Acked-by: Hans Verkuil <[email protected]>
Regards,
Hans
On 03/01/2014 02:17 PM, Sakari Ailus wrote:
> Timestamp buffer flags are constant at the moment. Document them so that 1)
> they're always valid and 2) not changed by the drivers. This leaves room to
> extend the functionality later on if needed.
>
> Signed-off-by: Sakari Ailus <[email protected]>
> ---
> Documentation/DocBook/media/v4l/io.xml | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/Documentation/DocBook/media/v4l/io.xml
> b/Documentation/DocBook/media/v4l/io.xml
> index d44401c..1bffb1c 100644
> --- a/Documentation/DocBook/media/v4l/io.xml
> +++ b/Documentation/DocBook/media/v4l/io.xml
> @@ -653,6 +653,20 @@ plane, are stored in struct
> <structname>v4l2_plane</structname> instead.
> In that case, struct <structname>v4l2_buffer</structname> contains an array
> of
> plane structures.</para>
>
> + <para>Dequeued video buffers come with timestamps. The driver
> + decides at which part of the frame and with which clock the
> + timestamp is taken. Please see flags in the masks
> + <constant>V4L2_BUF_FLAG_TIMESTAMP_MASK</constant> and
> + <constant>V4L2_BUF_FLAG_TSTAMP_SRC_MASK</constant> in <xref
> + linkend="buffer-flags">. These flags are always valid and constant
> + across all buffers during the whole video stream. Changes in these
> + flags may take place as a side effect of &VIDIOC-S-INPUT; or
> + &VIDIOC-S-OUTPUT; however. The
> + <constant>V4L2_BUF_FLAG_TIMESTAMP_COPY</constant> timestamp type
> + which is used by e.g. on mem-to-mem devices is an exception to the
> + rule: the timestamp source flags are copied from the OUTPUT video
> + buffer to the CAPTURE video buffer.</para>
> +
> <table frame="none" pgwide="1" id="v4l2-buffer">
> <title>struct <structname>v4l2_buffer</structname></title>
> <tgroup cols="4">
>
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