2

What is the maximum supported audio sampling rate supported with the Raspberry Pi's HDMI output? When I play 24 bit, 96KHz tracks in MPD, it appears to be resampling down to 48KHz, as reported by:

$ cat /proc/asound/card0/pcm0p/sub0/hw_params 
access: RW_INTERLEAVED
format: S16_LE
subformat: STD
channels: 2
rate: 48000 (48000/1)
period_size: 4096
buffer_size: 16384
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If you look at the Raspbian kernel source code, you will see that the limit it is set at 48 kHz.

It should be possible to overcome that limit if you modify the bcm2835-pcm.c file and recompile the kernel.

  • Thanks for the link. Do you know if there are separate limits for analog and HDMI? I believe the DAC only supports 48KHz, so I don't know what would happen if that gets exceeded on analog. – Elliott B Jan 16 '14 at 7:19
  • It's very unlikely that the analogue output has a separate, higher-spec DAC. – scruss Jan 16 '14 at 12:32
  • @ElliottB 48 kHz is the max for all sound devices on the Raspberry Pi. Without recompiling, you can't exceed that for analog or HDMI. – syb0rg Jan 16 '14 at 13:34
  • Right, I got that from your answer syb0rg. What I mean is, if I recompile, increasing HDMI to 192KHz, might that cause problems if some software tries to send 192KHz audio to the analog output? – Elliott B Jan 16 '14 at 17:23
  • @ElliottB I can't say for sure, I haven't tried it. – syb0rg Jan 16 '14 at 19:34

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