Minimum CPU for full HD streaming?

[IAmAndre]

Hi,

 

I have to live stream an event next week, and the problem is I'm not sure if any of the laptops I have at my disposal can do it. My personal laptop is a Huawei Matebook with a 6th gen core m5 CPU and 8GB of RAM. The laptop my employer is providing has a core i5 (3rd or 4th gen) and probably 8GB of RAM too.

Of course I can't bring my desktop there, so I want to know if any of the two laptops would be able to do it. I'll be receiving a full HD signal and use a capture card and OBS. If not, would it be possible to somehow drop the resolution to 720p to improve the performance?

 

Thanks

[Electronics Wizardy]

You you tried doing it on the laptops? They should be able to do it at low qualityes or with gpu acceleration.

 

What are you streaming from? Whats the source?

 

 

[IAmAndre]

1 minute ago, Electronics Wizardy said:

You you tried doing it on the laptops? They should be able to do it at low qualityes or with gpu acceleration.

 

What are you streaming from? Whats the source?

 

 

The signal will be provided through SDI cables. I can't try for now because it's a rather complex setup, but I guess it would still give me an idea.

[Electronics Wizardy]

1 minute ago, IAmAndre said:

The signal will be provided through SDI cables. I can't try for now because it's a rather complex setup, but I guess it would still give me an idea.

what program are you using?

[IAmAndre]

Just now, Electronics Wizardy said:

what program are you using?

OBS as I mentioned in the original post.

[Electronics Wizardy]

Just now, IAmAndre said:

OBS as I mentioned in the original post.

Just give obs a shot then, you should have quicksync that can do streaming just fine on there. Did you give obs a try?

[IAmAndre]

1 minute ago, Electronics Wizardy said:

Just give obs a shot then, you should have quicksync that can do streaming just fine on there. Did you give obs a try?

No but I think I'll try tomorrow just to get a rough idea of the performance. It turns out that the i5 would still deliver a better performance than the core m (which was to be expected).

[Electronics Wizardy]

1 minute ago, IAmAndre said:

No but I think I'll try tomorrow just to get a rough idea of the performance. It turns out that the i5 would still deliver a better performance than the core m (which was to be expected).

that i5 is pretty old, so the core m may be faster. Id also use quicksync that will us the gpu for encoding here.

[mariushm]

If you don't have quicksync or nvenc (no onboard graphics), an i3 or i5 should still be fast enough for real time software encoder using x264 (inside obs) 

Just go in configuration and change from default preset (veryfast) to superfast or even ultrafast  (the faster the fewer encoding complexity so image quality will worsen but you can counteract by giving it more bitrate). You can further speed things up like using for example --no-cabac which packs the video bits with a less cpu intensive algorithm so you encode faster but use 5-10% more bits or so, therefore you need higher bitrate to get same quality.

Yes, it may be better to just resize to 720p and use veryfast preset instead, and in worst case scenario it may be less cpu intensive to resize the image to exactly half, at 960x540 (you can use super cheap bilinear resizing with great quality to reduce to half, while for 720p you'd need to use bicubic resize or some more cpu intensive algorithm)

 

[IAmAndre]

2 minutes ago, mariushm said:

it may be better to just resize to 720p and use veryfast preset instead,

That's what I intended to do in the worst case scenario, but isn't "downscaling" some extra work for the CPU?

[mariushm]

It depends, some things can be accelerated using the video card ... for example if you capture some footage from a game, OBS could tell the video card to resize the image before it "downloads" it from the video card's memory.

However, if you apply overlays over the footage or do various things, OBS may need to get the full resolution, apply overlays and then either use cpu to resize or upload full size image to video card, resize if desired , encode ... if encoding using video card is possible.

 

Anyway, whatever downscaling the cpu does, it's less work than what extra work the x264 encoder would have to do to encode the higher resolution so you gain more free cpu for x264, potentially allowing you to set higher quality settings (preserve more quality in the bitrate you have)

 

Also... is that a conference or something like that? You said event... keep in mind that you may have a poor internet connection there, you could have loads of people on the wifi of that place. If the event doesn't give you wired internet or a separate internet connection things could be tricky.

While Twitch allows up to 6 mbps and youtube allows even 10-20mbps, you may not have enough of a stable internet connection there.

For 720p, with good quality settings in the encoder, 2-2.5 mbps would be enough. With ultrafast and everything on fast, you may need around 4 mbps to get some decent quality.

Worst case scenario, may want to consider having some phone with tethering or good internet plan as a backup, and set up your phone as access point and upload through your phone's plan to the net.

[IAmAndre]

25 minutes ago, mariushm said:

Also... is that a conference or something like that? You said event... keep in mind that you may have a poor internet connection there, you could have loads of people on the wifi of that plac

It's a conference and don't worry the internet will be optimal (wired, fixed IP address dedicated to streaming, crazy speeds). I'll give it a try tomorrow at home just to get a rough idea and see how it goes.