Mac Mini VLC 3.0 audio failure

[IainF]

Hi,

I've installed VLC 3 on two machines. A MacBook Pro and a Mac Mini, both running High Sierra. On the MBP this works fine but on the Mac Mini the audio is absent (this is with .mkv and mp4 files).

I've tried uninstalling all files with iTrash and reinstalling VLC 3.0 but no joy. I've also reset all the prefs after re-install but still nothing.

When I revert to VLC 2.2.8 (I think it is) then everything works fine.

The audio is going out via the digital optical out to a Sonos sound bar/sub/and play 3s for surround, video going to Sony TV via HDMI. I've checked that movies played via Quicktime player have normal sound. In addition trying to play these files via VLC 3.0 still has no audio.

I'm OK with sticking with VLC 2.2.8 on the Mac Mini for now but just wondered if anyone else had encountered similar problems and had any solutions.

Cheers

Iain

[fkuehne]

Please open Window -> Messages, keep it open, try to play something on Mac mini and safe the log as a file after you clicked stop. Please share the log here, so we can investigate what is going on there.

[nater]

The audio is going out via the digital optical out to a Sonos sound bar/sub/and play 3s for surround, video going to Sony TV via HDMI. I've checked that movies played via Quicktime player have normal sound. In addition trying to play these files via VLC 3.0 still has no audio.

I think I know what's going on. I went to submit a bug report for this problem, saw that the VLC site recommends I check the forums first for a similar problem, found your post and here I am.

I have a Mac mini (Late 2012). What it looks like VLC 3.0 is doing is assuming that if you are on at least a Mac Mini and using digital out that whatever you are sending the digital audio to can handle undecoded AC3 (Dolby Digital) or DTS audio bitstreams. In my case I have a JDS OL DAC hooked up to my Mac via optical digital output:

https://www.jdslabs.com/products/176/ol-dac/

This DAC does not have an AC3 or DTS decoder. In versions of VLC previous to 3.0, VLC will decode the AC3 or DTS bitstream into an uncompressed stereo audio stream and that would get sent to my DAC, and I can hear it properly no problem. VLC 3.0 will do that with AAC audio, but interestingly 3.0 no longer defaults to AAC tracks in MP4 files on my Mini if that file has an AC3 or DTS track. VLC 3.0 defaults to playing the AC3 or DTS track, which in the case of my JDS Labs OL DAC means I get to listen to digital static until I manually change to the AAC track. In the case of video files with only AC3 or DTS tracks, I cannot use VLC 3.0 for playback and get usable audio, it will only send the raw bitstream out to my DAC which means I can only hear digital noise. I've also found no way in VLC 3.0 to enable any sort of AC3 or DTS decoder either globally or on a per file basis while I've got my DAC hooked up to the optical digital output of my Mac Mini (which is the way I listen to everything - my DAC goes to a headphone amplifier and a speaker amplifier).

I'm fine with VLC being able to bitstream audio over digital outputs, but it should not default to this unless there has been some setup done with the user to configure the digital output so VLC knows what formats it can handle. A good example of how to do this is what the Sony Playstation 3 does:

http://manuals.playstation.net/document ... utput.html

In particular, step 5 there shows how you can tell the PS3 what formats your playback device supports. If for some reason the VLC team doesn't want to implement the equivalent feature, bitstreaming should definitely default to off on digital audio outs (i.e. AC3/DTS should be decoded by VLC and converted to an uncompressed stereo bitstream) and bitstreaming of compressed audio should be left to the end user to optionally enable.

[fkuehne]

I fear that your audio output device claims to support encoded audio, which in fact it does not. Can you see the Audio menu if you can disable encoded audio output?

[nater]

I fear that your audio output device claims to support encoded audio, which in fact it does not. Can you see the Audio menu if you can disable encoded audio output?

I'm not aware of anywhere on my Mac I have my optical out port configured to support encoded audio, and I'm not exactly sure where I would I see that.

On the Mac the audio output controls are in "Sound" in the System Preferences, and under "Output" I have selected "Digital Out" of type "Optical digital-out port" and below that it says "Settings for the selected device: The selected device has no output controls". Under the system app "Audio MIDI Setup" I have "Built-in Output" selected and under "Output" it says "Source: Digital Out" and the things I can configure are "Format" which I have set to "2 ch 24-bit Integer 96.0Khz" and "Configure Speakers..." which I have set to "Stereo".

