Blackmagic atem mini and OBS

JazzKitten

JazzKitten

New Member
Hi folks
I'm a relative newbie and I have so far produced one live streamed concert featuring my husband playing solo guitar, for which I had 2 cameras connected via HDMI video capture USB dongles, one connected via USB as a webcam, and I also used the webcam on my laptop.
It went well, although some viewers said the video did judder occasionally, it was watchable, and the sound quality was flawless, as we used a SubZero audio interface. The connection we had for this was a fast DSL and, yes, I was connected via ethernet not wifi. Since then we have upgraded to the fastest cable which is capable of downloading 120 mbps and uploading 20mbps. I've read the advice about resolution, frame rate, upload speed etc. here.

Today I attempted a test live stream and I don't think the quality was any better, which is disappointing as I was expecting the cable to be much better. On YouTube I was still getting the message that I wasn't sending enough video to YouTube so my viewers would have buffers, although my Android tablet connected to wifi seemed not to judder at all, so I don't understand why, but there you are! I've read as many tutorials and the excellent advice on this website as I can, up to press.

So I am now investigating the Blackmagic atem mini. I didn't want to have to buy another piece of kit when I thought OBS would do it, but a colleague of mine said that OBS was 'notorious for dropping frames' and that I should invest in something hardware instead. Then I read that people were using this kit with OBS and now I am confused. If OBS can handle the multi camera angles why do I need a piece of kit, and conversely, if this piece of kit handles the camera angles, why do I need OBS?
If it is just to stream a single camera output (that I gather the kit behaves as a single webcam) then surely I'm going to have the same problems with buffering, upload speeds to YouTube etc. that I think I should not be having given that we have the dog's doo-dahs of cable broadband now!

I'd be very grateful for any help or advice that anyone can give, because I'm obviously missing something, and as a newcomer have a lot to learn.

thanks in advance to anyone who can help.

Wendy
 
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Lawrence_SoCal

Active Member
Lots of things can interfere with a clean live stream, including things like Public Peering Internet routers which you'll have no insight into.
So, you may have not been using all of your DSL upload bandwidth, in which case switching to cable didn't do anything. Personally I prefer cable over DSL, but each has its strengths / weaknesses, and with so many people working/school from home, local Internet providers (ISP) are under strain. And some cable providers do a better job than others, and even within that, there can be variances at the neighborhood level (node saturation, etc). My point - lots of stuff can impact your results, some of it outside your view, and a lot of it having nothing to do with OBS itself. Your cable upload limit is 20mb/s. Have you don't a speedtest and seen what actual bandwidth you have available? is there anything else using that bandwidth while streaming (phones, tablets, smart TVs, etc)?
As to your question, I'm an OBS newbie, so hopefully others more knowledgeable than I will chime in.
Yes, OBS can handle multi-camera. Whether your computer can handle it is another question. Have you monitored your laptop's performance (Task Mgr) and made sure CPU, GPU, and RAM, and disk I/O not running close to 100%? Do you have background software running that may interfere (resource contention, usually CPU)?
 
JazzKitten

JazzKitten

New Member
Lawrence_SoCal said:
Lots of things can interfere with a clean live stream, including things like Public Peering Internet routers which you'll have no insight into.
So, you may have not been using all of your DSL upload bandwidth, in which case switching to cable didn't do anything. Personally I prefer cable over DSL, but each has its strengths / weaknesses, and with so many people working/school from home, local Internet providers (ISP) are under strain. And some cable providers do a better job than others, and even within that, there can be variances at the neighborhood level (node saturation, etc). My point - lots of stuff can impact your results, some of it outside your view, and a lot of it having nothing to do with OBS itself. Your cable upload limit is 20mb/s. Have you don't a speedtest and seen what actual bandwidth you have available? is there anything else using that bandwidth while streaming (phones, tablets, smart TVs, etc)?
As to your question, I'm an OBS newbie, so hopefully others more knowledgeable than I will chime in.
Yes, OBS can handle multi-camera. Whether your computer can handle it is another question. Have you monitored your laptop's performance (Task Mgr) and made sure CPU, GPU, and RAM, and disk I/O not running close to 100%? Do you have background software running that may interfere (resource contention, usually CPU)?
Click to expand...
Thanks Lawrence. I did check all those things, CPU was running no higher than 50%, I shut down all my apps apart from OBS and background running processes I didn't need. Also we switched off all our devices while the concert was happening.My laptop processor is
Intel(R) Core(TM) i5-3230M CPU @ 2.60GHz, 2601 Mhz, 2 Core(s), 4 Logical Processor(s). Maybe I need an upgrade.
Thanks again, and I hope someone will be able to answer my query about the blackmagic atem too.
Wendy
 
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Lawrence_SoCal

Active Member
Wendy - an Intel i5-3230M means 3rd generation Core CPU, and 11th generation CPUs should be announced/released in next few weeks. A 2 core/4 thread processor circa 2013 trying do do video encoding today... gonna be a stretch... possible maybe with OBS optimization. Also, laptops of that era rarely had SSDs, which can make a HUGE performance difference compared to a HDD
With that old a laptop (perfectly good for some things, video streaming.. not so much) I'd recommend:
- setting OBS Canvas and stream encoding to be 720p, dropping the bitrate to maybe 3000... I'm guessing you don't have an upper-end (for the time) gaming graphics card, so you especially want to keep video resource demands down. Audio quality, especially with what you are doing, is more important
- also, a SSD is likely to make the laptop much faster, and worth trying if you can borrow one to test with (copy existing HDD to SSD... need special tools/process to accomplish). I'd only recommend purchasing a SSD if you know you can return it regardless (ie SSD is not broken) because it may not help and I'd hate for you to be out the cost of the drive (drive performance metrics of queue length and avg latency could be indicators of bottleneck)
 
