<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div>Hello,</div><div><br></div><div>I am trying to implement a watermarking scheme that is not visible to human eye. The idea is to display a small subpicture at random location for each frame. There are 24 frames per second. Human eye should not catch the subpicture if it is displayed only for 1/24th part of a second.<br></div><div><br></div><div>My computed timeout for each subpicture is CEIL((1 * 1000 * 1000), 24) nanoseconds.</div><div><br></div><div>In my video filter, here is the relevant code for subpicture settings:<br></div><div><br></div><div> p_spu->i_start = date;<br> p_spu->i_stop = date + p_sys->i_timeout; // timeout from above calculations<br> p_spu->b_ephemer = true; // the subpicture is ephemeral<br> p_spu->b_fade =
false; // no fading. Just disappear</div><div><br></div><div>However, when I run vlc, I still see the subpicture appearing momentarily.<br></div><div><br></div><div>Thinking that my calculation is wrong, I modified the stop time to current time + 1 nanosecond.</div><div><br></div><div> p_spu->i_stop = date + 1;</div><div><br></div><div>However, that doesn't seem to make any difference. I still see the image momentarily on the screen.</div><div><br></div><div>Can someone please tell me what is it that I am missing? Is my logic flawed?<br></div><div><br>Thank you in advance for your help.</div><div><br>Regards,</div><div>Peter</div><div><br>
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