Audio Setup

Much of the following information is taken primarily from a document in the MH 6.8 source tree, miscellany/multimedia/READ-ME. You may wish to consult that document to see if it contains more recent information.

MIME pre-defines one audio type, audio/basic. This is for audio data encoded using 8-bit ISDN μ-law (Pulse Code Modulation). A sample rate of 8000/second and a single channel is assumed. This is the ``native'' format for the audio chips included with SPARCstations and for HP 9000/7xx series workstations. References to ``u-law'' or ``mu-law'' in other documents mean μ-law.

There are many different types of audio formats, some of which may use compression, multiple channels, and higher or lower sample rates. These types may also be used in MIME messages by using unofficial x- subtypes, such as audio/x-next. However, there must exist pre-agreement among users of x- subtypes as to what their meanings are and how they are handled.

Which audio programs to use and how to set up to use them is highly dependent on the type of workstation you have. Information is presently available for two types of workstations: Sun SPARCstations and HP 9000/710s. If other audio-capable workstations come with programs that can be instructed from the command line to record or to play particular files, then these programs can be used with MH one way or another.

If your workstation doesn't come with a built-in microphone, or an external microphone supplied by the vendor, you'll need to buy one. If the microphone doesn't have enough gain, you may have to keep the microphone close to your lips when recording. The SONY ECM-K7 microphone comes highly recommended; you can put the microphone on your desk and it will still pick up your voice.



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