[SirCastor]

I'm on a G4 sawtooth. I've got a FW digital/analog bridge. I'd really really like to setup my mac to play my DVDs out to my TV. I don't know how to do this though. I've looked and looked and can't seem to find it even addressed. Can I do this? and how?

[Spoffo]

People in the presentation and training business do it all the time with powerbooks and projectors by setting up the projector as a second VGA monitor in the video CP. This would work the same on any desktop Mac that has 2 monitor outputs. For most TV's you'd need some kind of outboard transcoder - VGA to Component or VGA to S-video - but those are pretty cheap.

The larger question, though, is why you would possibly want to do this? The picture quality of the Apple Software DVD player (or VLC) is vastly inferior to even a $35 DVD player from the drugstore, let alone a high-quality stand-alone. The stand-alones have dedicated, special-purpose chips for MPEG decoding and various video functions. A pure software product, especially one whose main design goal is that it work with a wide variety of general purpose processors and video cards, can't match them. Just look at the hideous amounts of combing you see from the Apple player with any DVD based on video-source material.

That's probably why no one talks about how to do it.

[SirCastor]

The biggest reason For getting my video out to TV was because it was free. I already had the equipment. I can go out and buy a cheap DVD player, but that's $35 (or more) out of my pocket. It's not a huge deal, it just means putting off some other stuff I want more

Thank you very much for the answer. I appreciate it. I'll probably end up going out and investing in a DVD player then, it was just a less expensive pipe dream.

[tooki]

Actually, the DV bridges aren't the right equipment for this task. DV bridges are not seen by the OS as a computer display. Instead, an application streams data directly to or from the unit.

In contrast, Apple DVD Player always outputs to one of the computer's displays. The VGA, DVI and S-video outputs on the graphics cards are all seen as computer displays.

I agree that a cheap DVD player is a better solution, though.

tooki

[tooki]

Note that while I do agree that a standalone player is a better solution, I have to take serious objection to this analysis:

Originally Posted by Spoffo

The larger question, though, is why you would possibly want to do this? The picture quality of the Apple Software DVD player (or VLC) is vastly inferior to even a $35 DVD player from the drugstore, let alone a high-quality stand-alone. The stand-alones have dedicated, special-purpose chips for MPEG decoding and various video functions. A pure software product, especially one whose main design goal is that it work with a wide variety of general purpose processors and video cards, can't match them. Just look at the hideous amounts of combing you see from the Apple player with any DVD based on video-source material.

In fact, software coding/decoding is decidedly better, provided enough CPU power is available. Why? Because a hardware codec is fixed. Software can be altered far more easily, and it happens. Software MPEG encoders produce, by a wide margin, better-quality video than hardware encoders, because software encoders don't have to work in real-time, so they can take their time analyzing the video and choosing the best way to encode it.

The reasons that computer-based DVD playback looks worse has to do with a few factors. One is that the DVD standards were designed for display on interlaced displays, with 1:1 correlation between saved pixels and TV scan lines. Even so, a badly-encoded DVD can show combing artifacts because of field mismatch.

The other is that DVDs are designed for TV use, and the high quality of computer displays shows off defects that a standard definition television tends to mask.

Finally, the computer will play most DVDs perfectly: those are discs that were mastered correctly. Most combing artifacts are simply badly mastered DVDs whose interlacing and field flags are incorrectly set. A disc whose content is interlaced should have flagged which field is which, and where the original film frame started. If this information is missing, or worse present but incorrect, combing can occur when the computer attempts to reconstruct the original frame.

Finally, a properly-mastered interlaced disc may look fine when displayed on a TV from a standalone player, but may have interlacing artifacts when outputting from the computer's S-video to a TV. Why? Because standard-def TVs are interlaced, so the output "syncs", so to speak. Scan lines match up perfectly. When the computer outputs DVD to a TV, it's taking the DVD video, scaling it to screen resolution, and then scaling it again to TV resolution. Each scaling is terrible for interlaced content.

So while I do agree that a standalone player is the better solution (no computer involved, you get a remote control, etc), it's usually not the computer's fault that DVD playback sometimes sucks.

tooki

[Spoffo]

I agree - - **in theory** and **with enough processing power**. But turning theory into reality requires a software player that takes advantage of all that processing power.

As far as I can tell, the Apple DVD player is a pretty simple little MPEG decoder that's hard-wired to de-interlace at a 3:2 film cadence no matter what the input. So, film material ususally looks acceptable and, in my experience, ALL video based material just combs like crazy. Sure, some video-based material is badly flagged on the disk and causes combing on most players, but not ALL of it. VLC is a little better, with some very basic de-interlace options like "blend" that smooth out video a bit.