Under the "Audio" menu in VLC 3.0 I don't see anything that mentions encoded audio output. I can choose the audio track, and I don't see any additional options when I have an AC3 or DTS track selected. Even when I have a 5.1 track selected, VLC 3.0 has a "Stereo audio mode" menu where it is set to Stereo, and the "Audio Device" menu is set to "System Sound Output Device". I can't find any other relevant options.

It's worth noting that Audio MIDI Setup becomes aware that an encoded digital audio stream is being sent out over the optical jack because in "Built-in Output" the "Format" drop down becomes grayed out and is fixed at "Encoded Digital Audio 48.0 kHz" as long as VLC is playing AC3 or DTS audio. When I go into "Configure Speakers" in Audio MIDI Setup at that time, it still shows "Stereo" as the active speaker selection.

VLC 3.0 is the only app on my system which behaves this way, and it is not the right way to handle this situation.

[zhgutov]

In my case I have the same issue.
VLC 2.2.8 works fine, but 3.0.0 generates noise.
Built in output of MacBook Pro configured to Stereo in Audio MIDI Setup.
TOSLINK cable connected from output to Lake People DAT RS 05 which accepts PCM data.
I don't see any reason to produce anything like "encoded data" by default when the output format is explicitly set to 2 channel 24-bit Integer 48 kHz.
The source track is 5.1, it has different bit depth (16-bit per sample), and if it is encoded already, why to decode and then to encode it again in different format?
Why not to send it just as uncompressed PCM which is supported everywhere?

[tartiflette74]

Same thing for me. Mac mini with tosslink to a non-AC3 DAC. Version 2.2.8 allows me to convert AC3 to stereo using Audio / Audio Device / Built-in output; VLC 3 always does pass through, whether I choose Built-in Output or Built-in Output (Encoded Output).

[fkuehne]

We will look into this. Thanks for the additional reports and details!

[tguillem]

Hello, your problems should be fixed.

Could you confirm it by testing the next nightly that will be available tomorrow: http://nightlies.videolan.org/build/macosx-intel/
It should be named vlc-3.0.2-20180310-*.dmg

[tartiflette74]

Hello,
With vlc-3.0.2-20180313-0545.dmg I now get stereo audio output through the toslink cable, whatever I choose in the menu audio / audio device. Does VLC knows the capabilities of the DAC connect through toslink (mine is not AC3 capable)? If it does, then I guess the issue is fixed; if it does not, then it seems that passthrough is now always disabled.
If VLC knows the capabilities of the DAC, then I would expect the audio device menu to let the user choose between auto / stereo / passthrough. If it does not, then only choose between stereo / passthrough.
Thanks!

[tangent]

Hello, your problems should be fixed.

Could you confirm it by testing the next nightly that will be available tomorrow: http://nightlies.videolan.org/build/macosx-intel/
It should be named vlc-3.0.2-20180310-*.dmg

I can confirm. I was unable to play AC3 audio tracks in VLC 3.0.1 through a Parasound Zdac v.2 connected to my Mac's optical output, but AAC tracks did work. I was getting rapid clicks (~10/sec) over the top of the audio with the AC3 track, which was very annoying! If I told VLC 3.0.1 to switch to an AAC track in the same movie file, the audio played correctly. Switching to the current nightly build allows both the AC3 and AAC tracks to play correctly. Thank you!

I take it the change is this one. The checkin comment implies that selecting Audio > Audio Device > Built-in Output (Encoded Output) should cause the symptom to reoccur on my AC3-free DAC here, but it does not. Can you verify that those using home theater receivers and such can still get hardware decoding over TOSLink, if they want it?

Does VLC knows the capabilities of the DAC connect through toslink (mine is not AC3 capable)?

I'm pretty sure TOSLink is a unidirectional medium. (As is S/PDIF.) The DAC cannot talk back, meaning that the sender — VLC in this case — cannot know whether the DAC is powered on, what formats it supports, what the delay constant is for the cabling, ICs, and software layers involved, etc. This is one of the many improvements that HDMI brings to the table, but since Macs don't have HDMI audio-only outputs, as some other devices do, that's no help to us.

For those using one of the newer Mac minis with HDMI output, I believe you can configure HDMI as the audio output only, with video going to DisplayPort or VGA. It's kind of a hack, but it's what we have now, lacking a second audio-only HDMI port.

[Londonguy]

I have similar. after pausing a video, the sound track is very choppy on continuing. Only happens with 3.0. I reverted back to 2.28 and the problem is gone.

Mac mini server quad.
10.3.2

[tartiflette74]

This issue is fixed for me with vlc-3.0.2-20180328-0644.dmg : the menu audio / audio device can toggle passthrough on or off for my Mac mini using the toslink connector. Merci