| Message ID | 1377471723-22341-4-git-send-email-sakari.ailus@iki.fi (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon 26 August 2013 01:02:03 Sakari Ailus wrote: > Some devices such as the uvc produce timestamps at the beginning of the > frame rather than at the end of it. Add a buffer flag > (V4L2_BUF_FLAG_TIMESTAMP_SOF) to tell about this. > > Also document timestamp_type in struct vb2_queue. > > Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> > --- > Documentation/DocBook/media/v4l/io.xml | 17 ++++++++++++----- > drivers/media/usb/uvc/uvc_queue.c | 3 ++- > include/media/videobuf2-core.h | 1 + > include/uapi/linux/videodev2.h | 10 ++++++++++ > 4 files changed, 25 insertions(+), 6 deletions(-) > > diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml > index b9a83bc..d3a725c 100644 > --- a/Documentation/DocBook/media/v4l/io.xml > +++ b/Documentation/DocBook/media/v4l/io.xml > @@ -654,11 +654,11 @@ 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>On timestamp types that are sampled from the system clock > -(V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC) it is guaranteed that the timestamp is > -taken after the complete frame has been received (or transmitted in > -case of video output devices). For other kinds of > -timestamps this may vary depending on the driver.</para> > + <para>The timestamp is taken once the complete frame has been > +received unless <constant>V4L2_BUF_FLAG_TIMESTAMP_SOF</constant> received -> received (or transmitted for output devices) > +buffer flag is set. If <constant>V4L2_BUF_FLAG_TIMESTAMP_SOF</constant> > +is set, the timestamp is taken when the first pixel of the frame is > +received.</para> received -> received (or transmitted) > > <table frame="none" pgwide="1" id="v4l2-buffer"> > <title>struct <structname>v4l2_buffer</structname></title> > @@ -1120,6 +1120,13 @@ in which case caches have not been used.</entry> > <entry>The CAPTURE buffer timestamp has been taken from the > corresponding OUTPUT buffer. This flag applies only to mem2mem devices.</entry> > </row> > + <row> > + <entry><constant>V4L2_BUF_FLAG_TIMESTAMP_SOF</constant></entry> > + <entry>0x00010000</entry> > + <entry>The buffer timestamp has been taken when the first > + pixel is received. If this flag is not set, the timestamp > + is taken when the entire frame has been received.</entry> Ditto: received -> received (or transmitted for output devices) > + </row> > </tbody> > </tgroup> > </table> > diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c > index cd962be..0d80512 100644 > --- a/drivers/media/usb/uvc/uvc_queue.c > +++ b/drivers/media/usb/uvc/uvc_queue.c > @@ -149,7 +149,8 @@ int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type, > queue->queue.buf_struct_size = sizeof(struct uvc_buffer); > queue->queue.ops = &uvc_queue_qops; > queue->queue.mem_ops = &vb2_vmalloc_memops; > - queue->queue.timestamp_type = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC; > + queue->queue.timestamp_type = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC > + | V4L2_BUF_FLAG_TIMESTAMP_SOF; > ret = vb2_queue_init(&queue->queue); > if (ret) > return ret; > diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h > index 6781258..6eb2d59 100644 > --- a/include/media/videobuf2-core.h > +++ b/include/media/videobuf2-core.h > @@ -307,6 +307,7 @@ struct v4l2_fh; > * @buf_struct_size: size of the driver-specific buffer structure; > * "0" indicates the driver doesn't want to use a custom buffer > * structure type, so sizeof(struct vb2_buffer) will is used > + * @timestamp_type: Type of the timestamp; V4L2_BUF_FLAGS_TIMESTAMP_* > * @gfp_flags: additional gfp flags used when allocating the buffers. > * Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32 > * to force the buffer allocation to a specific memory zone. > diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h > index 691077d..ca2b4fc 100644 > --- a/include/uapi/linux/videodev2.h > +++ b/include/uapi/linux/videodev2.h > @@ -695,6 +695,16 @@ struct v4l2_buffer { > #define V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN 0x00000000 > #define V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC 0x00002000 > #define V4L2_BUF_FLAG_TIMESTAMP_COPY 0x00004000 > +/* > + * Timestamp taken once the first pixel is received. If the flag is received -> received (or transmitted for output devices) > + * not set the buffer timestamp is taken at the end of the frame. This > + * is not a timestamp type. > + * > + * In general drivers should not