On Fri Feb 20 10:51 , Steve Steffler sent: > >SPDIF output is 2-channel PCM only. To get 5.1 output you need to >send your receiver a passthrough AC3 or DTS stream, or enable Dolby >ProLogic II on your receiver to simulate the surround effect. > >You won't get the system to send 6 channels of raw PCM via S/PDIF, >it's only capable of surround when a digitally encoded compressed >stream (AC3/DTS) is passing through, due to bandwidth restrictions of >the optical signal. > >That's what I've been led to believe on my own journey to get a >similar system working over here on an AD1986a. > >Best of luck, >Steve > >On Feb 19, 2009, at 3:07 PM, brashquido@xxxxxxxxxxxxxx wrote: > >> Hi All, >> >> I've installed ALSA 1.0.19 on a fresh install of Mythbuntu 8.10 on two >> seperate machines, and I am trying to get digital audio pass through >> to >> work properly. One machine with an ALC888 soundcard with SPDIF >> output, and >> the other with a VT1708B soundcard with HDMI output. I have digital >> output >> working using the mplayer "-ao alsa:device=spdif" or "-ao >> alsa:device=hdmi" >> commands respectively, and the Dolby Digital and DTS indicators >> light up on >> my receiver that it is getting a valid digital audio stream. >> Ultimately I >> know it works as I can hear the audio tracks in my movies. >> >> The problem I am having is that I only seem to be getting 2 channels >> on >> both machines, and not only in mplayer as I've tested using speaker- >> test >> and also MythDVD. Both these cards are capable of 7.1 sound, but >> ultimately >> I need to configure them to output 5.1 (as that is all the receivers >> they >> are being connected to are capable of). I've scoured the Internet, but >> don't seem to be able to find any information on configuring the >> number of >> channels for SPDIF output. Can someone please help me? >> >> >> >> ------------------------------------------------------------------------------ >> Open Source Business Conference (OSBC), March 24-25, 2009, San >> Francisco, CA >> -OSBC tackles the biggest issue in open source: Open Sourcing the >> Enterprise >> -Strategies to boost innovation and cut costs with open source >> participation >> -Receive a $600 discount off the registration fee with the source >> code: SFAD >> http://p.sf.net/sfu/XcvMzF8H >> _______________________________________________ >> Alsa-user mailing list >> Alsa-user@xxxxxxxxxxxxxxxxxxxxx >> https://lists.sourceforge.net/lists/listinfo/alsa-user > > >------------------------------------------------------------------------------ >Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA >-OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise >-Strategies to boost innovation and cut costs with open source participation >-Receive a $600 discount off the registration fee with the source code: SFAD >http://p.sf.net/sfu/XcvMzF8H >_______________________________________________ >Alsa-user mailing list >Alsa-user@xxxxxxxxxxxxxxxxxxxxx >https://lists.sourceforge.net/lists/listinfo/alsa-user With Mythtv the process is simple. Make sure you are using the ALSA driver directly and not the OSS emulation. Select the AC3/DTS passthrough option and everything should work fine..This is located in the General section of the setup section in mythfrontend. That's in theory. In practice I needed a good /etc/asound.conf to get it working properly. There is an example on this page, http://www.mythtv.org/wiki/Configuring_Digital_Sound make sure that you modify it for your device (e.g. some are based on hw 0,0.. but you might need 0,1 or 0,2) and also ensure you are using "mixed-digital" as your default output.. This will route all output to your s/pdif output and convert any non 48 Khz signal to 48Khz so your tuner/decoder will understand it. ## Uncomment the following to use "mixed-digital" by default # slave.pcm "dmix-digital" Make sure you add a comment to the line below. slave.pcm "dmix-analog" Once this is setup restart ALSA.... Go into the setup section of Mythtv as above and select ALSA:default as your audio output. Oh and before you start make sure you have compiled ALSA-lib with the dmix option. cheers Allan ------------------------------------------------------------------------------ Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise -Strategies to boost innovation and cut costs with open source participation -Receive a $600 discount off the registration fee with the source code: SFAD http://p.sf.net/sfu/XcvMzF8H _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
