In 18.04 opencv waitKey loop exit immediately
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0
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I have compiled and linked example from Example source
Successfully. In Ubuntu 16.03 begin to work after entering user to group video.
I did the same in 18.04 but program exits immediately.
I try to debug code and discovered that problem is waitKey.
If i change
if(waitKey(30) >= 0) break;
to
waitKey(30);
It works, but not correctly. How to correctly change the code?
18.04 video opencv
asked Nov 24 at 15:56
TadejP
1067
add a comment |
up vote
0
down vote
favorite
I have compiled and linked example from Example source
Successfully. In Ubuntu 16.03 begin to work after entering user to group video.
I did the same in 18.04 but program exits immediately.
I try to debug code and discovered that problem is waitKey.
If i change
if(waitKey(30) >= 0) break;
to
waitKey(30);
It works, but not correctly. How to correctly change the code?
18.04 video opencv
asked Nov 24 at 15:56
TadejP
1067
1
"It works, but not correctly." - please elaborate. If I read the documentation [1] correctly,waitKeywaits for x ms on key press. If no key is pressed it returns -1 and loop in your example breaks... [1] docs.opencv.org/3.1.0/d7/dfc/…
– honza-kasik
Nov 24 at 17:03
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I have compiled and linked example from Example source
Successfully. In Ubuntu 16.03 begin to work after entering user to group video.
I did the same in 18.04 but program exits immediately.
I try to debug code and discovered that problem is waitKey.
If i change
if(waitKey(30) >= 0) break;
to
waitKey(30);
It works, but not correctly. How to correctly change the code?
18.04 video opencv
asked Nov 24 at 15:56
TadejP
1067
I have compiled and linked example from Example source
Successfully. In Ubuntu 16.03 begin to work after entering user to group video.
I did the same in 18.04 but program exits immediately.
I try to debug code and discovered that problem is waitKey.
If i change
if(waitKey(30) >= 0) break;
to
waitKey(30);
It works, but not correctly. How to correctly change the code?
18.04 video opencv
18.04 video opencv
asked Nov 24 at 15:56
TadejP
1067
asked Nov 24 at 15:56
TadejP
1067
edited Nov 25 at 8:22
asked Nov 24 at 15:56
TadejP
1067
asked Nov 24 at 15:56
TadejP
1067
asked Nov 24 at 15:56
TadejP
1067
1067
1
"It works, but not correctly." - please elaborate. If I read the documentation [1] correctly,waitKeywaits for x ms on key press. If no key is pressed it returns -1 and loop in your example breaks... [1] docs.opencv.org/3.1.0/d7/dfc/…
– honza-kasik
Nov 24 at 17:03
add a comment |
1
"It works, but not correctly." - please elaborate. If I read the documentation [1] correctly,waitKeywaits for x ms on key press. If no key is pressed it returns -1 and loop in your example breaks... [1] docs.opencv.org/3.1.0/d7/dfc/…
– honza-kasik
Nov 24 at 17:03
1
1
"It works, but not correctly." - please elaborate. If I read the documentation [1] correctly,
waitKey waits for x ms on key press. If no key is pressed it returns -1 and loop in your example breaks... [1] docs.opencv.org/3.1.0/d7/dfc/…– honza-kasik
Nov 24 at 17:03
"It works, but not correctly." - please elaborate. If I read the documentation [1] correctly,
waitKey waits for x ms on key press. If no key is pressed it returns -1 and loop in your example breaks... [1] docs.opencv.org/3.1.0/d7/dfc/…– honza-kasik
Nov 24 at 17:03
add a comment |
1 Answer
1
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oldest
votes
up vote
0
down vote
accepted
Obviously API implementation changed from 2.4.9 to 3.2 so example needs to be corrected.
In ver. 2.4.9 when no key pressed in x ms time returns -1
In ver. 3.2 when no key pressed in x ms time returns 255
So code for both versions for me looks like this:
int k; // key
k=waitKey(30);
if( 255!=k && -1!=k )
break;
answered Nov 25 at 8:20
TadejP
1067
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
0
down vote
accepted
Obviously API implementation changed from 2.4.9 to 3.2 so example needs to be corrected.
In ver. 2.4.9 when no key pressed in x ms time returns -1
In ver. 3.2 when no key pressed in x ms time returns 255
So code for both versions for me looks like this:
int k; // key
k=waitKey(30);
if( 255!=k && -1!=k )
break;
answered Nov 25 at 8:20
TadejP
1067
add a comment |
up vote
0
down vote
accepted
Obviously API implementation changed from 2.4.9 to 3.2 so example needs to be corrected.
In ver. 2.4.9 when no key pressed in x ms time returns -1
In ver. 3.2 when no key pressed in x ms time returns 255
So code for both versions for me looks like this:
int k; // key
k=waitKey(30);
if( 255!=k && -1!=k )
break;
answered Nov 25 at 8:20
TadejP
1067
add a comment |
up vote
0
down vote
accepted
up vote
0
down vote
accepted
Obviously API implementation changed from 2.4.9 to 3.2 so example needs to be corrected.
In ver. 2.4.9 when no key pressed in x ms time returns -1
In ver. 3.2 when no key pressed in x ms time returns 255
So code for both versions for me looks like this:
int k; // key
k=waitKey(30);
if( 255!=k && -1!=k )
break;
answered Nov 25 at 8:20
TadejP
1067
Obviously API implementation changed from 2.4.9 to 3.2 so example needs to be corrected.
In ver. 2.4.9 when no key pressed in x ms time returns -1
In ver. 3.2 when no key pressed in x ms time returns 255
So code for both versions for me looks like this:
int k; // key
k=waitKey(30);
if( 255!=k && -1!=k )
break;
answered Nov 25 at 8:20
TadejP
1067
edited Nov 25 at 8:25
answered Nov 25 at 8:20
TadejP
1067
answered Nov 25 at 8:20
TadejP
1067
answered Nov 25 at 8:20
TadejP
1067
1067
add a comment |
add a comment |
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1
"It works, but not correctly." - please elaborate. If I read the documentation [1] correctly,
waitKeywaits for x ms on key press. If no key is pressed it returns -1 and loop in your example breaks... [1] docs.opencv.org/3.1.0/d7/dfc/…– honza-kasik
Nov 24 at 17:03