qt webcam viewer - V4lCapture

Source (link to git-repo or to original if based on someone elses unmodified work): Add the source-code for this project on opencode.net

5.9

Description:

qt webcam viewer for linux. it takes v4l data/image frames and show them in the qwidget. you need to modify the code for make it work in your machine. for width and height parts check the code please.

this project lives in sourceforge now please check it out.
http://qtv4lcapture.sourceforge.net

if you got any idea feel free to contact me.

Last changelog:

8 years ago

initial release

freelyP
7 years ago

Hi.
Nice application.
Trying to build and test in on Ubuntu 64 bit at my place , ( libv4l installed )
got the following ( both building from Qt Creator and using build.sh ):

state= 0
start oluo
dev: /dev/video0
Output #0, mp4, to './deneme1.mp4':
Stream #0.0: Video: mpeg4, yuv420p, 640x480, q=2-31, 10000 kb/s, 90k tbn, 24 tbc
heheheh
pOutputFormat->audio_codec: 86018
ses stream opened.
codec not found

Also when volume muted ( muted all ) and when middle level. ( then passes states 0 , 2 , 0

Why can't find codec ?

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Frienddy
7 years ago

Thank you for the post.
but, now i have a problem with Qt and openCV.
we usually put the openCV.show in the main.cpp, so when we run the program, the webcam will active as soon as possible. but in my program, i want show the webcam after another widget show.
for example, first i have widget for login, after i successfully login, next widget will show the webcam. how is it?
what shoul i do?
thank you for the attention.

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opakdil
7 years ago

I guess best solution is to move the code from main.cpp to the next form which should open webcam.

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Frienddy
7 years ago

now i can start it, but the problems now, what should i do to take the capture image for the video?
and i want to move the webcam form display, to another form.

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Frienddy
7 years ago

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tetsujin28
8 years ago

I try to compile today (2010.10.22) SVN version. When I pressed [Start Capture] button here's what I've got:

dev: /dev/video0
Output #0, mp4, to './denemel.mp4':
Stream #0.0: Video: mpeg4, yuv420p, 640x480, q=2-31, 10000 kb/s, 90k tbn, 24tbc
heheheh
pOutputFormat->audio_codec: 86018
ses stream opened
codec not found

Any idea what's wrong ?
Thanks

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opakdil
8 years ago

sound like you dont have codec to write mp4 file. but I am not sure you may disable volume and try it again.

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michaelwouters
8 years ago

Thank you for your posting your code. It
was a very quick way to get video capture going for me.

There seems to be a bug though. Your demo crashes very quickly if you just move the window around or resize it.

The problem seems to be calling update() on your display widget from within the capture thread. This is not allowed, AFAIK. The mandelbrot example that comes with Qt might be a better model for doing updates - the captured image is passed via a signal. Crashes in my own code stopped when I reimplemented updates this way.

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opakdil
8 years ago

thanks for the feedback. I check the mandelbrot and reimplement mycode same way. it looks pretier :) anyway and open a new open source project for this matter. and you can reach the project via here

http://sourceforge.net/projects/qtv4lcapture/

or here

http://qtv4lcapture.sourceforge.net/

it does not crashes anymore but somehow I break the libv4l part I am not sure about it :) it can save videos anyway:)

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kalac
8 years ago

it is a kernel bug, I have it too. Whem that happens, all usb devices stops working until reboot.

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opakdil
8 years ago

thanks for the feedback.

its not a suprise to me. sometime my all usb devices just dies and I start pulling and plugging them till they get better :) and that situation does not related to my app. when my app gaves that error it just dissapperas.

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