Files

QTrack Wave File (QLW)

QTrack stores each recording in a single file whose name will be whatever name has been given when the file is opened followed by a .QLW extension. This file is a non-standard proprietary format file unique to QTrack. It is not Windows WAV file compatible, and no other software on the market (as yet) is able to read or write to this type of file. It will not be possible to play such a file from the Windows Media Player or Sound Recorder applications for example.

Format

The file consists of a header followed by the wave information for the tracks. The data area has a flexible format which changes according to the number of tracks selected when the file was opened.

Number of tracks

The number of tracks that a QLW file can hold is decided at the time the file is created, and cannot be changed without reading and rewriting the entire file. The current version of QTrack does not support changing the number of tracks on an existing recording, however future versions of QTrack will support a conversion facility of this type. It is therefor necessary to think carefully about the number of tracks required before commencing a recording. Often the maximum number of tracks will be decided by performance considerations (see the Performance section) as well as the requirements of the music being recorded. Disk space will also be a consideration - more tracks mean more disk space used.

Disk space considerations

The amount of disk space used by a QLW file is dependant on three things; the number of tracks, the sampling rate, and the length of the recording. All are directly proportional factors. The formula for calculating space usage is as follows:

Disk space[in bytes] = ( ( ( No of tracks * Sample rate[in Hz] ) / Length of recording[in seconds] ) * 2 ) + 3000 [length of header].

As an example a 5 minute long 8 track recording at the highest quality 44100hz sample rate will chew it's way through 211, 683,000 bytes, or 206 Megabytes. Unless all 8 tracks are used in the recording we can obviously economize on disk space by cutting back on the number of tracks - but this has to be decided when the file is first created!

Normally the large amount of disk space needed by QTrack will not be a long term problem. Once the recording is complete, it can be mixed down into a raw stereo wave file (not the shareware version - see next paragraphs) , and the original multi-track QLW either archived to some form of removable storage or deleted.

Mixing

The track selectors, faders and pan controls allow any or all tracks of a recording to be mixed and played back via the soundcard, and this signal can be used for mix-down, perhaps to a tape recorder etc. Also, non-shareware (e.g. registered) versions of QTrack permit mixdown to a digital wave file (see next paragraph). To obtain the best quality sound, and to preserve the recordings against deterioration over time, I recommend first mixing down to a digital wave file (using the in-built facility within QTrack for this purpose), and then conversion of the resulting file to MPEG layer II format, using a 4 to 1 compression ratio.

Mixdown to a stereo or mono wave file

The standard (non-shareware) versions of QTrack have the facility to produce a stereo wave file mixed down from any number of the tracks of the original recording. At present this file is in raw format, with no header, and is not Windows WAV file compatible. However, most stereo wave file editors such as Cooledit, Ceres or Soundblaster Wave Studio and others will read this format, and can be used to convert to the standard Window wave file (RIFF) format.

Analogue mixdown (to a tape recorder etc).

It goes without saying that by playing a QTrack recording with the output from the soundcard connected to a tape recorder, minidisc recorder, another computer, etc, allows a stereo or mono mixdown to be made to any device capable of recording an analogue signal.

Importing wave files and other recorded sounds

At present QTrack does not support the importing of sound samples from existing wave files, but this facility will be added in the near future. Keep an eye out for new releases of QTrack. Of course any recorded sound can be brought into a QTrack recording simply by replaying the recording through the computers soundcard and using QTrack in the normal way.