tag:blogger.com,1999:blog-304223897607246523.post84863215316564323..comments2024-02-09T00:59:01.518-08:00Comments on Matt Ownby's Cool Projects: Wow! VBI injection is working! Holy cow!Matt Ownbyhttp://www.blogger.com/profile/01141290413986333512noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-304223897607246523.post-1302348396713765522013-11-26T06:07:31.431-08:002013-11-26T06:07:31.431-08:00Noooo, that would be coupling! :ONoooo, that would be coupling! :OAnonymoushttps://www.blogger.com/profile/16250722356441382990noreply@blogger.comtag:blogger.com,1999:blog-304223897607246523.post-47492913587428796122013-11-25T14:04:34.732-08:002013-11-25T14:04:34.732-08:00Or we could just assume the source video will alwa...Or we could just assume the source video will always the be Pi :oMatt Ownbyhttps://www.blogger.com/profile/01141290413986333512noreply@blogger.comtag:blogger.com,1999:blog-304223897607246523.post-89791401902212755312013-11-25T06:51:25.335-08:002013-11-25T06:51:25.335-08:00That makes sense if you're using the Pi as the...That makes sense if you're using the Pi as the NTSC video source. Its output is biased about 0.3V higher than the NTSC spec calls for, so it doesn't have to produce negative voltages. Your VBI output looks 0.3V low when it's mixed in. Setting it to 1.3V will make it work right for the Pi, but would be way too high for a proper NTSC source.<br />Perhaps we should use an analog input pin on the aux AVR to measure the peak voltage on the source video, and use that to determine the output level for the VBI signal. :)Anonymoushttps://www.blogger.com/profile/16250722356441382990noreply@blogger.com