FunctionPackage: cgToCDocOverviewCGDocRelNotesFAQIndexPermutedIndex
Allegro CL version 10.0
Unrevised from 9.0 to 10.0.
9.0 version


Arguments: device &key bits-per-sample samples-per-second channels notify-p wait-p

Sets the audio quality and other options for recording a wave file. This function is necessary for decent quality audio in MCI, since the default quality is rather low.

Each of the options bits-per-sample, samples-per-second, and channels may be either nil to not modify that attribute, or else an integer indicating a new value for that attribute. The values that have a desirable effect may depend on the sound card's driver, and it is not clear how to determine programmatically what values will work well.

bits-per-sample is the number of bits used to store each sample. The default is 8 (low quality). 16 is audio-CD quality and is recommended.

samples-per-second is the number of samples that are recorded for each second of sound. The default is 11025 (low quality). A common high-quality sampling resolution that has worked well in our brief tests on a basic sound card is 48000. Audio CDs use 44100, though in our tests on a basic sound card this value did not produce high-quality audio (perhaps the proper value is not exactly 44100). Some applications that burn audio CDs require that the wave file already be in 16-bit, 44.1k resolution format though.

channels (when non-nil) may be either 1 for a monophonic recording or 2 for a stereo recording.

If this function is called, it must be called before any recording is done on the device, or after mci-delete is called to erase everything that has been recorded on the device.

device is an mci-wave-audio instance. If wait-p is true, then this function does not return until the operation is complete; otherwise the function returns immediately and the operation is performed asynchronously. If notify-p is true, then mci-notify is called when the operation has completed.

See the sample recording session at mci-record for more information.

See cg-mci.htm for information about MCI support in Common Graphics.

Copyright (c) 1998-2015, Franz Inc. Oakland, CA., USA. All rights reserved.
Documentation for Allegro CL version 10.0. This page was not revised from the 9.0 page.
Created 2015.5.21.

Allegro CL version 10.0
Unrevised from 9.0 to 10.0.
9.0 version