Background sound on Vero4k

Help and Support Vero 4K / Vero 4K +
1

Having spent a few hours trying to sort out some ongoing problems - but this one I’ve not found the answer to.

It is that the background sound (traffic, footsteps even the in breath of a news announcer!) overwhelms the main sound. This happens on the live stream from DVBlink server and on recorded videos.

I don’t think this was there before the Sept or even Aug update.
The problem is not apparent on the raspi’s or straight Kodi on a win10 box

This is not present on the raspis - one using hdmi and one using analogue output.
I’ve run one of the Veros on a monitor side by side with the Win 10 pc outputting to a sound bar. The overdominant background is only present on the Vero4k
The other V4k is outputting analogue to a small speaker amplifier (nothing has changed in this set up) and the problem is most prominent on this machine. I dont know if the problem exists on HDMI but I’ll shift some kit around later today and see.
I’ve tried boosting the centre channel but it makes no difference.

[I have 2 V4ks 2 raspis running OSMC and one win10 PC (running Kodi aug2017 not osmc as a control) My main interest is streaming live TV from DVB-t and DVB-S card and using PVR . The backend server is DVBlink]

2

Please test with HDMI first.

It sounds like downmixing (which will happen with analogue)

3

Tx Sam but can you explain ‘downmixing’ and what remedies might there be?

Its so severe its almost not possible to watch the news - the news readers sound as if they are wearing iron lungs :wink: Overall the sound is as if it is coming from a tin box

4

It’s hard to really know what the issue is; but if you have a sample that may help.

Downmixing == 5.1 -> 2.0 conversion. This can sometimes result in a loss of audio quality. This is assuming the channel has surround.

Do you get the same problem with the SPDIF or HDMI output? Where possible these are preferred outputs and will always provide better sound.

The 3.5mm port is a CVBS port; so without the right cable audio can also sound less than ideal.

Also ensure that your device is up to date. I remember you said you disabled or started blocking updates, so I’m not sure what version of OSMC you are now running. If it worked before, then it sounds like a software issue rather than a hardware problem.

Sam

5

Can you get us full logs so we can see what your setup is, please?
And can you post the output of cat /usr/share/alsa/cards/AML-M8AUDIO.conf

Is your amplifier stereo? It sounds a bit like one channel may be reversed so you are cancelling out the mono signal.

Not clear what this vero is outputting sound to - SPDIF?

6

thats helpful
both of these V4ks are now on th September edition - the problem I was having with the DVBlink addon not loading is a dvblink issue - I have rigged a routine on hte server to restart the server on a regular basis and that by and large reduces the issue to tolerable.
One Vero is using spdif and the other (the one I used to use bluetooth on is forced to use anlogue as I have not sound out on the monitor (I have ordered an hdmi audio splitter) I do suspect it wont happen on hdmi but I ran out of time to get the hdmi monitor from another room and try it - will get back to you on that - unfortunately today was my only free day in ages

I am not sure about whether the channel has 5:1 maybe on the recording but I doubt it - we were just watching ITV and BBC news and the backnoise was dire

I’ll set up full debug logs and upload [edited later - log with full debug is here at paste.osmc.tv/awegacupuz
This covers a few moments runnig a recording which shows very noticeable background noise (footsteps almost louder than speech) and I was rewinding to get to the offending scene]

In answer to the amplifier - yes its a simple headphone amplifier in stereo only a volume control - as I say that part of the set up has not changed but much thanks for the suggestion of reversing the channels - sounds very logical

[edited later to say] I tried swapping the stereo channels - they’ve never been mixed up before as they’re color coded. But no change still a lot of background]

