PS3-Linear PCM vs. Bitstream--DTS Problem

[GQSioux]

I have a frustrating problem that I think I have resolved but first I want to make sure I have my info straight and that I am not being jipped of some sound quality.

I have my PS3 connected to my Panasonic SC-PT670 surround sound system via optical. From what I gather, setting the PS3 optical output to BITSTREAM is best when using Optical. After setting up my new Panasonic sound system I of course did a test. Dolby Digital sounds absolutely amazing!! Just to be sure, I switched to Linear PCM and tried a BluRay with Dolby 5.1, and while it sounded good, it wasnt as strong. It had to be turned up about 5 notches in volume to sound similar to what I got with bitstream. So my conclusion there, Bitstream all the way.

Things struck a blow when I tried DTS (keep in mind I'm still set to Bitstream). I switched to the DTS soundtrack of "Terminator 2" and there was zero sound. Turns out the Panasonic PT670, even though it says it can decode DTS, CANNOT decode DTS from an external source via optical! It only decodes DTS when you use it's built in DVD player. VERY misleading. I felt super jipped. I thought all hope was lost until I tried one other thing. For the heck of it, I switched to Linear PCM, and guess what? Sound came out of my Panasonic sound system! Not as powerful as the Dolby with Bitstream, but it was working (fyi: there was no DTS logo showing up on the receiver). So basically, my sound system will only let me heat a Blu-Ray with DTS while on Linear PCM. So the conclusion to my set up is, leave it on bitstream and try to use Dolby when I can. Sadly, not all Blu-rays come with Dolby, some are strictly DTS like The Bourne series and My Bloody Valentine 3-D. If I ever encounter a DTS only Blu-ray, I guess I have to switch my PS3 optical out setting back to Linear PCM. So that is my final question I'm hoping someone hear can tell me before I take back my Panasonic sound system. Obviously, toggling back and forth between bitstream and Linear is a pain and since my receiver can't decode DTS, I have no choice. When I switch to linear PCM for DTS Blu-rays, is what I am hearing a major step down in quality? It is not true DTS since no DTS logo is registering on the receiver? It doesnt sound bad to me, its just that I do have to turn the volume up slightly more than I would with Dolby/Bitstream.

 

[Uridium]

you are still getting the DTS audio with PCM. Just that the PS3 is decoding the DTS instead of the AMP.

btw what you've discovered is very common. Panasonic has been misleading customers with the 'DTS from internal DVD player only' for many years now.

Personally I'd take it back on principal.

 

[GQSioux]

But am I losing anything though? I mean, when the Dolby goes through my receiver via Bitstream, the Dolby logo shows up which confirms its registering. Obviously, since my receiver can't decode external DTS, I switch it to Linear PCM for DTS to work, but no DTS logo pops up on the receiver. Does that mean it's not true, full-blown DTS? Or is it basically the same except I have to turn the volume up a bit more?

 

[Uridium]

But am I losing anything though? I mean, when the Dolby goes through my receiver via Bitstream, the Dolby logo shows up which confirms its registering. Obviously, since my receiver can't decode external DTS, I switch it to Linear PCM for DTS to work, but no DTS logo pops up on the receiver. Does that mean it's not true, full-blown DTS? Or is it basically the same except I have to turn the volume up a bit more?

As i said it's EXACTLY the same. The DTS audio is compressed (like a zip file) on the DVD/Bluray. Something has to decompress this for you to hear it.

Bitstream means the PS3 is sending the DTS audio still compressed to your amp for it to do the decoding (unzipping)

Bitstream means the PS3 is doing the decoding (unzipping) and sending the audio uncompressed to your amp tooutput to your speakers.

Would appear that the volume level on internaly decoded DTS on your amp is slightly higher that's all.

 

[GQSioux]

so how about this, I put on the display while I was switching back and forth between DTS on PCM and Dolby while on Bitstream---

With Dolby, it said 48, kHz 640 kbps

with DTS on PCM, it said 48 kHz, 6 kbps (it was moving back and forth between 5.9-6 kbps)

So that's my concern.. whats up with the 640 kbps versus the 6 kbps?

 

[Uridium]

so how about this, I put on the display while I was switching back and forth between DTS on PCM and Dolby while on Bitstream---

With Dolby, it said 48, kHz 640 kbps

with DTS on PCM, it said 48 kHz, 6 kbps (it was moving back and forth between 5.9-6 kbps)

So that's my concern.. whats up with the 640 kbps versus the 6 kbps?

640k is AC3 standard so that's what I'd expect to see over bitstream.

Just re-read your first post though and you did say you are using optical aren't you, sorry i missed that.

