HD Advisor: Episode IV - A New Hope

Posted Fri Feb 27, 2009 at 11:45 AM PST by

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Answers by Joshua Zyber

HD Audio

Q: I've got a Yamaha RX-V1800 receiver which is compatible with the high-end audio formats for Blu-ray and HD DVD such as Dolby TrueHD and DTS-HD Master Audio. Now when I put in an HD DVD or Blu-ray and select the audio output in the movie menus, on the receiver it only displays Dolby Digital on the receiver instead of Dolby Digital Plus or DTS-HD. I was wondering if the audio was being output in the best way possible or if there was a specific thing that I need to do in order for it to actually output the audio in one of the advanced formats? Thanks for any kind of help.

A: First, let's make sure you've connected your disc players to the receiver in the most optimal fashion. If you're using either Coax digital or Toslink optical S/PDIF cables, those will not carry a high-resolution audio signal from any of the new Blu-ray (or HD DVD) audio formats. With those connection types, your audio will automatically be downgraded to standard Dolby Digital or DTS 5.1 formats.

Ideally, you want to use an HDMI connection from your Blu-ray/HD DVD player to the receiver. Once you've done that, you should go into each disc player's Setup menu and set the Audio options to output a native "Bitstream" audio signal. On certain Blu-ray players, you may also need to turn off any "Secondary Audio" options. At that point, your receiver should be able to receive the full Dolby TrueHD or DTS-HD Master Audio formats.

Of course, that assumes that your disc players will support native bitstream transmission of the high-res audio formats. Unfortunately, not all do. You'll have to consult the owner's manual for each unit.

Some Blu-ray or HD DVD players will decode TrueHD and DTS-HD internally. In that case, they'll convert the compressed codecs to Linear PCM and your receiver should indicate that it has received a multi-channel LPCM signal.

See my earlier Blu-ray and HD DVD Audio Explained article for more details.

More HD Audio

Q: I have a new receiver that supports all new digital sound types (TrueHD, 7.1, DTS-HD, etc.). I am running HDMI from my PS3 which I use for my Blu-ray playback. I looked online to which setting for sound I should set my PS3 up for. I settled on Bitstream because my receiver reads that it is playing in Dolby digital, etc. When I'm using Linear PCM as my sound setting for HDMI the display reads linear 2/0 etc. as the sound playback. I am confused to which one is more accurate for my current set up. Bitstream sounds better to me but a lot of people seem to suggest Linear.

A: Although this may at first seem to contradict what I wrote in the question above, if you've connected the Playstation 3 to a receiver by HDMI, you should set the PS3 for Linear PCM output. The PS3 is one of those Blu-ray players not capable of transmitting the high-resolution audio formats like Dolby TrueHD and DTS-HD Master Audio in native bitstream form. If you set the PS3's audio output for "Bitstream," it will downgrade each codec to standard Dolby Digital or DTS 5.1. However, the PS3 can decode these audio formats internally. Once it does that, it will output them as LPCM 5.1. There should be no loss in quality doing so.

TrueHD vs. Master Audio vs. PCM

Q: I have a Yamaha RX-V661 receiver with the Sony BDP-S550 hooked up via HDMI, and I notice all over the net that all of the new audio codecs: DTS-HD MASTER AUDIO, DOLBY TRUE HD, AND PCM are all bit-for-bit identical to the studio master. My question is: How come I can tell an audible different between all three? My Blu-ray player has the codecs and my receiver converts them to PCM; however all movies I've watched encoded with PCM sound aggressive (i.e. Black Hawk Down), all movies with DTS-HD MASTER AUDIO sound crystal clear, like shattered glass (i.e. Kingdom of Heaven), and all DOLBY TRUE HD tracks sound airy, spacious like (i.e. Spider-Man 2). Also, my receiver is properly calibrated to Digital Video Essentials and on each of those respective audio tracks, I have to turn the volume to different levels for reference: PCM I don't have to turn up as loud as DTS-HD MASTER AUDIO and I don't have to turn that up as loud as DOLBY TRUE HD. Why is this?

A: The short answer to your question is that 'Black Hawk Down' is not the same movie as 'Kingdom of Heaven', and neither one is the same movie as 'Spider-Man 2'. These are all different movies with different sound mixes. You can't compare the sound mixes of different movies and draw meaningful conclusions about the audio formats they're encoded with. It's an apples-to-oranges comparison.

The volume discrepancies you've noted can be the result of several different factors. First, again, not all soundtracks are the same as one another. Some are just mixed louder than others. Second, many Dolby tracks apply Dialogue Normalization, which will adjust the default volume across different movies to set a baseline where all dialogue is approximately the same loudness. This often results in Dolby tracks starting at a lower default level than other formats. On the other hand, DTS likes to crank the volume of their tracks up, because most listeners associate louder with better.

Louder is not better. It's just louder. Once you volume-match them, there are no inherent qualitative differences between any of the lossless or uncompressed audio formats.

I covered these issues in a little more depth in my Uncompressed vs. Lossless Audio article.


Q: Have any discs utilized the "Subtitle Styles" feature I've noticed in the onscreen PS3 menu? It would be nice to make them smaller sometimes, or to move them around.

A: As I recall, Sony experimented with this feature on their Blu-ray release of 'Immortal Beloved'. The implementation there offered the choice of positioning the subtitles either in the lower letterbox bar or on top of the 2.35:1 video image. The studio may have done this with one or two other titles as well, but soon discontinued the experiment and went back to their previous policy of placing one line of subtitles in the movie image and one below.

Speaking as the owner of a 2.35:1 projection screen, I really wish more studios would make use of this feature. As I explained in my Memo to the Studios article a while back, there's nothing more infuriating than trying to watch a foreign-language 2.35:1 movie on a 2.35:1 screen and finding out that the subtitles are cropped off because the studio put them in the lower letterbox bar.


Q: That is a very comprehensive review on the Toshiba HD-XA2 HD DVD player -- especially with your firmware addendums as Toshiba released new versions. A quick question about 24fps. It turns out that my Samsung HL67A750 DLP TV, although capable of accepting a 24 Hz signal and is claimed to be 120 Hz, converts the signal back to 60 Hz. In your testing would you say that the would be the better device to do the 3:2 pulldown rather than the TV?

A: For the benefit of other readers, I'll start with a link to my What's the Big Deal About 1080p24? article that explains the basic concepts of 3:2 Pulldown and 24 fps video playback.

I'm not familiar with that particular model. If your HDTV doesn't support a 24 fps playback rate, the native 24 fps video signal encoded on a Blu-ray disc (or HD DVD, in your case) must be converted to 60 Hz by the addition of 3:2 Pulldown. In theory, it shouldn't matter whether that happens inside the disc player or in your TV. All things considered, I think you're better off doing it as close to the source as possible. I'd recommend setting the player for the standard "1080p" mode without 24 fps.

This will have other practical benefits in the Toshiba HD-XA2 specifically. The way that player was designed, turning on the 24 fps mode automatically converts all video content to 1080p24, whether it was natively encoded on disc at that rate or not. That means any Standard-Def NTSC bonus features on a disc and any regular DVD discs will all be frame rate converted to 24 fps. If the video wasn't shot that way to begin with (most bonus features aren't), you'll get a very stuttered and jerky picture. Adding 3:2 Pulldown on top of that won't resolve the problem. It will only make things even worse. You'll really have a much easier time of things by just setting the player to regular 60 Hz playback.

Be sure to check back next week for another round of answers. Keep those questions coming.

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Tags: Joshua Zyber, HD Advisor (all tags)