The Sound bar takes SPDIF from the other Vero - if anything the SPDIF is slightly better than the analogue (i.e. background less prominent but miles worse than same soundbar using a Win10 PC SPDIF with straight Kodi - august 2017

this is the content of the conf file

Configuration for Amlogic M8 Audio

AML-M8AUDIO.pcm.default {
@args [ CARD ]
@args.CARD { type string }
type plug
slave.pcm {
@func concat
strings [ “dmix:” $CARD ]
}
}

confdir:pcm/front.conf

AML-M8AUDIO.pcm.front.0 {
@args [ CARD ]
@args.CARD { type string }
type hw
card $CARD
device 0
format S32_LE
}

confdir:pcm/surround51.conf

AML-M8AUDIO.pcm.surround51.0 {
@args [ CARD ]
@args.CARD { type string }
type route
ttable.0.0 1
ttable.1.1 1
ttable.2.4 1
ttable.3.5 1
ttable.4.3 1
ttable.5.2 1
slave.pcm {
type plug
slave {
pcm {
type hw
card $CARD
device 0
}
channels 8
format S32_LE
}
}
}

confdir:pcm/surround71.conf

AML-M8AUDIO.pcm.surround71.0 {
@args [ CARD ]
@args.CARD { type string }
type route
ttable.0.0 1
ttable.1.1 1
ttable.2.6 1
ttable.3.7 1
ttable.4.3 1
ttable.5.2 1
ttable.6.4 1
ttable.7.5 1
slave.pcm {
type plug
slave {
pcm {
type hw
card $CARD
device 0
}
channels 8
format S32_LE
}
}
}

confdir:pcm/hdmi.conf

AML-M8AUDIO.pcm.hdmi.0 {
@args [ CARD AES0 AES1 AES2 AES3 ]
@args.CARD { type string }
@args.AES0 { type integer }
@args.AES1 { type integer }
@args.AES2 { type integer }
@args.AES3 { type integer }
type hooks
slave.pcm {
type hw
card $CARD
device 1
format S16_LE
}
hooks.0 {
type ctl_elems
hook_args [
{
interface MIXER
name “IEC958 Playback Default”
lock true
preserve true
optional true
value [ $AES0 $AES1 $AES2 $AES3 ]
}
]
}
}

7

OK thanks. Just trying a few setups here - I don’t use analogue or spdif usually.

8

I expected that some of the DVBLink issues reported would indeed be backend related. I am sure they will be able to help you with that on the forum however as we have a lot of Vero 4K users with DVBLink backends that are not experiencing problems.

Stick with SPDIF if you can.
Soundbars can take advantage of 5.1, so with movies and TV shows things will sound better.

Your AML-M8AUDIO.conf is current. I made changes and most people said things were improved (fixed the muddied channels); but a couple of people said it didn’t work for them. As a result, I had to revert things. But I reverted things to July state. Were you watching the same channels / programmes back then?

Running

sudo -s
wget https://raw.githubusercontent.com/osmc/osmc/2b2b23dffcd1967216d79b27bd8a26130546de23/package/vero3-userland-osmc/files/usr/share/alsa/cards/AML-M8AUDIO.conf -O /usr/share/alsa/cards/AML-M8AUDIO.conf

May help. But as we discussed here: September update breaks 5.1 Audio - #4 by john_murray this broke things for you; hence why I reverted things.

Can you also take a quick photo or screenshot of audio settings in Kodi?

If I record BBC1 or ITV 1 News at Six, and output via analogue or SPDIF via 2 channels, will I hear it? If so, I can fix it.

Cheers,

Sam

9

What I meant was that one of the channels somehow got out of phase. The DAC does have a setting for that but I can’t imagine how it might get set, unless you’ve been messing with alsa. Since you don’t have the alsa utilties that’s unlikely.

I checked this morning and the phase inversion doesn’t affect spdif anyway so that can’t be the problem. And I can watch and record/playback BBC news using analogue without problems using TVheadend.

You haven’t said whether you get problems playing music or videos other than recorded off TV. If not, I guess the focus has to be on DVBlink.

10

@grahamh I guess you could be right about DVBlink though why should OSMC be absolutely fine on the Raspberry Pi’s which use analogue in the same way and the problem is only apparent on the 2 Vero4k’s? Furthermore the sound on the Win10 machine is perfect.- though that is straight Kodi not OSMC.

No there seem to be no problems with music when played through PA player, though I am no audiophile. I haven’t tested DVD videos but movies recorded from TV display same problem. I presume a DVD stored on the server and played via OSMC would bypass any DVBlink issues?? The reason I ask is that I can’t currently get the Vero4k to connect to a portable DVD unit usb - recognises it but the play button doesn’t work.

