xbmc audio problems


57 posts   Page 1 of 3   1, 2, 3
by BadBoyBubby » Thu Aug 09, 2012 8:33 am
Hi

I have seen similar problem mentioned in a few topics. I am currently running Xbian and I have the pi hooked up via HDMI to a tv with 2.0 audio. I assume the pi is sending 5.1 which is what most of my films are in and all I am getting is the two front left/right channels general sound is good but it drowns out any chat/voices which are to quiet to hear.

I assume the audio needs down mixing to 2.0 from 5.1 but nothing is doing this. Are there any variants have this function? rasbmc, openelec or rasbian+xbmc ?

should this be working in xbian ?

Thanks

Bubby
Posts: 31
Joined: Sun Jul 22, 2012 5:13 pm
by Koenkk » Thu Aug 09, 2012 8:59 am
Try changing your audio playback settings, system -> settings -> system -> audio playback
Posts: 148
Joined: Sun Jul 29, 2012 10:22 pm
Location: Netherlands
by BadBoyBubby » Thu Aug 09, 2012 12:42 pm
ok been having play around with the audio settings but no matter which settings I try speech in films seems real quiet. I have to turn volume high to hear speech clearly but when action scenes or music come on its way to loud.

I am sure anyone using 2.0 audio must be having similar problems playing dts 5.1 audio. In 5.1 the speech audio is direct to one center speaker which obviously I don't have.

I have had the same issue before on my HTPC windows 7 + Mediaportal changing the codec's used fixed this. In this case don't think different codec's could be used so don't know how to fix it.

I'm gonna try out the various xbmc's openelec/raspbmc etc see if any seem to work but I'm guessing they will all be basically the same version though so not having high hopes.

Thanks

Bubby
Posts: 31
Joined: Sun Jul 22, 2012 5:13 pm
by nadnerb » Thu Aug 09, 2012 12:55 pm
I have the same problem with Raspbmc.
Correct me if I'm wrong, but I believe the problem is with XBMC, so any distribution on the Pi will have the same problems.
User avatar
Posts: 175
Joined: Sun May 13, 2012 11:22 am
by Raspy-B » Thu Aug 09, 2012 10:04 pm
I'm also having this problem. Feels like I wasted like $50 on nothing because I only have a 2.1 setup :(
Posts: 8
Joined: Thu Aug 09, 2012 10:01 pm
by dom » Fri Aug 10, 2012 12:46 am
The 5.1 should be downmixed to 2.0 using the recommended Dolby weightings of the channels.
Can someone confirm there is definitely no centre (or other) channel present, using a test sample?
(e.g. One that cycles through the channels).
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 4011
Joined: Wed Aug 17, 2011 7:41 pm
Location: Cambridge
by BadBoyBubby » Fri Aug 10, 2012 10:30 am
Hi dom

thanks for the reply. What should be performing the downmix hardware or software is it built into the gpu function ?

I will look for a test video and try it on my system later today, it may be best if someone with 5.1 and 2.0 test it though to confirm.

Thanks

Bubby
Posts: 31
Joined: Sun Jul 22, 2012 5:13 pm
by dom » Fri Aug 10, 2012 10:55 am
BadBoyBubby wrote:thanks for the reply. What should be performing the downmix hardware or software is it built into the gpu function ?

There is an audio_mixer openMax component that does it. XBMC configures the number of input and output channels, and how they are mixed.
I stepped through the code recently and it seemed to be doing roughly the right thing (i.e. taking 5.1 input and producing 2.0 output). I could also hear the dialogue.

Can you confirm what you have in xbmc system/audio settings? HDMI or analogue? I assume passthrough is disabled and speaker set to 2.0 channels?
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 4011
Joined: Wed Aug 17, 2011 7:41 pm
Location: Cambridge
by BadBoyBubby » Fri Aug 10, 2012 12:39 pm
just been doing a bit more testing. Note I have switched to openelec and I'm getting exactly the same.

Audio setting are

output = hdmi
speaker = 2.0 i did try 5.1 no difference
boost downmix is on - doesn't seem to make much difference
output stereo all speakers tried with on and off no difference

all the others related to dts, truehd etc unticked.

Thanks

Bubby
Posts: 31
Joined: Sun Jul 22, 2012 5:13 pm
by BadBoyBubby » Sat Aug 11, 2012 12:20 pm
dom wrote:There is an audio_mixer openMax component that does it. XBMC configures the number of input and output channels, and how they are mixed.


How do I access this program and try different settings ?

Thanks
Bubby
Posts: 31
Joined: Sun Jul 22, 2012 5:13 pm
by Seth » Sat Aug 11, 2012 12:52 pm
I am having the same problem using XMBC with my stereo tv.

Playing a video file in XMBC voice levels are incredibly low while background sounds and music is incredibly high compared.

Playing the same video using my laptop and using VLC player the audio comes out fine...

Browsing around several forums here leaves me with the impression that the Downmixing doesnt work as it should, the sound in the center channel sems to come out incredibly low using XMBC

If I was a programmer i would try and fix the center channel sound output volume... but unfortunatly i am not, perhaps some bright soul out there would know how to fix this problem?

saw something about a "Merge pull" or something, but I am uable to decipher how exately to make that work. https://github.com/xbmc/xbmc/commit/31e6e58147ef95808b8757baef293069d62d8432
Posts: 1
Joined: Sat Aug 11, 2012 12:43 pm
by dom » Sat Aug 11, 2012 11:20 pm
I've found a bug in the channel mapping. Hopefully there will be a fix pushed out soon.
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 4011
Joined: Wed Aug 17, 2011 7:41 pm
Location: Cambridge
by Mick1152 » Sun Aug 12, 2012 5:30 am
dom wrote:I've found a bug in the channel mapping. Hopefully there will be a fix pushed out soon.


