[mythtv] [patch] multichannel ac3 audio v11

Rich Goodin rich at goodin.com
Sun Jan 15 20:57:24 UTC 2006

Hi Mark,

Thanks for all the work on the AC3 analog stuff. I've been playing  
around with ver 5 (I just found version 11 today) and had problems  
with the decoded data apparently not matching the channel. I've got  
an Audigy 2 with 5.1 surround and would be glad to test for you. I'm  
building 11 now to take a look.

Rich Goodin

On Jan 15, 2006, at 5:05 AM, Mark Spieth wrote:

> thanks to bill cizek and martin ebourne I got a bit of testing done  
> so Id thought Id release another public test version.
> It appears to work in 6 channel mode with timestretch however it  
> appears to shift the channels for bill.
> I need this confirmed on other setups if possible.
> this could mean a52 decoder and ac3enc in avcodec do things  
> slightly differently but have not determined what yet after looking  
> at it for a while.
> Ill need to run some back to back enc/dec tests but havent had time  
> yet.
> It also appears to work for analog out 6 channels in alsa though  
> cant confirm that 100%.
> 3 channels appears not to work due to a52 decoder doing something  
> wrong ( not that this is important for ac3 passthru people :)
> analog will probably not rematrix 2 to 6 channels correctly due to  
> the different output arrangement unless something can be done to  
> tell the driver what the channel->speaker pos mapping is but I  
> doubt that has been considered ATM.
> note it still requires a decent cpu to do timestretch due to lack  
> of mmx but does work (so Im told) and ac3 5.1 enc requires 5ms per  
> 32ms audio frame on my XP2000+. nice to hear the ticking of the dig  
> stream in my analog speakers :)
> If you have a nice 3G+ machine you shouldnt have any problems.
> feedback always welcome.
> cheers
> mark
> <mythtv_ac3.11.patch.bz2>
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