Question / Help ? about canvas size

If I am going to stream at 720, is it better to make my canvas at 720 or the 1080 that the camlink uses? I'm thinking in terms of cpu load.
 

Narcogen

Active Member
I don't think it makes any difference in terms of CPU load. The CPU is going to compress frames at the end of the process, so whether you start out and 1080 and then scale or start at 720 and don't probably won't make a lot of difference.

It may make a difference to your GPU, that has to render the full frame before it gets scaled and compressed. But if you're using an external capture device and not overloading your PC's GPU while streaming, that probably doesn't matter either.

Do a test, look at the log. Open that Status window and check for GPU or CPU overload messages.
 
Since you brought em up- I have 2 questions
1. Should I use h264 or one of the Apple options for encoding?
2.Will the devices such a magewell, aja extremetap, avermedia utap actually help with the heavy lifting on the computer in respect to OBS? From some of the things I've heard, they only help if you are recording.
 

FreeKillZero

New Member
1) Which streaming service are you planning on going through? Twitch prefers Constant Bit Rate and may forcibly end a stream session if it detects it's out of spec. Unfortunately, the Apple options are VBR (Variable Bit Rate) and have ended in my test streams with twitch after a second or two. This left x264 as my only option.

2) I'm using a Magewell USB HDMI Capture Plus over USB 3.0, mainly as a device to help with ingesting an audio/video signal - it allows me to get an HDMI signal from my consoles/Gaming PC over to the Mac. It doesn't really help with the encoding segment of streaming since I'm using x264 which is CPU dependent.
 
Thanks for the reply. I'm streaming car races to youtube. Currently trying to use camlink from my camcorder. I know less about gaming needs than I do about the camera bit. I'm trying to understand why I need to go from a $60, $150 to a $250+ link. I would hate to go up to the higher end and end up with the same poor performance I'm getting with the$150. If the higher end spread is actually do some of the heavy lifting so I don't need to run out and buy a new computer right away-like when I want to put a camera on each corner of the track- then the extra $$$ are worth it to me.
 

Narcogen

Active Member
None of these capture devices are doing the "heavy lifting"-- the encoding-- your PC has to do that. The ones that do encoding are above $250. Are you getting bad performance now? Do you have a logfile?
 
Yes, I cleared out all my preferences and started with a clean slate. Where yesterday after updating firmware there was no interlacing but high cpu use, today there is some horizontal interlace and stuttering and cpu usage seems to be down. About a !/2 second audio delay.
I was going to try it outside just in case the led lighting might have something to do with it. Of course the rains moved in.
I ran a stream with what I think are bare necessities for this weekend. The fps in lower right corner never went above 29. Stream is here: https://www.youtube.com/watch?v=HQBT-BI1AFo
 

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I was kind of hoping to add a stationary cam but obs didn't like it. Macbook has 2 usb ports bit on one root. However it doesn't seem to mind my Zoomh4n so I think I;ve "solved" the audio problem. Bonus is I can plug another mic into it and have facing the pa system-just don't have the time this week to get cabling and deal with more gremlins to plug pa in direct
 

Narcogen

Active Member
14:50:38.997: Output 'adv_stream': Number of lagged frames due to rendering lag/stalls: 5005 (55.3%)

Your GPU is overloaded. I'm guessing the 650M is not up to 1080p60. Try reducing canvas size or frame rate, one or the other-- if that doesn't help, try both.
 
Guess I'm going with 480. Only thing that got a halfway decent image and stayed below 50% cpu. I'm also guessing the 90* plus heat isn't helping the laptop any. I'm glad we're off for 2 months. This craps exhausting mentally. But then my cpu is 67 years old. Somehow I see a new computer in my future.
I was looking at $1500 unit on Dell. "oh, we'll finance it for you" Show me. "minium payment $51 a month for 30 years" Yeahhh, I'll get back to you on that
Thanks for all your help!
 
The 480 worked quite well. 4 hours with 400 dropped frames due to isp. But not acceptable for going forward. Any thoughts on a premade or diy pc? Looking to do something that will support 5 cameras, audio mixer/interface.
 
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