I'm trying something new, I'm trying a let's learn / let's code series. This one is about NTSC. This is the page that I referenced when I was learning NTSC: www.kolumbus.fi/pami1/video/pa...
Many thanks once again! The video has helped me a lot in terms of particular neat peculiarities I didn't get into. I wonder why it happened that most interesting materials come from the USA? And I have the mere explanation is that Americans more democratic in their intentions to spread a tution among others or, maybe, it's because Americans much more well educated
@CNLohr
7 жыл бұрын
I think some of it has to do with how little scarcity there is in America. In general we don't "need" to work absurd amounts of time and be particularly greedy on an individual level to maintain a reasonable standard of living. Though I will admit, my desire to teach others is pretty well rooted in my education from my university. I would rather encourage others to be self-sufficient instead of needing me and try to make money off that..
@CNLohr
7 жыл бұрын
That seems like a really unusual issue. It's kinda difficult to troubleshoot this sort of thing visually only. Google "kolumbus ntsc" and see if his timing helps you? I'm also confused about your inverted comment. NTSC Broadcast is inverted. NTSC wired is non-inverting. 0V = sync, .3V = black, 1V = white
@dkoxperiakoziukov3808
7 жыл бұрын
There is everything ok with colors. The first part of the screen is white and second is black. Vertical sync appears to be solved. It was because I forgot to draw 262 lines more to cover the second field of an interlaced frame. Now the picture is stable more or less. But the "jig-saw" edge still appears in the middle. Any ideas why? Is it too important to shift the vcync/blanking interval in the interlace scan line to a half the 63.55 uS?
@CNLohr
7 жыл бұрын
To answer your question about half-length synch... YES! It is absolutely critical. That is what triggers the horizontal sync. I believe your ripples are exclusively due to a bad HYSNC information. It's really cool to watch someone put this together step-by-step.
@dkoxperiakoziukov3808
7 жыл бұрын
Man, I thought that the 4.7 uS intervals are to control the HSync. The 90 degrees shift is put to affect the Vsync line. Am I correct or did I skip something?
@jojodi
9 жыл бұрын
I could just be bad at searching for it, but this seems like it is the only decent explanation of how NTSC works on youtube... Great stuff :)
@CNLohr
9 жыл бұрын
Brandon Pelfrey Thanks for that. And I agree, I do think NTSC is something that's not covered very well despite being so ubiquitous.
@subliminalvibes
Жыл бұрын
This video didn't exist when you wrote that... 👍😎 kzitem.info/news/bejne/lH2Au4FsqXWhmKw
@CNLohr
11 жыл бұрын
Composite is much more ubiquitous. It's also always had a place in my heart for some time.
@sliechti
11 жыл бұрын
Thanks for the video, very interesting/informative.
@Lynxdom
6 жыл бұрын
Very informative... thank you :)
@montassargh2840
9 жыл бұрын
you need more likes !! Thankx for the infos !
@invent0r137
2 жыл бұрын
Thanks for the info, but I have a question that I can't seem to find the answer to anywhere, I'm hoping you can help. Do the sync pulses control the electron beam deflection? That is, are the hsync pulses physically responsible for moving the electron beam from right to left during the horizontal retrace (and same for vsync)? If so, how do they do it?
@CNLohr
2 жыл бұрын
It's more complicated than that. There's some degree of resistance toward spurious events that could happen because of static / noise in the signal. So most TVs are sort of pattern-matching.
@lit2021
6 жыл бұрын
Noooo, those are not 20 lines of HSync! Those are 20 lines of vertical sync! Yes, they look like the horizontal sync pulses, but those are vertical sync pulses (VSync).. First there are the pre-equalizing pulses, then the actual vertical sync pulses, and afterwards the post-equalizing pulses.
@saket3143
7 жыл бұрын
Will there be a PAL version of these videos?
@merumerutho
8 жыл бұрын
dat Magfest shirt!! so cool
@iSolarSunrise
10 жыл бұрын
What about V-Sync? I heard that it has to be inverted horizontal sync or something...
@CharlesLohr
10 жыл бұрын
That's really good point. I've never head of "inverted" horizontal sync. Indded, though, vertical sync is based upon horizontal sync. It is when you double-time the horizontal sync it creates a vertical sync.
@CharlesLohr
10 жыл бұрын
To be fair, there is a bit of other funny stuff where it does flip around, back then forth, so I could see why someone would call that inverted sync. The website linked shows that.
@billkillernic
7 жыл бұрын
Prior to making this video you recalled the elements involved in your head because you read a book right? what was the name of that book/books? (specifically related to information needed to make the play list on coding NTSC )
@CNLohr
7 жыл бұрын
not really. Just stuff dad taught me when i was younger and that kolumbus site. Then I banged my head against a wall for hours while trying to code the thing to generate the video! Once I wrote a program to do it, I understood it!
@billkillernic
7 жыл бұрын
I actually want to push my point and shoot camera as a webcam and dont know where to start reading about signal manipulation.. the camera has an HDMI out (I know that NTSC is completely different thing than HDMI but I figure I should start from an older technology to understand how things work) I could use a capture device plug the HDMI in and get the signal via USB but I doubt applications (like skype) would recognize this as a webcam source... so I figure I only need a way to forward the HDMI signal through USB with a "webcam" header thingy or however its done in USB so I figure I need an fpga and a usb controller and I am done (assuming that I learned how to manipulate the signal from the source and also know how USB stacks work... but this can be done by reading books the question is which books :P do you have any good reads in mind that could help me out in my quest ? :P )
@CNLohr
7 жыл бұрын
If you have a HDMI capture card (to USB) almost all applications will recognize them as a valid imaging source, so you should be fine! Also, to read HDMI, you really need an FPGA-level system. It's nontrivial to read. Heck, even NTSC is pretty difficult -- err very difficult if you want to retain color!
@austin_ma
2 ай бұрын
TY big boy (2024)
@sliechti
11 жыл бұрын
I swear
@sliechti
11 жыл бұрын
I swear I thought it was my phone at 8:22. ipad + headphones.
@tedrobinson372
Жыл бұрын
59.94 Hz Not 59.97 Hz!
@CNLohr
Жыл бұрын
I always get the 29.97/59.94 combo mixed up.
@lbaungartner
6 жыл бұрын
I wish I knew what this video is about. (I have no idea of how I ended up here.)
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