2022-02-15 15:21:51

by Benjamin Gaignard

[permalink] [raw]
Subject: [RFC v2 7/8] media: uapi: Add V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSET control

The number of 'entry point offset' could be very variable.
Rather than use a large static array define a v4l2 dynamic array
of integer control.
The number of entry point offsets is reported by the elems field.

Signed-off-by: Benjamin Gaignard <[email protected]>
---
version 2:
- Define a new CID for entry point offsets parameters
.../userspace-api/media/v4l/ext-ctrls-codec.rst | 9 +++++++++
include/uapi/linux/v4l2-controls.h | 1 +
2 files changed, 10 insertions(+)

diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
index c3ae97657fa7..679595e94643 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
@@ -3101,6 +3101,15 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -

\normalsize

+``V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS (integer)``
+ Specifies the i-th entry point offset in bytes and is represented by
+ offset_len_minus1 plus 1 bits.
+ This control is a dynamically sized array. The number of entry point
+ offsets is reported by the ``elems`` field.
+ This bitstream parameter is defined according to :ref:`hevc`.
+ They are described in section 7.4.7.1 "General slice segment header
+ semantics" of the specification.
+
``V4L2_CID_STATELESS_HEVC_SCALING_MATRIX (struct)``
Specifies the HEVC scaling matrix parameters used for the scaling process
for transform coefficients.
diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
index 27f5d272dc43..700e6cce958c 100644
--- a/include/uapi/linux/v4l2-controls.h
+++ b/include/uapi/linux/v4l2-controls.h
@@ -2314,6 +2314,7 @@ struct v4l2_ctrl_vp9_compressed_hdr {
#define V4L2_CID_STATELESS_HEVC_DECODE_PARAMS (V4L2_CID_CODEC_STATELESS_BASE + 404)
#define V4L2_CID_STATELESS_HEVC_DECODE_MODE (V4L2_CID_CODEC_STATELESS_BASE + 405)
#define V4L2_CID_STATELESS_HEVC_START_CODE (V4L2_CID_CODEC_STATELESS_BASE + 406)
+#define V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSET (V4L2_CID_CODEC_STATELESS_BASE + 407)

enum v4l2_stateless_hevc_decode_mode {
V4L2_STATELESS_HEVC_DECODE_MODE_SLICE_BASED,
--
2.32.0


2022-02-16 11:30:40

by John Cox

[permalink] [raw]
Subject: Re: [RFC v2 7/8] media: uapi: Add V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSET control

On Tue, 15 Feb 2022 12:01:02 +0100, you wrote:

>The number of 'entry point offset' could be very variable.
>Rather than use a large static array define a v4l2 dynamic array
>of integer control.
>The number of entry point offsets is reported by the elems field.

If we are going to support multiple slice headers in a single control
then we are going to need to know how to split these entries between
them as I assume that the entry point offset entries for all slice
headers would just be catenated here. You could add extra elements here
or generate a completely new control but I think it would be easier to
reinstate the num_entry_point_offsets field in the slice_params
structure (its a field that userpace has in its hand anyway so its no
effort for it to fill in). num_entry_point_offsets is a field that RPi
wants (without needing the entry points themselves) so that would help
me.

