[mythtv-users] alsa, spdif, and multiple sample rates

Eric Jorgensen alhaz at xmission.com
Tue Dec 19 05:02:10 UTC 2006


One of my mythtv frontend boxes is a system with an au8830 sound card
that has a SigmaTel STAC9708/11 codec. 

This card supports at least 44.1khz and 48khz. iirc it also supports
32khz. 

Using mplayer, I can output pcm to my Sony DTS receiver at 44.1khz and
48khz depending on the source file. The receiver's front panel
display indicates what's coming over the wire when it syncs up, so there
is no confusion here. 

I couldn't get mythfrontend to output anything at all to the spdif
device until i used iecset to manually switch it to 48khz. 

After doing that, PCM, AC3, and DTS all work. 

This seems fairly obtuse. Why can't mythtv successfully change the
sample rate by itself? 

Here is my .asoundrc: 

pcm.au8830 {
   type hw
   card 0
}

ctl.au8830 {
   type hw
   card 0
}
!defaults.pcm.card 0
defaults.ctl.card 0
defaults.pcm.device 0
defaults.pcm.subdevice -1

defaults.pcm.iec958.card 0
defaults.pcm.iec958.device 0

And here is the output from aplay -l -- apologies for the length. 

**** List of PLAYBACK Hardware Devices ****
card 0: au8830 [Aureal Vortex au8830], device 0: AU88x0 ADB [adb]
  Subdevices: 32/32
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
  Subdevice #8: subdevice #8
  Subdevice #9: subdevice #9
  Subdevice #10: subdevice #10
  Subdevice #11: subdevice #11
  Subdevice #12: subdevice #12
  Subdevice #13: subdevice #13
  Subdevice #14: subdevice #14
  Subdevice #15: subdevice #15
  Subdevice #16: subdevice #16
  Subdevice #17: subdevice #17
  Subdevice #18: subdevice #18
  Subdevice #19: subdevice #19
  Subdevice #20: subdevice #20
  Subdevice #21: subdevice #21
  Subdevice #22: subdevice #22
  Subdevice #23: subdevice #23
  Subdevice #24: subdevice #24
  Subdevice #25: subdevice #25
  Subdevice #26: subdevice #26
  Subdevice #27: subdevice #27
  Subdevice #28: subdevice #28
  Subdevice #29: subdevice #29
  Subdevice #30: subdevice #30
  Subdevice #31: subdevice #31
card 0: au8830 [Aureal Vortex au8830], device 1: AU88x0 SPDIF [spdif]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: au8830 [Aureal Vortex au8830], device 2: AU88x0 A3D [a3d]
  Subdevices: 16/16
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
  Subdevice #8: subdevice #8
  Subdevice #9: subdevice #9
  Subdevice #10: subdevice #10
  Subdevice #11: subdevice #11
  Subdevice #12: subdevice #12
  Subdevice #13: subdevice #13
  Subdevice #14: subdevice #14
  Subdevice #15: subdevice #15
card 0: au8830 [Aureal Vortex au8830], device 3: AU88x0 WT [wt]
  Subdevices: 64/64
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
  Subdevice #8: subdevice #8
  Subdevice #9: subdevice #9
  Subdevice #10: subdevice #10
  Subdevice #11: subdevice #11
  Subdevice #12: subdevice #12
  Subdevice #13: subdevice #13
  Subdevice #14: subdevice #14
  Subdevice #15: subdevice #15
  Subdevice #16: subdevice #16
  Subdevice #17: subdevice #17
  Subdevice #18: subdevice #18
  Subdevice #19: subdevice #19
  Subdevice #20: subdevice #20
  Subdevice #21: subdevice #21
  Subdevice #22: subdevice #22
  Subdevice #23: subdevice #23
  Subdevice #24: subdevice #24
  Subdevice #25: subdevice #25
  Subdevice #26: subdevice #26
  Subdevice #27: subdevice #27
  Subdevice #28: subdevice #28
  Subdevice #29: subdevice #29
  Subdevice #30: subdevice #30
  Subdevice #31: subdevice #31
  Subdevice #32: subdevice #32
  Subdevice #33: subdevice #33
  Subdevice #34: subdevice #34
  Subdevice #35: subdevice #35
  Subdevice #36: subdevice #36
  Subdevice #37: subdevice #37
  Subdevice #38: subdevice #38
  Subdevice #39: subdevice #39
  Subdevice #40: subdevice #40
  Subdevice #41: subdevice #41
  Subdevice #42: subdevice #42
  Subdevice #43: subdevice #43
  Subdevice #44: subdevice #44
  Subdevice #45: subdevice #45
  Subdevice #46: subdevice #46
  Subdevice #47: subdevice #47
  Subdevice #48: subdevice #48
  Subdevice #49: subdevice #49
  Subdevice #50: subdevice #50
  Subdevice #51: subdevice #51
  Subdevice #52: subdevice #52
  Subdevice #53: subdevice #53
  Subdevice #54: subdevice #54
  Subdevice #55: subdevice #55
  Subdevice #56: subdevice #56
  Subdevice #57: subdevice #57
  Subdevice #58: subdevice #58
  Subdevice #59: subdevice #59
  Subdevice #60: subdevice #60
  Subdevice #61: subdevice #61
  Subdevice #62: subdevice #62
  Subdevice #63: subdevice #63





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