Re: [Ekiga-list] A comparison ALSA-PULSE



Alec Leamas wrote:
> 
>> Its setup is:
>>   stream       : PLAYBACK
>>   access       : RW_INTERLEAVED
>>   format       : S16_LE
>>   subformat    : STD
>>   channels     : 2
>>   rate         : 44100
>>   exact rate   : 44100 (44100/1)
>>   msbits       : 16
>>   buffer_size  : 22050
>>   period_size  : 5512
>>   period_time  : 125000
>>   tstamp_mode  : NONE
>>   period_step  : 1
>>   avail_min    : 5512
>>   period_event : 0
>>   start_threshold  : 22050
>>   stop_threshold   : 22050
>>   silence_threshold: 0
>>   silence_size : 0
>>   boundary     : 1445068800
>>
>>  

I attach more output.
What you have seen so far was the log when ekiga plays the ring tone (by far the most damaged sound).
When running the echo test the setup is different

  stream       : PLAYBACK
  access       : RW_INTERLEAVED
  format       : S16_LE
  subformat    : STD
  channels     : 1
  rate         : 8000			<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
  exact rate   : 8000 (8000/1)		<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
  msbits       : 16
  buffer_size  : 800
  period_size  : 160
  period_time  : 20000
  tstamp_mode  : NONE
  period_step  : 1
  avail_min    : 160
  period_event : 0
  start_threshold  : 1
  stop_threshold   : 800
  silence_threshold: 0
  silence_size : 0
  boundary     : 1677721600

And I cannot see any underrun at all. My echo test uses PCMA. It is possible that with a better
codec (i.e. higher rate that 8000), we see them again. Don't really know how to test.

I would say that the quality of the echo test with or without pulse is the same (but being only 8000
Hz, it is already not perfect and more difficult to judge).

All my tests so far have been run in debug, so the speed of ekiga/opal/ptlib is already lower the
release. The quality of the ring tone is though more or less the same. I will try to rerun
everything in release.

I have 2 points

1) Is the following true: ekiga-pulse gives bad audio quality because there are underruns.
So, if for some connection there are no underruns (e.g. my echo test) then, the quality is not
expected to be lower than alsa-direct, and we should not complain about pulse.

2) If underruns are (the) evil (or at least the biggest problem), then it would be good to print
some indication of how close to the underrun we are. Does alsa provide that? Is it already part of
my log?

I still have not fully understood your comments about the values printed in the log. I need to get
familiar with the terminology.

And I have not yet checked for overruns when reading from the microphone.

Andrea

Attachment: echo.direct.txt.gz
Description: GNU Zip compressed data

Attachment: echo.pulse.txt.gz
Description: GNU Zip compressed data



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