[mythtv] [mythtv-commits] Ticket #3608: Latest ffmpeg sync causes decoded AC3 audio to sound like it is going through a table fan.

Janne Grunau janne-mythtv at grunau.be
Mon Jun 25 01:54:08 UTC 2007

On Monday 25 June 2007 02:55:52 Mark Spieth wrote:
> I noticed you enabled liba52 and changed the ac3 stuff.

argh, wrong patch.

> you didnt need to change the ac3 stuff (looks regressed),

It's not. that's the final form of the ac3 decoder patch which is 
already approved but not committed upstream.

> just disable it.

Hah, funny. It has to be enabled as default. We don't want to add the 
liba52 dependency.

> since there are 2 ac3 decoders in the lavc, you cant be 
> sure which one its going to pick.

with the new patch the liba52 decoder will only picked if the internal 
ac3 decoder is enabled.

> I dont believe the internal decoder has ever
> been used before the latest ffmpeg sync.

No, how should it. it isn't even committed to ffmpeg's subversion repo. 
ffmpeg had a liba52 copy in libavcodec. It has been removed between our 
last two ffmpeg syncs.
Since we don't wanted to add liba52 as additional dependency I patched 
our libavcodec copy with a preliminary AC3 decoder patch.

> my current configure which works with channel 10 melb (AC3)
> is --enable-liba52bin --enable-liba52 --disable-decoder=ac3
> --enable-decoder=liba52
> I suspect 2 items are superfluous.

--enable-decoder=liba52 is superfluous. --enable-liba52bin uses liba52 
with dlopen(). It's not needed but I wouldn't call it superfluous.


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