Compare this with a mid-level stand alone with, say, a Faroudja or Silicon Image chip that does very sophisticated motion-adaptive de-interlacing and is able to sort out and rise above all sorts of bad flags, etc.

Could someone write an even better player in software to run on something like a dual G5? Probably. However, nobody has. All we have is two low-end utility players whose main appeal is that they'll run on anything Apple has built in the past 5 years.

[tooki]

No offense, but as far as I can tell, you know just enough about this to draw flawed conclusions.

There's no definitive way to display an interlaced video source on a progressive scan display without the potential for combing.

As for source that was originally progressive but was stored as interlaced video (e.g. cheap DVD movies made from a tape master rather than a new film telecine), if it's flagged correctly, it'll play correctly. Handling of improperly-flagged material should be a secondary consideration at best.

Note also that, on some hardware, Apple DVD Player 4 does have a deinterlacing filter. I would hardly call Apple DVD Player and VLC "low end". They both do good jobs at playback. (VLC's wonky interface notwithstanding.)

tooki

[production_coordinator]

El Gato EyeHome.. WAY over your budget of free, but works like a charm!

[Spoffo]

So, Tooki, educate me (seriously).

My perspective on DVD playback is much more from a home theater perspective, and from that perspective, the performance of the Apple player is pretty unimpressive. When I play back a good commercial DVD on the Mac (yes, using DVD Player 4.0) the feature itself, which has obviously been carefully mastered from film or, occasionally, 24 fps video, looks decent. However, most of the "extras", many of which were obviously shot on tape, comb like crazy . . . continuously . . . . on any sort of horizontal motion. This result is the same whether I'm watching on my ancient G3 PowerBook or my dual G5 tower.

These same segments, when played over my plasma from a Panasonic XP-50 player, which has a Foroudja DCDI de-interlacing chip, show essentially no visible combing . . . at most an occasional instantaneous comb on a cut.

Thus, my conclusion that the Apple player is hard wired to smoothly de-interlace film (which everyone says is by far the easier job because of the 3:2 repeated fields) but that on video, it doesn't even try. To my eye, it certainly looks like it's "de-interlacing" by just slapping every 2 video fields together to make a frame, jaggies and all. Or, viewed another way, to me it acts like it's designed to treat all DVD material as being film-based wihout reading flags, cadences or anything else.

My other conclusion is that when you read about the kinds of sophisticated, multiple algorithms that a chip like the Faroudja applies to produce a sharp, un-combed progressive image from 30fps video, this isn't surprising. My uneducated guess is that - patents aside - duplicating this kind of motion-adaptive video de-interlacing in software (in real time!) would be challenging on the biggest Mac.

So, seriously, I'd like to know where my line of reasoning jumps off the track.

[chefpastry]

Originally Posted by SirCastor

I'm on a G4 sawtooth. I've got a FW digital/analog bridge. I'd really really like to setup my mac to play my DVDs out to my TV. I don't know how to do this though. I've looked and looked and can't seem to find it even addressed. Can I do this? and how?

Back to your original question. I noticed that you have a Radeon 8500. Just plug an S-Video cable in to it and the other end of the cable to your TV and you'll be able to watch DVDs on your TV.

[SirCastor]

Originally Posted by chefpastry

Back to your original question. I noticed that you have a Radeon 8500. Just plug an S-Video cable in to it and the other end of the cable to your TV and you'll be able to watch DVDs on your TV.

That's an excellent solution, unfortunately, the TV doesn't match it. It was made sometime in the late 70's early 80's, sporting VHF and UHF connections. I'm pulling cable in through the VCR as the television doesn't handling the tuning. On a close not, if I can find a cable that'll go for s-video to RCA, I could do that... I thought i had one, but it may be back at my parent's house. That's unfortunately two states away. I'll check at thanksgiving.

[Uncle Skeleton]

Apple sells one for $20. Also powerbooks come with them.

[chefpastry]

I made several S-Video to Composite cables a while back when they used to cost an arm and a leg. If you have spare cables around and are comfortable with a soldering iron, it's pretty easy to do. Check the following link for direction.

http://www.epanorama.net/circuits/svideo2cvideo.html

[SirCastor]

Excellent chefpastry, Thanks!
Thanks to you too Skeleton, I just realized that my powerbook does have a monitor out to RCA. Doesn't do me much good for the tower, but I know where I'm going

Thanks for your ridiculous amount of knowledge as well Tooki.