Can I improve the recording performances of my MacBook Pro if I use a video capture card?

[Aerendir]

I have a MacBook Pro 16’ and I record connecting my iPhone 6 through the iOS app of OBS.

during recording, after a while, I see lags and the quality greatly decreases.

it is impossible for me to record at a very high quality.

I don’t stream, but simply record videos to upload them on YouTube later.

If I buy a video capture card, can I lower the workload on the cpu/gpu and improve performances during recordings?

 

[Lawrence_SoCal]

A capture card won't change your computer processing needs materially
Laptops, optimized for battery life, aren't always a good fit for the computationally demanding task of real-time video encoding.
Which generation/CPU (exactly) do you have?

I recommend monitoring hardware resource (CPU, GPU, RAM, etc) utilization [for ex. on Windows it would be using Task manager’s Performance tab and/or Resource Monitor] to see if your system is being maxed out with your settings

Also, your issue may NOT be your computer at all. You are using WiFi right? and a 3rd party app (as OBS Project hasn't created/release a mobile app)? There is no such thing, that I'm aware of, as an OBS Studio project iOS app. Some 3rd party apps are of higher quality than others. And you could be simply having WiFi traffic contention (which is why using WiFi anywhere in streaming data chain isn't recommended, especially for those not well-versed in network traffic, WiFi frequency utilization, and associated monitoring.

And an iPhone 6 is rather old (7 yrs) and not currently supported by Apple on latest iOS (requires 6s)
Do you reboot the iPhone before streaming? and make sure ALL other apps are shut off?

 

[Aerendir]

Firstly, thank you very much for your reply!

These are the specs of my laptop:

MacBook Pro (16-inch, 2019)
2,4 GHz Intel Core i9 8 core
32 GB 2667MHz DDR4
AMD Radeon Pro 5500M 8 GB
HD SSD

Coming to the connection between the computer and the phone, I'm NOT using WiFi, but I'm using the USB-c cable: the phone is directly connected to the computer.

The "official" app I'm using is OBS Camera (https://obs.camera/docs/getting-started/ios-camera-plugin-usb/).

I'm not rebooting my phone before the recording (NOT the streaming: I'm not streaming, but simply recording).
But I also tried to use a SONY ZV-1 camera and the problem persists (https://www.amazon.it/gp/product/B088S2CNFC/).

As I don't like the idea of buying a computer just for recording in high quality 4k, is there a way to delegate the expensive processing to an external graphic card? Because some videos require I use my computer, and using a new one means I have to configure it, keep it in synch with my laptop... is so difficult to accomplish such a task... and also really annoying

Finally, which is the purpose of a video capture card if it will not improve the performances of the acquisition?

 

[Lawrence_SoCal]

Your computer should be more than powerful enough
And using a wired connection to a camera is good. I have no idea the quality of the app you are using. I would suggest rebooting iPhone, not starting anything other than desired camera app, and putting into airplane mode.
With problem persisting when using Sony camera, then most likely it is your settings on the Mac
- of course, you should make sure NOTHING is running in the background that isn't required
- your OBS settings are appropriate. For us to take a look, follow the instructions of the pinned post in this forum

Please post a log with your issue! Here's how...

OBS Studio creates a log file each time you run it which contains very useful diagnostic information. Without a log file, it's much harder for any support volunteers to figure out problems and your post may be ignored. To upload a log file, go to the Help menu > Log Files > Upload Last Log...

obsproject.com

HOWEVER, an OBS log will NOT show how well your Operating System (macOS) is running, and overall system utilization. Such configuration and monitoring is up to you

Streaming typically requires H.264, a format which AMD is terrible at/about supporting. However, as you are recording, you may be able to record using the newer H.265 and offload the encoding to your AMD GPU?? Sorry, I have no idea if this would actually work, and if possible, what the quality would be nor how to set up OBS to do that. But from other discussions, seems probably doable. I leave you to do the research on this

The purpose of a capture card is to convert the video output of a device into a format that your computer can accept. For example, my DSLR has USB2.0 output (ie low res) or HDMI. A HDMI capture card would take the HDMI video signal from a device and convert it into a USB signal a compute can accept as a video stream input. A capture card is first and foremost a converter (similar to a cable modem)

 

[Aerendir]

Ok, thank you again for your extensive reply... and thank to have clarified to me what a video capture card's purpose is :)

In those days I'm not recording, so I don't have a log after the issues.
Anyway, I'm going to paste the link to the last log: maybe it contains something useful

https://obsproject.com/logs/RVK8S76T2-9jKzIN

Regarding the encoding, I don't have the option to use H.265, but only H.264.

This is the current configuration:

And this is the detail of the encoding options available

 

[Lawrence_SoCal]

Nothing jumps out at me. Hopefully someone else will comment. Hardware H264 would be what I'd recommend, without knowing better (and I don't when it comes to MacOS). Your CPU is plenty powerful enough to capture quality video recording. Though as I noted, I can't comment on the state of your operating system, and whether your macbook is thermally throttling

Once OS is confirmed running clean/lean (no excess processes consuming RAM or CPU) I would increase the bitrate to 5000 if thermal throttling isn't an issue for higher quality. 2500 kpbs for 1080p30fps H264 is low in my opinion, especially when you are looking for quality

 

[Aerendir]

Thank you for your suggestions: I will try to change the configurations and see what happens

When I record, I close all the applications that run in background, Google Drive and Dropbox too: I have nothing more than OBS active.

When I have to record, I open Chrome, but nothing more...

Hoping someone else can give more hints on this, in the meantime, thank you very much for your support!