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8e43c0ec9e
As cameras tend to have a quite specific set of capabilities (specific framerates for each resolution), getting the peer caps filtered by our probed caps can cause a big increase in the caps size which slows down things quire a bit. As for negotiation v4l2 iterates through the caps of the peer to find the first intersection with the probed caps, getting the fully expanded intersection of capabilities is not useful. Using the same testcase as for bug #702632, adding this patch on top of the patches suggested there speeds up getting the inital frame from around ~14-15 seconds to around ~3-4 seconds. https://bugzilla.gnome.org/show_bug.cgi?id=702638 |
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| .. | ||
| .gitignore | ||
| gstv4l2-marshal.list | ||
| gstv4l2.c | ||
| gstv4l2bufferpool.c | ||
| gstv4l2bufferpool.h | ||
| gstv4l2colorbalance.c | ||
| gstv4l2colorbalance.h | ||
| gstv4l2object.c | ||
| gstv4l2object.h | ||
| gstv4l2radio.c | ||
| gstv4l2radio.h | ||
| gstv4l2sink.c | ||
| gstv4l2sink.h | ||
| gstv4l2src.c | ||
| gstv4l2src.h | ||
| gstv4l2tuner.c | ||
| gstv4l2tuner.h | ||
| gstv4l2videooverlay.c | ||
| gstv4l2videooverlay.h | ||
| gstv4l2vidorient.c | ||
| gstv4l2vidorient.h | ||
| Makefile.am | ||
| README | ||
| tuner-marshal.list | ||
| tuner.c | ||
| tuner.h | ||
| tunerchannel.c | ||
| tunerchannel.h | ||
| tunernorm.c | ||
| tunernorm.h | ||
| v4l2_calls.c | ||
| v4l2_calls.h | ||
v4l2 plugins
============
The idea is a bit the same as the idea for the v4l1 plugins. We want
one generic v4l2element, and a few child objects (probably only two:
v4l2src and v4l2sink):
/-------- v4l2src
v4l2element ---=
\-------- v4l2sink
Both v4l2src and v4l2sink have a uncompressed and a compressed
recording-/playback-mode. Since this is all part of v4l2, the 'client'
of these elements, i.e. an application using v4l2src/v4l2sink, will
hardly notice this. All capsnego stuff is done inside, and the plugin
knows which formats are compressed and which are not.
Please note that the v4l1 and the v4l2 plugins are *not* compatible
concerning properties. Naming has been kept the same where possible,
but in some cases, properties had to be removed or added to make
full use of v4l2.
V4L2 API: http://linux.bytesex.org/v4l2/.
http://v4l2spec.bytesex.org/
/usr/include/linux/videodev2.h or
Kernel patches available from
http://dl.bytesex.org/patches/.
Articles:
http://lwn.net/Articles/203924/