bugLINGOT Is Not a Guitar-Only Tuner - Bugs: bug #38279, Sound wrapped when sampling with...

 
 

bug #38279: Sound wrapped when sampling with 16bit

Submitted by:  Ibán Cereijo <ibancereijo>
Submitted on:  Thu 07 Feb 2013 12:17:35 AM UTC  
 
Category: NoneSeverity: 5 - Blocker
Item Group: NoneStatus: Ready For Test
Privacy: PublicAssigned to: Ibán Cereijo <ibancereijo>
Open/Closed: Open

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Thu 07 Feb 2013 03:37:28 PM UTC, comment #1:

Added images with time and frequency response at different stages for sample formats of 16 (int) and 32 (float) bits.

The stages depicted are:

  • Before the antialiasing filter (data delivered by the audio layer).
  • After the filer.
  • After the downsampling.

The pictures show that the frequency response of the signals are completely different before the filter, as long as the waveform is destroyed in time domain.

The anlialiasing filter provides unwrapping implicitly, so we can recover the waveform.

Anyway, we must avoid the wrapping, by using float sample formats in ALSA and PA. JACK already uses float, and regarding OSS ..., we can delegate in the antialiasing filter.

(file #27419, file #27420)

Ibán Cereijo <ibancereijo>
Project AdministratorIn charge of this item.
Thu 07 Feb 2013 12:17:35 AM UTC, original submission:

Only sampling with PA and format FLOAT32LE seems to work.
See attached files.

Ibán Cereijo <ibancereijo>
Project AdministratorIn charge of this item.

 

(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach File(s):
   
   
Comment:
   

Attached Files
file #27420:  data_FLOAT32.zip added by ibancereijo (348KiB - application/zip - Images with time and frequency response at different stages for sample formats of 16 (int) and 32 (float) bits)
file #27419:  data_S16LE.zip added by ibancereijo (429KiB - application/zip - Images with time and frequency response at different stages for sample formats of 16 (int) and 32 (float) bits)

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -unavailable- added by ibancereijo (Submitted the item)
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    Follow 12 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Fri 08 Feb 2013 09:11:07 AM UTCibancereijoStatusConfirmed=>Ready For Test
    Thu 07 Feb 2013 03:37:47 PM UTCibancereijoStatusNone=>Confirmed
    Thu 07 Feb 2013 03:37:28 PM UTCibancereijoAttached File-=>Added data_S16LE.zip, #27419
      Attached File-=>Added data_FLOAT32.zip, #27420
    Thu 07 Feb 2013 03:14:32 PM UTCibancereijoAttached File#27415=>Removed
    Thu 07 Feb 2013 03:14:30 PM UTCibancereijoAttached File#27414=>Removed
    Thu 07 Feb 2013 03:14:28 PM UTCibancereijoAttached File#27413=>Removed
    Thu 07 Feb 2013 03:14:17 PM UTCibancereijoAttached File#27412=>Removed
    Thu 07 Feb 2013 12:17:35 AM UTCibancereijoAttached File-=>Added dump_alsa_44100_mic.txt.gz, #27412
      Attached File-=>Added dump_pa_44100_monitor_fail.txt.gz, #27413
      Attached File-=>Added dump_pa_44100_mic.txt.gz, #27414
      Attached File-=>Added dump_pa_44100_mic_FLOAT32LE.txt.gz, #27415

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