.TH "SDL_AudioCVT" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" .SH "NAME"SDL_AudioCVT\- Audio Conversion Structure.SH "STRUCTURE DEFINITION".PP.nf\f(CWtypedef struct{  int needed;  Uint16 src_format;  Uint16 dest_format;  double rate_incr;  Uint8 *buf;  int len;  int len_cvt;  int len_mult;  double len_ratio;  void (*filters[10])(struct SDL_AudioCVT *cvt, Uint16 format);  int filter_index;} SDL_AudioCVT;\fR.fi.PP.SH "STRUCTURE DATA".TP 20\fBneeded\fRSet to one if the conversion is possible.TP 20\fBsrc_format\fRAudio format of the source.TP 20\fBdest_format\fRAudio format of the destination.TP 20\fBrate_incr\fRRate conversion increment.TP 20\fBbuf\fRAudio buffer.TP 20\fBlen\fRLength of the original audio buffer in bytes.TP 20\fBlen_cvt\fRLength of converted audio buffer in bytes (calculated).TP 20\fBlen_mult\fR\fBbuf\fR must be \fBlen\fR*\fBlen_mult\fR bytes in size(calculated).TP 20\fBlen_ratio\fRFinal audio size is \fBlen\fR*\fBlen_ratio\fR.TP 20\fBfilters[10](\&.\&.)\fRPointers to functions needed for this conversion.TP 20\fBfilter_index\fRCurrent conversion function.SH "DESCRIPTION".PPThe \fBSDL_AudioCVT\fR is used to convert audio data between different formats\&. A \fBSDL_AudioCVT\fR structure is created with the \fI\fBSDL_BuildAudioCVT\fP\fR function, while the actual conversion is done by the \fI\fBSDL_ConvertAudio\fP\fR function\&..PPMany of the fields in the \fBSDL_AudioCVT\fR structure should be considered private and their function will not be discussed here\&..IP "\fBUint8 *\fP\fBbuf\fR" 10This points to the audio data that will be used in the conversion\&. It is both the source and the destination, which means the converted audio data overwrites the original data\&. It also means that the converted data may be larger than the original data (if you were converting from 8-bit to 16-bit, for instance), so you must ensure \fBbuf\fR is large enough\&. See below\&..IP "\fBint\fP \fBlen\fR" 10This is the length of the original audio data in bytes\&..IP "\fBint\fP \fBlen_mult\fR" 10As explained above, the audio buffer needs to be big enough to store the converted data, which may be bigger than the original audio data\&. The length of \fBbuf\fR should be \fBlen\fR*\fBlen_mult\fR\&..IP "\fBdouble\fP \fBlen_ratio\fR" 10When you have finished converting your audio data, you need to know how much of your audio buffer is valid\&. \fBlen\fR*\fBlen_ratio\fR is the size of the converted audio data in bytes\&. This is very similar to \fBlen_mult\fR, however when the convert audio data is shorter than the original \fBlen_mult\fR would be 1\&. \fBlen_ratio\fR, on the other hand, would be a fractional number between 0 and 1\&..SH "SEE ALSO".PP\fI\fBSDL_BuildAudioCVT\fP\fR, \fI\fBSDL_ConvertAudio\fP\fR, \fI\fBSDL_AudioSpec\fR\fR...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58