[mythtv-users] 0.24 Audio Upmixing Issues

Scott & Nicole Harris snharris99 at live.com
Tue Nov 23 01:37:31 UTC 2010

I am currently running MythTV 0.24.0+fixes
(0.24.0+fixes27315-0ubuntu0+mythbuntu1 to be exact) with a Turtle Beach 
Riviera connected to my receiver via an optical connection.  Stereo upmixing 
stopped working as of a couple builds ago.  I filed a bug 
http://svn.mythtv.org/trac/ticket/9257 and JYA incorrectly mistook my 
position that the ticket still doesn’t appear to be resolved and providing 
him with as much detail as possible to work with as fishing for PC 
configuration advice and locked the ticket.

However, I am more than willing to seek configuration advice if it is indeed 
a configuration issue.  I have managed to solve the MythMusic playback issue 
by setting the music audio device to ALSA:default, which allows me to use 
any detected device on the TV side (which admittedly I didn't know there was 
a spot to set the audio device for MythMusic).

On JYA's advice in the ticket that I was using the wrong device because 
"default" won't do pass through, I currently have it set to 
iec958:CARD=CMI8738,DEV=0, with no other settings other than enabling Dolby, 
DTS and upmixing.  This provides proper surround for surround enabled 
streams, however stereo streams are still not being upmixed.  I have cycled 
through every detected device, with every possible combination of settings 
that makes sense, and none of them result in stereo being upmixed.

This is in TV (live / recorded) only.  MythVideo appears to be upmixing.

As I indicate in the ticket, my results from aplay –L are...

    Discard all samples (playback) or generate zero samples (capture)
    C-Media CMI8738, C-Media PCI DAC/ADC
    Default Audio Device
    C-Media CMI8738, C-Media PCI DAC/ADC
    Front speakers
    C-Media CMI8738, C-Media PCI 2nd DAC
    Rear speakers
    C-Media CMI8738, C-Media PCI 2nd DAC
    4.0 Surround output to Front and Rear speakers
    C-Media CMI8738, C-Media PCI 2nd DAC
    4.1 Surround output to Front, Rear and Subwoofer speakers
    C-Media CMI8738, C-Media PCI 2nd DAC
    5.0 Surround output to Front, Center and Rear speakers
    C-Media CMI8738, C-Media PCI 2nd DAC
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
    C-Media CMI8738, C-Media PCI DAC/ADC
    IEC958 (S/PDIF) Digital Audio Output

Here is an output from playing a stereo only channel from this morning, 
which looks to me like it fully recognizes it is a pass through device that 
supports 6 channels, yet is still just doing the 2 channel with out 
attempting to upmix it.

