Text overlay on video (On Screen Display)

[GSM]

Hi group,

Anyone have any experience with ICs for overlaying text om a video signal?

ICs like:
NEC: uPD6464 or some other uPD64xx
ST: STV5730
Sanyo: LC74794M
ROHM: BU5963AS
or others

I'm mostly worried about the genlock function. They all have built-in PLLs
for genlock but PLLs always gives me headaches...
Also I'm curious about how easy these circuits are to control from a
uProcessor.

Any input, good or bad, is very appreciated.

/Ulf B

 

[Winfield Hill]

GSM wrote...

Anyone have any experience with ICs for overlaying text on
a video signal?

ICs like:
NEC: uPD6464 or some other uPD64xx
ST: STV5730
Sanyo: LC74794M
ROHM: BU5963AS
or others

I'm mostly worried about the genlock function. They all have
built-in PLLs for genlock but PLLs always gives me headaches...
Also I'm curious about how easy these circuits are to control
from a uProcessor.

In my experience the bigest problems with OSD chips revolve
around availability. You want a part you can get now, but you
don't want to see it dissappear just when your design becomes
successful. You can carefully select an IC with the features
you want, get a few chips and build one, but if you choose the
wrong part, that'll be the end of it. You'll no doubt find the
NEC Sanyo and Rohm parts hard to get, but the STV5730 seems
widely available, at least here in the U.S. Go with that one.

Thanks,
- Win

whill_at_picovolt-dot-com

 

[Luhan Monat]

Anyone have any experience with ICs for overlaying text om a video signal?

Hi,

Try this for a start...

http://www.brouhaha.com/~eric/pic/pictock.html

 

[GSM]

Hi Win,

Thanks a lot for your input. Most appreciated.
STV5730 seems like a popular chip. Most webpages that I've found on the
subject have been dealing with that circuit. There seem to be two problems
for me with that one however.

1. Only available for SMT. I am going to build very small series to start
with and plan to use through-hole boards.
2. It seems STV5730 has been discontinued, but maybe back in production
again. Lotsa confusion.

Well i guess i can find out on monday by calling the distributor.

One option would of course be to build my own solution, but it's to much
work. I did a video overlay design 15 years ago using about 10 PLD
circuits... And then I only had a 256*256 pixel memory. The CPU had to take
care of everything including fonts.



Once again thanx a lot.

/Ulf

 

[Winfield Hill]

GSM wrote...

Hi Win,

Thanks a lot for your input. Most appreciated.
STV5730 seems like a popular chip. Most webpages that I've found
on the subject have been dealing with that circuit. There seem
to be two problems for me with that one however.

1. Only available for SMT. I am going to build very small series
to start with and plan to use through-hole boards.

This is 2003, NEARLY 2004. Get with the program!

2. It seems STV5730 has been discontinued, but maybe back in
production again. Lotsa confusion.

I dunno, ST has data and appnotes and no discontinuance notice,
datasheet at http://www.st.com/stonline/books/pdf/docs/1178.pdf
and appnote at http://www.st.com/stonline/books/pdf/docs/1113.pdf

Nu Horizons has 6097 of the STV5730A in stock at $12.30 each,
$10.46 qty 100. Plenty of other sources.

One option would of course be to build my own solution, but it's
too much work. I did a video overlay design 15 years ago using
about 10 PLD circuits... And then I only had a 256*256 pixel memory.
The CPU had to take care of everything including fonts.

A modern CPLDs could probably hold your entire design! We made
a pretty good OSD reticle display using the Scenix / Ubicom fast
PIC-replacement SX series processors. But all-in-all a proper
VLSI OSD chip like the STV5730 is much better for the task.

Thanks,
- Win

whill_at_picovolt-dot-com

 

[GSM]

Thanx for your input Luhan

The solution is of course very compact and neat but it would require a lot
of work if you want to change the design.

/Ulf

 

[Al]

Thanx for your input Luhan

The solution is of course very compact and neat but it would require a lot
of work if you want to change the design.

/Ulf

Not exactly an IC, but....http://www.decadenet.com/bob2/bob2.html

Al