Some Channels/Programs Missing Foreground Audio (1 Viewer)

[rsbrux]

In the last several MP versions I have had problems with missing foreground audio on some channels, or only on certain programs on some channels. That is to say, with the default audio selection, I hear only background audio (e.g. environmental sounds) but no foreground audio (e.g. dialog). In some cases I have been able to get around this by selecting the NAR (narrration) channel instead of the default audio stream, but I now have a case where that is not an option. When I view or record series episodes on ORF 1 HD, the foreground audio is completely missing. Unlike some other channels which have displayed this problem, I also have no options for audio program (see screenshot). I have attached logs and a sample recording as well. I am currently using LAV filters, but have had similar problems in the past using other codecs.
What might be the cause or remedy of this problem?

 

[Owlsroost]

As this is AC3 audio (from your logs and the sample recording) I guess the problem is multi-channel (5.1) audio not being mixed down properly, so the centre (dialogue) channel is missing from the down mix.

What are your LAV Audio Decoder settings ?

What is your speaker layout ?

 

[rsbrux]

@Owlsroost
Thanks for your quick response!

Attached are screenshots of my LAV settings. The areas outlined in red were empty before; I filled them in after you had drawn my attention to the decoder settings. As a result, I can now hear foreground sound over the analog multichannel connection between my media center PC and my receiver, but not over the digital (TOSlink optical) connection, nor via headphones. This is the opposite of what I expected from reading the wiki page.

My speaker layout is classic 5.1 (3 front, 2 rear & LFE), but I often listen to the audio via headphones. In my receiver, these depend on an analog stereo feed, which I could only get to work in parallel with the digital output by using a hack described here. The need for the hack apparently goes back to a change in the structure of the audio stack between Windows XP and Vista, which is discussed in excruciating detail here. I have read about other workarounds, including one using graphedit, but could never get any of them to work. JRiver appears to have solved the problem with their "Zones" feature, presumably by using the graphedit approach.

Anyway, this is kind of a digression. The bottom line is that I now have at least one way of getting foreground audio, thank you! However, I don't get anything via headphones, despite trying a few other configurations.

 

[Owlsroost]

Attached are screenshots of my LAV settings.

@rsbrux - The attachments are missing....

 

[rsbrux]

@rsbrux - The attachments are missing....

Oops - sorry!

 

[Owlsroost]

Since you have both analog and digital connections from PC to audio system, which connection do you use for what ?

What I'm thinking about is decoding all audio in LAV to a 2 front + 2 rear speaker layout (so no bitstreaming, just multi-channel analog, and no output to the centre speaker). That would mix the centre channel into the front L+R outputs, which can then also be used to provide the stereo feed for headphones etc. This provides a 'phantom' centre channel using the front L+R speakers only. Note for this to work effectively the TV needs to be approximately half-way between the front L+R speakers.

I actually use the above scheme myself. I run analog 2 front + 2 rear multi-channel into the AVR, and also feed the same front L+R signals into another stereo input on the AVR for 'zone 2' outputs to another room (which can only come from an analog input on my AVR, which is a real pain because it means I can't get 'zone 2' feeds from the HDMI inputs....)

 

[rsbrux]

@Owlsroost
Thanks again for the prompt feedback! It does sound as if we have similar situations.
I use the digital (TOSlink, not HDMI) output from the HTPC for my regular speaker output. I need the analog output from the HTPC for my receiver's Zone 2, which is what feeds my headphones. My receiver also supports only analog for Zone 2, not digital. I originally had a 4.1 setup similar to what you describe, but never succeeded in getting the phantom center you describe, so I finally broke down and bought a center speaker. However, I do prefer the digital output, because the analog output from the PC has a lot of hum. If I let the receiver do the decoding, I get much cleaner audio.

 

[CyberSimian]

However, I do prefer the digital output, because the analog output from the PC has a lot of hum.

For several years I used the analogue output from my HTPC to a stereo analogue amplifier. The strange behaviour that I noticed was this:
The analogue output from the motherboard socket at the rear of the PC was much noisier than the analogue output from the headphone socket at the front of the PC.

From looking inside the case, the headphone socket uses a cable that connects the socket to the motherboard, and which snakes through the case between other components. I would have expected the cable to be susceptible to interference from within the case, and hence be worse than the motherboard socket at the rear, but the reverse was the case.

My current setup uses HDMI audio to the TV, and then analogue audio from the TV to the amplifier.

-- from CyberSimian in the UK

 

[rsbrux]

However, I do prefer the digital output, because the analog output from the PC has a lot of hum.

For several years I used the analogue output from my HTPC to a stereo analogue amplifier. The strange behaviour that I noticed was this:
The analogue output from the motherboard socket at the rear of the PC was much noisier than the analogue output from the headphone socket at the front of the PC.

That's a very interesting tip, thanks! Unfortunately, the output from the front panel jack on my HTPC is just as noisy as it is from the rear panel.
Thanks anyway.