I'm pretty sure from memory that the PS3 will only output 2ch PCM audio over optical due to limitations in optical bandwidth. This would explain the lower bitrate. If you had a HDMI input on your panny system you would be ok as the PS3 will do 5.1 PCM over HDMI.

Your problem really is the Panasonic system not accepting DTS from external sources. Panasonic are the only company who do this and need to stop.

Your only real option is to live with 2ch audio from DTS or change the system I'm afraid.

 

[GQSioux]

You are right, PS3 only handles 2 CH. So, is the PS3 cramming all 5.1 channels of the DTS soundtrack into 2 channels and my receiver is just resplitting all the sounds to the 5.1 system, therefore giving me a faux 5.1 sound???

So basically, how much am I losing when I'm only getting 2 CH Linear PCM? Is it really that huge of a loss? I know everyone says let your ears be the judge. It doesnt sound bad, the volume is definitely lower. I'm just annoyed that I am not getting the full, true DTS, thanks to Panasonic. I guess it's like comparing a 128 kbps mp3 to a 320 kbps mp3. Some people can care less, others can hear a difference.

 

[Uridium]

You are right, PS3 only handles 2 CH. So, is the PS3 cramming all 5.1 channels of the DTS soundtrack into 2 channels and my receiver is just resplitting all the sounds to the 5.1 system, therefore giving me a faux 5.1 sound???

So basically, how much am I losing when I'm only getting 2 CH Linear PCM? Is it really that huge of a loss? I know everyone says let your ears be the judge. It doesnt sound bad, the volume is definitely lower. I'm just annoyed that I am not getting the full, true DTS, thanks to Panasonic. I guess it's like comparing a 128 kbps mp3 to a 320 kbps mp3. Some people can care less, others can hear a difference.

Down to your ears i guess but i know the difference between proper DTS/AC3 and ProLogicII on my Onkyo is like chalk and cheese.

I'm guessing the Panasonic doesn't have a HDMI in you could use? As the PS3 will send full multichannel PCM audio over HDMI.

Personally I'd take it back if you stil can.

 

[GQSioux]

I got an idea from the Blu-ray.com forums. There's a thread there dedicated to PS3 and Receiver connections. So my receiver cant decode DTS from an external source via optical. Right now, I have to switch to Linear PCM to hear my DTS blu-rays, which reduces quality to 2 CH. My original question above was how much sound quality am I losing by doing this. Linear PCM + Optical = 2CH, with my receiver set to Pro Logic II, I get a simuated surround.

Someone said that another option is to set it back to Bitstream. Then on my optical output settings, to "uncheck" DTS 5.1--which tells the PS3 that my receiver cant decode DTS. I did that, and presto, I can now hear DTS blu-rays with Bitstream. So this is better, right?? So this is 5.1 as well? The PS3 is coverting DTS 5.1 to PCM 5.1?? That's what they're saying.

 

[Uridium]

when you press select on the Ps3 remote what audio does it say it's playing?

And what does your Panasonic say it's receiving?

The changes you've made will be telling the PS3 to downmix the DTS to somethnig else so I'm intrigued to see what it's actually sending to your amp seeing as Optical can only handle 2.0ch over PCM

 

[GQSioux]

I was hoping that unchecking DTS and leaving Optical set at bitstream would at least send some sort of other 5.1 signal to my receiver. It for sure rids me of having to toggle back and forth with PCM and Bitstream with the triangle button. I can now just leave it on Bitstream.

I had Rambo in, which is a DTS only Blu-ray, and from what I remember (not near my PS3 at the moment), when I press select, it shows DTS 7.1 6 kbps.

As for my receiver, there is no DTS logo lighting up. Just the Dolby Pro Logic II.

 

[Uridium]

I was hoping that unchecking DTS and leaving Optical set at bitstream would at least send some sort of other 5.1 signal to my receiver. It for sure rids me of having to toggle back and forth with PCM and Bitstream with the triangle button. I can now just leave it on Bitstream.

I had Rambo in, which is a DTS only Blu-ray, and from what I remember (not near my PS3 at the moment), when I press select, it shows DTS 7.1 6 kbps.

As for my receiver, there is no DTS logo lighting up. Just the Dolby Pro Logic II.

That tells us a couple of things then.

The low bitrate from the PS3 (DTS 7.1 6 kbps) shows the PS3 is downmixing to just 2.0ch stereo due to the bandwidth limitation of PCM over optical

Secondly the PLII light up on your amp confirms the PS3 is only sending a stereo output and the Panasonic is then converting to pseudo surround using the PLII DSP.