gstreamer/sys/v4l2
Jean-Christophe Trotin 7f763f2710 v4l2allocator: reference memory before the buffer is queued
In gst_v4l2_allocator_qbuf(), the memory is referenced after the
buffer is queued. Once queued (VIDIOC_QBUF), the buffer might be handled
by the V4L2 driver (e.g. decoded) and dequeued (gst_v4l2_allocator_dqbuf),
through a different thread, before the memory is referenced (gst_memory_ref).
In this case, in gst_v4l2_allocator_dqbuf(), the memory is unreferenced
(gst_memory_unref) before having been referenced: the memory refcount
reaches 0, and the memory is freed.
So, to avoid this crossing case, in gst_v4l2_allocator_qbuf(), the
memory shall be referenced before the buffer is queued.

https://bugzilla.gnome.org/show_bug.cgi?id=777399
2017-01-24 11:30:57 -05:00
..
ext v4l2: Update kernel headers to latest from media tree 2015-06-08 17:56:48 -04:00
gstv4l2.c v4l2: fix v4l2 probe build error 2016-07-07 23:55:33 +01:00
gstv4l2allocator.c v4l2allocator: reference memory before the buffer is queued 2017-01-24 11:30:57 -05:00
gstv4l2allocator.h gstv4l2bufferpool: handle -EPIPE from DQBUF to signal EOS 2015-06-09 21:56:40 -04:00
gstv4l2bufferpool.c v4l2bufferpool: remove duplicated line of code 2017-01-16 10:19:34 -05:00
gstv4l2bufferpool.h v4l2: Workaround driver not setting field correctly 2015-03-01 14:03:04 -05:00
gstv4l2colorbalance.c Fix FSF address 2012-11-04 00:07:18 +00:00
gstv4l2colorbalance.h Fix FSF address 2012-11-04 00:07:18 +00:00
gstv4l2deviceprovider.c v4l2: consistently check #ifdef HAVE_GUDEV instead of #if 2016-08-18 20:20:20 +01:00
gstv4l2deviceprovider.h pulse, v4l2: add missing G_END_DECLS in some places 2014-10-28 21:32:06 +00:00
gstv4l2object.c v4l2: Remove usage and definition of LOG_CAPS macro 2017-01-16 10:29:47 -05:00
gstv4l2object.h v4l2: use opened device caps instead of physical device ones 2016-07-07 17:46:06 -04:00
gstv4l2radio.c v4l2: use opened device caps instead of physical device ones 2016-07-07 17:46:06 -04:00
gstv4l2radio.h Fix FSF address 2012-11-04 00:07:18 +00:00
gstv4l2sink.c v4l2: Remove usage and definition of LOG_CAPS macro 2017-01-16 10:29:47 -05:00
gstv4l2sink.h v4l2: De-duplicate caps probing between src and sink 2013-08-19 13:08:18 -04:00
gstv4l2src.c v4l2: Remove usage and definition of LOG_CAPS macro 2017-01-16 10:29:47 -05:00
gstv4l2src.h v4l2src: device sequence/offset correction in case of renegotiation 2015-04-02 17:40:20 -04:00
gstv4l2transform.c v4l2: Add an error return to _try/_set_format 2016-06-07 17:02:43 -04:00
gstv4l2transform.h v4l2transform: Check if caps have changes before asserting 2014-05-08 15:56:36 -04:00
gstv4l2tuner.c v4l2: Use G_DEFINE_ macros for added thread safety 2013-08-19 12:48:35 -04:00
gstv4l2tuner.h pulse, v4l2: add missing G_END_DECLS in some places 2014-10-28 21:32:06 +00:00
gstv4l2videodec.c v4l2videodec: Keep part of the input buffer 2016-06-07 17:03:40 -04:00
gstv4l2videodec.h v4l2: Add initial support for alignment and cropping 2014-05-08 15:56:35 -04:00
gstv4l2vidorient.c v4l2: Use a copy of videodev2.h header 2014-03-15 13:54:47 +01:00
gstv4l2vidorient.h Fix FSF address 2012-11-04 00:07:18 +00:00
Makefile.am Rename GstDeviceMonitor to GstDeviceProvider 2014-06-26 14:57:36 -04:00
meson.build Add support for Meson as alternative/parallel build system 2016-08-20 11:21:12 +01:00
README Fix level for multi-channel case. 2007-02-22 14:35:28 +00:00
tuner.c v4l2: Use G_DEFINE_ macros for added thread safety 2013-08-19 12:48:35 -04:00
tuner.h v4l2: remove unused enumtypes and use generic marshaller 2013-08-04 11:03:49 +01:00
tunerchannel.c v4l2: Use G_DEFINE_ macros for added thread safety 2013-08-19 12:48:35 -04:00
tunerchannel.h Fix FSF address 2012-11-04 00:07:18 +00:00
tunernorm.c v4l2: Use G_DEFINE_ macros for added thread safety 2013-08-19 12:48:35 -04:00
tunernorm.h Fix FSF address 2012-11-04 00:07:18 +00:00
v4l2-utils.c v4l2: consistently check #ifdef HAVE_GUDEV instead of #if 2016-08-18 20:20:20 +01:00
v4l2-utils.h v4l2-util: Introduce GstV4l2Error 2016-06-07 17:02:34 -04:00
v4l2_calls.c v4l2: Also copy device_caps in gst_v4l2_dup 2016-07-10 21:37:24 -04:00
v4l2_calls.h v4l2: Remove usage and definition of LOG_CAPS macro 2017-01-16 10:29:47 -05:00

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/