JazzKitten

JazzKitten

New Member
@Lawrence_SoCal thanks for the response...my laptop is about that age. I will try dropping the canvas settings but the bitrate was set at 2500 last time I tried, throughout the whole stream as that was what the YouTube widget recommended. I don't have an upper end graphics card. I think it might be time for a new laptop - but I'm still curious to know whether the blackmagic atem mini would make any difference at all to the situation, or if it's all down to my poor old laptopl. Thanks again!
 
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Lawrence_SoCal

Active Member
My suggestion would be to see if you can borrow a newer laptop (something maybe 4yrs old or newer, that has an nVidia GPU), install OBS, and see if that makes a big difference

But, for right now, maybe try and optimize your current laptop setup, ... try reducing the OBS resource needs by dropping to a single camera? One issue you may have is if your laptop only has USB 2.0 ports, which will limit video resolution that can pass through (or compress it, which then your CPU has to decompress). If you laptop has USB 3.0 port, make sure your HDMI capture is also USB 3, and check driver version (most likely latest, BUT check vendor or related forums for your specific model, as sometimes newer doesn't always mean better)

This is an area outside my experience (never used blackmagic, or any other tool than OBS)... so take it for what its worth
I would think OBS vs something else comes down to what you are trying to accomplish,
If Blackmagic Atem mini meets your video stream compositing needs, and save buying a new laptop (and is cheaper), then maybe. The blackmagic isn't going to have the flexibility, power (and complexity) of OBS... whether that works for you or not is up to you. Also, as I expect current COVID-19 social distancing to go on for close to, if not more than a year, I'd recommend considering not just what you want to accomplish streaming now, but what you'd like your stream to look like 6 months or more from now. It could be the Blackmagic would work now, but not in the long run (again, it depends on what you want to do). I'm sure there are reviews out there comparing Atem mini vs OBS that would help you decide
 
JazzKitten

JazzKitten

New Member
Hi @Lawrence_SoCal I bit the bullet and bought a new laptop.
It has the following spec:
Processor Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz, 1992 Mhz, 4 Core(s), 8 Logical Processor(s)
Installed Physical Memory (RAM) 24.0 GB
And we tried a stream last week on our new cable broadband, which has a 20mbps upload speed. It was rather disappointing! The stream was cutting out and now I'm trying to investigate why. I've been looking into using NVENC encoder, as this is cited as a better way of encoding, but I can't find this as an option, I only have x264 and QuickSync H.264 as options, even thoruhg I know I have an NVidia graphics card.
I'm beginning to lose interest! Will post elsewhere about these problems, but wanted to thank you for your help. I will investigate the USB2/3. as this laptop has one of each.
Thanks again!
Wendy
 
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Lawrence_SoCal

Active Member
Congratulations on the new system
In terms of general system optimization, hopefully you have an NVMe SSD drive, vs a SATA SSD, or worse a SATA HDD.
In these forums are notes about setups for Windows laptop with Intel native GPU, plus an add-on nVidia GPU, to make sure you can make use of the nVidia GPU. Fortunately, my laptop just worked, so I haven't delved into the details. And now streaming from a desktop vs a laptop
Hang in there... can be a struggle, but I've found it worthwhile... but I'm also a geek... so take it for what its worth

JazzKitten said:
I've been looking into using NVENC encoder, as this is cited as a better way of encoding, but I can't find this as an option, I only have x264 and QuickSync H.264 as options, even thoruhg I know I have an NVidia graphics card.
Click to expand...
In OBS -> Settings -> Output page
Streaming - Encoder you don't have a Hardware (NVENC) option?
Which nVidia GPU do you have?

As for the stream cutting out, please describe more explicitly (in this or other thread).
Hopefully you've seen this link https://obsproject.com/blog/five-simple-tips-for-new-streamers
and @qhobbes posts regarding
Please post a log with your issue! Here's how...
Use the Log Analyzer.

Other considerations - making sure unnecessary background software isn't running (vendors are known to make you life 'easier' by loading up lots of junk and having it all auto-start... that stuff can get in the way, depending on circumstances
Also, having a new Internet circuit doesn't mean that all that bandwidth is available (WiFi interference), other devices consuming bandwidth, others in neighborhood can impact upload bandwidth... etc. Start by using a wired Ethernet (vs WiFi) connection if you aren't already. And then unless you are certain, turn off / airplane mode eReaders, etc other devices.... and unplug streaming boxes (Roku, AppleTV, etc).. some will think this is overkill, but any number of things can unexpectedly impact bandwidth (and download traffic still has ACK reply packets consuming a little upload bandwidth)
 
JazzKitten

JazzKitten

New Member
thanks again @Lawrence_SoCal !
I have an nVidia Quadro P520 and I can't see the NVENC option in the encoders - only the software encoders QuickSync and x264.
I've tried both wireless and wired connections and it doesn't' make any difference at all.
I will read those threads - thank you fro posting the link - back soon.
Thanks for helping me to get to the bottom of this issue.
All the best
Wendy
 
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