Dialogic 6.2 manual Infopkt Structure, Speech Infopkt Parameters

The Bfv API Functions

Infopkt Structure

Every infopkt consists of a header and data. The 4-byte header consists of a type code and a length. The type code defines the infopkt type, and the length field indicates the total length of the infopkt, including the header. Data consists of raw data, formatting parameters or, in the case of indirect infopkts, pointers to other files.

The maximum length of an individual infopkt is 30,000 bytes, but Dialogic recommends limiting the size to approximately 1K. This limit affects the size of infopkts only and has no effect on the size of a fax document, since large fax documents are simply converted to multiple infopkts within an infopkt stream.

When indirect infopkts point to other infopkt stream files, the maximum nesting depth is three. All file names that occur in indirect infopkts must be 0-terminated.

The infopkt.h file, located in the inc subdirectory, contains the definitions of the infopkt structures.

See Appendix E in Volume 6 of the Bfv API Reference Manual for the parameter values and defaults of each tag type infopkt.

Speech Infopkt Parameters

The INFOPKT_SPEECH_PARAMETERS infopkt defines the speech parameters for infopkt-formatted speech files. These parameters include the coding format, the compressed sample rate, the number of bits per sample, the analog front end (afe) rate, and the data format. In infopkt streams made up of simple speech files, this infopkt begins the infopkt stream. In infopkt streams made up of indexed prompt files, it begins each new speech file embedded in the stream.

Applications use the BfvSpeechRecord function to record speech in infopkt format (see the Bfv API Reference Manual, Volume 3 for a complete description). Valid settings for the data coding format, compressed sample rate for playback, and number of bits per sample are found with the BfvSpeechRecord function.

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