[UberGeek451]

OS - OpenELEC (Milhouse) Jarvis (Kodi 16) dev build 0930
Platform - RasPi 2 connected directly via HDMI to a Denon 5.1 ch AVR. Video is fed from Denon HDMI port to a Samsung 32" LCD TV.
Audio-Video Files - Stored on a FreeNAS LAN server as Samba shares accessed over fixed IP wired ethernet.

Greetings,
As my first Kodi post, I wanted to express my gratitude to all who made this software possible. This is truly beautiful code, and unlike other HTPC client/server programs I've used, it worked from the moment it was first installed two months ago.

I updated OpenElec from Beta 5.95 to Milhouse testbuild #0930 last month to take advantage of new audio features and started experimenting with various settings with Passthrough enabled. Streaming and local music files played without a hitch but there were persistent sync issues and occasional hangs during the playback of local music videos. Last week the following configurations were made to correct these errors:

Video Playback Settings:
* Sync playback to display – Enabled
* A/V sync method – Adjust PLL
* Display 4:3 videos as – Stretch 16:9 – Nonlinear
* Activate teletext – Off
* Scale Teletext to 4:3 - Off
* Playback mode of stereoscopic 3D videos – Ignore

Note: TV settings and all PVR addons were disabled and I don't own any 3D videos. I was completely baffled why teletext settings were in this menu vs. TV Settings.
After rebooting I experienced problems with missing Video on-screen-display (OSD) controls, loss of mouse and keyboard control. These included system hangs which lasted for days and could not eliminated by reversing these settings.

Fortunately I was able to fix these problems by deleting the guisettings.xml file.
Following this, Kodi was rebooted and I immediately tested several music videos with the new defaults. The sound was very tinny so I opened the Audio Settings (speaker icon) from the Video OSD control menu and made the following changes:
* Increased “Volume amplification” to 10db
* Enabled Passthrough
* Enabled Stereo upmix
At each step, audio quality improved dramatically! Eager to save these changes, I selected the option "Set as default for all videos"
Next, multiple System Settings menus required editing, the result of nuking guisettings.xml.

After rebooting, I noticed the audio quality was poor once again, and the OSD Audio settings were reviewed.
Oddly, the issue was resolved after Passthrough and Stereo upmix were disabled (reversing the previous changes). The result was full spectrum audio with a much richer bass. This also represented the best sound I have experienced to date.
Sadly, this experience was short lived and during the last few days I've noticed the following:
~ “Volume amplification” settings are inconsistently applied.
~ Edits to Audio Configurations in System Settings are not saved or arbitrarily revert after a reboot.
~ Configuration changes applied in System Settings are not consistently duplicated in the Video OSD menus and vice versa.
~ Occasionally after settings are reconfigured, Audio output will contain undesirable artifacts, attenuation, or harmonics (echo).
~ Standard and debug logs look very clean.

Here's the good news; beside this singular issue everything else is absolutely perfect. It took weeks to iron out all the minor glitches so I'm reluctant to attempt anything drastic like a reinstall or upgrade.
This really smells like corruption but could also be an incorrect setting or code bug.
Currently Passthrough is disabled but I will list the enabled values below as well:

A. Passthrough Enabled:
Audio Output:
1. Number of Channels – 7.1 (was 5.1)
2. Output Configuration – Best Match
3. Stereo Upmix – Disabled
4. Maintain original volume on downmix – Disabled
5. Resample quality – Medium
6. Enable Passthrough – On
7. Compatible AVR's.
"Dolby Digital (AC3) capable receiver" (Enabled)
“DTS capable receiver" (Enabled)
"Dolby Digital Plus (E-AC3) capable receiver" (Disabled)

Video Playback:
1. Adjust display refresh rate – Select: On start/stop
2. Sync playback to display – Disabled
3. A/V sync method – N/A
4. Display 4:3 videos as – Normal
5. Activate teletext – On
6. Scale Teletext to 4:3 - On
7. Playback mode of stereoscopic 3D videos – Ask me
Acceleration:
8. Allow hardware acceleration – MMAL – Enabled (OMXPlayer - Disabled)

Audio Playback:
Volume Adjustments – Use album levels
Files with ReplayGain Information – 89 db
Files without ReplayGain Information – 89 db

Video Player OSD settings:
1. Deinterlace Video – Auto
2. Deinterlace Method – "MMAL - Advanced"
3. View Mode – “Stretch 16:9”

B. Passthrough Disabled (Current settings showing changes from above):

Audio Output:
1. Number of Channels – 5.1
6. Enable Passthrough – Off

Video Playback:
2. Sync playback to display – Enabled
3. A/V sync method – Resample

Any comments or suggestions regarding configuration settings, sources of corruption, or additional edits would be much appreciated.
Thanks for your time.

