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Diffstat (limited to 'distrib/sdl-1.2.15/docs/man3/SDL_AudioCVT.3')
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diff --git a/distrib/sdl-1.2.15/docs/man3/SDL_AudioCVT.3 b/distrib/sdl-1.2.15/docs/man3/SDL_AudioCVT.3 new file mode 100644 index 0000000..f5e3489 --- /dev/null +++ b/distrib/sdl-1.2.15/docs/man3/SDL_AudioCVT.3 @@ -0,0 +1,68 @@ +.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\fR +Set to one if the conversion is possible +.TP 20 +\fBsrc_format\fR +Audio format of the source +.TP 20 +\fBdest_format\fR +Audio format of the destination +.TP 20 +\fBrate_incr\fR +Rate conversion increment +.TP 20 +\fBbuf\fR +Audio buffer +.TP 20 +\fBlen\fR +Length of the original audio buffer in bytes +.TP 20 +\fBlen_cvt\fR +Length 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\fR +Final audio size is \fBlen\fR*\fBlen_ratio\fR +.TP 20 +\fBfilters[10](\&.\&.)\fR +Pointers to functions needed for this conversion +.TP 20 +\fBfilter_index\fR +Current conversion function +.SH "DESCRIPTION" +.PP +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\&. +.PP +Many 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 |