[edited later - I tried running a dvd saved on central server (just so happens it was same series as recorded TV but DVD format) The backgroud sound again overwhelms the main sound/conversation - this is with DVBlink server stopped - so I am not sure the focus should be on dvblink]

One thing I have noticed is that music over live TV ‘wails’ at times like an old wind up gramaphone - you know changing pitch/key as the mechanism winds up or down. Most disconcerting - again only happens on the 2 Veros

I posted elsewhere as to whether there are better solutions than DVBlink but no replies - I guess there are few users DVBlink hasn’t answered any of my email questions about the adddon problems - they’re very quick and helpful when it comes to the server

PS I’ve now shifted a tv with hdmi sound connected it to the Vero4k and tried it over HDMI - the overwhelming background is just as bad.
So the TV which was sconnected to one of the PI’s using HDMI for sound and which worked fine with the PI is now connected to a Vero4k and sound directed to HDMI but all of a sudden we have the background overwhelming. Same clip.

J

11

I’m no expert, but I would think stopping the server isn’t going to change anything on the client. If music files play OK, at least we are only looking at the way OSMC plays videos. You might try disabling the DVBlink add-on. If no change, I would reinstall OSMC without any extras, check that it works, then see if just enabling the DVBlink add-on makes the difference. At least the experts would know where ton look, then.

I can’t immediately see what DVBlink does that TVheadend doesn’t.

12

@sam_nazarko Hi Sam tx again
I’ve tried the wget from github you suggested but the background sound is still very dominant - could be just optimism but it seems slightly better but still seriously distractig
the audio settings (I’ve tried to get all the various machine pi’s win10 and veros on same settings) are as follows
output either PCM or HDMI
no channels 2
output optimized
vol control steps 90
maintain original vol on downmix on (makes no difference on or off)
stereo upmix off (makes no difference on or off)
boost centre 0db (makes no difference whether set to 0 or 30db)
resample quality medium
threshold for pitch correction 2
keep audio device 1 minute
sed low volume noise off
play gui sounds only when playback stopped
gui sounds = Kodi
audio passthrough off (makes no difference on or off)
enable DSP processing off

As for recording - well I guess if you recorded with the same set up you’d notice it but it is noticeable live - it is not a ‘recorded’ material issue. . I have been using one specific clip because I know the specifics - two characters are having a conversation in a kitchen while one whips a bowl. The ‘slurping’ in hte bowl is almost as noticeable (on hte veros) as the conversation. It is perfectly normal run through exactly the same set up (HDMI) on a raspi 3
FWIW the spdif display same problem on the vero but less pronounced
Though I am running the clip using the DVBlink ‘recorded tv’

13

Than I may suggest you share a 1 minute part of that clip so that we can test to find the issue

14

Cancel the Fire Brigade I think I’ve got it

the two Vero’s are connected to audio devices which both have a fairly low input sensitivity whereas the raspis are not
To compensate I had bit by bit increased the audio amplification on each of the Vero’s to compensate - thats why a sudden change was not apparent.
This is the setting you can only reach (I think) when playing the live or video stream - you press the OK button on the Vero remote. this shows a progress/pause bar and at the right there’s a setting icon. Selecting this allows you to change the ‘audio and subtitle’ settings
The second item ‘Volume Amplification’ I had gradually increased to compensate for low amplification/sensitivity on the sound bar and headphone amplifiers - Any setting higher than about 20db over emphasizes the background sound compared with the main dialogue.

Many thanks for the help all the same

15

Good find! Yes — if you change the gain too much it can get distorted

Sam

16

Indeed. It must be applying some heroic compression. It doesn’t get any louder overall above 20dB.

And you don’t get that option with music, only video.

17

A quick post script to all that head banging logic :wink: I was sure I’d not raised that Db setting to the 50Db it was found at - I know that when one gets to the extremities of such settings one risks distortion.
Anyway chatting to No1 system critic I find she knew how to change this setting and had been using it to increase the volume !!! Arghh

18

But it’s not sticky AFAICT. It re-sets with each new video.

19

@grahamh I’m not sure about that being NOT sticky on videos - I generally use it for live tv
when one sets that control (audio amplification) on live it is still there next session even after a reboot- that’s true for live and recorded
I also note you can select ‘set as default for all media’ which I think is also sticky

20

You can either set it for all videos or just for one.