Video files: questions about audio stream


Maybe It’s nothing but Id like to ask about audio stream when I look a video file.

I always have the mention “side” displayed on my audio stream selection, regardless of the audio compression. What does that mean ?

example : “English - AC3 5.1(side) - 6 channels (default) (1/1)”

Equipement: samsung hw-N550 3.1ch SoundBar, vero 4k+, sony TV kd43xf2096, linked with HDMI, cec disabled. Passthrough is working, I tried fixed/best match/optimized on system/audio settings, still showing.

Have a good day

Where is this information being displayed?

The correct settings should be:

  • Passthrough: On
  • Output Configuration: Best match
  • Number of channels: 5.1 or 7.1 depending on if your soundbar supports Atmos/DTS-X

You could also try # of channels as 2.0

This information is shown in the “audio settings osd” when I chose an audio stream like original version or dubbed voices.
I have the settings you wrote. and I have tried 2.0 and 5.1, I noticed no change when passthrough is on. But if passthrough is off I have to stick to 2.0 channels.

Ah, I didn’t read your first post closely enough.

What’s displayed with the Audio track selection has nothing to do with the audio output settings.

As to why it shows 5.1(side) I’m not real sure. It should probably have something more like 5.1(rear) or 5.1(surround). Or just show 5.1

Don’t worry about it, it’s just a cosmetic issue with how the selection is displayed. It has nothing to do with how the audio is actually output.

Thanks for the help :slight_smile:

If you have a 7.1 setup, 5.1(side) is often routed to different channels than 5.1(rear).

It’s really just a hint to the decoder where the encoder had the virtual microphones located, but it is often completely wrong, even if it comes directly from a source like BluRay.

But what’s being displayed in the Track Selection screen is not affected by the actual audio settings is it? Does that selection screen really know if I have a 7.1, 5.1 or 2.0 setup?

5.1 side is the standard way of Dolby and DTS to encode 5.1 channels. It means that the rear channels of a 5.1 stream should be placed on the surround side channels of a 7.1 setup. What you see there is to be expected, @mrtnn :+1:t2:

We’ve had an extensive discussion about this when we tried to figure out where to place the surround channels of a 5.1 PCM file when outputting it in a 7.1 container (quite a long time ago now). Dolby and DTS want a non-upmixed 5.1 track to be played on the fronts and side backs only, not the surround back channels.

Yeah, OSMC does it right and puts 5.1 into the side of 7.1 regardless of the whether the “hint” says side or rear, because that hint is often unreliable.

Nope, that’s just what’s in the metadata of the stream. If you don’t passthough, OSMC figures out how to put the PCM, and your AVR then does whatever with it, depending on its settings. If you do passthrough, your AVR does all the decision making.

In general, AVRs often respect the hint of “side” or “rear”, while OSMC does not, and should not, since, again, it’s often incorrect.

Let’s not get into 7.1 DTS-HD MA formats that include hints similar to Atmos or DTS:X 3D audio, so that if you have a system with more than 7.1 speakers, an AVR could route the sound to the best location (overhead, rear, side, high front, etc.). Again, these are often wrong, and have been seen in the wild on commercial BluRay disks.