Forums > Jitter

Timing inaccuracy

May 16, 2008 | 11:41 am

I’m trying to have two videos respond to each other. to do this i need to know where a video is in its loop, so i’m using ‘gettime’ then triggering video 2 on half the time of the loop from 1.

the problem is that the time out of jit.qt.movie seems to skip values. for example if a clip is looping between 1000 and 2000 and i have a ‘sel 1500′, sometimes it bangs it, sometimes it skips the number 1500 and no bang is recorded.

i have achieved crude success using ‘if > 1500 but it is not accurate for my application.

Why does the time skip values? is there a setting to insure accuracy?

My video file’s frame rate is 25, the metro driving the jit.qt.movie is running at 40. each metro bang triggers a ‘gettime’ which if accurate would trigger the next movie at a specific value.


May 16, 2008 | 3:04 pm

total hack, and still not the exact accuracy you want, but this might
help. probably don’t even need the qlim object. hopefully somebody
has a better answer….
——–

max v2;
#N vpatcher 78 103 747 604;
#P window setfont "Sans Serif" 9.;
#P window linecount 1;
#P newex 109 258 83 196617 onebang;
#P newex 56 142 44 196617 qlim 40;
#P newex 108 230 84 196617 split 1500 1510;
#P newex 107 202 57 196617 route time;
#P message 16 143 44 196617 gettime;
#P message 133 114 30 196617 read;
#P newex 54 176 63 196617 jit.qt.movie;
#P toggle 56 89 13 0;
#P newex 56 111 51 196617 qmetro 2;
#P connect 0 0 4 0;
#P connect 7 0 2 0;
#P connect 4 0 2 0;
#P fasten 3 0 2 0 138 143 59 143;
#P connect 1 0 0 0;
#P connect 0 0 7 0;
#P connect 2 1 5 0;
#P connect 5 0 6 0;
#P connect 6 0 8 0;
#P connect 6 1 8 1;
#P pop;

On May 16, 2008, at 7:41 AM, josh wrote:

>
> I’m trying to have two videos respond to each other. to do this i
> need to know where a video is in its loop, so i’m using ‘gettime’
> then triggering video 2 on half the time of the loop from 1.
>
> the problem is that the time out of jit.qt.movie seems to skip
> values. for example if a clip is looping between 1000 and 2000 and
> i have a ‘sel 1500′, sometimes it bangs it, sometimes it skips the
> number 1500 and no bang is recorded.
>
> i have achieved crude success using ‘if > 1500 but it is not
> accurate for my application.
>
> Why does the time skip values? is there a setting to insure accuracy?
>
> My video file’s frame rate is 25, the metro driving the
> jit.qt.movie is running at 40. each metro bang triggers a ‘gettime’
> which if accurate would trigger the next movie at a specific value.


May 16, 2008 | 4:36 pm

[> 1500] -> [togedge]


May 24, 2008 | 8:40 am

thanks for your help. using the split ive managed to ge it under some control.

ciao,

josh


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