General Question

Ame_Evil's avatar

Is there a formula for the amount of space a video will take based on fps and resolution?

Asked by Ame_Evil (3046points) April 3rd, 2010

I’m sure there is, but does anyone know this?

I was wondering how much minutes of video you could get when using a 720×480 resolution camera at 25fps with a 20gb memory card. I haven’t bought the camera yet which is why I am asking this question. Also it may be useful for future knowledges.

I was hoping to get the formula in terms of time but don’t mind other ways as I can probably rearrange if you just know the formula and can copypasta.

So the variables I am interested in are: time, fps, resolution and memory.

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3 Answers

The_Idler's avatar

depends on the compression/file type.

as a guide though, one 720p 45min mkv on my PC is 1gb

BUT your camera is unlikely to be able to record in such a format/compression

LuckyGuy's avatar

It depends upon how much the background changes. If you are panning with a lot of noise it can take up to 10x the space of quiet scenes.

Typically, I get 15 seconds out of 21Mb. So that comes to 4 hours for 20 Gb.

njnyjobs's avatar

Without indicating a camera brand or the format it stores video, it would be difficult to provide you with a relevant answer. However, you can calculate raw uncompressed video file and use another conversion factor for the video file type you will be using. Following is the rule of thumb I use to calculate raw uncompressed video file size:

With camera set at 720×480, the resulting image is equal to 345,600 pixels per frame.

At 4 bytes per pixel, a frame of image is about 1.35MB (345,600pixels x 4bytes/1024000 bytes)

At 25fps , you will need about 33.75MB (1.35MB x 25fps) of disk space to store 1 second of video.

1GB of disk space equals to 1024MB or about 30.34 (1,024MB/33.75MB) seconds of video

20GB will yield about 10.11 (20GB x 30.34 sec / 60 sec) minutes of uncompressed video format.

For an online calculator, try this one: http://web.forret.com/tools/video_fps.asp

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