TAM as a TV

[flexo]

Hi everybody,

So the TV in our bedroom broke and I've been (stubbornly) pushing the 20th Anniversary Mac I had hiding in the closet as a replacement, ignoring my husband's pleads for a TV set.

I thought it would be great:

• Nice sound system.
• Remote that controls not only the sound but also the can turn the Mac on/off.
• TV input (btw, kudos, Verizon, for having everything from RF to HDMI outputs on your set top boxes.)
• Software with CC support from RF (again, Verizon, kudos, for not stripping that out from RF.)[1]

But the problem is Apple Video Player supports a maximum 640x480 resolution.

Which would be fine if the computer had a CRT screen. So now, I have a huge black box around the video when I set the resolution to 640x480. Most channels also now broadcast in HD only, which letterboxes the video, which makes the picture even smaller to the point where all I can see from the bed is just moving colorful blurs[2].

So my question is, is there a way to hack the AVP to support a 800x600 resolution or is there an alternative software that can upscale the input? I'm not sure if the 640x480 is a hardware limit or a software one (or both?) but I'm sure there has to be way to at least upscale the input?

All I could find on this was a FAQ on Quadra AVs, which had some links to alternative software but since it's from 1994, of course all the links are dead. And since apparently most people who search for Quicktime do so with the search term "apple video player", Google is useless.

1 People say I'm half-deaf so this is useful.

2 Unlike my hearing, my eyesight is pretty good. You know that guy you ask to read something to you when you can't? I am that guy usually.

 

[Trash80toHP_Mini]

Native res of the system is 340x240 that's"Pixel Doubled" (interpolated) to 640x480. Love the Video System, have from day one on the Quadra 630. Beautiful, crisp image on the high quality 20" and 21" CRTs I used for many TV-free years of watching VHS tapes and then DVD movies. I wouldn't think that the TAM's 800x600 LCD would display 640x480 very well at all. Then there's miniscule LCD diagonal and the thought of putting time on your TAM for mere boob-tube duty.

I've been known to go way out of my way to do the things i want to accomplish with classic Mac hardware, but I've gotta side with the hubby on this one. Get a big TV with VGA in, a Vidcard for your FatBack and play big screen games on your TAM!

Solarian anyone? [] ]'>

 

[Trash80toHP_Mini]

Forgot to mention, resolution's pretty much hardwired into the system, no tweaks available.

 

[flexo]

Ah damn it.. Now I have to admit I was wrong I can push my luck even further and try to use the G3 AIO I have as a replacement but that thing doesn't have IR support or RF in and it's huge (and well,.. let's say, unique looking.) so I really like having the TAM there.

So it is the hardware that upscales it to 640x480? Based on some glitches I've experienced dragging the window, I have a feeling that AVP doesn't do anything other than just draw the window, with the card writing directly to video memory?

 

[Trash80toHP_Mini]

May be even lower level than that. IIRC, a screen shot's a video memory dump, but if you do one while an AVP window is active, the window comes up blue screened.

 

[flexo]

Interesting find: I found "TV Monitor 1.0.1" from 1994 (not sure where, I found it on my TAM and downloaded just before Internet Explorer crashed - I think it was on one of the Info-Mac mirrors) and the release notes says one of the fixes for 1.0.1 was to make sure the window is not resized "beyond maximum size" since it would cause "frame rates to drop down"

Not sure if the image actually fit the window when this happened or if the image was still 640x480. If it's the former, maybe it is a software limitation due to hardware available at the time?

It also allows the window to be resized over 640x480 (not sure to what, but it almost covers the screen at 800x600) if I switch the color mode to PAL (this, of course, messes the colors up, but frame rate is more than acceptable)

Might be wishful thinking but I think there might be a way to make 800x600 happen here..

 

[Trash80toHP_Mini]

Could be, give it a shot. ISTR something about AVP being compatible with 800x600@60Hz SVGA, but not with Mac 16" resolution. 800x600 ought to upscale just fine from 640x480 (320x240/whatever) when going into "full screen" mode on your TAM.

 

[Gorgonops]

It also allows the window to be resized over 640x480 (not sure to what, but it almost covers the screen at 800x600) if I switch the color mode to PAL (this, of course, messes the colors up, but frame rate is more than acceptable)

 
Capture/Scaler chips like those in the Apple TV card treat PAL resolution as something like 720x576 instead of 640x480 for NTSC. (Technically if you included all the overscan NTSC should be about 512 lines tall, but the cards clip it because that overscan area of broadcast TV usually contained digital data relating to SAP, Closed Captioning, etc, that just looks like noise when rendered to video. Note, also, that they are *not* "scaling up from 320x240"; some software that does captures can't grab video any larger than that, but that's because of other system limitations.) I can only assume that when you're switching to PAL mode for whatever reason it's faking out the software into letting you pull the window to the PAL size while the hardware is still automatically locking onto the NTSC video signal enough it's giving you an at least partially coherent picture.
 
