Posted Fri Oct 2, 2009 at 12:00 PM PDT by Joshua Zyber
Editor's Note: Each Friday, High-Def Digest's own HD Advisor will answer a new round of questions from our readers. If you have home theater questions you need answered, send an email to [email protected]
Answers by Joshua Zyber
PS3 Audio Decoding Revisited
JZ: In a previous column, I wrote that there shouldn't be any difference between decoding Dolby TrueHD or DTS-HD Master Audio in a disc player versus bitstreaming them to an A/V receiver. This led to several follow-up questions from readers, which I will attempt to address together.
Q: I know you must be exhausted with questions about PS3 audio decoding. Let me throw one thought your way. The PS3 doesn’t give a Dialog Normalization flag value for Dolby codecs. This can make life difficult and confusing for enthusiasts who are trying to do soundtrack comparisons, or listen at a common volume. That is why I keep at least one player in bitstream mode.
Q: I'm pretty sure that I read most if not all your posts on the Playstation 3 and bitstreaming, but I notice a huge difference in sound volume with HD audio. I have a Toshiba HD-A35 player and I don't hear drop off in sound volume. Can you help me out?
Q: From recent readings, I saw that the PS3 Slim can pass through Dolby TrueHD and DTS-HD Master Audio via bitstream so an external amp can decode them. I have an old-school brick of a shiny black PS3 that doesn't have this functionality, but this does the decoding of the HD audio on-board, yes? So with decoding taking place at the PS3, is there any real benefit in me upgrading my amp to take advantage of the HD signals, or is the same information already being passed to my current amp?
A: I feel this merits clarifying my previous comments. In essence, the decoding of a lossless compression codec such as Dolby TrueHD or DTS-HD Master Audio should be a straightforward process. You should get identical results whether you perform the decoding in a disc player (such as the PS3) or in an A/V receiver. However, after the decoding is complete, an A/V receiver may offer additional processing that the disc player does not. For example, most Dolby soundtracks are flagged with a Dialogue Normalization value. If the disc player doesn't read the DialNorm flag when decoding, your audio may exit the player louder or softer in volume via decoded PCM than it might via bitstream transmission.
Note that Dialogue Normalization does not alter the quality or fidelity of a soundtrack. All DialNorm does is set a default starting volume for a soundtrack, similar to raising or lowering the volume control on your receiver. This is explained in more depth in my earlier Uncompressed vs. Lossless Audio article. A change in volume is not the same thing as a change in quality. A louder soundtrack is not automatically a better soundtrack. If the DialNorm flag is ignored, you may want to adjust your receiver's volume control a few notches to bring the soundtrack in line with other movies you've watched, but the content of the track will be unchanged. Although some users may find this a minor nuisance, I don't feel that it merits buying all new hardware for.
On the other hand, many A/V receivers can apply ProLogic IIx processing (which will expand a 5.1 soundtrack to 7.1 channels) to a bitstreamed audio signal but not a raw multi-channel PCM signal. The same problem may apply to other optional post-processing functions such as Cinema EQ. In a worst case scenario, some receivers may not be able to perform bass management or speaker level controls. If these are something you'd like or need to use, hardware that will send a bitstreamed audio signal may be beneficial.
Disc Incompatibility Issues / Firmware Updates
Q: Recently I rented a copy of 'Crank 2' through Netflix. When I tried to play it in my Samsung BDP-1500, the movie wouldn't play. I took the disc and played it on the PS3, and it worked perfectly. Will I have to change my player to play the newer movies, or did I just have bad luck?
A: Unfortunately, disc compatibility issues like this continue to crop up on new releases due to the complexity of Blu-ray's ever-changing encryption and BD-Java programming. Just recently, I found that 'X-Men Origins: Wolverine' wouldn't play on two out of my three Blu-ray players.
In most cases, issues like this can be resolved by your Blu-ray player's manufacturer through a firmware update. The first thing you should do is check the current firmware on your player, and then visit the manufacturers' web site to see if there is a more recent firmware. Firmware files can usually be burned to a CD, loaded onto a USB drive, or updated via Ethernet connection. Follow the instructions that the manufacturer provides. If your firmware is up-to-date and the disc still won't play, email the manufacturer a description of the problem (providing the UPC of the disc helps) and ask if they have a solution ready.
Upconverted Standard-Def Content on Blu-ray
Q: 'Star Trek: The Original Series - Season 2' includes a 'Deep Space Nine' episode that I understand is a 1080p upconversion from a 480i master. My concern is that Paramount is testing to see if people will accept this for 'Star Trek: The Next Generation' Blu-ray releases. Let's face it, to scan the original film footage, re-edit, and create new special effects takes time and money. Do you think this is likely?
A: Personally, I don't think there's cause to fear here. That 'Deep Space Nine' episode you reference was included as a bonus feature. It was never intended to be the primary content on the disc.
I discussed the problems with remastering TV series such as 'Star Trek: The Next Generation' and 'Deep Space Nine' for high definition in an earlier column. Because these shows were post-produced on SD video, their final masters currently exist only in standard definition form. To remaster them, the original film elements would need to be re-edited from scratch. It can be done, but as you note, will probably be time-consuming and expensive.
I doubt that Paramount or CBS Home Entertainment have an agenda to release complete season sets of 'TNG' or 'DS9' on Blu-ray in upconverted form. There would be little to no benefit in that for anyone. More likely, the shows will simply not be released on Blu-ray until such time as a full-blown reconstruction and remastering can be performed.
Some questions that the HD Advisor receives are best answered with a consensus of opinions from our readers. If you can help to answer the following question, please post your response in our forum thread linked at the end of this article. Your advice and opinions matter too!
Surge Protector Recommendations
Q: I recently purchased a 46" Samsung LCD HDTV. Upon purchase, the salesperson strongly encouraged me to buy a high-tech surge protector. He told me a horror story about a man who purchased a new TV, and it was "destroyed" by a power surge from a storm. I did not buy the surge protector that was over $100.00. I am currently using a standard $15.00 surge protector that I purchased from Wal-Mart. Is there a legitimate concern in not having a surge protector specialized for HDTVs?
JZ: I highly recommend investing in a good surge protector. However, I don't believe that you necessarily need to buy an expensive (read: overpriced) model sold in the home theater section of the store. On the other hand, a cheap unit may not offer enough protection for your expensive gear. I'll leave this to our other readers to recommend some good, reasonably-priced models.
Check back soon for another round of answers. Keep those questions coming.
Joshua Zyber's opinions are his own and do not necessarily reflect those of this site, its owners or employees.
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