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Ittaidv  
#1 Posted : Thursday, January 22, 2015 9:08:16 PM(UTC)
Ittaidv

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Allthough we could test it, we mostly don't really have time before a gig to do this, hence the question.

We stream from Belgium, and rely on the venue's internet connections. These are mostly normal dsl lines, sometimes fast, but mostly slow. The maximum upload speed we ever had was 5mbps.

Most of the time we stream in 1080 or 720, but I never really thought about streaming in SD.

Since encoding is not really my cup of tea, I always wondered if there would be a quality or pc performance difference between streaming say 3mbps in SD, 720 or HD?

I recently learned here that recording a HD file in 12mbps is a bad idea because it can cause errors in the encoding, Martin reccomends at least 25. Would this also be true for streaming in HD at 3mbit for example?
Speegs  
#2 Posted : Saturday, January 24, 2015 8:05:05 AM(UTC)
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Ittaidv wrote:
Allthough we could test it, we mostly don't really have time before a gig to do this, hence the question.

I recently learned here that recording a HD file in 12mbps is a bad idea because it can cause errors in the encoding, Martin reccomends at least 25. Would this also be true for streaming in HD at 3mbit for example?


I could be missing something, but usually setting the Bitrate for streaming is all about a compromise between the available bandwidth and what you expect. Generally people want the best their link can reliably do. Your resolution has to fit in with the bitrate.

So if you have a 5mbit Link dedicated to the gig, a 3mbit bitrate would be about where I would put your target bitrate.

Generally speaking and each link is different because of how reliable it may be, but you would want to use between 60-80% of your upload speed. 60 being safer than 80. Otherwise you may experience dropped frames too often and jerky/blocky video.

This guide might be useful, it's for youtube non-live video but generally is a decent guide.

https://support.google.c...ube/answer/1722171?hl=en

I find it's a bit harsh. 3mbit and 720p resolution looks pretty nice. 5mbit, 720p does look nicer of course. I've also found 5mbit 1080p doesn't look too bad, but below 5mbit 1080p you really should move back to 720p. I imagine others might disagree and it does depend on if you have fast action video or mostly static camera angles.

Hope that helps a little.
Ittaidv  
#3 Posted : Saturday, January 24, 2015 12:29:40 PM(UTC)
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Well, for me it's very hard to judge. To be honest, in low bitrates I wouldn't bet anything on the difference between 1080, 720 and sometimes even SD.

Since I don't really notice a huge difference, I asked the question. Might be a lot better cpu whise to encode less pixels and throttle back to SD in the same bitrate.

For example when there are a lot of coloured fast lights, we have a lot of 'blocking' in our video. I never ran a test that was long enough to see if this would change when throttling back the amount of pixels. Wouldn't take the risk to do that during a paied gig and I don't have these lights in our office to test it.
sinc747  
#4 Posted : Tuesday, January 27, 2015 12:39:31 PM(UTC)
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Jan Ozer, a frequent contributor to Streaming Media Magazine, has a great YouTube video showing optimum bit rates for various resolutions as used by major networks and streaming services.

For example, he shares that about 1,500kpbs is an ideal bit rate for the average SD video with a resolution of 480p at 30 fps.

It is definitely worth watching all the way through.

Configuring Your Streaming Video:


- Tom
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Ittaidv on 1/27/2015(UTC)
GeorgeR  
#5 Posted : Tuesday, January 27, 2015 1:44:29 PM(UTC)
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Ittaidv wrote:
Allthough we could test it, we mostly don't really have time before a gig to do this, hence the question.

We stream from Belgium, and rely on the venue's internet connections. These are mostly normal dsl lines, sometimes fast, but mostly slow. The maximum upload speed we ever had was 5mbps.

Most of the time we stream in 1080 or 720, but I never really thought about streaming in SD.

Since encoding is not really my cup of tea, I always wondered if there would be a quality or pc performance difference between streaming say 3mbps in SD, 720 or HD?

I recently learned here that recording a HD file in 12mbps is a bad idea because it can cause errors in the encoding, Martin reccomends at least 25. Would this also be true for streaming in HD at 3mbit for example?


I do all my YouTube Live Streams at 480. While I have petty decent upload speed (12 mbps on good days) I want to leave some wiggle room just in case.

While not HD, 480 gives me a good looking video on both a computer and mobile for viewers.
thepelell  
#6 Posted : Wednesday, January 28, 2015 4:32:24 PM(UTC)
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a lot also depends on how much movement you have in your image. If you have to broadcast a classical concert, a speech or convention, 3Mb at 720 is more than enough. If you have to broadcast fast moving objects like race cars as I do, 3Mb at 720 is bare minimum.
doyousee.me  
#7 Posted : Thursday, January 29, 2015 7:05:46 PM(UTC)
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if you can adapt your footage to your bandwidth and you're a bit experienced with tweaking the encoder, you can go even as far down as 2mbit for 720 and still have a nice image.

Always keep in mind that the human eye is really not that good in seeing details, but is very good in detecting movement. so you're better off having a smooth, non gl-glitching (umbilical brothers reference, sorry) video in a lower pixel resolution or colour depth than you would be with a high-res stuttering video.

(we webcast a 720 video at 1250kbps average last august which was very ok to look at. subject was 300 mph dragracing with zoomed-in cameras, so i had to tweak the encoder a lot, but got it in the air nicely)
experience is everything!

M@ik

(as you may know we already help a few european vmixers with their livestreaming, there's always room for 1 more :) )
Ash  
#8 Posted : Saturday, January 31, 2015 8:19:55 PM(UTC)
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Hi

Had a look at the Jan Ozer video and put the info into a spreadsheet if it helps.

https://docs.google.com/...D6hynA8/edit?usp=sharing

Gives a bit of a guide but recommend looking at the video first.

Cheers

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sinc747 on 1/31/2015(UTC)
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