Blu-ray 5.1 Sound Not Playing in Surround

[Brandonloshe]

I am working on an Encore project with Dolby Digital 5.1 surround sound. I have a DVD and Blu-ray made. Both have 5.1 surround sound. My issue is that the Blu-ray is being down-mixed to stereo, but the DVD plays fine on the same sound system. Why is that? The sound system confirms that there are 5.1 channels present at 640 kbps when I hit the "info button on the remote." The only difference between the DVD audio and the Blu-ray audio is the extra option that I have to select for the Blu-ray export settings in Premiere Pro (which I selected "Blu-ray-compliant primary stream"), and the bitrate. Through long trials and error with Encore, I learned Encore will transcode (and of course, down-mix) anything above 448 kbps for DVD. BUT, for Blu-ray, having the audio all the way maxed to 640 seems to be fine with Encore. At least I get the desired "Don't Transcode" status. Could the higher bitrate that I am using for the Blu-ray audio be the problem? Or why else would the Blu-ray disk's surround mix be down-mixed to stereo? Any help is greatly appreciated!

[Richard M Knight]

I would try at a lower bit rate. I have never used 640 as all my discs are sold as a Bluray/DVD package so I use the highest dvd rate for both masters. I have never had your 'stereo' problem

[Brandonloshe]

Ok, thanks for your response. I'll give that a try and report back whether or not it worked.

[Brandonloshe]

Hi Richard, just for clarification, your projects have been in 5.1 with 448 kbps, correct?

[Richard M Knight]

This is one of my AC3 masters.

[Brandonloshe]

Still no luck. The surround is still being down-mixed to stereo. But when I hit the "Info" button, it does say 5.1 at 448 kbps. Any other thoughts? Do you have .ac3 export settings out of Premiere?

[neil wilkes]

I do not use Encore but I have to ask - what other options do you have for your downmix settings please?

I see the metadata is set to prefer stereo downmix.....

640kbps is out of spec for DVD (although fine for Blu-ray) and although some players will handle it most will not - for DVD you should not go above 448kbps but as this did not sort the problem I do wonder about the metadata.

Is it the same player for both DVD & BD? Can you check on a different playback system to eliminate the player as the problem?

[Brandonloshe]

Thanks for your reply Neil. Perhaps I should mark this as solved, but I still never figured out entirely everything. Here is what I found, though: The only Blu-ray player connected to a 5.1 system that I had access to at the time played the DVD at 448kbps perfectly the way it was  supposed to in 5.1. That same player played the BD also at 448kbps only as stereo. But when I hit "Info," on the blu-ray player remote, it would show the correct metadata (5.1 and 448kbps). I never did solve this problem on this player.

Finally, I bought an USB blu-ray drive to connect to my MacBook Pro. I then played the Blu-ray disk (which is a real pain to do on an apple computer), and outputted the audio via HDMI. This allowed me to connect to several different 5.1 systems with just my laptop and portable Blu-ray drive. Going this route consistently worked.

So in conclusion, I believe that I did everything correct after all. My best guess is that there is just something wrong between the first Blu-ray player → receiver combo that I tried. At least that's what I tell myself to help me sleep at night and put the project to rest.

[neil wilkes · Accepted solution]

It is almost certainly the firmware/player setup in the initial player at fault here,

What happens when these things are sent out from the factory is the default settings in every player are minimal options that will get sound & picture up on as wide a range of systems as possible - the idea is that you then tweak the player options to match your needs.

As this is a Blu-ray player it will almost certainly be set to basic mode - stereo output. Why? Because there are so many ways to connect the audio system:

1 - Analogue Stereo

2 - Analogue Surround

3 - HDMI Digital

4 - CoAxial Digital

5 - Lightpipe/TOSlink/ADAT digital (all the same).

Because of the complex situation with audio on Blu-ray, the older options (4 & 5) are restricted and usually option 3 is set to stereo downmix mode - or the amplifier is set to stereo downmix mode (unlikely). This is simply because there are weird mandatory audio setups (almost everything about Blu-ray is over complicated - it is the epitome of why you should never design media formats by committee) so we have the following mandatory forms (by Mandatory, every player must be capable of this output)

A - PCM at up to 24/192 in 5.1 and up to 7.1 in 24/96.

B - Dolby True HD (Stereo component only - Mandatory Multichannel configuration with Dolby True HD is the AC3 (Dolby Digital) core audio stream and the full 5.1/7.1 lossless output is optionally supported only ("optionally supported" means it is up to the hardware manufacturer to decide of they want this ON or OFF)

C - DTS-HD Master Audio (Stereo component only - mandatory part is the DTS Core Audio, lossless multichannel is optionally supported)

D - Dolby Digital (24/48 resolution) at up to 640kbps

E - DTS Core Audio.

All the rest is optional. So it is quite possible to play a disc, have the Dolby True HD light (or the DTS-HD Master Audio) and actually be getting lossy audio.

Additionally, lossless multichannel cannot be output down the so-called "legacy" digital connections (options 4 & 5 above) because the upper resolutions cannot go down these connections as there is insufficient bandwidth - down these connections you can get 24/48 5.1 at best, possibly 24/48 7.1 but I am not sure there. So all are restricted rather than just allowing only 16/24 bit at 48kHz and restricting the rest as that would be almost impossible to pull off. That said, some consoles will automatically resample and/or truncate the bitrate & shoe-horn it into a degraded output.

Check the audio setup in the old player, and make sure it is not set to downmix to stereo.

[neil wilkes]

Sadly, Blu-ray is constantly undergoing changes all the time and even worse than this no 2 players are going to work in the same way because of the bewildering amount of stuff that is not mandatory and either optional (which in short means "if we can be bothered to include it") or simply ignored altogether.

So the odds on your player/amp combo being at fault is alarmingly high. There are many possible places where the problem could be, so let's run through some of them for you to try:

1 - Flawed player firmware.

This is the most common source of trouble, as all players are basically cut-down PC's with an enormous range of possible hardware - memory installed can go from the spec minimum (which varies according to the player profile, sadly) to almost none at all unless you have a USB drive attached to the system, and even on more expensive models (A Pioneer Elite we ran across once not only had no memory installed, but it's manual went on to say that USB support was on a best effort basis, operation was not guaranteed and not all devices would even work at all - yet this is a $300 player).  Another issue under "Firmware" is that far too many manufacturers simply obsolete a player when firmware iissues are found instead of fixing the player bug and updating the firmware (which is the players Operating System when you get right down to it)

2 - Format not supported, or partly supported.

3 - Your Audio connection itself. 

Optical (aka TOSlink or ADAT or lightpipe) and CoAxial connections are considered as "legacy" connections, and a good number of players will simply not output surround at all over these connections because you cannot get 5.1 channels of 24/192 or 7.1 channels of 24/96 down them, so what happens is that with very few exceptions (PS3/PS4 actually will output lossless surround over lightpipe but I suspect they degrade it before doing so) you just won't get surround down those legacy connections as it is usually disabled unless outputting over HDMI or analogue. It certainly won't work if your player is set to output lossless (decoding in the player).

The 2 main codecs - DTS-HD Master Audio & Dolby True HD - are what is called "mandatory" codec support but what you won't get told by sales blurb is that the mandatory part is actually stereo, not surround. Most players will output DTS-HD Master Audio and Dolby True HD, but because there are also hidden "core audio" streams embedded in these streams you can have the lossless lights up but actually be hearing AC3 or DTS Core Audio as well.

The best rule of thumb is to never use legacy audio connections.