1 .TH "SDL_AudioCVT" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference"
3 SDL_AudioCVT \- Audio Conversion Structure
4 .SH "STRUCTURE DEFINITION"
17 void (*filters[10])(struct SDL_AudioCVT *cvt, Uint16 format);
25 Set to one if the conversion is possible
28 Audio format of the source
31 Audio format of the destination
34 Rate conversion increment
40 Length of the original audio buffer in bytes
43 Length of converted audio buffer in bytes (calculated)
46 \fBbuf\fR must be \fBlen\fR*\fBlen_mult\fR bytes in size(calculated)
49 Final audio size is \fBlen\fR*\fBlen_ratio\fR
51 \fBfilters[10](\&.\&.)\fR
52 Pointers to functions needed for this conversion
55 Current conversion function
58 The \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\&.
60 Many of the fields in the \fBSDL_AudioCVT\fR structure should be considered private and their function will not be discussed here\&.
61 .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\&.
62 .IP "\fBint\fP \fBlen\fR" 10This is the length of the original audio data in bytes\&.
63 .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\&.
64 .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\&.
67 \fI\fBSDL_BuildAudioCVT\fP\fR, \fI\fBSDL_ConvertAudio\fP\fR, \fI\fBSDL_AudioSpec\fR\fR
68 .\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58