Anyway, yes, it's a hardware limitation that prevents you from pulling the window any bigger. The way those scaler chips work is, indeed, they capture the raw video, apply a scaling factor to it, and DMA the result into video memory, and the hardware in them is *only* capable of scaling *down* from the input resolution, not up. If the LCD screen in the TAM lacks an upscaler to stretch a 640x480 video mode to fill 800x600 then the only way to make it happen would be to use software to grab every frame off the TV card and upscale it using the main CPU. I *kinda* have a suspicion that the 603e in a TAM isn't fast enough to do that in real time.

 

[Gorgonops]

The way those scaler chips work is, indeed, they capture the raw video, apply a scaling factor to it, and DMA the result into video memory

Actually, I just realized this isn't technically quite true in this case; per Trash's comment about "the window comes up blue screened" after checking the Developer Note I can confirm he's correct that it happens at an even lower level and he's also correct about technically the maximum resolution for NTSC being 320x240 in this particular case. (Unlike the BTTV cards I was thinking of the chip in TAM ignores interlace and only captures at 320x240 non-interlaced, and has a crude pixel-doubling function for window sizes larger than that.) Anyway, instead of being DMA'ed as "frame" into video RAM this system essentially feeds the scaled video information directly into the video system's DAC as a hardware overlay.

Not that it changes anything about being unable to pull the window up to fill the whole screen, unfortunately.

 

[flexo]

Hmm interesting.. yeah I am not even sure why they even made TV capabilities of this machine so prominent (front bezel keys, remote, etc) since the LCD does not support upscaling. 

By the way, can you share the Developer Note? I think it might be an interesting read.

 

[Gorgonops]

I wasn't able to find one specifically for the TAM, I gleaned the information from the one for the 5400. (Same TV card hardware. A shorter description of it is in the 5500/6500 note but it's a little less clear about the limitations.) I'm... sort of hesitant to link it directly because Apple seems to be actively playing whack-a-mole with sites hosting them, but googling for it turns it up fairly easily.

 

[Macintoshguy1984]

Would a digital to analog converter box work?

 

[Trash80toHP_Mini]

Anyway, instead of being DMA'ed as "frame" into video RAM this system essentially feeds the scaled video information directly into the video system's DAC as a hardware overlay.

Yep, I've figured it was piped straight thru somehow ever since I realized I couldn't do a screenshot/VRAM Dump with anything but a blank AVP window to show for it.. I had to fake up a Screen Shot/VidCap composite illustrating me playing a game on the Laser 128 using the Tuner Card in my 6360 to throw a Window onto the 21" Radius monitor.

 

[just.in.time]

The TAM display resolution can't be set to fill the display at 640*480? (Like the wallstreet PowerBook for example)

 

[flexo]

The TAM display resolution can't be set to fill the display at 640*480? (Like the wallstreet PowerBook for example)

Nope, it just adds huge black borders around the picture.

 

[just.in.time]

I did not know that. Today I learned something new.

I'd be torn between the novelty of using a vintage Mac as a TV (such as the TAM, Mac TV, any of models with tuners or RCA jacks) and trying to preserve the hardware. I guess if it was one without a built in display I would definitely consider it.

 

[Trash80toHP_Mini]

Works great, the progressive scan, non-interlaced image is much more clear and crisp on a computer monitor than on a TV when playing VHS/DVD media. I've used a Road Apple 5x00, my 20" Radius display (my first ever color monitor for the Mac) after that when its image got too fuzzy to use as a TPD and then my Radius PrecisionColor 2150 primary display as my bedroom "TV" after moving to NC. The first TV I've had since Y2K was a 32" 720p I bought about seven years ago. Haven't tried it a a media monitor for obvious reasons, but it worked great as an extended desktop aux. Mac display when it sat next to the 21" CRT before I moved later that year.

Your sweet spot for a smallish bedroom TV (but a lot larger screen than your TAM) would be a RoadScrapple 5x00 15 incher with a horribly discolored or disfigured case that's all patched up, sanded silky smooth and painted black as a FauxProtoMac™ of the Director's Edition that's featured in MoMA's Industrial Design Collection. RetroMac and Fashion Forward AIO TV all at the same time. Run that one across the hubby for your bedroom TV! It's also a great excuse to add another Mac to your collection!