Mac DVD player that can increase playback speed while preserving audio quality?
April 18, 2007 11:43 AM   Subscribe

Is there a Mac DVD player that will allow me to increase the playback speed while not causing the actors to sound like Karen Walker from "Will and Grace" or the resident munchkins from Oz?

I love to watch movies but I don't really have a lot of free time. With my old PC, I used WinDVD, which allowed me to increase the playback speed. Usually, I would watch DVDs at 1.25-1.5 times the regular speed. The great thing about it was that when the speed is increased, the program automatically adjusts the pitch of the voices, so that instead of the voices sounding like chipmunks, they sound just like the actors speaking more quickly.

Is there a similar program that I can download for a Mac? I run OSX Tiger on a MacBook. As far as I can tell, the OSX DVD player (which sucks!) doesn't let me increase playback speed and neither does VLC player. I don't need lots of bells 'n' whistles, only the ability to increase the speed and still get audio. I'm willing to pay under $50.

One other thing: Often when I watch DVDs using the OSX DVD player or VLC player, the program just closes right in the middle of the movie playing. Anybody know why?
posted by HotPatatta to Computers & Internet (15 answers total)
 
In answer to the 'one other thing': this smacks of a problem during the switch from one layer of a DVD to the other (typically halfway through the movie). I can't explain why this would cause a crash though.
posted by spark at 11:57 AM on April 18, 2007


the program automatically adjusts the pitch of the voices

Actually, it's not. When sound speeds up, it becomes higher. You are in fact looking for a program that does adjust pitch. A program like Audacity can do this for sound files (the "Change Tempo without Changing Pitch" effect), but I haven't seen anything for DVD or video playback.


As for the closing half way through: If it really is the middle (or pretty close), it's possible your drive is having issues switching DVD layers. Someone a few days ago had a comment or question about that problem, but I think they needed to replace the drive.
posted by niles at 11:59 AM on April 18, 2007


Actually, I'm an idiot. Ignore the first part of my comment. You know what you're talking about.
posted by niles at 12:00 PM on April 18, 2007


I don't think you'll find what you are looking for. One of the bad sides of the Mac world is Apple's vertical integration makes the 3rd party market for many applications dry up. No one is going to go out of their way to make a better iTunes for the Mac, so you're just stuck with it. The same is true for the DVD player.

Having said all that, adding such a feature to VLC would be great and is probably possible though I am not the guy to do it. Maybe you can drop a feature request to the VLC team somwhere?
posted by chairface at 12:24 PM on April 18, 2007


I thought that VLC does do this ... I would give that a shot, since it's really the only other serious DVD player besides Apple's.

And the crashing-halfway-through sounds like a layer-switching problem. You can try playing a DVD in VLC to see if it still happens (it should in the case of hardware), or try playing a single-layer DVD (there are some, if you Google there are lists) and seeing if the problem doesn't happen.

I kinda suspect hardware, since I don't think that the DVD Player application actually does anything in terms of changing layers; it just interprets the data coming from the drive. If the drive errors, though, the whole system might be choking. (Which should never happen, but it wouldn't be the weirdest thing I've ever heard.)

You can get pretty decent DVD+/-RWs these days for under $50, as long as you get one that works with Apple Disc Burning (hard to tell beforehand, but install it and check Apple System Profiler to be sure -- Pioneer drives are usually good) you can toss it in your Mac and everything should be fine, so a bad drive isn't really even that big a deal. (Although...on a laptop or iMac, it would be worse, come to think of it.)
posted by Kadin2048 at 12:38 PM on April 18, 2007


Bummer. Before I bought my Mac, all I heard was how great they are. "They just work. Period," I always read. From my few months of experience with mine, it's not what they are cracked up to be. Maybe if I needed it for more than DVD watching, email, and word processing, I'd notice a positive difference. But for the casual user, it doesn't seem like it's worth the money to buy a Mac. And the Mac programs suck. The DVD player and Safari are so limited.
posted by HotPatatta at 1:29 PM on April 18, 2007


It's things like this that make me uneasy about all the Mac promotion that's going on these days.
posted by chrismear at 2:18 PM on April 18, 2007


OK, let's clear up the technical issue here.

