[mythtvnz] No sound on videos

[Nick Rout]

On Thu, Feb 18, 2010 at 3:53 PM, Steve Hodge <stevehodge at gmail.com> wrote:
> On Thu, Feb 18, 2010 at 1:40 PM, Robin Gilks <g8ecj at gilks.org> wrote:
>>
>> > On Wed, 17 Feb 2010 19:17:55 +1300, you wrote:
>> > Next problem: One of the files I want to be able to play has 24 kHz
>> > audio, and that still does not play.  I am guessing that means that
>> > the sound chip on the motherboard does not work below 32 kHz.  So does
>> > anyone know how to tell Alsa to upsample anything below 32 kHz?  I
>> > imagine what is needed is:
>> >
>> >   24 kHz => 48 kHz
>> >   22.5 kHz => 44.1 kHz
>> >
>>
>> Create (if you don't already have one) a file called .asoundrc in the home
>> account of the user running mythtv with the following
>>
>> pcm.!default {
>>    type plug
>>    slave.pcm "spdif"
>>    slave.rate 48000
>> }
>>
>> Works for me....
>
> I've done it that way as well, but it's not quite ideal as it resamples
> everything to 48kHz, regardless of what the hardware can actually take. Most
> S/PDIF inputs take 32, 44.1, and 48kHz so ideally you don't want to resample
> if the source is one of those rates. Anyone know if/how ALSA can be
> instructed to leave 32kHz and 44.1kHz data alone and resample everything
> else to 48kHz?

Yes the standard says spdif should take a number of sample rates,
however commonly the audio hardware in soundcards will only pass
48kHz. At least that's the way I understand it. So leaving 44.1 as
44.1 may not work, hardware dependent.