Problems with recording video

Ian Davidson id012c3076 at
Wed Dec 12 08:13:20 PST 2012

I am trying to record video.  The recording time can be over an hour and 
if I try to record to a single file, the file can get too large.

I wrote a script to attempt to record a series of shorter videos - and 
then use Ctrl-C to stop recording when I wanted to finish. Below is a 
simplified version of the script.
v4l2-ctl -i 1
while [ $counter -lt 100 ]; do
     let counter=counter+1
     `gst-launch-1.0 v4l2src norm=PAL num-buffers=100 ! 
! queue ! mux. alsasrc num-buffers=440 ! audioconvert ! 
'audio/x-raw,rate=44100,channels=2' ! queue ! mux. avimux name=mux ! 
filesink location="$fullFileName"`

Note that this test version has the num-buffers set to 100 for the video 
source.  When I run this script for a short while, I get the following 
on the console
[ian at localhost ~]$ ./testScript
Video input set to 1 (Composite1: ok)
./testScript: line 8: Setting: command not found
./testScript: line 8: Setting: command not found
[ian at localhost ~]$

The first video records without any comment, the second and subsequent 
attempts get that 'Setting: command not found' message.

The final video - the one that is terminated by the Ctrl-C - does not 
seem to have recorded the video properly.  When I try to view the 
videos, that final video does not display the actual material, just a 
'filmstrip'.  If I carry the videos from my Linux box to a Windows 
machine, editors fail to open the final AVI file.

Thus far, two questions.
1) What is the meaning of that 'command not found'?
2) Why does the final video, terminated by Ctrl-C not work?

I then noticed that I have num-buffers on both the video and audio 
sources - so I removed the 'num-buffers=440' - but now the first video 
did not come to a natural end but waited until the Ctrl-C.

Third question. Do I need to have num-buffers on both sources?

Your help is appreciated.

Ian Davidson
/239 Streetsbrook Road, Solihull, West Midlands, B91 1HE/
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