DVD audio is not stored as a compressed waveform. If it were, then faster playback would cause higher pitch.

DVD audio uses a codec based on the same principle as MP3. Those kinds of codecs take the sound, divide it into brief chunks, and run those through a Fourier transform. What gets stored is the coefficients for the Fourier series which will reproduce the waveform. Only not quite; they don't preserve some information, and that's why the compression is good. Low-amplitude coefficients get dropped, and phase information isn't preserved, because humans can't hear that.

So the reproduced waveform won't look anything like the original if fed into an oscilloscope, but will sound the same to us.

What programs like WinDVD do in speeded playback is to treat the packets as if they're describing shorter time periods. But it continues to use the same base frequency for the fourier series, so what you get is a faster playback without a frequency shift.

It's relatively easy to do this, but it has to be done in the codec decode step. It can't be done as post-processing in a player program. What comes out of the codec is a waveform. The waveform could be played at a higher rate, but that would result in a shift in frequency.
posted by Steven C. Den Beste at 2:38 PM on April 18, 2007


Thanks, Mac Dr. Den Beste.
Can someone else translate that into English for me?
posted by HotPatatta at 2:59 PM on April 18, 2007


He's telling me I'm wrong (which is right) about the details but it doesn't help you much. He's suggesting that the right way to do it is pretty deep in the decoding software so you really need it incorporated into the playback software.
posted by chairface at 4:02 PM on April 18, 2007


HotPatatta, the sound on a DVD is stored as a frequency spectrum, not as a moving wiggle. In that, it's entirely different than a CD or an old style LP, both of which did store and reproduce wiggles.

A spectrum can be thought of as a three-dimensional plot with time on one axis, frequency on another, and the brightness at any point (on a scale of white to gray to black) indicating the amplitude of that frequency at that point in time. Here's an example.

The sound you hear on DVD playback changes because the spectrum changes over time. But if you change the timebase of the spectrum, it doesn't cause any of the frequencies to move up or down. It just changes the duration of the sounds. In other words, what you're doing is to squash or spread the spectrum diagram along the horizontal time axis, without affecting the vertical frequency axis in any way. So it plays faster or slower, but doesn't shift the frequency.

That's what WinDVD on the PC does during rapid playback (or during slow playback, which it also supports). Cyberlink PowerDVD on the PC (my preferred playback program) has the same feature.

But that has to be done during the step which converts the spectrum back into a moving wiggle, which is what has to be sent to the speakers or headphone. That step is in the codec, and if the codec doesn't support that feature then you're screwed.
posted by Steven C. Den Beste at 4:56 PM on April 18, 2007


From what I've gathered, QuickTime has the library routines to do this (for audio, anyway) so I suspect it might be possible for a developer to implement this without 'reinventing the wheel'.

System 10.5 is supposed to have an improved DVD player. Perhaps your wish-list feature will be included.

As far as the current version goes, I've never had a problem with it. The UI is better than the other apps I've used and it's never crashed. The few times I've had a disc so badly-damaged as to be unplayable the DVD app has given an error message (as it should).
posted by D.C. at 5:23 PM on April 18, 2007


This is sort of a roundabout solution, but maybe you could try running WinDVD in Parallels? I'm not sure how well that will work, but you can try a demo for free first. At $70 it's a bit more than you want to pay, but if you're so inclined, there are certainly many other ways to acquire software.
posted by tracert at 5:24 PM on April 18, 2007


$70 $80

Opps, my apologies.
posted by tracert at 5:30 PM on April 18, 2007


I'm not helping, but I gotta say I looove the 1.4x playback (with audio) feature on my PVR (a Pioneer 533). Speech is just barely intelligible, so it's perfect for the languid PBS documentaries that I frequently watch but don't want to invest the full 55 minutes in.

And to confirm the feasibility of it all ... Since PVRs/DVRs use precisely the same encoding technology as DVDs, there certainly should be software out there that can do this. All it does is skip frames and play back the unskipped frames normally.
posted by intermod at 7:50 PM on April 18, 2007


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