gst_v4l2_open() is called by gst_v4l2_device_provider_probe_device(),
where the GstV4l2Object is created without an associated GstElement.
If gst_v4l2_open() fails, it raises a bus message, but without an
element, a precondition check fails on
gst_element_message_full_with_details() generating a crash if running
with fatal-warnings debug mode.
GstV4l2Error is a helper to raise error bus messages when it is
appropiated. This patch changes the direct bus messages to this
helper, and the elements will actually send the error message.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/merge_requests/694>
When using this mode each frame is split in two fields, each one being
transferred using its own buffer.
This is implemented with the V4L2_FIELD_ALTERNATE field format in v4l2.
This mode is enabled using a caps filter such as
"v4l2src ! video/x-raw\(format:Interlaced\)"
Here are the main changes related to this feature:
- use the INTERLACED caps feature with this mode.
- in this mode both fields of a given frame have the same sequence/offset
so adjust the algorithm checking for lost field/frame accordingly.
- double pool's min number of buffers as each frame requires 2 buffers.
Fix#504
Co-authored-by: Zeeshan Ali <zeenix@collabora.co.uk>
The previous patch did not even compile on any possible platform or C
standard. That commit also didn't have a proper commit message.
Android ships Linux with a different signature for ioctl. They first
released an ioctl with int as request type, and later "fixed" it by
adding an override with unsign, which is still not matching Linux and
BSD implementation which uses unsigned long int.
This method will check if a buffer, base on it's video meta,
can be imported. It will also try and adapt the request stride
in case this is the only that miss-match.
https://bugzilla.gnome.org/show_bug.cgi?id=583890
Some camera firmware crash is TRY_FMT is called during streaming. As a
side effect. This try and detect that the same format as currently
running is about to be tried, and skip renegotiation.
https://bugzilla.gnome.org/show_bug.cgi?id=796789
This way we can pass the pad name instead of the element for tracing
which helps identifying which v4l2object is used withing M2M element
like decoder, encoder and transform. For the reference, pads are name
<parent-name>:<pad-name>.
The library has started preventing a lot of interesting use cases,
like CREATE_BUFS, DMABuf, usage of TRY_FMT. As the libv4l2 is totally
inactive and not maintained, we decided to disable it. As a convenience
we added a run-time environment that let you enable it for testing.
GST_V4L2_USE_LIBV4L2=1
This of course only works if you have enabled libv4l2 at build time.
skip_try_fmt_probes quirk is set, V4L2 object will not probe for
interlace-mode and colorimetry to avoid relying on try_fmt. This quirk
will be used by v4l2src to avoid desastrous startup time with slow
USB webcams.
When this quirk is enabled, caller will have to iterate over the
negotiated caps as it may contains unsupported formats. If the peer
didn't choose a specific interlace-mode, or colorimetry, the value
chosen by the driver is set into the caps. For this reason, when this
mode is enabled, gst_v4l2_object_set_format() will require writable
caps.
https://bugzilla.gnome.org/show_bug.cgi?id=785156
First step of a larger cleanup, all function from v4l2_calls are in fact
methods on GstV4l2Object. This split makes the code really confusing.
This also remove no longer unused macros.
The same physical device can export multiple devices. In
this case, the capabilities field now contains a union of
all caps available from all exported V4L2 devices alongside
a V4L2_CAP_DEVICE_CAPS flag that should be used to decide
what capabilities to consider. In our case, we need the
ones from the exported device we are using.
https://bugzilla.gnome.org/show_bug.cgi?id=768195
In the V4L2 single-planar API, when format is semi-planar/planar,
drivers expect the planes to be contiguous in memory.
So this commit change the way we handle semi-planar/planar format
(n_planes > 1) when we use the single-planar API (group->n_mem == 1).
To check that planes are contiguous and have expected size, ie: no
padding. We test the fact that plane 'i' start address + plane 'i'
expected size equals to plane 'i + 1' start address. If not, we return
in error.
Math are done in bufferpool rather than in allocator because the
former is aware of video info.
https://bugzilla.gnome.org/show_bug.cgi?id=738013
Since we can get the minimum number of buffers needed by an output
device to work, use it to set min_latency which will determine how many
buffers are queued.
https://bugzilla.gnome.org/show_bug.cgi?id=736072
M2M devices were sharing the same properties as src and sink. Most of
these made no sense. This patch reduces the number of propeties and
makes io-mode clearer by having capture-io-mode and output-io-mode. This
also accidently fixed a bug in gstv4l2transform io-mode code, where the
capture io-mode could not be set.
https://bugzilla.gnome.org/show_bug.cgi?id=729591
This moves away from copying information and store everything inside
the GstVideoInfo structure. The alignement exposed by v4l2 api
is now handled using proper offset.
In order to correctly set the pool min/max, we need to probe for CREATE_BUFS
ioctl. This can be done as soon as the format has been negotiated using a
count of 0.