2010-11-22 07:25:45.064 TV: Changing from None to WatchingLiveTV
2010-11-22 07:25:45.064 TV: State is LiveTV & mctx == ctx
2010-11-22 07:25:45.067 TV: UpdateOSDInput done
2010-11-22 07:25:45.067 TV: UpdateLCD done
2010-11-22 07:25:45.067 TV: ITVRestart done
2010-11-22 07:25:45.159 VDPAU: Added 2 output surfaces (total 4, max 4)
2010-11-22 07:25:45.330 Player(0): DecoderGetFrame() called with NULL 
2010-11-22 07:25:46.281 
RingBuf(myth:// Waited 0.2 
seconds for data
            to become available... 3912 < 32768
2010-11-22 07:25:46.281 Checking to see if there's a new livetv program to 
switch to..
2010-11-22 07:25:46.397 VDPAU Painter: Clearing VDPAU painter cache.
2010-11-22 07:25:46.400 MythPainter: 8 images not yet de-allocated.
2010-11-22 07:25:46.444 Clearing OpenGL painter cache.
2010-11-22 07:25:46.522 VDPAU: Created 2 output surfaces.
2010-11-22 07:25:46.523 VDPAU: Created VDPAU render device 1360x768
2010-11-22 07:25:46.560 Player(0): Forcing decode extra audio option on 
(Video method requires it).
2010-11-22 07:25:46.560 AFD: Opened codec 0x1fe3200, id(MPEG2VIDEO) 
2010-11-22 07:25:46.560 AFD: codec AC3 has 2 channels
2010-11-22 07:25:46.561 AFD: Opened codec 0x2057290, id(AC3) type(Audio)
2010-11-22 07:25:46.561 AFD: Audio Track #1 is A/V stream #1 and has 2 
channels in the English language(6647399).
2010-11-22 07:25:46.666 AFD: Selected track 1: English AC3 2ch (A/V Stream 
2010-11-22 07:25:46.666 AFD: Initializing audio parms from audio track #1
2010-11-22 07:25:46.666 AFD: Audio format changed
            from id(NONE)     -1Hz -1ch -1bps     to id( AC3)  48000Hz  2ch 
16bps  pt
2010-11-22 07:25:46.666 AO: Killing AudioOutputDSP
2010-11-22 07:25:46.797 Pulse: PulseAudio not running
2010-11-22 07:25:46.803 AO: Sample rate 44100 is supported
2010-11-22 07:25:46.803 AO: Sample rate 48000 is supported
2010-11-22 07:25:46.803 AO: Sample rate 88200 is supported
2010-11-22 07:25:46.803 AO: Sample rate 96000 is supported
2010-11-22 07:25:46.803 AO: 2 channel(s) are supported
2010-11-22 07:25:46.821 AO: AC3 or DTS capable
2010-11-22 07:25:46.822 AO: 6 channel(s) are supported
2010-11-22 07:25:46.822 AO: Killing AudioOutputDSP
2010-11-22 07:25:46.822 AO: Original codec was AC3, signed 16 bit, 48 kHz, 2 
2010-11-22 07:25:46.822 AO: enc(0), passthru(1), canAC3(1), canDTS(1), 
canLPCM(0), configured_channels(6), 2 channels supported(1)
2010-11-22 07:25:46.822 AO: Opening audio device 'iec958:CARD=CMI8738,DEV=0' 
ch 2(2) sr 48000 sf signed 16 bit reenc 0
2010-11-22 07:25:46.822 Opening ALSA audio device 
2010-11-22 07:25:46.823 ALSA: SetParameters(format=2, channels=2, 
rate=48000, buffer_time=200000, period_time=50000)I]
2010-11-22 07:25:46.824 ALSA: Buffer time = 200000 us
2010-11-22 07:25:46.824 ALSA: Period time = 50000 us
2010-11-22 07:25:46.824 ALSA: Buffer size = 9600 | Period size = 2400
2010-11-22 07:25:46.824 AO: Audio fragment size: 4800
2010-11-22 07:25:46.824 AO: Audio Stretch Factor: 1
2010-11-22 07:25:46.824 AO: Ending Reconfigure()
2010-11-22 07:25:46.825 AudioPlayer: Enabling Audio
2010-11-22 07:25:46.825 AO: Reconfigure(): No change -> exiting
2010-11-22 07:25:46.825 AO: kickoffOutputAudioLoop: pid = 2859
2010-11-22 07:25:46.825 AO: OutputAudioLoop: Play Event
2010-11-22 07:25:46.948 AO: Pause 0
2010-11-22 07:25:46.949 AO: Pause 1
2010-11-22 07:25:46.957 AO: OutputAudioLoop: audio paused
2010-11-22 07:25:46.987 AO: Pause 0
2010-11-22 07:25:46.990 VDPAU: Added 2 output surfaces (total 4, max 4)
2010-11-22 07:25:47.007 AO: OutputAudioLoop: Play Event
2010-11-22 07:25:53.907 TV: Attempting to change from WatchingLiveTV to None

Can anyone offer me any advice on getting upmixing going again?

When JYA indicates in the ticket that it is fixed in changeset r27299, does 
that mean if I have 0.24.0+fixes27299, we are on the same page, or does 
“changeset” 27299 mean that it may still take a few builds to work back in?
Could the Mythbuntu builds be even further behind? This is one thing that 
has always been a bit of a mystery to me, and may clear up a lot.


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