Hi Hans, On 3/14/19 3:11 PM, Hans Verkuil wrote: > On 1/21/19 11:48 AM, Stanimir Varbanov wrote: >> Hi Hans, >> >> On 1/18/19 11:13 AM, Hans Verkuil wrote: >>> On 1/16/19 1:37 PM, Stanimir Varbanov wrote: >>>> This changes v4l2_pix_format and v4l2_plane_pix_format sizeimage >>>> field description to allow v4l clients to set bigger image size >>>> in case of variable length compressed data. >>>> >>>> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx> >>>> --- >>>> Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst | 5 ++++- >>>> Documentation/media/uapi/v4l/pixfmt-v4l2.rst | 3 ++- >>>> 2 files changed, 6 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst b/Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst >>>> index 7f82dad9013a..dbe0b74e9ba4 100644 >>>> --- a/Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst >>>> +++ b/Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst >>>> @@ -30,7 +30,10 @@ describing all planes of that format. >>>> >>>> * - __u32 >>>> - ``sizeimage`` >>>> - - Maximum size in bytes required for image data in this plane. >>>> + - Maximum size in bytes required for image data in this plane, >>>> + set by the driver. When the image consists of variable length >>>> + compressed data this is the maximum number of bytes required >>>> + to hold an image, and it is allowed to be set by the client. >>>> * - __u32 >>>> - ``bytesperline`` >>>> - Distance in bytes between the leftmost pixels in two adjacent >>>> diff --git a/Documentation/media/uapi/v4l/pixfmt-v4l2.rst b/Documentation/media/uapi/v4l/pixfmt-v4l2.rst >>>> index 71eebfc6d853..54b6d2b67bd7 100644 >>>> --- a/Documentation/media/uapi/v4l/pixfmt-v4l2.rst >>>> +++ b/Documentation/media/uapi/v4l/pixfmt-v4l2.rst >>>> @@ -89,7 +89,8 @@ Single-planar format structure >>>> - Size in bytes of the buffer to hold a complete image, set by the >>>> driver. Usually this is ``bytesperline`` times ``height``. When >>>> the image consists of variable length compressed data this is the >>>> - maximum number of bytes required to hold an image. >>>> + maximum number of bytes required to hold an image, and it is >>>> + allowed to be set by the client. >>>> * - __u32 >>>> - ``colorspace`` >>>> - Image colorspace, from enum :c:type:`v4l2_colorspace`. >>>> >>> >>> Hmm. "maximum number of bytes required to hold an image": that's not actually true >>> for bitstream formats like MPEG. It's just the size of the buffer used to store the >>> bitstream, i.e. one buffer may actually contain multiple compressed images, or a >>> compressed image is split over multiple buffers. >>> >> >> Do you want me to change something in the current documentation, i.e. >> the quoted above? > > Hmm, it looks like this discussion stalled (i.e. I forgot to reply). > > How about this: > > "When the image consists of variable length compressed data this is the > number of bytes required by the encoder to support the worst-case I don't think 'encoder' is the right word here: s/encoder/encoder or decoder > compression scenario. Clients are allowed to set this field. However, > drivers may ignore the value or modify it." Can we rephrase to: "Clients are allowed to set sizeimage field, but however drivers my ignore the value or modify it." -- regards, Stan
