redusing file size

Special Interest Groups Audio Processing
1

I have a file consisting 5sec noise and 55 sec silence in OGG format
The size is about 1MB
If I only export the 5 sec noise part the size will be about 100 kB
The 55 sec silence takes in other words 900kB

Can I do anything in Audacity to reduce the size to lets say 150 kB?

Kire

2

Please note that ogg is a Container format for lossless and lossy compressed audio and also for text, speech and video.
The question is now what your file actually is and what format your target should be.
Just to judge from the size, I’d expect it to be flac (lossless).
Your target file size speaks for a conversion to Vobis (1 min is 162 kb big at highest quality, 44100 Hz/mono, applied to a similar file).

However, you should either post the file here or give the exact specifications (e.g. with MediaInfo).

Have you tried importing the file into Audacity?
Just export it afterwards as ogg file (under the type combo box of the export dialog).
However, that’s a lossy compression and you should avoid this if you intent to use the file in a scientific fashion (or what is 5 s noise else good for, I wonder?).

3

This is 55 seconds of silence and about 5 seconds of noise, mono, exported from Audacity as an OGG file with default options.
Note the file size.

As Robert says, it would seem that your file is not “OGG Vorbis” encoded.

4

Thank you both for your info
I loaded ogg file and saved ogg vorbis in both the named cases.
But i think there was some problem with how i created the 55s silence.
How can I add 55s of silence to the 5s long file without disturbing the 5s?

Kire

5

You want the entire file to be 1 minute long, yes?
If so:

  1. Open Audacity
  2. Generate 1 minute of silence (Generate menu)
  3. Import your 5 second audio clip (File menu > Import Audio). It will appear below the “silence” track.
  4. Use the Time Shift tool to slide the 5 second clip left/right so that it plays at the time that you want it to (or leave it at the start if you want it to play immediately with 55 seconds of silence following).
  5. Export (File menu > Export Audio. Select “Ogg Vorbis Files” as the file type).