Skip to main content

    Support

    Offers

BIslander's profile
BIslander
20th Anniversary celebration
1st Like
1st Reply

Problem Solver

 • 

499 Messages

Monday, May 8th, 2023 5:42 PM

Closed

Audio: Auto Detect vs Expert

Highly technical question.   The MLB Network originates in stereo, not 5.1.  When I set my XG1v4 box to Expert, it sends MLB in DD 2.0 and I can apply a surround mode to upmix stereo to 5.1.  But, when set to Auto Detect (DD+), the output is 5.1 with sound in the L/R channels and the other channels all silent.  Since it arrives as 5.1, I cannot upmix it to get sound in the other speakers.   Is that the way Auto Detect is designed to work, trapping a stereo signal in a 5.1 package? 

Meanwhile, YouTube (a largely stereo platform) outputs in 5.1 using the Xfinity app on the X1.  That happens with both audio setings, either Auto Detect or Expert.   With Auto, it's DD+ and with Expert, it's PCM.  But, the actual content is stereo in both cases with sound in the L/R channels and the others silent.   Not optimal if you want to upmix so that there's a center channel and sound in the surrounds.

Question

 • 

Updated 

2 years ago

 • Edited

1.9K

4

Andyr1

Gold Problem Solver

 • 

8K Messages

2 years ago

This is a long-time bug with the XG1v4. For QAM channels, Expert mode will pass on audio as-is. For anything IP-based (IP channels, OnDemand, Cloud DVR, possibly apps), anything that is DD 2.0 or PCM 2.0 will be 'converted' to DD+5.1. Only DD+ will pass on as-is.

4

Andyr1

Gold Problem Solver

 • 

8K Messages

2 years ago

When I first got my XG1v4, it worked properly in Expert mode. It changed at some point after an update. For awhile, even QAM channels were doing that. Basically, that show on FS1 is probably only sending a basic PCM 2.0 or DD 2.0 audio feed. The XG1v4, for some stupid reason, converts it to DD+5.1, but only fills the left and right channels. As you have found out, most AV receivers will not apply any surround processing to anything with more than 2 channels. Since it thinks it's getting 5.1, it does nothing and passes it on as-is.

0

0

BIslander

Problem Solver

 • 

499 Messages

2 years ago

It would be good if Xfinity support weighed in here.  

6

0

XfinityChristy

Official Employee

 • 

2K Messages

@BIslander  I see you already know about the auto-detect and expert mode settings. With these settings updated, you're receiving the audio provided with the broadcast. However, if you would like to read more about using Dolby ATMOS with X1 you can do so here: https://www.xfinity.com/support/articles/dolby-atmos-x1 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

2 years ago

0

BIslander

Problem Solver

 • 

499 Messages

@XfinityChristy​ I am hoping you can address the odd behavior described in the initial post where stereo content can get trapped in a 5.1 output with most channels silent.  How should Expert and Auto Detect work with various types of audio encodes from the providers? 

As for Atmos, I get it just fine from third party apps accessed through X1.

2 years ago

0

XfinityChelseaB

Official Employee

 • 

1.6K Messages

@BIslander, We would like to investigate this further. If you could send our team a direct message with your full name, the name listed on the account (if different), and the service address associated with your account, I'd be more than happy to look into this for you.

 

To send a Direct Message, please click on the chat icon in the top-right corner of the screen, next to the bell icon, and then type or select "Xfinity Support" to initiate a direct message.

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

2 years ago

0

BIslander

Problem Solver

 • 

499 Messages

2 years ago

0

BIslander

Problem Solver

 • 

499 Messages

Well, direct messaging didn't lead anywhere useful.  The support people simply said Expert provides the best available Dolby sound.  Oh well.  

2 years ago

Rustyben

Expert

 • 

24.6K Messages

2 years ago

very limited data presented in this thread, but with expert mode, if your sound system/bar shows it is a digital audio stream (like dolby) your received stream is unchanged from the production facility (audio mixer board/editor) to your 'sink' (audio equipment). AAC is just a container (like a box) that only contains a data stream. Presuming your equipment is decoding properly, you are seeing a stream as 'made' or created. If no center audio is added there can't be any recreated center speaker audio. edit: If you are watching a DVR of the program, and it is from the cloud DVR, it is only in left/right stereo.

(edited)

2

0

BIslander

Problem Solver

 • 

499 Messages

@Rustyben​ Thanks, but as noted in the initial post, that is not what always happens, which is why I posed the question.   YouTube content is almost exclusively stereo and many platforms send it as DD+ 2.O.  My XG1v4 outputs it as 5.1 with L/R the only active channels. Expert sends it as PCM while Auto Detect sends a DD+ encode. 

Clearly, Expert is not simply sending the stream "as made, unchanged from the production facility".  It would be great if Xfinity would explain what is actually going on! 

I would add that the on-screen description of Expert Mode says, "The best available Dolby sound will be passed through to your audio system."  So, why does this mode on the XG1v4 send YouTube as 5.1 PCM with the only actual sound in L/R?

(edited)

2 years ago

forum icon

New to the Community?

Start Here