>
>> based -> Based
>>
>>> +		NULL,
>>> +	};
>>>  	static const char * const mpeg_mpeg2_level[] = {
>>>  		"Low",
>>>  		"Main",
>>> @@ -625,6 +630,8 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
>>>  		return h264_fp_arrangement_type;
>>>  	case V4L2_CID_MPEG_VIDEO_H264_FMO_MAP_TYPE:
>>>  		return h264_fmo_map_type;
>>> +	case V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE:
>>> +		return h264_decoding_mode;
>>>  	case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:
>>>  		return mpeg_mpeg2_level;
>>>  	case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:
>>> @@ -844,6 +851,7 @@ const char *v4l2_ctrl_get_name(u32 id)
>>>  	case V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX:		return "H264 Scaling Matrix";
>>>  	case V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS:		return "H264 Slice Parameters";
>>>  	case V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS:		return "H264 Decode Parameters";
>>> +	case V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE:		return "H264 Decoding Mode";
>>>  	case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:			return "MPEG2 Level";
>>>  	case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:			return "MPEG2 Profile";
>>>  	case V4L2_CID_MPEG_VIDEO_MPEG4_I_FRAME_QP:		return "MPEG4 I-Frame QP Value";
>>> @@ -1212,6 +1220,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
>>>  	case V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_IDC:
>>>  	case V4L2_CID_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE:
>>>  	case V4L2_CID_MPEG_VIDEO_H264_FMO_MAP_TYPE:
>>> +	case V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE:
>>>  	case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:
>>>  	case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:
>>>  	case V4L2_CID_MPEG_VIDEO_MPEG4_LEVEL:
>>> diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
>>> index e1404d78d6ff..206fd5ada620 100644
>>> --- a/include/media/h264-ctrls.h
>>> +++ b/include/media/h264-ctrls.h
>>> @@ -26,6 +26,7 @@
>>>  #define V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX	(V4L2_CID_MPEG_BASE+1002)
>>>  #define V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS	(V4L2_CID_MPEG_BASE+1003)
>>>  #define V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS	(V4L2_CID_MPEG_BASE+1004)
>>> +#define V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE	(V4L2_CID_MPEG_BASE+1005)
>>>  
>>>  /* enum v4l2_ctrl_type type values */
>>>  #define V4L2_CTRL_TYPE_H264_SPS			0x0110
>>> @@ -33,6 +34,12 @@
>>>  #define V4L2_CTRL_TYPE_H264_SCALING_MATRIX	0x0112
>>>  #define V4L2_CTRL_TYPE_H264_SLICE_PARAMS	0x0113
>>>  #define V4L2_CTRL_TYPE_H264_DECODE_PARAMS	0x0114
>>> +#define V4L2_CTRL_TYPE_H264_DECODING_MODE	0x0115
>>> +
>>> +enum v4l2_mpeg_video_h264_decoding_mode {
>>> +	V4L2_MPEG_VIDEO_H264_SLICE_BASED_DECODING,
>>> +	V4L2_MPEG_VIDEO_H264_FRAME_BASED_DECODING,
>>> +};
>>>  
>>>  #define V4L2_H264_SPS_CONSTRAINT_SET0_FLAG			0x01
>>>  #define V4L2_H264_SPS_CONSTRAINT_SET1_FLAG			0x02
>>> @@ -111,6 +118,8 @@ struct v4l2_h264_pred_weight_table {
>>>  	struct v4l2_h264_weight_factors weight_factors[2];
>>>  };
>>>  
>>> +#define V4L2_H264_MAX_SLICES_PER_FRAME			16  
>>
>> Are there arrays in these compound control structs where this define can be used?
> 
> No, slices_params is a separate control, but I initialize
> slices_params_ctrl_cfg.dims[0] to this value.
> 
>> Is this define standards-based or a restriction of V4L2?
> 
> It's defined by the standard.

OK, can you add a comment before the V4L2_H264_MAX_SLICES_PER_FRAME define
mentioning this? Perhaps with a reference to the standard as well.