use this flag if the end-of-frame > + * timestamps is as good quality as the start-of-frame one; the > + * V4L2_EVENT_FRAME_SYNC event should be used in that case instead. > + */ > +#define V4L2_BUF_FLAG_TIMESTAMP_SOF 0x00010000 > > /** > * struct v4l2_exportbuffer - export of video buffer as DMABUF file descriptor > Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml index b9a83bc..d3a725c 100644 --- a/Documentation/DocBook/media/v4l/io.xml +++ b/Documentation/DocBook/media/v4l/io.xml @@ -654,11 +654,11 @@ 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>On timestamp types that are sampled from the system clock -(V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC) it is guaranteed that the timestamp is -taken after the complete frame has been received (or transmitted in -case of video output devices). For other kinds of -timestamps this may vary depending on the driver.</para> + <para>The timestamp is taken once the complete frame has been +received unless <constant>V4L2_BUF_FLAG_TIMESTAMP_SOF</constant> +buffer flag is set. If <constant>V4L2_BUF_FLAG_TIMESTAMP_SOF</constant> +is set, the timestamp is taken when the first pixel of the frame is +received.</para> <table frame="none" pgwide="1" id="v4l2-buffer"> <title>struct <structname>v4l2_buffer</structname></title> @@ -1120,6 +1120,13 @@ in which case caches have not been used.</entry> <entry>The CAPTURE buffer timestamp has been taken from the corresponding OUTPUT buffer. This flag applies only to mem2mem devices.</entry> </row> + <row> + <entry><constant>V4L2_BUF_FLAG_TIMESTAMP_SOF</constant></entry> + <entry>0x00010000</entry> + <entry>The buffer timestamp has been taken when the first + pixel is received. If this flag is not set, the timestamp + is taken when the entire frame has been received.</entry> + </row> </tbody> </tgroup> </table> diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c index cd962be..0d80512 100644 --- a/drivers/media/usb/uvc/uvc_queue.c +++ b/drivers/media/usb/uvc/uvc_queue.c @@ -149,7 +149,8 @@ int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type, queue->queue.buf_struct_size = sizeof(struct uvc_buffer); queue->queue.ops = &uvc_queue_qops; queue->queue.mem_ops = &vb2_vmalloc_memops; - queue->queue.timestamp_type = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC; + queue->queue.timestamp_type = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC + | V4L2_BUF_FLAG_TIMESTAMP_SOF; ret = vb2_queue_init(&queue->queue); if (ret) return ret; diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index 6781258..6eb2d59 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -307,6 +307,7 @@ struct v4l2_fh; * @buf_struct_size: size of the driver-specific buffer structure; * "0" indicates the driver doesn't want to use a custom buffer * structure type, so sizeof(struct vb2_buffer) will is used + * @timestamp_type: Type of the timestamp; V4L2_BUF_FLAGS_TIMESTAMP_* * @gfp_flags: additional gfp flags used when allocating the buffers. * Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32 * to force the buffer allocation to a specific memory zone. diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h index 691077d..ca2b4fc 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -695,6 +695,16 @@ struct v4l2_buffer { #define V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN 0x00000000 #define V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC 0x00002000 #define V4L2_BUF_FLAG_TIMESTAMP_COPY 0x00004000 +/* + * Timestamp taken once the first pixel is received. If the flag is + * not set the buffer timestamp is taken at the end of the frame. This + * is not a timestamp type. + * + * In general drivers should not use this flag if the end-of-frame + * timestamps is as good quality as the start-of-frame one; the + * V4L2_EVENT_FRAME_SYNC event should be used in that case instead. + */ +#define V4L2_BUF_FLAG_TIMESTAMP_SOF 0x00010000 /** * struct v4l2_exportbuffer - export of video buffer as DMABUF file descriptor
Some devices such as the uvc produce timestamps at the beginning of the frame rather than at the end of it. Add a buffer flag (V4L2_BUF_FLAG_TIMESTAMP_SOF) to tell about this. Also document timestamp_type in struct vb2_queue. Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> --- Documentation/DocBook/media/v4l/io.xml | 17 ++++++++++++----- drivers/media/usb/uvc/uvc_queue.c | 3 ++- include/media/videobuf2-core.h | 1 + include/uapi/linux/videodev2.h | 10 ++++++++++ 4 files changed, 25 insertions(+), 6 deletions(-)