Regards

John Cox

>Signed-off-by: Benjamin Gaignard <[email protected]>
>---
>version 2:
>- Define a new CID for entry point offsets parameters
> .../userspace-api/media/v4l/ext-ctrls-codec.rst | 9 +++++++++
> include/uapi/linux/v4l2-controls.h | 1 +
> 2 files changed, 10 insertions(+)
>
>diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>index c3ae97657fa7..679595e94643 100644
>--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>@@ -3101,6 +3101,15 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
>
> \normalsize
>
>+``V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS (integer)``
>+ Specifies the i-th entry point offset in bytes and is represented by
>+ offset_len_minus1 plus 1 bits.
>+ This control is a dynamically sized array. The number of entry point
>+ offsets is reported by the ``elems`` field.
>+ This bitstream parameter is defined according to :ref:`hevc`.
>+ They are described in section 7.4.7.1 "General slice segment header
>+ semantics" of the specification.
>+
> ``V4L2_CID_STATELESS_HEVC_SCALING_MATRIX (struct)``
> Specifies the HEVC scaling matrix parameters used for the scaling process
> for transform coefficients.
>diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
>index 27f5d272dc43..700e6cce958c 100644
>--- a/include/uapi/linux/v4l2-controls.h
>+++ b/include/uapi/linux/v4l2-controls.h
>@@ -2314,6 +2314,7 @@ struct v4l2_ctrl_vp9_compressed_hdr {
> #define V4L2_CID_STATELESS_HEVC_DECODE_PARAMS (V4L2_CID_CODEC_STATELESS_BASE + 404)
> #define V4L2_CID_STATELESS_HEVC_DECODE_MODE (V4L2_CID_CODEC_STATELESS_BASE + 405)
> #define V4L2_CID_STATELESS_HEVC_START_CODE (V4L2_CID_CODEC_STATELESS_BASE + 406)
>+#define V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSET (V4L2_CID_CODEC_STATELESS_BASE + 407)
>
> enum v4l2_stateless_hevc_decode_mode {
> V4L2_STATELESS_HEVC_DECODE_MODE_SLICE_BASED,

2022-02-16 18:10:50

by John Cox

[permalink] [raw]
Subject: Re: [RFC v2 7/8] media: uapi: Add V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSET control

On Wed, 16 Feb 2022 18:19:10 +0100, you wrote:

>
>Le 16/02/2022 à 11:54, John Cox a écrit :
>> On Tue, 15 Feb 2022 12:01:02 +0100, you wrote:
>>
>>> The number of 'entry point offset' could be very variable.
>>> Rather than use a large static array define a v4l2 dynamic array
>>> of integer control.
>>> The number of entry point offsets is reported by the elems field.
>> If we are going to support multiple slice headers in a single control
>> then we are going to need to know how to split these entries between
>> them as I assume that the entry point offset entries for all slice
>> headers would just be catenated here. You could add extra elements here
>> or generate a completely new control but I think it would be easier to
>> reinstate the num_entry_point_offsets field in the slice_params
>> structure (its a field that userpace has in its hand anyway so its no
>> effort for it to fill in). num_entry_point_offsets is a field that RPi
>> wants (without needing the entry points themselves) so that would help
>> me.
>
>Would that means num_entry_point_offsets field in slice parameter control
>+ one control for the entry points themselves ?
>or the both on slice parameter control (like now) ?

I meant num_entry_point_offsets field in each slice parameter control +
one control for the entry points themselves. Given that you have a
varible number of entry points associated with each slice and you have a
variable number of slices this seems the easiest answer to me both to
construct in userspace and to use in the driver.

Regards

JC

>Regards
>Benjamin
>
>>
>> Regards
>>
>> John Cox
>>
>>> Signed-off-by: Benjamin Gaignard <[email protected]>
>>> ---
>>> version 2:
>>> - Define a new CID for entry point offsets parameters
>>> .../userspace-api/media/v4l/ext-ctrls-codec.rst | 9 +++++++++
>>> include/uapi/linux/v4l2-controls.h | 1 +
>>> 2 files changed, 10 insertions(+)
>>>
>>> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>>> index c3ae97657fa7..679595e94643 100644
>>> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>>> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>>> @@ -3101,6 +3101,15 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
>>>
>>> \normalsize
>>>
>>> +``V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS (integer)``
>>> + Specifies the i-th entry point offset in bytes and is represented by
>>> + offset_len_minus1 plus 1 bits.
>>> + This control is a dynamically sized array. The number of entry point
>>> + offsets is reported by the ``elems`` field.
>>> + This bitstream parameter is defined according to :ref:`hevc`.
>>> + They are described in section 7.4.7.1 "General slice segment header
>>> + semantics" of the specification.
>>> +
>>> ``V4L2_CID_STATELESS_HEVC_SCALING_MATRIX (struct)``
>>> Specifies the HEVC scaling matrix parameters used for the scaling process
>>> for transform coefficients.
>>> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
>>> index 27f5d272dc43..700e6cce958c 100644
>>> --- a/include/uapi/linux/v4l2-controls.h
>>> +++ b/include/uapi/linux/v4l2-controls.h
>>> @@ -2314,6 +2314,7 @@ struct v4l2_ctrl_vp9_compressed_hdr {
>>> #define V4L2_CID_STATELESS_HEVC_DECODE_PARAMS (V4L2_CID_CODEC_STATELESS_BASE + 404)
>>> #define V4L2_CID_STATELESS_HEVC_DECODE_MODE (V4L2_CID_CODEC_STATELESS_BASE + 405)
>>> #define V4L2_CID_STATELESS_HEVC_START_CODE (V4L2_CID_CODEC_STATELESS_BASE + 406)
>>> +#define V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSET (V4L2_CID_CODEC_STATELESS_BASE + 407)
>>>
>>> enum v4l2_stateless_hevc_decode_mode {
>>> V4L2_STATELESS_HEVC_DECODE_MODE_SLICE_BASED,

