[mythtv-users] AC3 passthrough not working

Richard Shaw hobbes1069 at gmail.com
Sun Apr 12 02:10:30 UTC 2009


On Sat, Apr 11, 2009 at 8:53 PM, Nick Morrott <knowledgejunkie at gmail.com> wrote:
> On 12/04/2009, Richard Shaw <hobbes1069 at gmail.com> wrote:
>> On Sat, Apr 11, 2009 at 8:31 PM, Allen Edwards
>> > Why on earth would you want to resample.  The goal should bit true digital
>>  > output.  Pass the bits to the receiver and let it do a DAC.  For best
>>  > quality, don't decode, encode, decode just decode.
>>  > Allen
>>
>>
>> He may not have a choice. Some sound cards will not output anything
>>  other than 48kHz. My nForce3 based MB didn't seem to want to but then
>>  again, I haven't tried now that I've gone to an AMD chipset MB.
>
> And similarly, some S/PDIF inputs require 48kHz PCM input. This is why
> you'll see messages stating that digital TV recordings work (48kHz)
> but CDs ripped to MP3 (44kHz) do not.
>
> Nick

Interestingly enough, I just did a simple test on my desktop, i.e.
"aplay -D spdif Shutdown1.wav" or something like that. I just picked a
file out of /usr/share/sounds and it worked! aplay showed it was a
44.1kHz file. I tried /usr/share/sounds/alsa first but those we
already 48kHz. Now I just need to see if my Home Theater receiver
minds 44.1kHz PCM audio.

Richard


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