[Webkit-unassigned] [Bug 183375] New: Quality of the audio received in Safari degrades significantly when injecting network impairment jitter >= 300ms

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=183375

            Bug ID: 183375
           Summary: Quality of the audio received in Safari degrades
                    significantly when injecting network impairment jitter
                    >= 300ms
           Product: WebKit
           Version: Safari 11
          Hardware: Unspecified
                OS: Unspecified
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: WebRTC
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: juchwang at cisco.com
                CC: youennf at gmail.com

We suppose Safari may not handle jitter buffer well. In our end-to-end audio quality test, we injected network impairment with jitter and found the audio quality degraded a lot on Safari as a receiver. The jitter impairment greater than 300 ms can easily cause Safari drop rtp packages, leading to crappy sound.

We compared the result among different browsers and found Safari->Safari and Chrome->Safari were poor audio quality. However, Firefox->Safari was good.

Details:
Safari->Safari  
Impairment case                 MOS     Delay(ms)
jitter 100ms downlink UDP       4.2     228
jitter 200ms downlink UDP       4.08    536
jitter 300ms downlink UDP       2.36    373
jitter 400ms downlink UDP       2.54    515
jitter 500ms downlink UDP       1.85    386
jitter 500ms uplink UDP         1.98    525
jitter 400ms uplink UDP         2.03    474
jitter 300ms uplink UDP         2.04    427
jitter 200ms uplink UDP         4.17    595
jitter 100ms uplink UDP         4.18    319

Chrome->Safari  
Impairment case                 MOS     Delay(ms)       
jitter 100ms downlink UDP       4.29    201
jitter 200ms downlink UDP       4.04    461
jitter 300ms downlink UDP       2.33    417
jitter 400ms downlink UDP       1.86    417
jitter 500ms downlink UDP       1.72    474
jitter 500ms uplink UDP         1.64    366
jitter 400ms uplink UDP         1.93    484
jitter 300ms uplink UDP         3       460
jitter 200ms uplink UDP         4.24    759
jitter 100ms uplink UDP         4.21    315

Firefox->Safari
Impairment case                 MOS     Delay(ms)
jitter 100ms downlink UDP       4.51    157
jitter 200ms downlink UDP       4.47    337
jitter 300ms downlink UDP       4.47    428
jitter 400ms downlink UDP       4.49    568
jitter 500ms downlink UDP       4.49    672
jitter 500ms uplink UDP         4.5     730
jitter 400ms uplink UDP         4.47    570
jitter 300ms uplink UDP         4.46    440
jitter 200ms uplink UDP         4.48    336
jitter 100ms uplink UDP         4.46    233

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