Ticket #167 (new enhancement)

Opened 2 years ago

Last modified 2 months ago

Support AC3 Passthrough

Reported by: FireRabbit Owned by: lennart
Milestone: Component: core
Keywords: Cc: eric@…, anssi@…, belegdol@…, philip@…

Description

It would be great if PulseAudio could pass AC3 audio streams directly to a SPDIF/IEC958 alsa device without modifying them. This enables surround sound receivers to function properly.

I could dig up some free 5.1 channel sample files if this would help.

Thanks!

Change History

in reply to: ↑ description   Changed 2 years ago by X04D

  • priority changed from normal to high
  • component changed from daemon to core
  • severity changed from normal to major

What's the status on this? Is true passthrough available yet?

  Changed 2 years ago by candrews

Another vote for this one!

  Changed 2 years ago by Garlic

I vote for this, too

  Changed 2 years ago by hackeron

Hmm, you can't do passthrough in pulseaudio? -- Looks like I'm moving back to plain alsa for now.

  Changed 2 years ago by lennart

  • priority changed from high to low
  • severity changed from major to minor

  Changed 2 years ago by hackeron

Why is the only way to support 5.1, 7.1 or any other kind of surround sound changed to a low priority feature?

  Changed 2 years ago by coling

Pulse supports surround just fine. Just not via AC3 passthrough.

follow-up: ↓ 9   Changed 2 years ago by hackeron

OK, how would I get surround sound through SPDIF (optical or coaxial) with pulseaudio?

in reply to: ↑ 8   Changed 2 years ago by coling

Replying to hackeron:

OK, how would I get surround sound through SPDIF (optical or coaxial) with pulseaudio?

I'd ask this on the PA mailing list as Trac is not the correct medium to discuss this. The short answer is load an alsa sink with a device=spdif:0 or something like that (/me has not tried). If you look at the ML archives, there are people discussing exactly this over the last few days (and me jumping in with an incorrect comment to muddy the waters ;))

  Changed 2 years ago by coling

My last comment here: You probably want to see Jim Duda's thread: "0.9.8 - Invalid value for card". HTHs

  Changed 2 years ago by lennart

SPDIF doesn't support uncompressed audio with more than two channels. Only AC3 via SPDIF supports more than two.

For analog audio however, we do support surround just fine.

  Changed 20 months ago by ari

+1 for AC3 passthrough support over SPDIF in pulseaudio. This is the only feature I really miss in pulseaudio in my soon-to-be linux media center.

When playing back a movie that has ac3 / dolby audio and spdif is being used, and there is no other audio stream active (no mixing) then it would be great for pulseaudio to let the ac3 stream go through spdif with no decoding/encoding overhead... which I'm guessing would affect the stream quality.

  Changed 4 months ago by fa5hion

16 months since last comment. Any estimate on when this feature is going to be implemented? AC3 passthrough with PA would be awesome. Lennart?

  Changed 4 months ago by Anssi

  • cc anssi@… added

  Changed 2 months ago by belegdol

  • cc belegdol@… added

  Changed 2 months ago by foolip

  • cc philip@… added
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