Talk:Audio Video Bridging

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Requirements for AV streaming[edit]

This sentence from the article doesn't sound accurate: "A much more stringent requirement comes from the need to keep multiple digital speakers properly in phase: for the professional environment, this means keeping streams synchronized within approximately one microsecond." One microsecond represents an approximately 7-degree phase shift on a 20KHz signal (the highest frequency the average human can hear). On a 1KHz tone, it's less than half of a degree. In any case, a 7-degree phase shift at any frequency would not be audible, therefore a requirement to have speakers in-phase by one microsecond or less is unrealistically stringent in my opinion. Does the contributor of this material (or anyone else) have a reliable source which asserts that sub-microsecond synchronization is a common or standard requirement? I would estimate that an accuracy in the range of 10-50 microseconds would be the most stringent standard that anyone would realistically be expected to uphold. In practice, most audio delay processors allow you to delay an audio signal at a granularity of 0.1 milliseconds (i.e. 100 microseconds). SnottyWong talk 23:09, 2 April 2010 (UTC)

I changed the wording to "one millisecond or less". Let me know if there are any objections. SnottyWong talk 16:42, 3 April 2010 (UTC)
The timing-critical use case that gets mentioned here is phase-steered line arrays. Very small phase shifts are used between speakers to aim the sound field. I suggest you revert you edits - it is not mistake. Requesting a citation or elaboration/justification is reasonable. --Kvng (talk) 04:14, 5 April 2010 (UTC)
Ahh, I suppose you're right. I've undone the edit. I think I was thrown off by the wording "the need to keep multiple digital speakers properly in phase". To keep speakers in phase (enough for the average ear), you generally wouldn't need a granularity less than 1 ms, but to do beam steering you could certainly get into the microsecond range. SnottyWong talk 14:46, 5 April 2010 (UTC)

Other references[edit]

Found these on Audio over Ethernet and removed them as per WP:EL. Perhaps they may be of use here. --Kvng (talk) 01:00, 24 June 2010 (UTC)

Devices supporting the standard[edit]

I note that this brochure for the Dante-MY16-AUD card for Yamaha digital sound Mixers says "AVB ready" in the documentation. Should we list it as an available device on the page? --Rjmunro (talk) 13:18, 23 August 2010 (UTC)

If you can make a case that an announcement is WP:NOTABLE, you can say they've made an announcement. You can't say it is available or that it is expected to be available. See WP:FUTURE. --Kvng (talk) 18:40, 23 August 2010 (UTC)
This seems a bit early to me. As far as I know, AVB hasn't even been fully defined yet. There can't be any devices that are fully compatible with AVB until it is fully defined. So, I'm not even sure what the statement "AVB Ready" would indicate. It might just mean that the device has hardware that will be capable of supporting AVB (i.e. with a firmware upgrade) once it is fully defined. If that's the case, then I personally don't think we need to mention it in the article. SnottyWong confabulate 23:38, 24 August 2010 (UTC)


I read something about the 802.1BA standard today and wanted to read it, so I typed "802.1BA" into the Wikipedia front page and it took me to a search page. IMO, that specific search should redirect straight to this page; there's no reason to send a user anywhere else first. I don't know how to set it up myself or I would do it ("Be Bold") so if someone could point me in the right direction I'd appreciate it. Naptastic (talk) 16:50, 25 February 2011 (UTC)

 Done --Kvng (talk) 19:09, 28 February 2011 (UTC)

This is a verbatim copy of a copyrighted white paper[edit] Very probably members of the AVnu alliance have posted it here themselves, but copyright issues should be clarified by a formal statement from the copyright holders, particularly since the original paper says "(C) 2009 by AVnu Alliance. All rights reserved". The corresponding illustrations all have legitimate licenses, and it looks like the original authors have contributed them. --Nettings (talk) 13:35, 2 March 2011 (UTC)

