[PATCH v4.2 4/4] v4l: Document timestamp buffer flag behaviour
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 --- Documentation/DocBook/media/v4l/io.xml |8 1 file changed, 8 insertions(+) diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml index 451626f..f523725 100644 --- a/Documentation/DocBook/media/v4l/io.xml +++ b/Documentation/DocBook/media/v4l/io.xml @@ -654,6 +654,14 @@ plane, are stored in struct v4l2_plane instead. In that case, struct v4l2_buffer contains an array of plane structures. +Buffers that have been dequeued come with timestamps. These +timestamps can be taken from different clocks and at different part of +the frame, depending on the driver. Please see flags in the masks +V4L2_BUF_FLAG_TIMESTAMP_MASK and +V4L2_BUF_FLAG_TSTAMP_SRC_MASK in . These flags are guaranteed to be always valid +and will not be changed by the driver. + struct v4l2_buffer -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v4.2 4/4] v4l: Document timestamp buffer flag behaviour
On 02/07/2014 11:52 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 > --- > Documentation/DocBook/media/v4l/io.xml |8 > 1 file changed, 8 insertions(+) > > diff --git a/Documentation/DocBook/media/v4l/io.xml > b/Documentation/DocBook/media/v4l/io.xml > index 451626f..f523725 100644 > --- a/Documentation/DocBook/media/v4l/io.xml > +++ b/Documentation/DocBook/media/v4l/io.xml > @@ -654,6 +654,14 @@ plane, are stored in struct > v4l2_plane instead. > In that case, struct v4l2_buffer contains an array > of > plane structures. > > +Buffers that have been dequeued come with timestamps. These > +timestamps can be taken from different clocks and at different part of > +the frame, depending on the driver. Please see flags in the masks > +V4L2_BUF_FLAG_TIMESTAMP_MASK and > +V4L2_BUF_FLAG_TSTAMP_SRC_MASK in +linkend="buffer-flags">. These flags are guaranteed to be always valid > +and will not be changed by the driver. That's a bit too strong. Different inputs or outputs may have different timestamp sources. Also add a note that the SOE does not apply to outputs (there is no exposure there after all). For EOF the formulation for outputs should be: "..last pixel of the frame has been transmitted." For the COPY mode I think the SRC_MASK bits should be copied as well. That should be stated in the documentation. Regards, Hans > + > >struct v4l2_buffer > > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v4.2 4/4] v4l: Document timestamp buffer flag behaviour
Hi Hans, Thanks for the comments. Hans Verkuil wrote: > On 02/07/2014 11:52 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 >> --- >> Documentation/DocBook/media/v4l/io.xml |8 >> 1 file changed, 8 insertions(+) >> >> diff --git a/Documentation/DocBook/media/v4l/io.xml >> b/Documentation/DocBook/media/v4l/io.xml >> index 451626f..f523725 100644 >> --- a/Documentation/DocBook/media/v4l/io.xml >> +++ b/Documentation/DocBook/media/v4l/io.xml >> @@ -654,6 +654,14 @@ plane, are stored in struct >> v4l2_plane instead. >> In that case, struct v4l2_buffer contains an array >> of >> plane structures. >> >> +Buffers that have been dequeued come with timestamps. These >> +timestamps can be taken from different clocks and at different part of >> +the frame, depending on the driver. Please see flags in the masks >> +V4L2_BUF_FLAG_TIMESTAMP_MASK and >> +V4L2_BUF_FLAG_TSTAMP_SRC_MASK in > +linkend="buffer-flags">. These flags are guaranteed to be always valid >> +and will not be changed by the driver. > > That's a bit too strong. Different inputs or outputs may have different > timestamp Fixed. > sources. Also add a note that the SOE does not apply to outputs (there is no The flags are already documented separately, but I can add that to make it explicit. > exposure there after all). For EOF the formulation for outputs should be: > "..last pixel of the frame has been transmitted." Added. > For the COPY mode I think the SRC_MASK bits should be copied as well. That > should > be stated in the documentation. Good point. I'll make that a separate patch as it changes a number of drivers. Perhaps this could be a good occasion to clean up some timecode field usage from those drivers, too. -- Kind regards, Sakari Ailus sakari.ai...@iki.fi -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
