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| author | Philipp Zabel <p.zabel@pengutronix.de> | 2015-05-04 07:51:04 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@osg.samsung.com> | 2015-05-12 03:50:53 -0300 |
| commit | 8cee396bfa77ce3a2e5fe48f597206c1cd547f9c (patch) | |
| tree | 04676c7cb74ea8d58b4c4f1d43af192a166080dc /Documentation/DocBook/media/v4l/io.xml | |
| parent | 6425f646ffb1da577501098331da38df91d6aa6d (diff) | |
[media] DocBook media: document codec draining flow
Document the interaction between VIDIOC_DECODER_CMD V4L2_DEC_CMD_STOP and
VIDIOC_ENCODER_CMD V4L2_ENC_CMD_STOP to start the draining, the V4L2_EVENT_EOS
event signalling all capture buffers are finished and ready to be dequeud,
the new V4L2_BUF_FLAG_LAST buffer flag indicating the last buffer being dequeued
from the capture queue, and the poll and VIDIOC_DQBUF ioctl return values once
the queue is drained.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Diffstat (limited to 'Documentation/DocBook/media/v4l/io.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/io.xml | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml index 1c17f802b471..cff2ffd3c8a6 100644 --- a/Documentation/DocBook/media/v4l/io.xml +++ b/Documentation/DocBook/media/v4l/io.xml @@ -1129,6 +1129,18 @@ in this buffer has not been created by the CPU but by some DMA-capable unit, in which case caches have not been used.</entry> </row> <row> + <entry><constant>V4L2_BUF_FLAG_LAST</constant></entry> + <entry>0x00100000</entry> + <entry>Last buffer produced by the hardware. mem2mem codec drivers +set this flag on the capture queue for the last buffer when the +<link linkend="vidioc-querybuf">VIDIOC_QUERYBUF</link> or +<link linkend="vidioc-qbuf">VIDIOC_DQBUF</link> ioctl is called. Due to hardware +limitations, the last buffer may be empty. In this case the driver will set the +<structfield>bytesused</structfield> field to 0, regardless of the format. Any +Any subsequent call to the <link linkend="vidioc-qbuf">VIDIOC_DQBUF</link> ioctl +will not block anymore, but return an &EPIPE;.</entry> + </row> + <row> <entry><constant>V4L2_BUF_FLAG_TIMESTAMP_MASK</constant></entry> <entry>0x0000e000</entry> <entry>Mask for timestamp types below. To test the |