How to calculate exact size of wav file

[chrisdee]

Hello. I'v google'd around trying to find a formula for this. I finally found :

size = sample rate * number of channels * (bits per sample /8) * time in seconds.

So a 44.1 hHz, stereo 16 bit wav file lasting 60 seconds should be :

Size = (44.1 * 2 * (16/8) * 60) / 1024
Size = 10,3359 MB

I tried recording in protools at 60 bpm for one minute in stereo.
Looking in the Project window in ProTools it says each channel is 5.07 MB, wich is 10,14 MB in stereo. In addition I looked at it in OSX Finder, and it says one channel is 5.1 MB, wich is 10.2 in stereo.

All this different results makes me a bit confused. Am I using the wrong formula or does both ProTools and Finder calculate things differently ?

I would apreciate someone with insight clearing this up for me:)

[JrummerJ]

Just looks like a little rounding is going on. I would forget about the formula take the number that you got when you recorded for 1 minute (I don't think the bpm matters at all).

I recently checked this out for a live recording I was about to do. I wanted to know if I could burn the session to 1 DVD and send it home with my friend who has a pro tools rig and would be doing the mixing. I figured out ahead of time that each minute of recording (@ 24 bit 48KHz) took ~8.7 MB. So I multiplied 8.7MB X 4 tracks X 90 minutes = 3132 MB or 3.13 GB. In the end this almost exactly what the file sizes were.

J

[chrisdee]

So the calcuation is right ?

[JrummerJ]

Either way is close enough, isn't it? It is only .03MB difference per track. Though, I would think that the Pro Tools Project Window is more accurate since it goes out one more decimal place.

J

[Rail Jon Rogut]

You're just calculating the data - there's also the header info, BWF chunk, overview, region data chunk, etc....

[chrisdee]

I see. Well, thank you for all the answers. I guess the formula is correct when calculating only the raw data.

[1ace1]

It's about 10 meg a min for full stereo (44.1 16BIT)

Approx (with no maths)

A:)

[SKI]

Back in the days of OS9 before we had OSX and greater disk capabilities Digi made the numbers available.

16/44
1trk 1 min=5mb
2trk 5 min=50mb
2trk 60 min=600mb
24trk 1 min=120mb
24trk 5 min=600mb
24trk 60 min=7gb

16/48
1trk 1 min=5.5mb
2trk 5 min=55mb
2trk 60 min=662mb
24trk 1 min=132mb
24trk 5 min=662mb
24trk 60 min=7.8gb

24/44
1trk 1 min=7.5mb
2trk 5 min=75mb
2trk 60 min=900mb
24trk 1 min=180mb
24trk 5 min=900mb
24trk 60 min=10.5gb

24/48
1trk 1 min=8.2mb
2trk 5 min=83mb
2trk 60 min=991mb
24trk 1 min=198mb
24trk 5 min=991mb
24trk 60 min=11.6gb

[JFCMan]

Hi there chrisdee, thank you for your formula - It's helping me a lot - I was going around the bend trying to figure out how to do this and the web is just so confusing with so many different ideas and "delicate" egos and extremely strong opinions. Some of us just want simple answers that are at least in the ball park and don't require much higher education to understand.