Opened 7 years ago

Closed 7 years ago

#9989 closed Patch - Bug Fix (fixed)

no sound with 5ch AC3 audio with 6 CH audio out

Reported by: markspieth Owned by: jyavenard
Priority: minor Milestone: 0.25
Component: MythTV - Audio Output Version: Master Head
Severity: medium Keywords:
Cc: Ticket locked: no


If a 5 channel AC3 audio program is played with a 5.1 alsa audio output, no sound is heard. This is because alsa does not support 5 ch output. The solution is to upmix 5ch audio to 6 ch if required.

channel affected is OneHD with some sports like Nascar having this format.

patch attached.

Attachments (1)

28-audio5chan (7.5 KB) - added by markspieth 7 years ago.

Download all attachments as: .zip

Change History (5)

Changed 7 years ago by markspieth

comment:1 Changed 7 years ago by jyavenard

Is this with digital audio out (PCM) or analog out ?

On my hdmi output, where 5 channels isn't supported, then it gets converted to AC3 and play 5.0 just fine

comment:2 Changed 7 years ago by jyavenard

could you provide a sample?

I remember recording one of those, but I guess it will be faster with a provided sample.

I see issues with the existing patch, in particular it will break mono-audio playback...

I will redo it and hopefulyl will be done today

comment:3 Changed 7 years ago by jyavenard

Ok, I've found one (the fear factor on One HD)

After a quick glance at your patch I can see the following problems:

  • Mono will be upmixed through freesurround upmixer (and not the mono -> stereo one)
  • If upmixing isn't enabled, then the 5.0 to 5.1 conversion will not occur. And you can't toggle the upmixer as it only works if source is stereo.

comment:4 Changed 7 years ago by Github

  • Milestone changed from unknown to 0.25
  • Resolution set to fixed
  • Status changed from new to closed

Allow 5.0 audio playback on hardware not supporting it.

ALSA doesn't support 5.0 audio and myth could only upmix mono and stereo. Extend upmixer to work with 5.0 audio. Based on a patch by Mark Spieth Fixes #9989

Branch: master Changeset: 909b444ede4dd08fe1e468b969aa9928bbc6a131

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