Digital passthrough not working for me

Could someone please help?

I have a Sony STR-SL7 receiver which supports Dolby Pro Logic, DTS, and Dolby Digital. I have it hooked up to a Samsung LCD and the Hub (HDMI). I’m trying to watch a movie that has DTS audio… but digital passthrough doesn’t work. Stereo works just fine, but there’s a problem with the digital handshake I guess? The passthrough works just fine with my Cable DVR box. Any suggestions would be appreciated

Hmmm.    It’s not beyond the realm of possibility, as audio capabilities ARE part of the EDID handshake, but I don’t think the Hub pays any attention to it.   

At least, I don’t think I’ve heard anyone else narrow it down to that…  

What format is your movie, and exactly what flavor of DTS is it?

I’ll post later about the type of format. can’t check right now… but I did get it to work by plugging in the optical direct to the Hub from the receiver. Now it works great and picks it up correctly as DTS.  So direct optical works but passthrough via HDMI doesn’t seem to work.  I’ll try other formats later and see if its universal or format specific.

Make sure your AVR is configured to pick up the audio on HDMI.   


The passthrough via HDMI works fine if I do Stereo in the Hub audio options, so I don’t think it’s a configuration problem.It’s only when I select ‘digital pass through’ that it doesn’t work. If I plug in optical straight to the Hub and choose ‘digital pass through via optical’ then the digital audio works fine.

I tested two files. One was M2TS file with:

ID                               : 4352 (0x1100)
Menu ID                          : 1 (0x1)
Format                           : AC-3
Format/Info                      : Audio Coding 3
Duration                         : 1h 37mn
Bit rate mode                    : Constant
Bit rate                         : 640 Kbps
Channel(s)                       : 6 channels
Channel positions                : Front: L C R, Surround: L R, LFE
Sampling rate                    : 48.0 KHz
Stream size                      : 447 MiB (11%)
Language                         : English

The other is an MKV file with:

ID                               : 2
Format                           : DTS
Format/Info                      : Digital Theater Systems
Codec ID                         : A_DTS
Duration                         : 2h 2mn
Bit rate mode                    : Constant
Bit rate                         : 1 510 Kbps
Channel(s)                       : 6 channels
Channel positions                : Front: L C R, Surround: L R, LFE
Sampling rate                    : 48.0 KHz
Resolution                       : 24 bits
Stream size                      : 1.29 GiB (18%)
Language                         : English

Could it still be a configuration problem if Stereo works but Digital Passthrough doesn’t?  I would think that the differentiation would be automatic?

hmmm. So it’s not just DTS that’s broken, it’s also DD5.1, huh. Does your AVR give any indication of receiving ANY audio?

Quite honestly I think it’s that my TV doesn’t pass through digital audio. That’s the easiest explanation… It’s a Samsung T4671F which I’d say came out around 3 years ago. It’s not new, but it’s certainly not antique. If this is the case then I am surprised. But if others have no such issues passing through with other TVs then I guess this is the simplest explanation. 

Could you confirm how you’ve got this wired up?

Reading through, it sounds like the following:

Hub >  TV > AVR ?

Which is a weird way of doing it; my 2 year old Panasonic plasma can’t pass through digital audio like that…  

It makes more sense to plug all your media devices into the AVR and then have one HDMI cable running to your TV.

I just thought it could be done through TV. What is digital passthrough for if not to pass it through the TV? 

Ahhh…   Now we’re getting somewhere.

Digital Passthrough means that it’s passing through the ORIGINAL stream through the HUB (or the DTS core, depending) unmodified, whereas “Stereo” does a complete decode of the stream and downmixes it to 2 channel PCM, or sometimes AC3-2.0.

Yes, not too many TV’s I’m aware of do their own passthrough of multichannel audio.  :)

mzaur wrote:

I just thought it could be done through TV. What is digital passthrough for if not to pass it through the TV? 

My Panasonic TV will pass-through 2ch digital audio (outputs via optical).  Like Tony says, it’s just the multi-channel signal that it can’t cope with.  :)

Hi, I think you have the same problem i postet some weeks ago.

In firmware 1.02.21 the digital passthrough with my  LG-TV works fine . with all 1.03… Beta´s i only get Stereo.

Is it possible that you test 1.02.21 on you´re WDTV ?.

It must be an error in the firmware because i have the same problems with my digital satreceiver. One firmware brings passthrough 5.1, amnother firmware brings only stereo. (also the same problems with Xbox360 and Sony BDP S370)

The Panasonic manual states that my TV is only capable of passing through 2.0 via the optical output.  I’ve never noticed a difference between the firmwares because that limitation makes it useless.  My setup is:

Hub (or Live) Optical Out > Pioneer 5.1 amp 

Hub (or Live) HDMI > Panasonic 1080p TV

Maybe someone with a newer TV capable of handling digital passthrough of encoded multichannel audio can test your theory out…  there have certainly been a LOT of changes made to the HDMI module in all the Live beta firmwares and it’s possible (or even likely) they’ve broken something else along the way.  

I have a new Samsung LED LCD TV, which has an Optical Digital Audio output.  I’ve learned that if the source device (in my case, an HD cable box) is connected to the TV via HDMI, the Digital Audio out from the TV does NOT pass 5.1 audio; only passes PCM audio.  Frustrating part is that the cable box itself does not pass 5.1 channel audio through it’s Digital Audio Out connections if connected to the TV via HDMI; it DOES pass 5.1 if connected to the TV via Component video.  All sounds rather illogical to me…

Does anyone know whether the WD TV Live Plus will pass 5.1 channel audio from it’s Digital Audio output, if using HDMI to connect to the TV?  My 5.1 receiver does not have HDMI inputs.



Cactus, Welcome to the forums.

Yes it does do this, but many people report problems with Audio / Video Sync.  

It’s very common for the AUDIO to be presented ahead of the VIDEO, since the TV takes a substantial amount of time to decode VIDEO, whereas the Receiver takes very little time to decode AUDIO.

If your AVR has the capability of adding DELAY, then that may not be a problem for you.

Thanks, “Propeller Head”.  My receiver does not have that capability, but hopefully, the issue will not be too evident.  I’ve not seen it on my previous HD TV, but it was connected to my cable box and to my DVD player via Component video.  Don’t know if HDMI would be worse, since it’s carrying a higher resolution (old TV was 720P max.).  But then, this is a new, “state of the art” Samsung TV, so perhaps it’s better at decoding the video.


I have seen people reporting sync issues, but what I can tell you is this…

If the audio is connected by optical to the receiver, the receiver would have to handle any delay… if the audio is connected by HDMI, the HDMI signal is supposed to have delay instructions in the stream, so that things stay in sync.