optimal bit rate for streaming video?

[Juliana Lethdetter]

Is there any consensus as to the optimal bit rate for streaming video via display on in-world objects, other than "lower is probably better"? 

I've got an item that's been in-world for about five years now, which displays a looped Webm video file streaming at 375 kbps.  I arrived at that particular rate after testing a variety of bit rates and resolutions, attempting to find the lowest-impact, quickest-loading clip I could use that wouldn't make the video so ugly I hated it.  I was working off the assumption that whatever streaming rate media uses, it's eating up a portion of the 1500 kbps max available for the viewer's communication back and forth with the servers--  but truly, I've never known for sure if that's the case, or if it was once true, but is no longer so today.  Just within the past year I've seen crystal-clear projections of high-resolution movie footage in-world that certainly don't appear as if they're subject to such limitations...

I'm now in-progress on upgrading the item, and bumping the video in question up to say, even 750 kbps, would create a noticeable and satisfying increase in quality.  But I don't want to do that at the expense of creating issues in the local environment.

[Jenna Huntsman]

The viewer's bandwidth cap is extremely misleading - It's only used for some communications between the viewer and the region. Anything else is unthrottled. (Including, but not limited to, streaming media).

So, use whatever bitrate is appropriate for the resolution of the video. This calculator gives a pretty good recommendation, given some other information.

[bigmoe Whitfield]

1500 on the network slider is maximum for the SL viewer,  it's a bug, you go higher it causes packet loss and something else.   LL has to fix it,  not heard anything about it in least a year.

[Henri Beauchamp]

The bandwidth setting in the viewer parameters is only impacting sim server with viewer UDP communications and is negotiated, with a throttling mechanism: the throttling is imposed by the server, meaning that unlike what an SL (and OpenSim) urban legend pretends, there is strictly no negative impact on using the highest setting: I always have mine set to the maximum (which got raised from 512 Kbps in the past to 10 Mbps nowadays), and this ever since I created my own viewer, back in 2007.

It shall be noted that today's servers bandwidth is like two orders of magnitude (or perhaps even three, i.e. 100 to 1000 times) what it used to be when that throttling mechanism was designed to avoid network congestion, back in 2002 or 2003... This is to a point that the throttling is never seen happening any more, even with the max bandwidth setting.

Also, while in the past the textures were served by the sim servers via UDP, they are nowadays served by separate (and now CDN) servers via HTTP, which bandwidth is in no way limited by any setting in the viewer. This is also the case for assets data (meshes, sounds, animations, inventory assets, etc). Only the objects data (creation, removal, type, position, rotation, parenting, colors, material and texture UUIDs, mesh or sculpty UUIDs, etc), world data (parcels, etc), various triggers (notifications, sounds start/stop, animations start/stop, environment changes, etc), chat and IMs, groups data (members list, etc) and other small amounts of sundry data are still transmitted via UDP (and here you still want the highest bandwidth setting, especially to retrieve objects data the quickest possible on rezzing).

Like Jenna wrote, the streaming media are NOT impacted either by this UDP bandwidth setting, and in fact they are not even communications between the viewer and SL servers, but between the viewer and whatever third party serving that media (only the URL of the media is stored on SL servers and transmitted by them to the viewer).

Edited September 5, 2022 by Henri Beauchamp

[Juliana Lethdetter]

Thank you, Henri, for that very detailed and complete explanation.  Like bigmoe, I had often heard packet loss cited as the likely end result of setting any viewer in excess of the throttle, and simultaneously wondered how this could even be an issue 20 years down the road.

Thank you also, Jenna, for your initial answer, and the link to the bitrate calculator.  The particular calculator you cited contained no option for selecting Webm as the codec, but then, neither did any of the others I searched for thereafter;  most of them seemed to be (logically) engineered with an eye towards determining bitrates for livestreaming on platforms like Twitch (a much more contemporary application!)  They were useful nonetheless.

I ultimately wound up encoding the new video to Webm using 2-pass VP9, variable bit-rate, with a target of 3000 kbps.

[Jackson Redstar]

20 hours ago, bigmoe Whitfield said:

1500 on the network slider is maximum for the SL viewer,  it's a bug, you go higher it causes packet loss and something else.   LL has to fix it,  not heard anything about it in least a year.

