Mac OS X - No 5.1 sound from AAC or DTS when transcoding to AC3

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Memphiz Offline
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Post: #16
dddamian - the interesting part would be to know when m_transcode is set...

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DDDamian Offline
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Post: #17
(2013-01-24 01:30)Memphiz Wrote:  well the hdmi/analog/optical setting is more then confusing indeed - i think you will +1 that statement too...

Yeah, it's one thing to say -1 to settings, but this one is just a silly legacy one when we already know the device type from the enumeration. And where does USB audio fit in (except to add another factor for confusion)? We already know what each device is capable of. Saying less settings is great if you have a device easily shoe-horned into three broad catagories (what the hell is analog lol - it should be PCM or "kill my passthrough" - there is no "analog" on a digital device capable of running XBMC).

m_transcode is set if output is optical and AC3 is checked - that's it. It's only set in SoftAE::LoadSettings() or its CA equivalent. If the intermediate (possibly decoded) stage is PCM and > 2,0 then it gets transcoded as "optical" cannot pass >2.0 PCM. Note that this is not even a true statement with modern optical/coax devices.

We already have a setting called multichannel LPCM. This really supercedes "optical". New "optical" or coax outputs handle multichannel PCM fine, as do USB cards. Almost all HDMI drivers (all meeting the standard) support it.

Basically no matter whether it's "analog", optical, coax, HDMI or USB, if you have multichannel LPCM checked, that's what you get, otherwise transcode. The only exception would be *none* of the options checked, then you just output PCM 2.0.

So:
2.0 PCM = 2.0 PCM on all devices

>2.0 PCM (whether native or decoded due to un-checked format like DTS)
- if multi-channel LPCM selected output multi-channel LPCM
- if multi-channel LPCM not selected and AC3 selected transcode to AC3
- if multi-channel LPCM not selected and AC3 not selected downmix to 2.0

Note that the above applies to "analog", "optical/coax", USB or HDMI equally - no setting needed.

System: XBMC HTPC with HDMI WASAPI & AudioEngine - Denon AVR-3808CI - Denon DVD-5900 Universal Player - Denon DCM-27 CD-Changer
- Sony BDP-S580 Blu-Ray - X-Box 360 - Android tablet wireless remote - 7.1 Streem/Axiom/Velodyne Surround System
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DDDamian Offline
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Post: #18
Meh - just wait till it's PR'd Tongue

In the meantime with those commits in AAC/DTS go to AC3 2.0.

The other thing that setting does is confuse the speaker layout setting, which should only apply to PCM too.

System: XBMC HTPC with HDMI WASAPI & AudioEngine - Denon AVR-3808CI - Denon DVD-5900 Universal Player - Denon DCM-27 CD-Changer
- Sony BDP-S580 Blu-Ray - X-Box 360 - Android tablet wireless remote - 7.1 Streem/Axiom/Velodyne Surround System
If I have been able to help feel free to add to my reputation +/- below - thanks!
(This post was last modified: 2013-01-24 03:57 by DDDamian.)
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jjd-uk Offline
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Post: #19
I presume there must be some logic that tells XBMC when to transcode based on the Audio Output settings, could you hook into this to keep LPCM as 5.1 while it's being passed through ffmpeg for encoding to AC3 5.1 and only limit LPCM to 2.0 when it's being sent direct to SPDIF?

Ah sorry for the noise, on second reading Damain appears to have said the same thing but in a far more techie way which didn't sink in on first reading.
(This post was last modified: 2013-01-24 14:10 by jjd-uk.)
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DDDamian Offline
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Post: #20
Your summary was much better Wink

System: XBMC HTPC with HDMI WASAPI & AudioEngine - Denon AVR-3808CI - Denon DVD-5900 Universal Player - Denon DCM-27 CD-Changer
- Sony BDP-S580 Blu-Ray - X-Box 360 - Android tablet wireless remote - 7.1 Streem/Axiom/Velodyne Surround System
If I have been able to help feel free to add to my reputation +/- below - thanks!
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jjd-uk Offline
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Post: #21
I'm also in agreement that there are far too many audio settings presented to the beginner or the simply clueless, so I wonder if things could be done in smarter way that makes it easy post-installation to get running, with as little interaction from the user as possible, while having more advanced tweaks buried down a layer.

I believe settings are going to be looked at post-Frodo? So would now be a good time to start a discussion on the way forward on audio settings? If so I can start ball rolling as I've some ideas, maybe over on the new Team Member Feature Discussion forum?
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Junior Mint Offline
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Post: #22
I have a Mac Mini connected to a Sony receiver via optical (Toslink) cable. The receiver doesn't support AAC 5.1. But I have a lot of video files that contain AAC 5.1 audio tracks.

So, should I stick with XBMC v11 "Eden" and wait until XBMC v12.1 is released? Or does XBMC v11 also *not* support transcoding AAC 5.1 to AC3 5.1?
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Memphiz Offline
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Post: #23
tell us - i'm unsure if it supports it - if you ask me - it doesn't...

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Junior Mint Offline
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Post: #24
I had to look up the symbols on my receiver to remind myself what they meant.

I played a couple of movie files containing 2-channel AAC and 6-channel (5.1) AAC audio tracks. With both Plex and XBMC "Eden", the Sony receiver showed "Opt" and Dolby Digital when playing the 5.1 AAC tracks. However, when I played the same files with XBMC "Frodo" and the new Plex beta which is based on Frodo, the receiver showed "LCPM" and Dolby ProLogic II. So it looks like the "Frodo" down-mixes 5.1 AAC to 2-channel Dolby ProLogic II audio.

I guess I'll stick with XBMC 11 "Eden" until this is resolved. Or I can re-rip some of my discs so they have 5.1 AC3 instead of AAC.
(This post was last modified: 2013-01-30 05:03 by Junior Mint.)
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lucanoid Offline
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Post: #25
@Juniro Mint yes Eden transcode AAC, but Frodo doesn't the devs know and said they'll fix it but no ETA http://forum.xbmc.org/showthread.php?tid=148687&page=2
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Junior Mint Offline
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Post: #26
Does anyone know if this problem has been fixed in the nightlies, yet?
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Memphiz Offline
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Post: #27
Yes i know - its not and it won't for a while cause its hard to integrate into the new audio engine and nobody has taken that task yet.

AppleTV2/iPhone/iPod: HowTo find debug logs and everything else which the devs like so much: click here
HowTo setup NFS for XBMC: Wiki NFS
HowTo configure avahi (zeroconf): Wiki Avahi
READ THE IOS FAQ!: iOS FAQ
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Junior Mint Offline
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Post: #28
(2013-02-11 11:47)Memphiz Wrote:  Yes i know - its not and it won't for a while cause its hard to integrate into the new audio engine and nobody has taken that task yet.

Memphiz,

Thanks for the status update.
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jOe22 Offline
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Post: #29
Hello, just asking

Is there something new to this in 12.1 ?
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phase700b Offline
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Post: #30
No. AAC 5.1 isn't transcoded to AC3 5.1 yet.
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