You're kinda my hero, thank you.
Posts: 18
Joined: Sat Apr 21, 2012 12:20 am
by jose1711_ » Sun Aug 12, 2012 2:16 pm
Posts: 45
Joined: Sat Jul 21, 2012 10:03 am
by BadBoyBubby » Tue Aug 14, 2012 10:48 am
Hi

Just tried following the links through from jose1711 post and got a bit lost.

Does this mean the fault is known by the xbmc developers who are looking into it ?

I got to the xbmc github but couldn't find anything about it in there.

or is this a fault on the pi which dom is looking at :?

basically I just want to know if there might be a fix at some point :)

Thanks

Bubby
Posts: 31
Joined: Sun Jul 22, 2012 5:13 pm
by dom » Tue Aug 14, 2012 11:51 pm
I believe the fix is now in omxplayer (you can get it with apt-get upgrade).
I don't think the fix is in any prebuilt xbmc yet.

Can you try the file with omxplayer, to see if it fixes your issue?
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 4011
Joined: Wed Aug 17, 2011 7:41 pm
Location: Cambridge
by BadBoyBubby » Wed Aug 15, 2012 9:52 am
Hi dom

Tested with omxplayer and seems fine so the fix should show up in xbmc at some point ?

Thanks for your help

Bubby
Posts: 31
Joined: Sun Jul 22, 2012 5:13 pm
by dom » Wed Aug 15, 2012 10:03 am
I believe it is fixed here:
https://github.com/huceke/xbmc/tree/raspberrypi

Gimli is trying to get the raspberry pi port of xbmc into the mainline xbmc code, so he's produced a new tree based off the mainline with a clean set of patches.
I don't imagine there will be any fixes on the original tree (https://github.com/xbmc/xbmc-rbp), so it depends when raspbmc/openELEC/xbian switch to the new tree.

You can see progress on the mainlining here:
https://github.com/xbmc/xbmc/pull/1282
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 4011
Joined: Wed Aug 17, 2011 7:41 pm
Location: Cambridge
by Koenkk » Fri Aug 17, 2012 10:00 pm
I will test this xbmc tree soon ;)
Posts: 148
Joined: Sun Jul 29, 2012 10:22 pm
Location: Netherlands
by BadBoyBubby » Sun Aug 19, 2012 7:53 pm
oh great thanks was just looking to see if xbmc had been updated for it yet.

Once this has been confirmed as working in xbmc I am moving to raspberry pi as my media pc and selling my old antec fusion built HTPC on ebay, then reinvesting in a nas drive and some 500mb homeplug adapters.

Then hopefully getting another pi to learn programming on and get my son involved in some projects :D

Thanks

Bubby
Posts: 31
Joined: Sun Jul 22, 2012 5:13 pm
by jam3zs » Tue Aug 21, 2012 7:59 pm
Does anyone know if this is likely to be fixed on Raspbmc also?
Posts: 1
Joined: Tue Aug 21, 2012 7:56 pm
by BadBoyBubby » Tue Aug 21, 2012 9:06 pm
jam3zs wrote:Does anyone know if this is likely to be fixed on Raspbmc also?


I think the same version of xbmc is used in all raspberry pi based xbmc systems so they all should eventually include this fix.

Bubby
Posts: 31
Joined: Sun Jul 22, 2012 5:13 pm
by bewa » Sat Sep 15, 2012 11:08 pm
Has anyone seen if this is fixed?

The problem i get (which i think is the same or similar) is when playing 6 channel AC3 (Dolby Digital 5.1) and downmixing to Stereo.
The audio is all over the place.

I've played with pretty much every combination of Audio settings in OpenElec and I tried raspbmc and it was the same.
He's the audio info for one of the files:

Code: Select all
Audio
ID                                       : 2
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Mode extension                           : CM (complete main)
Format settings, Endianness              : Big
Codec ID                                 : A_AC3
Duration                                 : 20mn 58s
Bit rate mode                            : Constant
Bit rate                                 : 384 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 16 bits
Compression mode                         : Lossy
Stream size                              : 57.6 MiB (12%)
Language                                 : English
Default                                  : Yes
Forced                                   : No


Surprisingly downmixing 6 channel DTS works fine!

Code: Select all
Audio
ID                                       : 2
Format                                   : DTS
Format/Info                              : Digital Theater Systems
Muxing mode                              : Header stripping
Codec ID                                 : A_DTS
Duration                                 : 2h 22mn
Bit rate mode                            : Constant
Bit rate                                 : 1 510 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 24 bits
Compression mode                         : Lossy
Stream size                              : 1.51 GiB (20%)
Language                                 : English
Default                                  : Yes
Forced                                   : Yes
Posts: 5
Joined: Sat Sep 15, 2012 10:58 pm
by BadBoyBubby » Wed Sep 19, 2012 8:20 am
Has the fix for this been implemented in any release yet. In the last week I have tried raspbmc, openelec and xbian and all are still showing the problem.

Thanks

Bubby
Posts: 31
Joined: Sun Jul 22, 2012 5:13 pm
by dom » Wed Sep 19, 2012 8:53 am
bewa wrote:Has anyone seen if this is fixed?

The problem i get (which i think is the same or similar) is when playing 6 channel AC3 (Dolby Digital 5.1) and downmixing to Stereo.
The audio is all over the place.

I've played with pretty much every combination of Audio settings in OpenElec and I tried raspbmc and it was the same.
He's the audio info for one of the files:

Can you make the file available so I can look into it?
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 4011
Joined: Wed Aug 17, 2011 7:41 pm
Location: Cambridge