[mythtv-users] corrupt audio with time stretch and SPDIF passthrough

Andrew mythtv at heathsworld.com
Sun Mar 21 04:17:22 UTC 2010


On Fri, Mar 19, 2010 at 9:57 AM, Jean-Yves Avenard <jyavenard at gmail.com>wrote:

> On 20 March 2010 01:55, Jean-Yves Avenard <jyavenard at gmail.com> wrote:
> >> and need to change it to run trunk or bleeding.
>
> Oh and if your amp is 5.1 ; make sure you set 5.1 for the speaker
> configuration in mythtv.
>
> Don't use stereo...
>
> Unlike 0.21 and 0.22 where you had to set Stereo for digital sound to
> get 5.1 ; the new audio code requires to be set at 5.1 is you want 5.1
> sound.
>

I do have it set to 5.1 and both ac3 and DTS checked. Pretty sure I have the
right version because when I changed my repo to Avenard all the audio
options changed to the new version. The receiver is decoding 5.1 perfectly
and time stretch works well.  Not sure if it matters but I have upmix set to
"best" and digital output device set to "ALSA:iec958:{ AES0 0x02 }.  Do I
need to setup a fallback audio device as shown in the mythtv digital audio
wiki (such as AES0=0x04,AES1=0x82,AES2=0x00,AES3=0x02)?

Some output that may be of interest.

root at myth:~# iecset -x
AES0=0x04,AES1=0x82,AES2=0x00,AES3=0x02
-------------------------------------------------------------------------
root at myth:~# aplay -L
default:CARD=Intel
    HDA Intel, AD198x Analog
    Default Audio Device
front:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    Front speakers
surround40:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    4.0 Surround output to Front and Rear speakers
surround41:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Intel,DEV=0
    HDA Intel, AD198x Analog
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=Intel,DEV=0
    HDA Intel, AD198x Digital
    IEC958 (S/PDIF) Digital Audio Output
null
    Discard all samples (playback) or generate zero samples (capture)
----------------------------------------------------------------------------------------------------------
root at myth:~# iecset
Mode: consumer
Data: audio
Rate: 48000 Hz
Copyright: permitted
Emphasis: none
Category: PCM coder
Original: original
Clock: 1000 ppm
---------------------------------------------------------------------------------------------------------

All outputs above are in the "working properly" state.  And lastly, is there
a command that I can use to check the state of the SPDIF or at least trouble
shoot what might be happening when sound borks?  Note that when this happens
even using mplayer on the command line will not work so it's like the SPDIF
is still getting stuck in nowhere.  Let me know if there is anything I can
do to help troubleshoot.
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