S-video?!

RinksCustoms

The TV driver seems very powerful, i have·two questions. I noticed that the tv driver includes settings for doing s-video output.

Is this very·difficult to implement?

What would need to be changed in the VAR/DAT blocks of my program to make this work?

Is there bennefits to using this output over broadcast or baseband?


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Definetly a E³ (Electronics Engineer Extrodinare!)
"I laugh in the face of imposible,... not because i know it all, ... but because I don't know well enough!"

potatohead

One major benefit would be higher overall resolution. An S-video signal has better color resolution, preventing artifacting from happening. (some pixels being colored, depending on where they are on the screen.) This is also a minus, if you want to exceed the standard color resolution, which is 80 good, useful, colors.

Broadcast is fickle, but works on anything that has a tuner. I've used the Parallax reference TV driver in broadcast mode on the demo board and it can generate a pretty nice signal. On HYDRA it's not so clean. Has to do with the crystal chosen, I think.

Seems to me, S-video would be indicated for text and or graphical displays with resolutions above 320 pixels horizontally. How much of that you see, depends on your display. Older TV's, in general will display the color resolution differences well enough, but may or may not respond to the higher number of pixels.

RinksCustoms

it'd be nice to have s-video, but it's a brick wall of a learning curve with the TV and graphics objects, and there's hardly any documentation for these powerful objects. I have a proto board and a handmade DAC on pins 4..8 (includes the aural res), so that just adds to the fun .·

My cut/hack/slash/axe! approach did little to make the graphics demo work properly (which worked fine on my breadboarded version of a demo board) And i had a semi-functional GUI on the PropTerminal, so it shouldn't be my programing too much. I don't know, guess it's back to square one..

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Definetly a E³ (Electronics Engineer Extrodinare!)
"I laugh in the face of imposible,... not because i know it all, ... but because I don't know well enough!"

Kaio

RinksCustoms,

I would recommend to use the same pins (12-15) as on demo board. This will prevent you from trouble with the default driver settings. Otherwise you have to change some bits in the driver located in your Propeller Tool directory and then it will work for ever with your board.

Thomas

LoopyByteloose

Take a look at Wikipedia under S Video for a good introduction. If that helps, also try them for NTSC. Together, I suspect the whole thing will seem a lot clearer.

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"Everything in the world is purchased by labour; and our passions are the only causes of labor." -- David·Hume (1711-76)········

···················· Tropically,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

ericball

S-Video may be·a minor challenge because the Prop's video generator combines the chroma with the luma before output to the three pin DAC (output = luma[noparse][[/noparse]0..2] +/- chroma).· So for S-Video you'd need to have two synchronized instances of the TV object.· One would generate the luma via one DAC and the other would create the chroma on a separate DAC.
·

RinksCustoms

After reading the HYDRA teaser chapters, i understand alot better how the tv driver works. Mike Green elagantly explained in another thread how the tv and graphicks objects interact with one another.

and by adding this bit of code to the demo's:
-in the CON block
basepin = n (n = pin number where my DAC starts)

and this in the block where it starts the tv driver
tvparams_pins := (basepin & $38) << 1 | (basepin & 4 == 4) & %0101
right before this code:

longmove(@tv_status, @tvparams, paramcount)
tv_screen := @screen
tv_colors := @colors
tv.start(@tv_status)


and add "tvparams_pins" on the same line as the "pins" in the DAT block a few lines below "tvparams"
DAT
tvparams··············· long··· 0·············· 'status
····························long··· 1·············· 'enable
tvparams_pins·········long··· %001_0101 'pins

and no mater what basepin I use now, 0,4,8,12,16,or 20 the code will work fine as long as I use one of these pins as the basepin for the 4 pin DAC for he video.


I'm looking for an old s-video cable i have lying around, that's next to tool with. Thanks for all your help guys!

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Definetly a E³ (Electronics Engineer Extrodinare!)
"I laugh in the face of imposible,... not because i know it all, ... but because I don't know well enough!"

Post Edited (RinksCustoms) : 7/4/2007 9:29:05 PM GMT