> 
> Will fix the other typos you reported.
> 
> Thanks for the review.

My pleasure,

	Hans
Paul Kocialkowski July 25, 2019, 7:20 p.m. UTC | #4
Hi,

On Wed 03 Jul 19, 14:28, Boris Brezillon wrote:
> @@ -125,6 +134,10 @@ struct v4l2_h264_pred_weight_table {
>  struct v4l2_ctrl_h264_slice_params {
>  	/* Size in bytes, including header */
>  	__u32 size;
> +
> +	/* Where the slice starts in the output buffer (expressed in bytes). */
> +	__u32 start_byte_offset;
> +

As I understood, we would also need to specify the beginning of the slice
relative to the beginning of the start code so we don't have to assume
fixed-size start codes or have to do the parsing in the kernel.

This can certainly be done as a subsequent patch/series, and definitely not
necessarily by you (don't want to add more on your shoulders at this point)!

Cheers,

Paul

>  	/* Offset in bits to slice_data() from the beginning of this slice. */
>  	__u32 header_bit_size;
>  
> -- 
> 2.21.0
>
diff mbox series

Patch

diff --git a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
index 3ae1367806cf..47ba2d057a92 100644
--- a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
+++ b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
@@ -1748,6 +1748,14 @@  enum v4l2_mpeg_video_h264_hierarchical_coding_type -
     * - __u32
       - ``size``
       -
+    * - __u32
+      - ``start_byte_offset``
+      - Where the slice payload starts in the output buffer. Useful when
+        operating in frame-based decoding mode and decoding multi-slice
+        content. In this case, the output buffer will contain more than one
+        slice and some codecs need to know where each slice starts. Note that
+        this offsets points to the beginning of the slice which is supposed to
+        contain an ANNEX B start code
     * - __u32
       - ``header_bit_size``
       -
@@ -1931,7 +1939,10 @@  enum v4l2_mpeg_video_h264_hierarchical_coding_type -
       -
     * - __u16
       - ``num_slices``
-      - Number of slices needed to decode the current frame
+      - Number of slices needed to decode the current frame/field. When
+        operating in slice-based decoding mode (see
+        :c:type:`v4l2_mpeg_video_h264_decoding_mode`), this field
+        should always be set to one
     * - __u16
       - ``nal_ref_idc``
       - NAL reference ID value coming from the NAL Unit header
@@ -2022,6 +2033,40 @@  enum v4l2_mpeg_video_h264_hierarchical_coding_type -
       - 0x00000004
       - The DPB entry is a long term reference frame
 
+``V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE (enum)``
+    Specifies the decoding mode to use. Currently exposes slice-based and
+    frame-based decoding but new modes might be added later on.
+
+    .. note::
+
+       This menu control is not yet part of the public kernel API and
+       it is expected to change.
+
+.. c:type:: v4l2_mpeg_video_h264_decoding_mode
+
+.. cssclass:: longtable
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - ``V4L2_MPEG_VIDEO_H264_SLICE_BASED_DECODING``
+      - 0
+      - The decoding is done at the slice granularity.
+        v4l2_ctrl_h264_decode_params->num_slices can be set to anything between
+        1 and then number of slices that remain to fully decode the
+        frame/field.
+        The output buffer should contain
+        v4l2_ctrl_h264_decode_params->num_slices slices.
+    * - ``V4L2_MPEG_VIDEO_H264_FRAME_BASED_DECODING``
+      - 1
+      - The decoding is done at the frame granularity.
+        v4l2_ctrl_h264_decode_params->num_slices should be set to the number of
+        slices forming a frame.
+        The output buffer should contain all slices needed to decode the
+        frame/field.
+
 .. _v4l2-mpeg-mpeg2:
 
