[jbrains]

Hello, everyone. First-time poster. Please be gentle.

Summary: Background audio is loud(er), hissy/choppy on XBMC 12+ compared to XBMC 11 on my Mac Mini. Problem does not occur on my MacBook Air.

The Details

System:
Mid-2010 Mac Mini
2.4 GHz Intel Core 2 Duo,
4 GB 1067 MHz DDR3 RAM,
NVIDIA GeForce 320M 256 MB video at 1920x1080@60 Hz using OpenGL version 2.1 NVIDIA-8.24.15 310.90.9.05f01,
built-in audio at 44100 Hz sample rate,
played through Altec Lansing speakers (I tried the MacBook Air with those speakers and it's not just the speakers, I promise you.)
OS 10.9.4 (Darwin 13.3.0 x86_64, build 13E28)
All XBMC versions installed from .dmg
XBMC versions tried: OK on 11.0, problem on 12.2, 12.3, 13.1, 14.0a2
For this report, the problematic version is XBMC 13.1 tagged 20140604-84725b0

Steps to reproduce:
Play a video on XBMC 11.0 and notice that it sounds fine. Play the same video on XBMC 13.1 and notice that the background audio sounds louder and hissy/choppy, while the foreground audio has a bit of echo.

File I’m playing (problem occurs on a variety of codecs/containers):
H.264 / MP4 source: http://link.jbrains.ca/1usw9OA (124 MB)

—— begin MediaInfo details ——
General
Complete name : /Volumes/Macintosh HD-1/Users/jbrains/Downloads/Low Carb Living.mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42
File size : 124 MiB
Duration : 27mn 34s
Overall bit rate mode : Variable
Overall bit rate : 629 Kbps
Encoded date : UTC 2011-11-30 22:05:37
Tagged date : UTC 2011-11-30 22:05:37
gsst : 0
gstd : 1654281
gssd : BADC21FA2MM1360507003936350
gshh : r7---sn-ab5e6nls.c.youtube.com

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : [email protected]
Format settings, CABAC : Yes
Format settings, ReFrames : 1 frame
Format settings, GOP : M=1, N=25
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 27mn 34s
Bit rate : 3 407 Kbps
Maximum bit rate : 5 389 Kbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 25.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.066
Stream size : 672 MiB
Encoded date : UTC 1970-01-01 00:00:00
Tagged date : UTC 2011-11-30 22:05:55

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 27mn 34s
Bit rate mode : Variable
Bit rate : 132 Kbps
Maximum bit rate : 190 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Stream size : 26.2 MiB (21%)
Title : IsoMedia File Produced by Google, 5-11-2011
Encoded date : UTC 2011-11-30 22:05:46
Tagged date : UTC 2011-11-30 22:05:55

—— end MediaInfo details ——

Logs (too big for Pastebin; used Filebin)
XBMC 11.0 http://filebin.ca/1W3997JLyyLY
XBMC 13.1 http://filebin.ca/1W39wl9m2ZYW

Audio samples (recorded using Audio Hijack Pro):
Archive with samples from both playbacks: http://link.jbrains.ca/1AYC56C (1.4 MB)

[Martijn]

Can you also try 13.2beta3 to be sure?
Remember that you need to check the audio settings.

[jbrains]

I tried 12.2, 13.2b1, 13.2b2, 13.2b3 and 14.0a2. I tried everything in the audio settings (Confluence skin, Advanced and Expert mode). All I know is that 11 sounds fine and every version 12+ I've tried doesn't, and I have no idea which audio settings might relate. I changed 'em all, one by one. I was hoping someone with more experience would have a suggestion to narrow down the search.

[Martijn]

Ok was just checking to be sure as you only mentioned beta2. So if it's also in 14.0 then the experts can look at why.

Edit:darn only now I see you already said that you tested them.

[jbrains]

Can you also try 13.2beta3 to be sure?
Remember that you need to check the audio settings.

Ok was just checking to be sure as you only mentioned beta2. So if it's also in 14.0 then the experts can look at why.

Edit:darn only now I see you already said that you tested them.

No worries. I suspect that this is either something very difficult or very easy.

[Memphiz]

can you move those 2 logs to xbmclogs.com - can't access your site from work... Also are you using volume amplification?

[jbrains]

can you move those 2 logs to xbmclogs.com - can't access your site from work... Also are you using volume amplification?

New links to the logs.

