WAVanalysator V1.2 (12/2002)

This is free software. Use it at your own risk. Distribute it freely as long as you don't earn money with it. Always include help file.

What's this?

WAVanalysator is a Windows program for analyzing a stereo WAV file to discover if it is effectively stereo or only mono.

I use it for processing movies broadcasted by TV stations over DVB where mono sound is usually broadcasted as a stereo MPEG1 layer2 stream. When creating a CD version of a movie, I want to have real mono sound when a movie has effectively only mono sound.

WAVanalysator works only with PCM 16 bit stereo WAV files (any samplerate) smaller than 2 GB.

Typical Usage

1. Load a stereo WAV file by either selecting it in the file open dialog or starting WAVanalysator with the file as parameter at the command line.
2. Find out whether the relevant movie part is stereo, mono or has "description for blind people" (see "how it works"). Observe what the output looks like and use the slider for jumping to several positions. Listen if a position belongs to the movie or to a commercial break. If you have a Surround Sound Amplifier, listen if the sound comes from the center speaker only. That's also an indication for mono sound. After listening at some positions, you should know if the movie is stereo or mono. In the sample below, the simpsons episode seems to be mono, only the commercials are in stereo.
3. Convert the original stereo file to a mono file with your favourite sound editor if it seems to be mono sound.
4. Create your movie with the original stereo sound or with a real mono audio stream.

sound file of a Star Trek episode in mono with commercial breaks

How it works

WAVanalysator reads in about 550 points of the sound file. At each point, the desired number of samples is read in and left and right channel are compared. If the sound comes from a movie with typical stereo sound, right and left channel are different more or less. Lower volume results in smaller differences. Because of that, WAVanalysator "normalizes" the values before comparing channels (the WAV file remains untouched - don't panic!). The resulting colored bars in the output panel represent the differences.

Some movies are broadcasted with "description for blind people". That means the left channel usually has only the (mono) movie sound and the right channel has the same and additionally spoken descriptions of what's happening in the movie. The description is spoken in pauses where no actor is speaking. WAVanalysator tries to detect this kind of sound file. If you have such a file, jump to a position that's marked red and listen if you hear the decription on the right channel. Then, you should only extract the left channel with your sound editor program and use it as the movie sound (or create two audio streams).

Options

Samples per Point of Analysis sets how many samples are compared for each of the 550 test points.

Normalisation factor describes how much a sound editor's normalize function would amplify the sound.

Changelog

V1.0 (05/2002)

• first public version

V1.1 (06/2002)

• timeline grid with time labels
• moving time label that automatically appears when using the trackbar slider
• hyperlinks for web page and documentation in about window

V1.2 (12/2002)

• bugfix: loading of short WAV files (some seconds) leaded to an endless loop

Contact

EMail: mail@uwe-freese.de

WWW: http://www.uwe-freese.de