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. Only for MJPEG is this statement true since each buffer will contain a single compressed JPEG image. Regards, Hans