XBMC 11 log (OK): http://xbmclogs.com/show.php?id=263618
XBMC 13.1 log (problem): http://xbmclogs.com/show.php?id=263619

Regarding volume amplification:
XBMC 11 (OK): Yes, 50.0 dB (for normal-sounding volume for most shows I set the adjustable volume at about -36 dB)
XBMC 13.1 (problem): Yes, 50.0 dB (for normal-sounding volume for most shows I set the adjustable volume at about -2 dB)

And now I think you've hit on the problem--and a related annoying problem. First, let me thank you for figuring out what I was doing wrong!

On XBMC 13, when I set audio amplification to 0.0 dB, I have good news and bad news. Good news: the audio sounds clean, the way it sounds on XBMC 11. Bad news: now I have to either crank up my speakers or my Mac system volume in order to hear any audio. This means that, for example, when the auto-updater chimes, it blares and scares the hell out of me. This is especially bad if it chimes at 3:40 and wakes me up. This is in fact why I started using volume amplification with XBMC 11 a few years ago. I'd love to know if there's something else I can do to raise the volume level within XBMC 12+ without cranking up the system volume.

So it appears that something changed that affected audio amplification from XBMC 11 to XBMC 12, which triggered this problem, and solving this problem appears to trigger another problem. I could use some help solving *that* problem.

Also, I don't know whether you consider this video amplification issue a problem with XBMC 12+ or not. For me, it's an obstacle, because I don't want to raise my system volume and have other sounds on the computer blaring in order to be able to hear audio on XBMC.

Thank you again for pointing me in a direction that works.

[jbrains]

Just a quick update.

I have just tested with XBMC 12.3, setting audio amplification to 0.0 dB, and I think I've found settings that somewhat work. I have to raise the system volume, but not as much as I thought I would have to. I can try these settings for a while and see whether the raised system volume is a big distraction.

If, by chance, you decide that this audio amplification issue is a problem, let me know whether I can help. When I boost volume amplification up to around 25 dB, the sound imbalance becomes apparent to me.

I'll try 13 and 14 and see how far I get.

Thanks again.

[jbrains]

I tested with XBMC 13.1 stable, and have similar behavior, so I feel comfortable that Memphiz found the source of the problem. Thanks.

[Memphiz]

The volume amplification is a poor mans solution atm. There is some work beeing done for allowing audio dsp addons. With that in i think there coud be an addon for proper drc (dynamic range compression) which would allow a volume boost without noise.

I for myself have my macmini connected to my amp via hdmi and have the blings and blongs (system sounds) set to the internal speakers via osx audio-midi-setup ... so those will never yell over my amp ...

[jbrains]

Thanks, Memphiz! That really helps. I can try the same setup to see how it sounds.

[steve1977]

The volume amplification is a poor mans solution atm. There is some work beeing done for allowing audio dsp addons. With that in i think there coud be an addon for proper drc (dynamic range compression) which would allow a volume boost without noise.

I for myself have my macmini connected to my amp via hdmi and have the blings and blongs (system sounds) set to the internal speakers via osx audio-midi-setup ... so those will never yell over my amp ...

I also have to use the amplification add-on and the audio quality is horrible. I cannot turn the amp higher as my wife will kill me if she switches to another device and it blows the windows out?

Is there really absolutely no other way these days? I could switch my macmini to bootcamp windows, but prefer not to. Other ideas?

[Ned Scott]

You could use this: http://loudmax.blogspot.ru

I'm not sure on the full details, but I think you can set it up with Audio Units and Soundflower to create a virtual sound device in OS X, which then compresses the audio. XBMC can either use the "default" audio output device or select "Soundflower" directly.

I understand the basic concepts here, but I've only done some basic stuff with Soundflower, and I've never messed with Audio Units before. I might give this a shot myself, though.

[jbrains]

Just following up: I've been using my setup for a few weeks and it's working great. Audio Amplification at 20 dB is loud enough to help, but not at all distorted or mushy. Thanks for all your help.

[steve1977]

I guess we need to live with the volume amplification for now. Unfortunately, this does not help when playing music (over airplay or directly from msuic library), where I will still need to crank up the volume. And then when watching a movie, I need to remember to turn it down not to blow out the windows.

I still hope we OSX users will also one day have a similar XBMC audio experience as Windows and Openelec users. This is really the biggest issue for me with XBMC these days. Everything else just works perfectly!