Re: [PATCHv2 02/12] videodev2.h: add V4L2_FMT_FLAG_DYN_RESOLUTION

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On 8/14/19 2:53 PM, Paul Kocialkowski wrote:
> Hi,
> 
> On Mon 12 Aug 19, 13:05, Hans Verkuil wrote:
>> From: Maxime Jourdan <mjourdan@xxxxxxxxxxxx>
>>
>> Add an enum_fmt format flag to specifically tag coded formats where
>> dynamic resolution switching is supported by the device.
>>
>> This is useful for some codec drivers that can support dynamic
>> resolution switching for one or more of their listed coded formats. It
>> allows userspace to know whether it should extract the video parameters
>> itself, or if it can rely on the device to send V4L2_EVENT_SOURCE_CHANGE
>> when such changes are detected.
> 
> Makes sense and looks good to me:
> Reviewed-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
> 
> The docs aren't saying that this only applies to stateful decoders, but I think
> it is quite clear that this can't apply to stateless decoders.
> 
> Cheers,
> 
> Paul
> 
>> Signed-off-by: Maxime Jourdan <mjourdan@xxxxxxxxxxxx>
>> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
>> [hverkuil-cisco@xxxxxxxxx: added flag to videodev2.h.rst.exceptions]
>> [hverkuil-cisco@xxxxxxxxx: updated commit text: 'one or more' instead of 'all']
>> Acked-by: Tomasz Figa <tfiga@xxxxxxxxxxxx>
>> ---
>>  Documentation/media/uapi/v4l/vidioc-enum-fmt.rst | 8 ++++++++
>>  Documentation/media/videodev2.h.rst.exceptions   | 1 +
>>  include/uapi/linux/videodev2.h                   | 1 +
>>  3 files changed, 10 insertions(+)
>>
>> diff --git a/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst b/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst
>> index ebc05ce74bdf..719f1ed64f7d 100644
>> --- a/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst
>> +++ b/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst
>> @@ -135,6 +135,14 @@ one until ``EINVAL`` is returned.
>>  	between frames/fields. This flag can only be used in combination with
>>  	the ``V4L2_FMT_FLAG_COMPRESSED`` flag, since this applies to compressed
>>  	formats only. This flag is valid for stateful decoders only.
>> +    * - ``V4L2_FMT_FLAG_DYN_RESOLUTION``
>> +      - 0x0008
>> +      - Dynamic resolution switching is supported by the device for this
>> +	compressed bytestream format (aka coded format). It will notify the user
>> +	via the event ``V4L2_EVENT_SOURCE_CHANGE`` when changes in the video
>> +	parameters are detected. This flag can only be used in combination
>> +	with the ``V4L2_FMT_FLAG_COMPRESSED`` flag, since this applies to
>> +	compressed formats only.

I added "It is also only applies to stateful codecs." at the end of this
paragraph.

Regards,

	Hans

>>  
>>  
>>  Return Value
>> diff --git a/Documentation/media/videodev2.h.rst.exceptions b/Documentation/media/videodev2.h.rst.exceptions
>> index a0640b6d0f68..adeb6b7a15cb 100644
>> --- a/Documentation/media/videodev2.h.rst.exceptions
>> +++ b/Documentation/media/videodev2.h.rst.exceptions
>> @@ -181,6 +181,7 @@ replace define V4L2_PIX_FMT_FLAG_PREMUL_ALPHA reserved-formats
>>  replace define V4L2_FMT_FLAG_COMPRESSED fmtdesc-flags
>>  replace define V4L2_FMT_FLAG_EMULATED fmtdesc-flags
>>  replace define V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM fmtdesc-flags
>> +replace define V4L2_FMT_FLAG_DYN_RESOLUTION fmtdesc-flags
>>  
>>  # V4L2 timecode types
>>  replace define V4L2_TC_TYPE_24FPS timecode-type
>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>> index 67077d52c59d..530638dffd93 100644
>> --- a/include/uapi/linux/videodev2.h
>> +++ b/include/uapi/linux/videodev2.h
>> @@ -777,6 +777,7 @@ struct v4l2_fmtdesc {
>>  #define V4L2_FMT_FLAG_COMPRESSED		0x0001
>>  #define V4L2_FMT_FLAG_EMULATED			0x0002
>>  #define V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM	0x0004
>> +#define V4L2_FMT_FLAG_DYN_RESOLUTION		0x0008
>>  
>>  	/* Frame Size and frame rate enumeration */
>>  /*
>> -- 
>> 2.20.1
>>
> 




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