On 10/18/2016 12:04 AM, Clemens Ladisch wrote:
> Jay Foster wrote:
>> On 10/16/2016 11:47 PM, Clemens Ladisch wrote:
>>> Jay Foster wrote:
>>>> The sound comes out in short bursts with pauses in between.  Each pause
>>>> is accompanied with an underrun error
>>>> [...]
>>>> This makes me think the problem I am having is with the pcm plugin that
>>>> does the resampling.
>>> Apparently, it uses too much of your CPU (whatever it is).  [...]
>> 'aplay -D plughw:0 test.wav" did not make any difference.
>> [...]
>> would I have any better luck telling aplay to select the 44100 Hz output
>> rate and resample 220500 to 44100 instead?
> The exact target rate does not matter for CPU usage, and it's probably
> using 44100 already.
>
> Which resampling algorithm are you using? ("aplay -v -D plughw:0 test.wav")
> (The fastest one would be "linear".)
>
>> 400MHz armv5te
> This CPU might be too weak to do real-time resampling without special
> assembler optimizations.
>
>
> Regards,
> Clemens
>
The output from 'aplay -v -D plughw:0 test.wav'
Playing WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 22050 Hz, Mono
Plug PCM: Rate conversion PCM (44100, sformat=S16_LE)
Converter: libspeex (builtin)
Protocol version: 10002
Its setup is:
   stream       : PLAYBACK
   access       : RW_INTERLEAVED
   format       : S16_LE
   subformat    : STD
   channels     : 1
   rate         : 22050
   exact rate   : 22050 (22050/1)
   msbits       : 16
   buffer_size  : 11025
   period_size  : 2756
   period_time  : 125011
   tstamp_mode  : NONE
   tstamp_type  : MONOTONIC
   period_step  : 1
   avail_min    : 2756
   period_event : 0
   start_threshold  : 11025
   stop_threshold   : 11025
   silence_threshold: 0
   silence_size : 0
   boundary     : 722534400
Slave: Route conversion PCM (sformat=S16_LE)
   Transformation table:
     0 <- 0
     1 <- 0
Its setup is:
   stream       : PLAYBACK
   access       : MMAP_INTERLEAVED
   format       : S16_LE
   subformat    : STD
   channels     : 1
   rate         : 44100
   exact rate   : 44100 (44100/1)
   msbits       : 16
   buffer_size  : 22052
   period_size  : 5513
   period_time  : 125011
   tstamp_mode  : NONE
   tstamp_type  : MONOTONIC
   period_step  : 1
   avail_min    : 5513
   period_event : 0
   start_threshold  : 22052
   stop_threshold   : 22052
   silence_threshold: 0
   silence_size : 0
   boundary     : 1445199872
Slave: Hardware PCM card 0 'USB Audio Device' device 0 subdevice 0
Its setup is:
   stream       : PLAYBACK
   access       : MMAP_INTERLEAVED
   format       : S16_LE
   subformat    : STD
   channels     : 2
   rate         : 44100
   exact rate   : 44100 (44100/1)
   msbits       : 16
   buffer_size  : 22052
   period_size  : 5513
   period_time  : 125011
   tstamp_mode  : NONE
   tstamp_type  : MONOTONIC
   period_step  : 1
   avail_min    : 5513
   period_event : 0
   start_threshold  : 22052
   stop_threshold   : 22052
   silence_threshold: 0
   silence_size : 0
   boundary     : 1445199872
   appl_ptr     : 0
   hw_ptr       : 0
underrun!!! (at least 562.873 ms long)
Status:
   state       : XRUN
   trigger_time: 66491.687393162
   tstamp      : 66492.250212039
   delay       : -20
   avail       : 11045
   avail_max   : 11045
underrun!!! (at least 566.130 ms long)
Status:
   state       : XRUN
   trigger_time: 66494.2985491
   tstamp      : 66494.569089846
   delay       : 2734
   avail       : 8291
   avail_max   : 11045
underrun!!! (at least 551.742 ms long)
Status:
   state       : XRUN
   trigger_time: 66496.265264033
   tstamp      : 66496.816978168
   delay       : -20
   avail       : 11045
   avail_max   : 11045
underrun!!! (at least 518.706 ms long)
Status:
   state       : XRUN
   trigger_time: 66498.535974737
   tstamp      : 66499.54651071
   delay       : 2734
   avail       : 8291
   avail_max   : 11045
underrun!!! (at least 512.702 ms long)
Status:
   state       : XRUN
   trigger_time: 66500.843756142
   tstamp      : 66501.356430555
   delay       : -20
   avail       : 11045
   avail_max   : 11045

Looks like aplay is using libspeex (builtin) for conversion.  How can I 
select linear as you suggested?

Jay


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