binary file is too big in size

[farn]

Hi,

I wrote a simple VI to do playback of sound files and to record signals. It seems to do what I want (although I appreciate general feedback on good programming habits). The bigger issue I have is that the binary file it is saving is way too big in size. A few seconds of recording gives a few megabytes of data. Although I can open the binary file in matlab and analyze the data just fine, the big file size doesn't sound right. 

Does anyone know why this is the case? I tried saving the data in something other than doubles, but it still gives large file sizes. Played around with the byte order too without much success. Any help is appreciated (LV 2009 file attached).

Thanks.

FA

[Coq_Rouge · Accepted solution]

If your DAQ unit is 16 bit or less, simply store data as I16. you store data as DBL and that is 8 bytes pr number. It is no problem making wav files in I16 format. However wav files (in Labview at least) is not a compressed. So the file size will be much bigger than MP3 files that is a compressed file format.

[farn]

That's a good piece of advice and was one of the first things I tried. It did make the file 2-3 times smaller, but still a few seconds of continuous measurement gave a 1mb file even for I16, which still sounded a bit too big for me. Maybe I'm expecting too much?

[RavensFan]

What is your data acquisition rate?

[Darin.K]

Uncompressed CD audio requires roughly 1 MB for every six seconds.  Hopefully that sets the scale for your expectations.

[farn]

I am sampling at 'cd quality' (44.1kHz) for various reasons (including recording sound files), so maybe I was expecting too much. Thanks for the replies anyway.

FA

[RavensFan]

44.1 kHz of 16 bit data will cost you 88.2 KB/sec.  A binary file for double float data (8 bytes), will cost you 352.8 KB/sec.