My laptop has the built-in camera
$ dmesg | grep uvideo
uvideo0 at uhub0 port 4 configuration 1 interface 0 "Micron Built-in iSight"
rev 2.00/1.84 addr 2
video0 at uvideo0
$
and video(1) usually fails to grab frames in the default resolution of
640x480. No problems so far with 320x240 and 252x288.
In video(1)'s verbose mode, this results in a bogus `run time' being
printed due to the use of the uninitialized variable `tp_start', which
is only initialized after the first frame was grabbed successfully.
In the following run I waited about 10 seconds before aborting with ^C:
$ video -v
video device /dev/video:
encodings: uyvy
frame sizes (width x height, in pixels) and rates (in frames per second):
320x240: 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30,
30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30
352x288: 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30,
30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30
640x480: 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30,
30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30
controls: brightness, saturation, gamma, sharpness
Xv adaptor 0, Intel(R) Textured Video:
encodings: yuy2, uyvy
max size: 1280x800
using uyvy encoding
using frame size 640x480 (614400 bytes)
using default frame rate
^Crun time: -32862651769276.644531 seconds
^^^^^^^^^^^^^^^^^^^^^^
Index: app/video/video.c
===================================================================
RCS file: /cvs/xenocara/app/video/video.c,v
retrieving revision 1.12
diff -u -p -r1.12 video.c
--- app/video/video.c 23 Oct 2014 07:36:06 -0000 1.12
+++ app/video/video.c 19 Jun 2015 09:06:27 -0000
@@ -1406,6 +1406,10 @@ stream(struct video *vid)
long frames_played = -1, frames_grabbed = 0, fus = 50000;
int sequence = 20, ret, err, todo, done;
+ /* Guard against uninitialized variable in case no frame is grabbed. */
+ if (vid->verbose > 0)
+ gettimeofday(&tp_start, NULL);
+
if (vid->fps && !vid->nofps) {
fus = 1000000 / vid->fps;
timerclear(&frit.it_value);
