[pulseaudio-discuss] [PATCH] fix profile configurations for IEC/SPDIF outputs

Colin Guthrie gmane at colin.guthr.ie
Mon Jun 21 01:01:29 PDT 2010

'Twas brillig, and pl bossart at 21/06/10 03:44 did gyre and gimble:
> I find it very strange to encode with a52 and rely on surround40.
> The latter duplicates what PulseAudio could do,

I appreciate that the mapping "iec958-surround-40" may be irrelevant
seeing as spdif only support stereo PCM, but the I don't really follow
the "duplicates what PA could do" bit. Can you explain a bit?

> and the former is a lossy codec that will decrease the audio quality
> while increasing the workload on your computer. You are probably
> better off sending stereo and letting your receiver doing the
> post-processing.

Hmm, I don't follow here. What if your source is 5.1? Are you saying we
should downmix the 5.1 source to stereo and then send the stereo over
spdif then let the receiver try and do the best it can with it, e.g. via

To me that doesn't make sense. I'd rather encode my 5.1 source as DD/AC3
and send the whole thing over spdif. But that said, if it's a really bad
method of working, then I'd say get the replacement implemented before
removing potentially useful bits without any timetable for it's replacement.

So how do you propose to send 5.1 streams over spdif without using pure
passthough if not via a DD/AC3 encoder of some sort? Are you able to
implement DDL or DTS?



Colin Guthrie

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