Output File Size Limits / Interval Recording

[Matuku]

Hi, I've been asked to help a mate set up a camera on his boat - he wants to be able to film long periods of time (say, 10 hours at a strech).

We are using a Go Pro Hero 7, and (for now) a Atmos Connect HDMI/USB Capture Device.

It works great with OBS right out of the box.

However, what I'd like to ask for help on, please, if it's even possible, is this :

Can I specify a certain output file size (For example, 1GB) that when reached ceases and a new file starts ?

The issue we forsee (without this) is massive and unweildy files from many hours of recording, when you may only need 10 mins of video.

Anyone got any thoughts please ? If I can't do the above, is there another solution I don't know about ? Or maybe OBS is not the right tool and you could suggest an alternative ?

Thanks !

 

[qhobbes]

If you use CBR you could calculate the duration of the desired file size and set an output timer to stop at that time. I'm not sure of way of automating the start recording but you could use something like UP Deck from a phone (with timer set on phone) if the boat has WiFi (Internet not required).

 

[Matuku]

If you use CBR you could calculate the duration of the desired file size and set an output timer to stop at that time. I'm not sure of way of automating the start recording but you could use something like UP Deck from a phone (with timer set on phone) if the boat has WiFi (Internet not required).

Thanks ! I'm knew to this so ...... CBR ?

 

[qhobbes]

There's 3-5 types of bitrate control:
CBR - Constant Bitrate - The bitrate per second does not change*. The same amount of data is used to render an all black frame as full color frame.
VBR - Variable Bitrate - The bitrate changes per content. An all black frame would use less much data than a full color frame
ABR - Average Bitrate - Combination of CBR and VBR
CRF - Constant Rate Factor - A quality level is chosen instead of a bitrate. Generally 0 is best and higher numbers are lower quality
Lossless - The quality is exactly the same as the input. This requires a lot of data but in some cases less CPU. CRF 0 is sometimes lossless.

So suppose I use CBR 4000Kbps. There's 8000 Kb per 1 MB so 2 seconds per MB. 1000 MB in a 1 GB so 2000 seconds. 2000 / 60 = 33 minutes and 20 seconds. EDIT: You also need to take audio bitrate into account. Just divide 8,000,000 by your combined audio and CBR bitrates and that will indicate how many seconds you can store per GB.