Prevue Guide Forums

tin wrote:Do you think you might be able to post the resulting prevue guide logo picture? I want to stuff it into the TVguide version we currently have

The one from my video? Sure: http://img696.imageshack.us/img696/9215/pglogo.png

also - dunno if any of your videos have this, perhaps the end of scroll prevue logo?

Sure, and since I know more people want this too, I'll even super-denoise it for you guys.

Behold the difference between a single frame grab of it, and 16 frame grabs of it all equally blended together -- each contributing 6.25% to the final picture's brightess (before/after): http://img704.imageshack.us/img704/9862/temp1mr.png

As can be seen, this technique literally kills grain and noise without harming resolution one iota.

From there I removed the horrible VHS color resolution issue (before/after): http://img200.imageshack.us/img200/9077/temp2fs.png (this is done by editing luma/color separately in Photoshop -- i.e., before/after seen separately looks like this: http://img199.imageshack.us/img199/4021/temp3z.png)

Anyway, those are all 2x zoomed nearest neighbor style to allow close visual inspection. Here are the two results at 1x zoom:

http://img535.imageshack.us/img535/4966/denoise.png (denoise only)
http://img408.imageshack.us/img408/5223 ... restor.png (denoise + chroma/luma processing)


Note: the pglogo.png file was only denoised by blending 4 frames 25%/25%/25%/25%. It's not perfect, but it's enough...

Love the technique! I will update my .iffs as soon as I get a chance

swest or anyone else: Should you want to make a similar Amiga-style intro, let me know, I'll make a disk image with a startup-sequence saying exactly what you want it to say, so that you can bung it into WinUAE and export video from it

Why, If I have any more Prevue Guide storytelling ideas, I might just call you on that.

Swest77, any chance your source videos for these that you posted way back are S-VHS rather than VHS? I think we have to now get hold of some S-VHS recordings to be able to do any further reverse engineering (unless Ari turns up any new gems of information soon!)

tin wrote:Swest77, any chance your source videos for these that you posted way back are S-VHS rather than VHS? I think we have to now get hold of some S-VHS recordings to be able to do any further reverse engineering (unless Ari turns up any new gems of information soon!)

Nono - remember the information does not come over the satellite in the VBI of any particular channel, it is its own data feed requiring a modem-like device to decode it. So S-VHS videos won't help us, since there is no data there (plus, it was WGN that we thought that was true of).

Anyway, I have some good things coming, but it could be a while. Also, I have some information as to how exactly the CTRL feed works, but we need to figure out exactly how that data was received. I'm pretty sure it came in over a different pin of the serial port than the standard Rx/Tx pins.

Oh. I was pretty sure from what I read it came over in VBI of WGN superstation for EPG Sr/Jr, but later when prevue guide was introduced, I concluded that it would be in the VBI of the prevue guide channel itself (i.e the raw videos with the satellite listings). After all that was the video that I thought we collectively decided was patched through the demod, audio and then genlock cards - because they all have an in and an out, and it stands to reason only one satellite receiver needed, tuned to the satellite version of prevue guide? Video, 3 channel audio and data all coming through the same broadcast? Maybe I have assumed too much

Regarding serial, I have noticed that when you press 5/6/7/8 in diagnostic mode, it toggles the status of the CD DSR and RTS lines. However I have not seen the previously said state where the Amiga send $01 $02 $03 out of the serial port when switching audio through diagnostic mode. Which is a bit odd.

tin wrote:Oh. I was pretty sure from what I read it came over in VBI of WGN superstation for EPG Sr/Jr, but later when prevue guide was introduced, I concluded that it would be in the VBI of the prevue guide channel itself (i.e the raw videos with the satellite listings). After all that was the video that I thought we collectively decided was patched through the demod, audio and then genlock cards - because they all have an in and an out, and it stands to reason only one satellite receiver needed, tuned to the satellite version of prevue guide? Video, 3 channel audio and data all coming through the same broadcast? Maybe I have assumed too much

The VBI stuff here and on Wikipedia was from swest77... I believe he either remembered this incorrectly, or it was explained to him badly at TV Guide, because it turns out that this data was never sent over any form of VBI anywhere. It was sent as an audio feed that was on the same transponder as WGN, and later the Prevue Guide backhaul - therefore, only one input was needed, and one card decoded data from one frequency, one card switched audio between the three audio frequencies, and one card overlaid video from another frequency. swest posted about this possibility here.

tin wrote:Regarding serial, I have noticed that when you press 5/6/7/8 in diagnostic mode, it toggles the status of the CD DSR and RTS lines. However I have not seen the previously said state where the Amiga send $01 $02 $03 out of the serial port when switching audio through diagnostic mode. Which is a bit odd.

Huh... Very interesting.

AriX wrote: The VBI stuff here and on Wikipedia was from swest77... I believe he either remembered this incorrectly, or it was explained to him badly at TV Guide, because it turns out that this data was never sent over any form of VBI anywhere. It was sent as an audio feed that was on the same transponder as WGN, and later the Prevue Guide backhaul - therefore, only one input was needed, and one card decoded data from one frequency, one card switched audio between the three audio frequencies, and one card overlaid video from another frequency. swest posted about this possibility here.

Just to keep the forum up to date after our chat on IRC, I've gone back to swest's post and can see now that the data was sent through via another audio subcarrier. Makes a lot of sense - especially with the Atari EPG Jr, as it basically was constantly loading from tape! Right so that's the VHS idea out of the window

tin wrote:

AriX wrote:The VBI stuff here and on Wikipedia was from swest77... I believe he either remembered this incorrectly, or it was explained to him badly at TV Guide, because it turns out that this data was never sent over any form of VBI anywhere. It was sent as an audio feed that was on the same transponder as WGN, and later the Prevue Guide backhaul - therefore, only one input was needed, and one card decoded data from one frequency, one card switched audio between the three audio frequencies, and one card overlaid video from another frequency. swest posted about this possibility here.

Just to keep the forum up to date after our chat on IRC, I've gone back to swest's post and can see now that the data was sent through via another audio subcarrier. Makes a lot of sense - especially with the Atari EPG Jr, as it basically was constantly loading from tape! Right so that's the VHS idea out of the window

Right. My belief that the data was relayed via WGN's (and later also via the Prevue C-band backhaul video's) VBI's is information that came to me through suits. And I always just assumed it was true because whenever I looked at WGN's VBI directly in those days, it was visibly jam-packed with truckloads of data.

However, Ari's source isn't a suit, but rather worked deep in the technological trenches of it all. So ever since he found this out, I've simply assumed I was misinformed. In any case, that old "EPG DATA" subcarrier listing I found (from the EPG days) would seem to confirm it. I.e., by the time Prevue Guide rolled around, there were probably 5 audio subcarriers. 1) Left, 2) right, 3) music, 4) 2400 baud data, 5) control (75 or 110 baud, can't remember).