Yup, needs to be removed and then paraphrased with a citation at least. W Nowicki (talk) 23:11, 27 September 2011 (UTC)
I have posted a copyright violation notice on the author's talk page. If there is no response, we will need to delete it. --Kvng (talk) 16:43, 29 September 2011 (UTC)

IEEE 802 LMSC is refering this document.[edit]

At a tutorial in IEEE Plenary Meeting, San Antonio, 2012, the engineers are referring this document. It means this articles is important or well written? --Cheol (talk) 01:51, 13 November 2012 (UTC)

One of the presenters is the primary author of this article. -—Kvng 21:38, 14 November 2012 (UTC)


Rumor has it that the Netgear/BSS switch is not a good choice or is no longer available. -—Kvng 17:35, 12 April 2013 (UTC)

Netgear GS716Tv2 with GS716TAV-10000S (EAV) software license DOESN'T work! Davygrvy (talk) 23:06, 9 August 2013 (UTC)

AVB support in the Pathport switch is also dubious. ~KvnG 18:26, 4 June 2013 (UTC) The AVB hardware support is claimed to be there in the Pathport switch but not yet available in software 10:50, 19 February 2015

Figures 5 and 6[edit]

I think the "D" in the blue circle in the lower left of figures 5 and 6 should be an "L".


@Kvng:, thanks for adding the infobox. I'm not sure on the minimum latency spec. From what I've read, 2ms is referenced as the typical latency for a gigabit network with up to 7 switch hops. However, AVB supports much lower latency modes than that, down to (I think) 0.25ms for a direct connection between two AVB devices (i.e. 1 hop). I'm having trouble finding a source for that information, but I'll continue looking.

The "minimum latency" now has a source reference linked to it. There the 0.25ms is cited as the maximum (not minimum!) latency per hop, with a total maximum latency of 2ms (7 hops). I'd edit the infobox, but I cannot find where to change the word "minimum" in the page sources? The AVB specifiaction does not specify a minimum required latency (that I know of), it would be counter-intuitive. — Preceding unsigned comment added by (talk) 14:34, 3 July 2016 (UTC)

Also, the Netgear GS724T switch hasn't been discontinued, only the BSS-branded version of it is no longer being sold by BSS. However, Netgear still sells it (although without AVB) and Biamp distributes it with the AVB license installed. There is also a GS724Tv4 switch that might already be available, and supposedly you'll be able to purchase the AVB license separately. Not sure how that will work yet. If I can rustle up some sources for any of this stuff, I'll add it to the article. ‑Scottywong| converse _ 23:40, 21 April 2014 (UTC)

2 ms is the standard latency and this is the minimum latency for a simple node. Longer or shorter can theoretically be negotiated but I don't know how this is done or whether devices are required to do this. IEEE 1722.1 would probably be a good reference to start research. AVnu documents would also be relevant but these are only available to AVnu members so referencing them poses a WP:V issue.
Since the AVB packet time is 0.125 ms, 0.250 ms is probably the practical minimum latency but without a source, this is WP:OR.
We shouldn't be listing switches whose availability is not established. I don't see any information about availability of an AVB version of the Netgear switch on Biamp or Netgear sites. ~KvnG 10:51, 22 April 2014 (UTC)
I found some refs for both the latency and Netgear switch info, and modified the article. Let me know if you have any objections. ‑Scottywong| spill the beans _ 15:23, 24 April 2014 (UTC)
Netgear stuff looks good. The D-Mitri reference has some problems. A primary reference from an equipment manufacturer is not necessarily a reliable source for AVB as a whole. The 0.25 ms figure is quoted "per-hop" and it is not clear if that is a switch hop or a hop onto and then off of the network for audio (I think we're interested in the latter for the purposes of the infobox). The 2 ms figure I had originally put in the info box is also mentioned in this reference. If we're looking for a consensus among references, 2 ms is looking good. ~KvnG 13:27, 4 May 2014 (UTC)

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