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V4L2 kernel drivers allow configuration of the hardware settings via a
mechanism called controls. These can be referred to by name such as
"Brightness" and "White Balance Temperature". The user-space command line
client for setting these controls (v4l2-ctl) normalises these names such
that they only contain lower case alphanumeric characters and the
underscore '_'. e.g:
Kernel v4l2-ctl
----------------------------------------------------
Brightness brightness
White Balance Temperature white_balance_temperature
Focus (absolute) focus_absolute
GStreamer seems to want to follow this pattern but failed for controls with
more than one consecutive non-alphanum character. e.g. GStreamer would
produce "focus__absolute_" rather than "focus_absolute".
This commit fixes that issue. Backwards compatibility is preserved by
normalising all control names before comparison.
https://bugzilla.gnome.org/show_bug.cgi?id=725632
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|---|---|---|
| .. | ||
| 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 | ||
| gstv4l2videodec.c | ||
| gstv4l2videodec.h | ||
| gstv4l2videooverlay.c | ||
| gstv4l2videooverlay.h | ||
| gstv4l2vidorient.c | ||
| gstv4l2vidorient.h | ||
| Makefile.am | ||
| README | ||
| 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/