Opened 10 years ago

Closed 10 years ago

Last modified 10 years ago

#9257 closed Bug Report (Fixed)

Audio Upmixing Does Not Appear to be Working

Reported by: Scott Harris <snharris99@…> Owned by: JYA
Priority: minor Milestone: unknown
Component: MythTV - Audio Output Version: 0.24-fixes
Severity: medium Keywords:
Cc: Ticket locked: yes


Upmixing of 2 channel audio appears to have been broken in the last couple auto builds.

Mythbuntu 10.04 64 bit, mythfrontend 24.0+fixes27280-0ubuntu0+mythbuntu1

results from aplay -L, which lines up with result when scanning for audio devices within myth.

    Discard all samples (playback) or generate zero samples (capture)
    C-Media CMI8738, C-Media PCI DAC/ADC
    Default Audio Device
    C-Media CMI8738, C-Media PCI DAC/ADC
    Front speakers
    C-Media CMI8738, C-Media PCI 2nd DAC
    Rear speakers
    C-Media CMI8738, C-Media PCI 2nd DAC
    4.0 Surround output to Front and Rear speakers
    C-Media CMI8738, C-Media PCI 2nd DAC
    4.1 Surround output to Front, Rear and Subwoofer speakers
    C-Media CMI8738, C-Media PCI 2nd DAC
    5.0 Surround output to Front, Center and Rear speakers
    C-Media CMI8738, C-Media PCI 2nd DAC
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
    C-Media CMI8738, C-Media PCI DAC/ADC
    IEC958 (S/PDIF) Digital Audio Output

MythTV Audio Settings in "General"...

Audio output device: default:CARD=CMI8738[[BR]] Dolby: Enabled
DTS: Enabled
Speaker Config: 5.1
Upconvert: enabled
Upmix Quality: Best
Advanced audio configuration: enabled
Separate digital output device: enabled
Digital output device: ALSA:iec958:{ AES 0x02 }

I have no special config files, this is all from a standard installation. These setting produced upmixed audio up until the last couple builds for the channel I played in the attached log. Attached to my receiver with an optical connection.

Attachments (1)

playback.log (13.2 KB) - added by Scott Harris <snharris99@…> 10 years ago.
output from mythfrontend -v audio playing a channel with stereo only sound

Download all attachments as: .zip

Change History (9)

Changed 10 years ago by Scott Harris <snharris99@…>

Attachment: playback.log added

output from mythfrontend -v audio playing a channel with stereo only sound

comment:1 Changed 10 years ago by Scott Harris <snharris99@…>

I should add that using any other card after an audio scan other than default:CARD=CMI8738

produces no audio for TV (live or recorded). I had to enable the separate digital output device, because without it, sound in MythMusic was "garbled", almost like it was trying to shove the rear speaker output through the front speakers, slightly behind.

comment:2 Changed 10 years ago by Kenni Lund [kenni a kelu dot dk]

Component: MythTV - GeneralMythTV - Audio Output
Owner: set to JYA
Status: newassigned

comment:3 Changed 10 years ago by JYA

Resolution: Fixed
Status: assignedclosed

Fixed in r27299

comment:4 Changed 10 years ago by anonymous

I installed r27299 this morning, with the same results, no upmixed audio.

I did notice this morning (and it may have been there earlier and I didn't notice it) that the "Digital output device:" setting beside the "Separate digital output device:" option is now marked as deprecated. I tried disabling the separate output device setting and kept my audio output divice as "default:CARD=CMI8738". With this setup, with Live / Recorded TV, I had stereo only sound with "Speaker configuration" set to stereo, and no sound at all with it set to 5.1. I had to re-enable the separate to get my 5.1 back for TV.

comment:5 Changed 10 years ago by JYA

default is usually not a digital enabled device, e.g. you can not have passthrough

fix your audio settings and use the proper device output

comment:6 Changed 10 years ago by anonymous

The only other device that produces any sound at all is "iec958:CARD=CMI8738,DEV=0" which was both the intuitive choice for me in the first place, and does not require the "separate digital output" setup to get full surround on TV feeds with a surround audio track. However, as I indicated in the original ticket, using it makes the audio from MythMusic horrific. The stereo sound from MythMusic is completely garbled like 5 channels of sound are trying to come through 2 channels, with a delay...imagine a horrible echo on everything you hear.

Regardless of that, even using the iec card, there is still no upmixing present on 2 channel TV feeds.

comment:7 Changed 10 years ago by Scott Harris <snharris99@…>

I now have my settings as follows Audio output device: ALSA:iec958:CARD=MCI8738,DEV=0[[BR]] Doly Digital: Enabled
DTS: enabled
Speaker configuration: 5.1
Upconvert stero to 5.1 surround: enabled
Upmix Quality: Best
Nothing enabled in Advanced audio configuration

I solved the MythMusic "garbled" issue by setting the Audio device in Music Settings>General to "ALSA:default". I did not know that setting was there, so it was set to use the default device from the general settings.

I have full surround surround on TV (if it's a surround feed), without using a separate digital output device. However, stereo TV feeds are still coming through as 2 channel only, with no upmixing.

comment:8 Changed 10 years ago by JYA

Ticket locked: set

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