2022-02-16 18:37:05

by Benjamin Gaignard

[permalink] [raw]
Subject: Re: [RFC v2 7/8] media: uapi: Add V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSET control


Le 16/02/2022 à 11:54, John Cox a écrit :
> On Tue, 15 Feb 2022 12:01:02 +0100, you wrote:
>
>> The number of 'entry point offset' could be very variable.
>> Rather than use a large static array define a v4l2 dynamic array
>> of integer control.
>> The number of entry point offsets is reported by the elems field.
> If we are going to support multiple slice headers in a single control
> then we are going to need to know how to split these entries between
> them as I assume that the entry point offset entries for all slice
> headers would just be catenated here. You could add extra elements here
> or generate a completely new control but I think it would be easier to
> reinstate the num_entry_point_offsets field in the slice_params
> structure (its a field that userpace has in its hand anyway so its no
> effort for it to fill in). num_entry_point_offsets is a field that RPi
> wants (without needing the entry points themselves) so that would help
> me.

Would that means num_entry_point_offsets field in slice parameter control
+ one control for the entry points themselves ?
or the both on slice parameter control (like now) ?

Regards
Benjamin

>
> Regards
>
> John Cox
>
>> Signed-off-by: Benjamin Gaignard <[email protected]>
>> ---
>> version 2:
>> - Define a new CID for entry point offsets parameters
>> .../userspace-api/media/v4l/ext-ctrls-codec.rst | 9 +++++++++
>> include/uapi/linux/v4l2-controls.h | 1 +
>> 2 files changed, 10 insertions(+)
>>
>> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>> index c3ae97657fa7..679595e94643 100644
>> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
>> @@ -3101,6 +3101,15 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
>>
>> \normalsize
>>
>> +``V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS (integer)``
>> + Specifies the i-th entry point offset in bytes and is represented by
>> + offset_len_minus1 plus 1 bits.
>> + This control is a dynamically sized array. The number of entry point
>> + offsets is reported by the ``elems`` field.
>> + This bitstream parameter is defined according to :ref:`hevc`.
>> + They are described in section 7.4.7.1 "General slice segment header
>> + semantics" of the specification.
>> +
>> ``V4L2_CID_STATELESS_HEVC_SCALING_MATRIX (struct)``
>> Specifies the HEVC scaling matrix parameters used for the scaling process
>> for transform coefficients.
>> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
>> index 27f5d272dc43..700e6cce958c 100644
>> --- a/include/uapi/linux/v4l2-controls.h
>> +++ b/include/uapi/linux/v4l2-controls.h
>> @@ -2314,6 +2314,7 @@ struct v4l2_ctrl_vp9_compressed_hdr {
>> #define V4L2_CID_STATELESS_HEVC_DECODE_PARAMS (V4L2_CID_CODEC_STATELESS_BASE + 404)
>> #define V4L2_CID_STATELESS_HEVC_DECODE_MODE (V4L2_CID_CODEC_STATELESS_BASE + 405)
>> #define V4L2_CID_STATELESS_HEVC_START_CODE (V4L2_CID_CODEC_STATELESS_BASE + 406)
>> +#define V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSET (V4L2_CID_CODEC_STATELESS_BASE + 407)
>>
>> enum v4l2_stateless_hevc_decode_mode {
>> V4L2_STATELESS_HEVC_DECODE_MODE_SLICE_BASED,