The technologies of network chat

[Silent_Buddha]

GSM voice codec used to be 13.2 kbit/s with horrible quality, now it's 12 kbit/s with much better quality. Low bandwidth compression technology has improved greatly in the last 15 years.

Xbox party chat supports up to 8 people at once, and assuming a 16kbit codec, it would require 128kbit downstream and 16kbit upstream just for voicechat. Thankfully most broadband services are way faster than that. Also, just like MSN voice chat, it'll always be p2p, not hosted. Hosting party chat is not a smart solution these days when individuals have decent broadband connections that can easily handle 8-16 people at once.

Considering some people are still limited to 128-256k upload speeds I find P2P chat highly unlikely, especially for 8 people. If that were the case, we'd hear a lot more complaining about the variable quality of the voice chat. And even with that the quality of individual users connections (sometimes quite horrible) does not affect Live chat in way that I've heard of. Other than for the isolated person.

Instead we hear the opposite which is that quality is universally decent, which points to dedicated voice chat servers.

VOIP is very latency sensitive, bandwidth can only help so much. Relying on P2P chat is going to lead to some seriously variable chat quality.

Regards,
SB

 

[betan]

Doesn't make much sense.
Lots of games use p2p chat for up to 16 players (I have seen) with little quality issues.
Human auditory system and brain are a bigger hurdle than BW. Accidentally they are a limiting factor on bw too, as in a group people don't tend to speak at the same time continuously.

Also actual gameplay is much more latency sensitive than voice chat which can get away fine with silence gaps. I'd find it stupid not to supply dedicated servers for mp, but voice chat for latency reasons.

That said, MS could provide dedicated voice chat servers to free some upload bandwidth on the client side which could be helpful when playing mp, but I doubt they care that much and if they do, it'd be once again the wrong side.

What's most likely is that cross game chat and in game chat use the exact same infrastructure.
Of course instead of guessing, you can always use a network monitoring or packet sniffing tool ala wireshark to find out what uses what.

 

[corduroygt]

Considering some people are still limited to 128-256k upload speeds I find P2P chat highly unlikely, especially for 8 people. If that were the case, we'd hear a lot more complaining about the variable quality of the voice chat. And even with that the quality of individual users connections (sometimes quite horrible) does not affect Live chat in way that I've heard of. Other than for the isolated person.

16kbit upload is well within the 128-256kbit/s upload speeds. You only need to upload your own voice data, while receiving 7 others. Then a simple algorithm will determine what time the packets were sent based on their timestamps, and play them in that order. This will introduce some lag, but well within a couple hundred ms, which doesn't matter with VOIP.

Instead we hear the opposite which is that quality is universally decent, which points to dedicated voice chat servers.
VOIP is very latency sensitive, bandwidth can only help so much. Relying on P2P chat is going to lead to some seriously variable chat quality.
Regards,
SB

It is extremely preposterous to assume XBL uses dedicated servers for voice chat when it doesn't use dedicated servers for online gaming, which requires more bandwidth and processing power, as well as being more sensitive to latency. It is not 1997 any more, voip technology has matured.

 

[Silent_Buddha]

It is extremely preposterous to assume XBL uses dedicated servers for voice chat when it doesn't use dedicated servers for online gaming, which requires more bandwidth and processing power, as well as being more sensitive to latency. It is not 1997 any more, voip technology has matured.

If you say so, but flies completely opposite to any experiences I've had in MMO's where bandwidth for the game even with 50-100 people in the scene with multiple enemy mobs was lower than voice chat with less than 10 people. But CPU processing was maxed which would make addtional processing for voice chat less desirable. Granted now days with multi-core CPU's the processing load wouldn't be as dire, but back when I raided heavily it was still predominantly 1-2 cores. And anyone running anything other than a voice chat client on their machine (some even opted to run the clients on other machines) was instantly noticeable.

I'm going to guess that a multiplayer game on console with 4-8 people is going to generate orders of magnitude more bandwidth.

But meh, at this point we're just going around each other...

Regards,
SB

 

[corduroygt]

If you say so, but flies completely opposite to any experiences I've had in MMO's where bandwidth for the game even with 50-100 people in the scene with multiple enemy mobs was lower than voice chat with less than 10 people. But CPU processing was maxed which would make addtional processing for voice chat less desirable. Granted now days with multi-core CPU's the processing load wouldn't be as dire, but back when I raided heavily it was still predominantly 1-2 cores. And anyone running anything other than a voice chat client on their machine (some even opted to run the clients on other machines) was instantly noticeable.

I'm going to guess that a multiplayer game on console with 4-8 people is going to generate orders of magnitude more bandwidth.

But meh, at this point we're just going around each other...

Regards,
SB

I can only surmise that those voice chat clients were horribly inefficient then. Here's the setup.txt file from C&C generals:

If you are setting up a server, it is important that your connection speed
is setup correctly. The connection speed for the server determines how
frequently clients connected to the server are updated. This has a direct
effect on the experienced "lag" of the players connected to your server.

The game will automatically determine your bandwidth and use it to determine
the appropriate number of players your game can host. The number of players
is scaled up using the following criteria:

Upload Bandwidth equal to or greater than 0.5 Mbps allows up to 8 players
Upload Bandwidth equal to or greater than 1.0 Mbps allows up to 16 players
Upload Bandwidth equal to or greater than 2.0 Mbps allows up to 32 players


Cable modems and DSL with an upload bandwidth of 128k/sec are NOT allowed
to host.

