Test the Effects of W4V Compression - SM5

Song Meter SM5 User Guide
Core Product
SM5
Accessory

Before configuring a Song Meter to record in the W4V compressed format, you can use Kaleidoscope Lite to compare uncompressed and compressed sample recordings.

About this task

W4V is a compressed audio format designed by Wildlife Acoustics for bioacoustics applications. You can use it to significantly reduce the storage space used by your recordings.

Unlike compression formats like MP3, which are designed for casual listening and discard high-frequency content to reduce space, W4V compression does not apply frequency-dependent modifications to the recorded audio. Instead, increasing levels of W4V compression result in a uniform increase in background noise. In recordings from many outdoor environments, this noise increase is not discernible.

To determine if using W4V compression will have a significant effect on your recordings, you can compare compressed and uncompressed versions of the same recordings using the free Kaleidoscope Lite Analysis Software.

Procedure

  1. Configure your recorder to record audio as uncompressed, WAV files.
  2. Deploy the recorder and collect example recordings, mimicking the conditions and location of a real deployment.
  3. Download and install Kaleidoscope Analysis Software.
    You do not need to pay for a license or use a trial license for this purpose.
  4. Configure a batch process to convert a WAV file to a W4V file.
    1. Set the Input directory to a directory containing the WAV files you want to convert.
    2. Under Inputs, select WAV (and W4V) files.


    3. Set the Output directory to an empty directory.
    4. Under Outputs, select WAV (or W4V) files, and set Compression to W4V-8 (50%).


    5. Select Process Files.
  5. Repeat Step 4 for any other level of Compression you want to test.
    W4V-4 (75%) provides the greatest amount of compression. It reduces file size by 75% and has the greatest effect on background noise levels.
  6. Using File > Open..., open the original .wav file and any .w4v conversions in the Kaleidoscope Viewer to visually inspect and listen to them.
  7. If you normally analyze your data in Kaleidoscope, perform any other analysis steps you typically perform on both compressed and uncompressed files the see if the compression impacts your results.
  8. If you normally analyze your data using software that cannot open W4V files directly, convert the compressed files back to WAV files.
    Converting from W4V back to WAV keeps the increased noise floor introduced by the W4V compression. This step mimics the required workflow for recording directly in W4V, then converting to WAV for greater software compatibility.
    1. Set the Input directory to the folder containing the compressed W4V files.
    2. Under Inputs, select WAV (and W4V) files.
    3. Set the Output directory to a new, empty directory.
    4. Under Outputs, select WAV (or W4V) files, and set Compression to None.
    5. Select Process Files.
      The new output directory will contain WAV files that are compatible with third-party software, but have the same noise levels as files recorded directly to the compressed W4V format.