I go into debug settings cant remember the exact name now, and set mine to 30000, I have 300mb up and down. Been doing like that now over a year no issues that I am aware of

[bigmoe Whitfield]

4 hours ago, Jackson Redstar said:

I go into debug settings cant remember the exact name now, and set mine to 30000, I have 300mb up and down. Been doing like that now over a year no issues that I am aware of

your not getting 30k,  anything above the 1500 and it's not actually doing anything if I remember right too.   @Whirly Fizzle  should be able to help me remember what I'm thinking of here.

[Jackson Redstar]

6 hours ago, bigmoe Whitfield said:

your not getting 30k,  anything above the 1500 and it's not actually doing anything if I remember right too.   @Whirly Fizzle  should be able to help me remember what I'm thinking of here.

maybe that is why I havent had any issues. But honestly just another reason why SL is so hard for new residents. You have to set your net work bandwidth. Then your cache sizes. your video memory.....

[Henri Beauchamp]

6 hours ago, bigmoe Whitfield said:

your not getting 30k,  anything above the 1500 and it's not actually doing anything if I remember right too.

It depends on the viewer. Mine allows more (and does implement corresponding preset in LLViewerThrottleGroup, even though extrapolation ensues anyway, above the upper preset). I just raised the limit to 32 Mbps (and the default to 8 Mbps) for next release.

Edited September 6, 2022 by Henri Beauchamp

[Henri Beauchamp]

6 minutes ago, Jackson Redstar said:

You have to set your net work bandwidth. Then your cache sizes. your video memory.....

I did consider removing entirely the bandwidth setting from the Preferences floater, but it still may make sense for people with very limited Internet link...

This said, the default settings should be good for most people (and it is how I setup the defaults in the Cool VL Viewer, so that you do not have to fiddle with obscure settings in order to get good results).

Edited September 6, 2022 by Henri Beauchamp

[arabellajones]

41 minutes ago, Henri Beauchamp said:

I did consider removing entirely the bandwidth setting from the Preferences floater, but it still may make sense for people with very limited Internet link...

This said, the default settings should be good for most people (and it is how I setup the defaults in the Cool VL Viewer, so that you do not have to fiddle with obscure settings in order to get good results).

Why is it still called just "bandwidth", which could be misleading?

OK, it could be that there isn't room to change the label to "UDP Bandwidth" but I just checked Firestorm and it's not a problem there: plenty of room.

Cool VL Viewer does a good job with the pop-up help. Firestorm directs you to a web page for a "suggestion", and I am not sure which is better. I would call the web page an "explanation", but I am English, and so speak a different language. (And it's not JIRA.)

I run my "bandwidth" at 350 Kbps for Firestorm. It shows a slider with different recommendations depending on the internet connection type, and I don't think those have changed since the days of UDP-only texture delivery. With the reductions in UDP traffic that sort of reduction works for me, but I am not sure how the bandwidth setting really works. I am not going to assume that every SL-user has an exclusive connection. My bottleneck is the DSL to my ISP, and I could have a family member start downloading a video.

I'm OK with my settings, but the internet has changed. SL has changed. Does the "bandwidth" setting need an up-to-date explanation?

[Jackson Redstar]

1 hour ago, Henri Beauchamp said:

I did consider removing entirely the bandwidth setting from the Preferences floater, but it still may make sense for people with very limited Internet link...

This said, the default settings should be good for most people (and it is how I setup the defaults in the Cool VL Viewer, so that you do not have to fiddle with obscure settings in order to get good results).

if in 2022 your network cant handle 1.5mbs or it "may cause issues" then that person might really need to upgrade from AOL dialup LOL

[arabellajones]

3 hours ago, Jackson Redstar said:

if in 2022 your network cant handle 1.5mbs or it "may cause issues" then that person might really need to upgrade from AOL dialup LOL

The problem there may be in the viewer or in the server. "Too-high settings can cause the viewer to request data that is not available." is in the Firestorm web-page on the subject.

I haven't found a clear explanation on the Second Life website.

[Henri Beauchamp]

Quote

Why is it still called just ”bandwidth”, which could be misleading

This is one of the things I have changed already together with the allowed max value:

It was called that way merely for an historical reason, since during the first years of SL, everything was indeed transiting via UDP !

6 hours ago, arabellajones said:

Cool VL Viewer does a good job with the pop-up help.

I try to keep my tool tips as informative as possible, and they are indeed worth a full documentation (some are very detailed and quite long)...

 

Quote

”Too-high settings can cause the viewer to request data that is not available.”

LOL !   A total non-sense... 🤣

Edited September 6, 2022 by Henri Beauchamp