Online gaming uses more bandwidth than voice chat for the same number of players.

 

[Shifty Geezer]

It is extremely preposterous to assume XBL uses dedicated servers for voice chat when it doesn't use dedicated servers for online gaming, which requires more bandwidth and processing power, as well as being more sensitive to latency.

I see that as actually supporting the argument for dedicated voice servers. The cost of running the voice servers will be considerably less than hosting for games, and provides a feature worth the annual fee which would more than cover their costs.

Are there no devs here who can actually say for sure what Live! does?

 

[patsu]

May be case-by-case. For small scale MP games, I'd imagine Microsoft has already optimized the infrastructure such that they may not require a voice chat server. For mid to large scale games, then you may (will) need it.

 

[corduroygt]

What would be the benefit of dedicated voice chat servers exactly? For games it removes the host advantage issue as well as alleviate higher upstream bandwidth requirements. There is no host advantage problem with voip as well as minimal processing and upstream bandwidth requirements. Cell phones make do with 12 kbits, not to mention people have big moments of silence on voice chat so the average bandwidth is even lower.

 

[patsu]

The voice channels may be (are) point-to-point. I agree that most of the time, at the CPU level, voice comms is mostly idling. This is why my friend could skip a chip or two to save $$$ when he implemented a VoIP daughterboard for someone. He simply time shared the CPU.

We needed a dedicated server for maintaining an online directory and also route the initial connect calls globally. There were some value added services that we provided (voice mail, call forwarding, terminating POTS calls).

 

[JPT]

If the Voice chat is 1-1 then that means if I'm in a 8 man squad I need to send 7 copies of my voice data to different endpoints, in addition to the game data to the "server/host". And if I am the host, then there is a more game data that I need to upload to the other players.

 

[specwarGP2]

I'm going to guess that a multiplayer game on console with 4-8 people is going to generate orders of magnitude more bandwidth.
SB

So are you saying that the chat in P2P games is on a server, not the hosts console?

 

[Scott_Arm]

I found this article (http://blogs.msdn.com/xboxteam/archive/2006/02/08/528321.aspx) which suggests that xbox live games are limited to 64kbps total. If you can play a game and fit voice chat within that 64kbps, then the bitrate for the chat itself, per player, is very low. Generally you can only talk to your team, which in most games is 6-8 players, which is the size of party chat.

It doesn't answer the p2p vs dedicated question, but I'm assuming most games would be p2p, if not all.

First, is that bandwidth constraint still a requirement? Is that bandwidth requirement limiting the number of players we're seeing in games online? If they made the limit something in the range of 100kbps, would the latest Call of Duty had supported more players in a match, for instance? That number must affect the ability to produce MMOs, and maybe a game like MAG (which I haven't played, so I don't know how voice chat works, or what kind of connection you need to play it).

Having squad-only chat, like in Battlefield, could be a way around that issue, since you don't have to chat with everyone on your team. If you can only talk to 4 or 5 people at a time, you can use more of that bandwidth for game updates and have more people in the game.

 

[corduroygt]

If the Voice chat is 1-1 then that means if I'm in a 8 man squad I need to send 7 copies of my voice data to different endpoints, in addition to the game data to the "server/host". And if I am the host, then there is a more game data that I need to upload to the other players.

Not really, there's a thing called IP Multicast, and the intermediary routers of ISP's would take care of duplicating packets for you.

 

[MfA]

No multicast over the general internet.

 

[JPT]

Not really, there's a thing called IP Multicast, and the intermediary routers of ISP's would take care of duplicating packets for you.

Multicast across the Internet? To my knowledge that is NOT a service being provided to joe average anywhere.
Fine an ISP can do it within their own network, maybe if your ISP got some special peering agreements, but usually multicast is a no go on the Internet.

 

[assen]

I see that as actually supporting the argument for dedicated voice servers. The cost of running the voice servers will be considerably less than hosting for games, and provides a feature worth the annual fee which would more than cover their costs.

Are there no devs here who can actually say for sure what Live! does?

No, of course, NDAs haven't been magically lifted for voice chat-related topics

 

[makattack]

I see that as actually supporting the argument for dedicated voice servers. The cost of running the voice servers will be considerably less than hosting for games, and provides a feature worth the annual fee which would more than cover their costs.

Are there no devs here who can actually say for sure what Live! does?

Not sure how different it is from XNA, but there are little to no controls for XNA developers to implement their own voice. It's all controlled by live. All you really can do is limit who speaks:

http://blogs.msdn.com/shawnhar/archive/2007/12/20/network-bandwidth-voice.aspx

 

[patsu]

Is that bandwidth requirement limiting the number of players we're seeing in games online? If they made the limit something in the range of 100kbps, would the latest Call of Duty had supported more players in a match, for instance? That number must affect the ability to produce MMOs, and maybe a game like MAG (which I haven't played, so I don't know how voice chat works, or what kind of connection you need to play it).

In MAG, the squad leaders can talk to his squad members (8 max) and other squad leaders (3 other). You can also hear comrades and enemies near you. I posted a 128 player photo session in the MAG thread. Unfortunately, the video is not clear enough to judge the voice quality.

The platoon leaders can talk to platoon leaders, squad leaders and his squad. The OIC can talk to the platoon leaders, squad leaders and his own squad.


In Playstation Home, they had open mic for all 64 people in the same space (if they were close to each other). It worked ok but they turned it off.