[mythtv] Internal DVD Player multichannel support
m-mythtv at goof.com
Mon May 1 18:53:09 UTC 2006
I'm willing to lend a hand on this patch as well. I'm not quite in the same
boat as Ed, in that I have an actual receiver, but it is 11 years old, and
originally you were to purchase an external AC3 decoder for it. I had the
external decoder, but it crapped out a few years back. Because the receiver is
quite good and there is no other reason to replace it, I've just purchased DVD
players with built-in AC3/DTS decoders since the loss of the external AC3
decoder. Because the receiver has a DB25 input for carrying pre-decoded audio
to the 5.1 channels, I'd like to wire up an adapter for the sound card output.
I have not taken a look at the patch yet, though I've been aware of its
existence and intended to look at it once I get a few other things about my
myth system stable. Does it currently provide for both AC3/DTS decoding to 6
analog outputs as well as decoding DPL/DPLII to 6 analog outputs? Having
mythtv (and whatever ends up playing DVDs when done through myth) properly
output to all 6 channels given source material in DPL/DPLII and AC3/DTS would
make life a lot easier - I could just leave the receiver in "external decoder"
mode and be done with it. Maybe a keystroke in the different playback modes to
switch between surround and "bypass" (stereo (front L+R), but with intelligence
to steer bass to the LFE channel) would be a good thing to do as well.
Let me know if there's a way I can help out on this.
Thanks for the effort so far on the patch.
Ed W wrote:
>> this is what it does.
> Aha, wasn't obvious that it did that just by eyeballing the patch - I
> could just see the AC3 stuff and misunderstood - sorry
> So what's the big barrier to getting some of this committed? Most of it
> looked quite reasonable just eyeballing the patch?
>> you can do this too. I was just supporting what people wanted. works fine.
>> AC3 reencoding is in audiobase only. however I needed to pass some info
>> between the layers.
>> this is part of my rethink but it is necessary in some way. Ideally the
>> audio layer should control the decode parameters instead of being pushed
>>from decoder to audio layer. its a bit nasty.
>> no point reencoding if its already AC3 and no timestretch is being used.
>> just wastes CPU. and it does use a fair bit.
> I guess the issue is probably that the decoder is setup before
> initialising the audio? If we initialised the audio first then we could
> request a certain number of channels, have it fail and tell us how many
> it's really got and then fall back to using that? This wouldn't catch
> the case of someone with a multichannel card and only two speakers
> hooked up, but it would help for the two channel card or spdif setup?
> Seems really promising anyway! What can I do to help some or all of
> this get committed?!
> Ed W
> mythtv-dev mailing list
> mythtv-dev at mythtv.org
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