Hello,
In class yesterday you mentioned that you could lower FPS to save HDD space. I was curious, when it comes to getting more days of recording does lowering the FPS or the bitrate have a higher effect? for example if I have a camera set to 30 FPS and the bitrate set to 4096. would I get more HDD space by lowering the FPS to 15 or by lowering the bitrate to 2048.
With regarding to "storage space", all that is taken into account is the "bitrate" (data that is transmitted/recorded).
If you have 6MB/s constant bitrate on a camera for example, that is what you'll record (more or less), regardless if you're looking at a 2MP camera or a 4K (8MP), 6MB/s is 6MB/s.
All of the settings combined (bitrate, compression, frames, etc.) will affect the "quality" of the video.
For example: for simple mathematical explanation, if you have a 2MP, h.264 camera at 25FPS, a 2MB/s bitrate, an average scene (not much or no movement or detail) scene it is looking at wants 2MB/s at 100% detail/quality. If the scene suddenly gets more complex, it will need more than the allotted 2MB/s but, since it can't, the stream will be compressed instead and quality will be lost for it to achieve the 2MB/s bitrate.
H.265 can get the same image quality with roughly half the bitrate. So, in the example above with h.265 and 2MB/s bitrate, the camera at 100% detail would only need 1MB/s instead of 2MB/s for the average scene with an extra 1MB/s spare in case the scene becomes more complex; depending on how complex, it's possible the stream will remain at 100% quality.
So, instead of increasing bitrate to retain quality, which would also consume more storage, we change to the h.265 compression; we maintain the same 2MB/s bitrate but, the stream doesn't drop in quality.
Reducing frame rates, I-Frames, resolution and such will lower the total amount of "data" being sent therefore reducing the total required bitrate needed for the image to reach 100% quality, and turn since it will require less bitrate this will also conserve HDD storage space.
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