Setting the v4l2 device parameters may influence video properties
such as width, height and pixel format.
This patch moves v4l2_set_parameters to be executed before fetching
the video properties, avoiding errors such as (pal vs ntsc):
The v4l2 frame is 829440 bytes, but 691200 bytes are expected
Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
With some (buggy) drivers, the VIDIOC_G_STD ioctl returns a std_id that cannot
be matched with any of the enumerated v4l2_standard structures (for example
std_id = 0 or std_id = 0xffffff). Do not fail when we reach the end of the
enumeration without a valid match.
Fixes ticket #2370
Note: This commit message has been modified by Giorgio Vazzana, the original
commit message was:
"Fixed regression for mandatory VIDIOC_ENUMSTD support by v4l2"
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
In particular, print the standard supported by the selected input.
Additionally, use PRIx64 everywhere when printing standards.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Also disable it by default since it looks currently buggy. The
usefulness of such library is mostly limited to backward compatibility
with very old devices.
This is consistent with the rest of the file and makes listing of
emulated formats possible when ffmpeg is compiled with libv4l2.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
An input channel could have been previously set with another application, like
v4l2-ctl, so if no input channel is specified use the previosly selected one.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
The current code returned a period=0, resulting in identical pts for all frames
after time-filtering. This is because AV_TIME_BASE_Q={1, AV_TIME_BASE} and
not {AV_TIME_BASE, 1}. With this patch the correct period in microseconds is computed.
struct buff_data contains a pointer to struct video_data, so passing the
file descriptor again is redundant.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
In particular:
1) save errno before it (possibly) gets overwritten by other calls
2) do not forget to enqueue the buffer again in case of error
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This will avoid the possibility that we dequeue more buffers than we
have obtained from the v4l2 driver.
Fixes ticket #1570
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Generally speaking, there are two types of v4l2 devices [1]:
1) devices that support a standard, like PAL or NTFS (tv cards, for example). For
this class of devices the framerate is fixed by the standard (for example PAL uses
25 fps) and the v4l2 driver cannot usually negotiate a different framerate (unless
it can skip frames on the driver side, to save I/O bandwidth).
2) devices for which the notion of standard does not make sense (webcams, for example).
For these devices it is usually possibile to request a desidered framerate.
In either case, the desidered frame rate can be requested when the VIDIOC_G_PARM
ioctl returns the V4L2_CAP_TIMEPERFRAME flag in the capability field.
Currently the code does not check for V4L2_CAP_TIMEPERFRAME and supports only the
second category of devices, returning a time per frame of 0/0 for devices in the
first group that do not permit to negotiate the framerate.
This patch adds support to read the correct framerate in all cases.
[1] http://linuxtv.org/downloads/v4l-dvb-apis/standard.html
Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
Since the user is expected to choose the standard by name (with -standard
option), add the possibility to list all the supported standards.
Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
Because libavdevice/v4l2 is a demuxer, it makes sense to look for
decoders instead of encoders when listing the formats supported by the
device.
Signed-off-by: Stefano Sabatini <stefasab@gmail.com>
Make device_try_init() return an error value, and allow to properly
report errors which are not due to a wrong pixel/codec configuration.
In particular, report intelligible feedback in case of busy device.
Lukasz Marek
Michael Niedermayer
Federico Simoncelli
Derek Buitenhuis
mrlika
Giorgio Vazzana
Carl Eugen Hoyos
Rémi Denis-Courmont
Diego Biurrun
Clément Bœsch
Nicolas George
Anton Khirnov
Stefano Sabatini
Stephan Hilb
Martin Storsjö