jitter buffer size?
anshuman26:
I would like to note that, though the Admin mentions that it is fully adaptive, I don't think it is actually working. My buffer size ALWAYS seem to remain at 190ms and I have tested it in various network conditions.
I hope the Obi guys can take a look at this.
LeftRight:
Why would this (190 ms) be a problem?
According to E-model (refer to one of research paper below):
http://www.recursosvoip.com/docs/english/AssessingVoIPCallQualityUsingtheE-model.pdf
If you don't see the packet loss, the latency of 190 ms means you have a estimated MOS 4.2~4.4 for G711 codec (above 4.0 for G729), which also means you would experience very good voice quality for most of your calls.
When latency goes beyond 350 ms, you might start feel voice degradation ... so I would guess you have a fairly good network environment where your OBi device sits in, and the Internet connection to the other party is also good for VoIP calls.
anshuman26:
@leftright
You are assuming all the latency is coming from jitter buffer only. That graph gives MOS for one way total delay (part of which is delay introduced from jitter buffer). In reality, latency comes from several other factors as well.
I am not complaining about voice quality but about latency. The voice quality is great but there is some latency introduced due to this jitter. Though it is not bothersome, it is still noticeable.
For example, I did a simple test where both the Obi110 and my computer was connected to the same router. I did an echo test to Google voice both from Obi110 and from gmail on my computer and there was a noticeable difference in latency.
earthtoobi:
in the latest firmware( 2575),notice that the jitter buffer changes based on network conditions.i have seen it go as low as 60ms.looks like there were some fixes that went in
squalk:
Quote from: LeftRight on September 02, 2011, 05:33:23 pm
[I prefer] a fully adaptive jitter buffer algorithm
Fully agree that algorithm optimization may be needed in long term (balancing off latency and packet loss??), but I just don't see a necessity of adding parameters for the manual configuration.
Add the option for manual jitter buffer but default to auto jitter buffer. Was that so hard?
Some of us have very low latency verizon fios (fiber) [and effectively zero jitter] at home and don't need the added delay of assumptions.
Tier 4 fios does not use software rate-limiting so FULL bi-directrional saturation STILL has very low latency
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