Blu-Ray sound question

Chong Warrior · 16 Dec 2009 at 22:59

Just bought a Sony 360 Blu-Ray player. Playing it on a Panasonic 42" plasma with panasonic home theatre kit connected with optical cable for sound.

Hooked it up with Swordfish and it plays fine but with Terminator Salvation the sound will only work through the theatre kit during the menu's, once the film starts the sounds only works though the TV in stereo. No matter what settings I try it won't work.

What's that about? Do I need some kind of HDDTS amp now just to watch Blu-Ray with half decent sound??

rare · 16 Dec 2009 at 23:56

Someone may shoot me down, but I was under the impression that optical doesnt have sufficient transfer bandwidth for the new HD codecs.

dbmzk1 · 17 Dec 2009 at 00:10

Rare is correct.

Swordfish uses Dolby Digital, hence it works fine.

Terminator Salvation on the other hand uses DTS-HD Master Audio. Good old optical just can't carry that much bandwidth, you will need to use HDMI.

Chris1712 · 17 Dec 2009 at 00:32

dbmzk1 said:
Rare is correct.

Swordfish uses Dolby Digital, hence it works fine.

Terminator Salvation on the other hand uses DTS-HD Master Audio. Good old optical just can't carry that much bandwidth, you will need to use HDMI.

It still has a DTS core which optical will use. How have you the optical connected, from your TV or straight from the Bluray. You want the latter, most TV's either pass out just Stereo, or nothing at all.
You need a lot more licensing to let DTS through stuff than AC3, thats why the WDTVv1 didn't have DTS and most cheapo network machines/tv's don't.

dbmzk1 · 17 Dec 2009 at 01:15

Chris1712 said:
It still has a DTS core which optical will use. How have you the optical connected, from your TV or straight from the Bluray. You want the latter, most TV's either pass out just Stereo, or nothing at all.
You need a lot more licensing to let DTS through stuff than AC3, thats why the WDTVv1 didn't have DTS and most cheapo network machines/tv's don't.

Indeed, but as the decoding is done on the player and because SPDIF can only transmit 2 channel PCM, the chances are due to it being a cheaper player that it will only send a stereo PCM signal, rather than the 5.1 DTS core. Hence if he wants 5.1 on Blu-rays that use DTS-HD MA or Dolby TrueHD he will have to use HDMI.

sswats · 17 Dec 2009 at 11:22

Go through the menus in the bluray player and see if you can set the output to DTS.

probedb · 17 Dec 2009 at 13:21

dbmzk1 said:
Indeed, but as the decoding is done on the player and because SPDIF can only transmit 2 channel PCM, the chances are due to it being a cheaper player that it will only send a stereo PCM signal, rather than the 5.1 DTS core. Hence if he wants 5.1 on Blu-rays that use DTS-HD MA or Dolby TrueHD he will have to use HDMI.

Nope it won't. The core track doesn't have to be decoded, it's just pulled out and sent over S/P-DIF.

I have a PS3 and have never had any problems with audio on BR, DTS-HD MA or otherwise. I just get the core tracks over S/P-DIF every time.

There's generally an option for secondary audio with Blu-Ray which I think allows for mixing of menu sounds and soundtracks etc. If you just have primary audio on it should be ok?

Chris1712 · 17 Dec 2009 at 15:15

dbmzk1 said:
Indeed, but as the decoding is done on the player and because SPDIF can only transmit 2 channel PCM, the chances are due to it being a cheaper player that it will only send a stereo PCM signal, rather than the 5.1 DTS core. Hence if he wants 5.1 on Blu-rays that use DTS-HD MA or Dolby TrueHD he will have to use HDMI.

Unusual for a bluray player to default to decoding and PCM, but it could actually be the problem. Check that your SPDIF (Optical) output is set to Bitstream not PCM.

El_Watcher · 17 Dec 2009 at 16:52

I would also check that the Panasonic audio system can decode DTS. A friend of mine had a similar problem with the PS3 where DD tracks would be fine, but DTS were silent. Basically the Panasonic theatre system would only decode DD from optical in, but would do DTS from a DVD built into the amp.

If this is the case, you may need to see if the player can transcode DTS into Dolby.

Chong Warrior · 17 Dec 2009 at 19:07

My Panasonic theatre kit does decode DTS. I don't understand why it doesn't play any sound at all, even if it could get a stereo signal it could still use Pro-Logic and produce a better sound than my TV's speakers.

Corasik · 17 Dec 2009 at 20:22

dbmzk1 said:
Rare is correct.

Swordfish uses Dolby Digital, hence it works fine.

Terminator Salvation on the other hand uses DTS-HD Master Audio. Good old optical just can't carry that much bandwidth, you will need to use HDMI.

DTS MA includes DTS Core which should be sent over the SP/DIF automatically.

probedb · 18 Dec 2009 at 09:43

Chong Warrior said:
My Panasonic theatre kit does decode DTS. I don't understand why it doesn't play any sound at all, even if it could get a stereo signal it could still use Pro-Logic and produce a better sound than my TV's speakers.

Did you try turning off secondary audio as I advised?

Corasik · 18 Dec 2009 at 09:49

dbmzk1 said:
Indeed, but as the decoding is done on the player and because SPDIF can only transmit 2 channel PCM, the chances are due to it being a cheaper player that it will only send a stereo PCM signal, rather than the 5.1 DTS core. Hence if he wants 5.1 on Blu-rays that use DTS-HD MA or Dolby TrueHD he will have to use HDMI.

Incorrect, as I said if you select bitstream it sill output the DTS Core. DTS is an "extension" system, so ALL DTS movies include a DTS core which is compatible with all DTS recievers. However if you select PCM output, the bluray player will attempt to decode to PCM and send the audio to the HDMI.

There should be a config option in the player to inform it that SP/DIF is the primary output for sound, and it will correctly bitstream the DTS core. DTS doesnt need decoding BTW, the DTS core is stored in every DTS soundtrack, there are then extensions which "upgrade" the DTS core to DTS HD, or DTS/MA. Every bluray player has the ability to simply extract and stream the DTS Core soundtrack from a DTS HD/MA disk.

While its true that SP/Dif does only support 2channel PCM, it does support 5.1 channel compressed bitstream be it Dolby Digital(or DD+), and DTS and DTS96/24. Infact the only grey area is Dolby TrueHD, as occasionally its rumoured that on a few disks the DD+ 640kbps track was accidently skipped (contrary to bluray minimum specification). However I've yet to find a TrueHD disk that wont play back a DD+ version.

Corasik · 18 Dec 2009 at 09:55

For the Sony 360, just go to Setup, Audio, and select Audio Output Priority and select Optical / SP-DIF, then for Dolby Digital make sure Dolby Digital is selected not PCM, and for DTS make sure DTS is selected not PCM. Finally for 2 channel PCM you can pick 48/16 or 96/24 depending on what your amp can handle (mine does 96/24). If the Dolby Digital soundtrack is missing on any disks, it should be able to downmix to 2 channel PCM and your amps Dolby Prologic should kick in.

Chong Warrior · 18 Dec 2009 at 10:28

Cheers for the suggestions. I found the problem. The panasonic home theatre kits aren't capable of decoding DTS over the optical cable, only with a DVD in the drive... which is poor.

I had to change the option for DTS to PCM so it would stop trying to send a DTS signal to down the optical cable. Then it worked

Corasik · 18 Dec 2009 at 10:54

Ahh, thats a silly limitation for a piece of kit with a dts decoder.. I guess the DVD part of the kit does all the decoding, and the amp is more basic. Ah well, at least you can get PCM working