Comments on: Chapter 14: Images, Video, and Audio

By: Derek

Derek — Sun, 27 Sep 2015 22:21:34 +0000

In reply to john. Hi John, missed your messages. I guess that you may have worked it out by now, but it is v4l (letter l), not v41. Kind regards, Derek.

By: john

john — Wed, 23 Sep 2015 00:00:30 +0000

Regarding the last post…
I tried rm /var/lib/dpkg/lock and that seemed to fix the error messages. So I was apparently able to complete the update command.

When I attempt to install the packages (your next step on p. 477), I get two errors:
unable to locate package libv41-dev
unable to locate package v41-utils

Any clue why these are missing??

By: john

john — Tue, 22 Sep 2015 23:42:12 +0000

new question. Got past last issue and now can ping via PC connection.
On page 477, you have
~# sudo apt-get update
when I run this I get two errors:
could not get lock /var/lib/dpkg/lock
unable to lock the administration directory

Any clue about how to fix this? Searching the net yields different opinions.

Thanks

By: iman

iman — Wed, 08 Jul 2015 22:09:18 +0000

Hi Derek
I’m not sure I put this in a correct place or not.
I Run the Audiodevices example on my BBB but it seems the app couldn’t detect my USB sound card.
The program shows noting in all field.
I’m wondering am I have to do something to export my USB sound card to my QT app like the
export QWS_MOUSE_PROTO=LinuxInput:/dev/input/event1 for adding Touch screen to my QT APP,
Or it should be detect it automatically?
This is the result of aplay -l

card 0: default [C-Media USB Headphone Set], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0
Any help will appreciated
Thank You
Iman

By: Derek

Derek — Tue, 16 Jun 2015 01:23:39 +0000

In reply to David Rodriguez. Hi David, you could write a Bash script that calls fswebcam to capture a single frame and passes the name. It then sleeps and loops. You could also use the script to pull in the GPS location from a UART GPS device. Hope that helps, Derek.

By: David Rodriguez

David Rodriguez — Mon, 15 Jun 2015 15:03:01 +0000

Hi Derek, is there a way to take pictures with fswebcam in a loop and storing them with different names?

By: David

David — Mon, 15 Jun 2015 05:02:07 +0000

Hello Derek, im currently using fswebcam to generate pictures in a loop but I dont know how to save them with different names could you suggest any way?, also is there any way to georeference the file using gps input?

By: Derek

Derek — Wed, 03 Jun 2015 00:36:27 +0000

In reply to Peter. Thanks Peter! If you use the OpenCV C++ library you can use the putText() drawing function to add text. Kind regards, Derek.

By: Peter

Peter — Tue, 02 Jun 2015 00:58:38 +0000

Hi Derek. What a great book!!! I managed to connect an old Genius webcam and a Sony Playstation 2 Eye-Toy camera to the BeagleBone Black following this chapter.

I was wondering if you have came across a way to add/overlay text on the video from C/C++, i.e. add the time, local temperature etc?

Thank you.

By: Chavdar

Chavdar — Wed, 22 Apr 2015 20:33:29 +0000

In reply to Derek. Worked like a charm. By the way thanks for the nice book.