Cheers

[Jdiesel]

Is there a reason you are reluctant to upgrade to a newer build? The build you are on is an almost 2 month old nightly build. These test builds will have the occasional issue and if you aren't willing to update or do some testing yourself they probably aren't the best option for you. It is tough to give support on a old version of a test build as many of the issues since then have likely already been fixed, if the issues exist on the latest nightly build post a log in the test build thread for support.

Oh, in case you didn't know upgrading to a new nightly build will not overwrite your settings or database.

If it is an issue with the settings not sticking, which I ran into a one point myself, a clean install fixed it for me but this means your will lose your database and settings. If you need help backing up your settings let me know as it makes restoring from a clean install much easier.

[popcornmix]

It sounds like you are adjusting audio settings while playing video from audio OSD.
I'd suggest using the settings in system/audio settings (not when playing a video) as that is the normal way of adjusting these settings.

Personally I'd turn off amplification unless you have a compelling reason (it can distort audio).
amplification doesn't work when passthough is used which may explain your inconsistent behaviour (amplification will work for, say mp3 and aac but not for dts and ac3).

[UberGeek451]

Thanks for the replies.

@Jdiesel
I'm actually looking forward to a newer build with a clean set of configurations. The reason for my reluctance is primarily the result of confusion and frustration regarding the numerous Audio-Video settings and what I may have done wrong. There are so many different setups, conflicting opinions, outdated wiki's, hidden menus, and updated features, it's become nearly impossible to make sense of it all. For example, the Raspberry Pi FAQ, a good WiKi, states "Sync playback to display" and "adjust PLL" are the recommended dvdplayer settings. Unfortunately, "adjust PLL" has wreaked havoc on my system every time and I just recently learned in a post from FernetMenta that "sync playback to display" should not be enabled with audio passthrough. Despite the majority opinion to do otherwise, disabling passthrough not only solved pernicious sync problems, it improved audio quality as well....well, as long as Kodi is willing to cooperate.
To sum it up, I'm most interested in getting it right before applying any potential errors to a new install.

@popcornmix
Your assumption is indeed correct and this is where my audio problems first began. The evolution of these features seem to indicate they were intended only on a per video basis which can be useful. In my particular situation, the "Set as default for all videos" option seemed to be the kiss of death. I was under the mistaken impression that this was simply a shortcut to the System Settings and by changing the OSD audio settings and selecting the default option would specifically apply to the dvdplayer (Video), not PapPlayer (Audio), however, the results indicated otherwise. I don't think there's an equivalent in System Settings but one certainly has a direct impact on the other with unpredictable consequences. This directly impacted “Volume amplification”, a feature that seems to do much more than its name suggests. Originally I had used this as a quick way to match the output to the input of my AVR. When audio problems arose this seemed to behave more like an unpredictable band pass filter or equalizer.

Very interesting, this is a first! "amplification will work for, say mp3 and aac but not for dts and ac3". I assume this applies only when passthough is disabled?
Also, when you say "turn off amplification", I assume you mean moving the slider to its minimum setting? Although I've never noticed distortion while adjusting this control in a functioning system, once the system is operating properly, I intend to match Kodi's output to the HDMI input level in my Denon settings menu.

[popcornmix]

Very interesting, this is a first! "amplification will work for, say mp3 and aac but not for dts and ac3". I assume this applies only when passthough is disabled?
Also, when you say "turn off amplification", I assume you mean moving the slider to its minimum setting? Although I've never noticed distortion while adjusting this control in a functioning system, once the system is operating properly, I intend to match Kodi's output to the HDMI input level in my Denon settings menu.

Yes, if passthrough is active, then kodi doesn't touch the audio - the receiver decodes it. As such Kodi cannot adjust the volume, or amplification.

Set amplification to 0 to disable. If the audio is encoded using the full range, then any amplification applied will result in clipping which may cause distortion.
Normally audio is not encoded full range (at least for most of the video) so a small amount of amplification may not distort.

Really I'd suggest you set volume to 100% and amplification to 0. Then you will get the full signal out and it will be the same volume whether passthough is enabled or not.
If different inputs on the Denon produce different volume out, then it would be best to adjust this on the Denon (if possible).

Also calibrating the volume level for a single video or audio track won't necessarily be useful as the video you are using may or may not be full range.
Personally I find iplayer is louder than most of my own rips, so I normally have to juggle the volume (on receiver) a little at start of playback. There isn't really a solution for that.

[UberGeek451]

Thanks for the suggestions popcornmix.

I actually went thru these steps last night. Kodi's low output level required me to max out the Denon's input to 25 db and it's still not quite enough.

I would really appreciate if you or any other members could take a look at my Passthrough Enabled/Disabled settings above and offer any suggestions or variations.
I'm anxious to compare the two configurations and move on to the latest build.

BTW, my Kodi box must have received a packet of magic sauce from one of you guys...it seems to have healed itself shortly after I posted!