Why the massive difference in conversion size

Audacity Help Forum Windows
1

I’m trying to convert video to audio and chop the audio down to what I’m wanting. The video length is 1 hour 22 minutes, give or take.

When I convert on Linux it is around 2.3Gb, I have no audio output from the computer though due the trouble with Realtek driver they are dealing with on Linux. So to do any audio manipulation I have to do it in Windoze. When I try to do it on Windoze 10 it won’t let me. The same exact file converts over 4.22Gb which is all the free hard drive space I have available on Windoze. I have removed everything from Windoze that I can remove so I’m stuck with only 4.22Gb to use for file conversion. I have longer videos I’m also wanting to convert over so obviously I can’t do anything with them until I get the Windoze version to behave like the Linux version.

Why the big discrepancy between converted file sizes? Both are supposed to be converting at 44,100/32 bit. What else do I need to look at on Windoze so I can get it to convert over with a much smaller file size like Linux does?

2

First, we need to be clear about what exactly you are doing …

How are you “converting”?
(and same question for Windows)


Mono or stereo?


Where / how are you measuring that?

3

It’s pretty easy when it comes up and says you have no hard drive space left and when you start there is 4.22Gb. Really easy to figure that one out.

Using stereo both Linux and Windoze.

I’m opening the .mp4 file using Audacity so it will automatically bring up the audio file/graph. From that I can cut it where I cut to cut it and then save the rest.

Pretty much the only thing from standard setup that I have changed is where Audacity is supposed to save the file, otherwise everything has been left unchanged from the way it is when installed, on both version.

4

Let me add into the previous answer a bit. When you go to Preferences and click on Directories it shows you how much hard drive space is available to use. I checked that before and after the importing of the file on both Windoze and Linux.

5

Looking at the panel on the left end of a track shows some useful information.
Example:





In the above image you can see that the track is:

  1. Channels = 1 Mono
  2. Sample rate = 44100 Hz
  3. Sample format = 32-bit float = 4 bytes per sample (1 byte = 8 bits)

Also, you can see the precise length of the track by selecting the track, then looking in the “Selection Toolbar” (See: https://manual.audacityteam.org/man/selection_toolbar.html)


For an unedited track, you can then calculate the size of the project:

Channels x Rate x bytes-per-sample x duration(seconds)

So, for example, if you have one stereo track (2 channels), 32-bit float, 44100 Hz, 1 hour 22 minutes:

1 hour = 60 x 60 = 3600 seconds
22 mins = 22 x 60 = 1320
so duration = 3600 + 1320 = 4920 seconds

So, size in bytes =
2 x 44100 x 4 x 4920 = 1735776000 bytes = 1.735776 Gigabyte
(The actual size of the Audacity project will be just a little more than this)

As soon as you start working on the audio, the project size will increase due to data retained for “Undo”.
The Undo data is automatically deleted when the project is closed.

6

Yes, but I’m ending up with a major discrepancy between Linux and Windoze in the file size, WHY? In reality I was using 48,000 on Linux and 44.1 on Windoze, so I should have been getting a smaller temp file size but instead I was getting one which is almost twice the size and maybe more, it runs out of hard drive space before it can even finish chugging away at the file.

I know when it comes up and shows the audiograph, if I go to Windoze shell and start click on This PC it will continue to drop in file size each time I click on This PC, no other programs are running. Is that Audacity saving space for Undo that I’m witnessing. It finally gets it down where nothing is left and then the window pops up saying I’ve run out of hard drive space on Audacity. Initially will show like 800 mb left when the audiograph comes up but by the time its all done doing whatever it has taken up all the hard drive space.

7

Okay, just tried another file for comparison purpose.

Preferences/Directories shows:
3.6Gb-2.6Gb on Windoze when importing a 33 minute, 35 second video
4.8Gb-4.2Gb in Linux for the same video.

Why is it not the same? What is the difference? How can I get it to convert using the smaller size on Windoze. I need to be able to listen to the audio so I know where I want to cut the audio, but I have no audio output on Linux.

8

Preferences/Directories shows the amount of free space, not the amount of used space.

9

So why did the amount of free space drop so much more dramatically on Windoze then it did on Linux. Audacity was the only program running at the time. Why did I lose 1Gb of hard drive space running Windoze, but only lose .6Gb on Linux? It was the same video being imported into Audacitty.

10

Maybe Windows is using disk space for something unrelated at the same time.