diff options
author | Philipp Zabel <p.zabel@pengutronix.de> | 2015-05-04 07:51:04 -0300 |
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committer | Mauro Carvalho Chehab <mchehab@osg.samsung.com> | 2015-05-12 03:50:53 -0300 |
commit | 8cee396bfa77ce3a2e5fe48f597206c1cd547f9c (patch) | |
tree | 04676c7cb74ea8d58b4c4f1d43af192a166080dc /Documentation/DocBook/media/v4l/vidioc-decoder-cmd.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/vidioc-decoder-cmd.xml')
-rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml index 9215627b04c7..73eb5cfe698a 100644 --- a/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml +++ b/Documentation/DocBook/media/v4l/vidioc-decoder-cmd.xml @@ -197,7 +197,17 @@ be muted when playing back at a non-standard speed. this command does nothing. This command has two flags: if <constant>V4L2_DEC_CMD_STOP_TO_BLACK</constant> is set, then the decoder will set the picture to black after it stopped decoding. Otherwise the last image will -repeat. If <constant>V4L2_DEC_CMD_STOP_IMMEDIATELY</constant> is set, then the decoder +repeat. mem2mem decoders will stop producing new frames altogether. They will send +a <constant>V4L2_EVENT_EOS</constant> event when the last frame has been decoded +and all frames are ready to be dequeued and will set the +<constant>V4L2_BUF_FLAG_LAST</constant> buffer flag on the last buffer of the +capture queue to indicate there will be no new buffers produced to dequeue. This +buffer may be empty, indicated by the driver setting the +<structfield>bytesused</structfield> field to 0. Once the +<constant>V4L2_BUF_FLAG_LAST</constant> flag was set, the +<link linkend="vidioc-qbuf">VIDIOC_DQBUF</link> ioctl will not block anymore, +but return an &EPIPE;. +If <constant>V4L2_DEC_CMD_STOP_IMMEDIATELY</constant> is set, then the decoder stops immediately (ignoring the <structfield>pts</structfield> value), otherwise it will keep decoding until timestamp >= pts or until the last of the pending data from its internal buffers was decoded. |