 ``V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS (struct)``
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 471ff5c91f43..70d994be27e1 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -394,6 +394,11 @@  const char * const *v4l2_ctrl_get_menu(u32 id)
 		"Explicit",
 		NULL,
 	};
+	static const char * const h264_decoding_mode[] = {
+		"Slice-based",
+		"Frame-based",
+		NULL,
+	};
 	static const char * const mpeg_mpeg2_level[] = {
 		"Low",
 		"Main",
@@ -625,6 +630,8 @@  const char * const *v4l2_ctrl_get_menu(u32 id)
 		return h264_fp_arrangement_type;
 	case V4L2_CID_MPEG_VIDEO_H264_FMO_MAP_TYPE:
 		return h264_fmo_map_type;
+	case V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE:
+		return h264_decoding_mode;
 	case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:
 		return mpeg_mpeg2_level;
 	case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:
@@ -844,6 +851,7 @@  const char *v4l2_ctrl_get_name(u32 id)
 	case V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX:		return "H264 Scaling Matrix";
 	case V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS:		return "H264 Slice Parameters";
 	case V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS:		return "H264 Decode Parameters";
+	case V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE:		return "H264 Decoding Mode";
 	case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:			return "MPEG2 Level";
 	case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:			return "MPEG2 Profile";
 	case V4L2_CID_MPEG_VIDEO_MPEG4_I_FRAME_QP:		return "MPEG4 I-Frame QP Value";
@@ -1212,6 +1220,7 @@  void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
 	case V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_IDC:
 	case V4L2_CID_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE:
 	case V4L2_CID_MPEG_VIDEO_H264_FMO_MAP_TYPE:
+	case V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE:
 	case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:
 	case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:
 	case V4L2_CID_MPEG_VIDEO_MPEG4_LEVEL:
diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
index e1404d78d6ff..206fd5ada620 100644
--- a/include/media/h264-ctrls.h
+++ b/include/media/h264-ctrls.h
@@ -26,6 +26,7 @@ 
 #define V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX	(V4L2_CID_MPEG_BASE+1002)
 #define V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS	(V4L2_CID_MPEG_BASE+1003)
 #define V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS	(V4L2_CID_MPEG_BASE+1004)
+#define V4L2_CID_MPEG_VIDEO_H264_DECODING_MODE	(V4L2_CID_MPEG_BASE+1005)
 
 /* enum v4l2_ctrl_type type values */
 #define V4L2_CTRL_TYPE_H264_SPS			0x0110
@@ -33,6 +34,12 @@ 
 #define V4L2_CTRL_TYPE_H264_SCALING_MATRIX	0x0112
 #define V4L2_CTRL_TYPE_H264_SLICE_PARAMS	0x0113
 #define V4L2_CTRL_TYPE_H264_DECODE_PARAMS	0x0114
+#define V4L2_CTRL_TYPE_H264_DECODING_MODE	0x0115
+
+enum v4l2_mpeg_video_h264_decoding_mode {
+	V4L2_MPEG_VIDEO_H264_SLICE_BASED_DECODING,
+	V4L2_MPEG_VIDEO_H264_FRAME_BASED_DECODING,
+};
 
 #define V4L2_H264_SPS_CONSTRAINT_SET0_FLAG			0x01
 #define V4L2_H264_SPS_CONSTRAINT_SET1_FLAG			0x02
@@ -111,6 +118,8 @@  struct v4l2_h264_pred_weight_table {
 	struct v4l2_h264_weight_factors weight_factors[2];
 };
 
+#define V4L2_H264_MAX_SLICES_PER_FRAME			16
+
 #define V4L2_H264_SLICE_TYPE_P				0
 #define V4L2_H264_SLICE_TYPE_B				1
 #define V4L2_H264_SLICE_TYPE_I				2
@@ -125,6 +134,10 @@  struct v4l2_h264_pred_weight_table {
 struct v4l2_ctrl_h264_slice_params {
 	/* Size in bytes, including header */
 	__u32 size;
+
+	/* Where the slice starts in the output buffer (expressed in bytes). */
+	__u32 start_byte_offset;
+
 	/* Offset in bits to slice_data() from the beginning of this slice. */
 	__u32 header_bit_size;