Recommended settings for video streaming

[Ledgem]

(This is technically not a playback issue)

I've received new orders from work: convert an analogue source to digital, and prepare it for web streaming. I'll be converting it to DVD as well. A single digital file will correspond to the DVD chatpers.

Most likely the streaming will be done for our university students. The university LAN is 10 mbps. The file format will either be MP4 or MOV, most likely coded in H264.

As of now all of my conversion work has been to DVD; I have very little experience with encoding for web streaming. I can use some of the presets for encoding designated for streaming over a LAN, but I wanted to get the opinions first: what resolution should these videos be at, and what overall filesize should they be? I guess I can adjust quality settings based around that.

[Eviltape]

10 megabits? Well, that's around 1250kb/s. So that means you can probably fit in an 96kpbs MP3/AAC+ with a 800kb/s video bitrate. Maybe take the video resolution down to a width of 600px with keeping the aspect ratio.

You should ask Doom9 about this stuff, since this is probably critical to keeping your occupation and they really know what they're talking about.

[martino]

Audio; take it down to AAC 64kbps or even 48. Since it's a webstream people shouldn't really care about quality much as long as it delivers what it should (I'm assuming that you will not be streaming orchestra concerts ). Furthermore these will still sound better than an MP3/RM/WMA equivalent.

Video; I'd suggest the usual 640x360 (or at least that's what I usually see on web streams). But make it 640x352 or 640x368 if you will be using H264 to keep it mod16 (if you are worried about the AR deviation you can always set the Sample AR in the container). And depending on the source, but if you go with high settings (lots of bframes and reference frames, etc) you could go pretty low with the bitrate, 600kbps for example.

[Ledgem]

Just to post back: In order to maintain the video aspect ratio I went with 640x427 video. I locked the video bitrate at 800 kbps, set the audio to AAC 64 kbps mono. Using H.264 to encode, B-frames enabled, video footage is deinterlaced as it is encoded. These are all video clips of "live action" (mostly interviews), generally 2-7 minutes in length. Filesizes seem to be coming in at 19 MB to 25 MB, and the quality is excellent. Thanks much for the advice!

By the way, Eviltape, thanks for the concern about my job - I'd be going to Doom9 if I were a professional or getting into this for the long haul, but this is a university job I have and will be leaving relatively soon Generally I just do video importing and conversion to DVD (using Final Cut Pro and DVD Studio Pro), but sometimes they throw extra media tasks at me. Setting up encodes for web streaming just happened to be the extra of the month, I suppose.

[grey_moon]

10mbps? I would cry if I was forced to work with that

Is the target audience just the LAN or the internet too? If it is the internet is that the total bw available to the uni or is it just the slice that has been allocated to your project? If it is the total then it might be an idea to check with the networking bods to make sure that you can stream out without taking out the connection. The same goes for internally too, if the media is to be streamed to a large class then you really need to consider if the network is capable of handling it.

[Ledgem]

The target audience is the students, and not all of them live in housing that is hooked up to the university LAN. I've never heard of someone on dial-up or DSL, though. 10 Mbps is the standard jack speed within university buildings. The university connection is OCsomething, bandwidth should be 600 something (MB/s? Mbps?)... I used to know those numbers. Either way, I don't believe that the class that will be using this is very large, so I'd hope it'd be OK. We should have checked with IT first, but they don't seem to like us much ;P

Many classes (some of them quite large - 300-400 students) are experimenting with streaming full lectures. The university had better either have a bunch of dark fiber available or actively be working on boosting the infrastructure.

[TheFluff]

User shorter I-frame intervals than usual. Also read up on the VBV settings so the bitrate doesn't fluctuate too much since that can cause stuttering and/or buffering problems in some scenes.

[grey_moon]

Originally Posted by Ledgem

We should have checked with IT first, but they don't seem to like us much ;P

Hee hee hee, if they do their job right they will be after you guys right off the bat

With very large classes they just need to multicast (never tried it tbh).

The uni I'm currently working for has gig back everywhere, 100mpbs to all desktops and has recently upgraded their connection to the academic backbone to 1 gig. The networking bods ofc throttled the dango out of everything and didn't tell anyone and I only noticed when my servers were taking a long long time to update and my source was on the academic backbone too

In terms of network restrictions I would get a network model over an average and busy period and see how much of the pie is left and then carve that up. The busy period I would only be concerned about during exam times or other important events. Actually the networking bods should be doing all that stuff for u guys