docs/man3/SDL_AudioSpec.3
author Aaron Wishnick <schnarf@gmail.com>
Wed, 18 Jun 2008 04:51:10 +0000
branchgsoc2008_audio_resampling
changeset 2655 b8e736c8a5a8
parent 2283 546f7c1eb755
child 4311 1238da4a7112
permissions -rw-r--r--
Added beginnings of resampling code.
     1 .TH "SDL_AudioSpec" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" 
     2 .SH "NAME"
     3 SDL_AudioSpec \- Audio Specification Structure
     4 .SH "STRUCTURE DEFINITION"
     5 .PP
     6 .nf
     7 \f(CWtypedef struct{
     8   int freq;
     9   Uint16 format;
    10   Uint8 channels;
    11   Uint8 silence;
    12   Uint16 samples;
    13   Uint32 size;
    14   void (*callback)(void *userdata, Uint8 *stream, int len);
    15   void *userdata;
    16 } SDL_AudioSpec;\fR
    17 .fi
    18 .PP
    19 .SH "STRUCTURE DATA"
    20 .TP 20
    21 \fBfreq\fR
    22 Audio frequency in samples per second
    23 .TP 20
    24 \fBformat\fR
    25 Audio data format
    26 .TP 20
    27 \fBchannels\fR
    28 Number of channels: 1 mono, 2 stereo
    29 .TP 20
    30 \fBsilence\fR
    31 Audio buffer silence value (calculated)
    32 .TP 20
    33 \fBsamples\fR
    34 Audio buffer size in samples
    35 .TP 20
    36 \fBsize\fR
    37 Audio buffer size in bytes (calculated)
    38 .TP 20
    39 \fBcallback(\&.\&.)\fR
    40 Callback function for filling the audio buffer
    41 .TP 20
    42 \fBuserdata\fR
    43 Pointer the user data which is passed to the callback function
    44 .SH "DESCRIPTION"
    45 .PP
    46 The \fBSDL_AudioSpec\fR structure is used to describe the format of some audio data\&. This structure is used by \fI\fBSDL_OpenAudio\fP\fR and \fI\fBSDL_LoadWAV\fP\fR\&. While all fields are used by \fBSDL_OpenAudio\fP only \fBfreq\fR, \fBformat\fR, \fBsamples\fR and \fBchannels\fR are used by \fBSDL_LoadWAV\fP\&. We will detail these common members here\&.
    47 .TP 20
    48 \fBfreq\fR
    49 The number of samples sent to the sound device every second\&. Common values are 11025, 22050 and 44100\&. The higher the better\&.
    50 .TP 20
    51 \fBformat\fR
    52 Specifies the size and type of each sample element 
    53 .IP "\fBAUDIO_U8\fP" 10Unsigned 8-bit samples
    54 .IP "\fBAUDIO_S8\fP" 10Signed 8-bit samples
    55 .IP "\fBAUDIO_U16\fP or \fBAUDIO_U16LSB\fP" 10Unsigned 16-bit little-endian samples
    56 .IP "\fBAUDIO_S16\fP or \fBAUDIO_S16LSB\fP" 10Signed 16-bit little-endian samples
    57 .IP "\fBAUDIO_U16MSB\fP" 10Unsigned 16-bit big-endian samples
    58 .IP "\fBAUDIO_S16MSB\fP" 10Signed 16-bit big-endian samples
    59 .IP "\fBAUDIO_U16SYS\fP" 10Either \fBAUDIO_U16LSB\fP or \fBAUDIO_U16MSB\fP depending on you systems endianness
    60 .IP "\fBAUDIO_S16SYS\fP" 10Either \fBAUDIO_S16LSB\fP or \fBAUDIO_S16MSB\fP depending on you systems endianness
    61 .TP 20
    62 \fBchannels\fR
    63 The number of seperate sound channels\&. 1 is mono (single channel), 2 is stereo (dual channel)\&.
    64 .TP 20
    65 \fBsamples\fR
    66 When used with \fI\fBSDL_OpenAudio\fP\fR this refers to the size of the audio buffer in samples\&. A sample a chunk of audio data of the size specified in \fBformat\fR mulitplied by the number of channels\&. When the \fBSDL_AudioSpec\fR is used with \fI\fBSDL_LoadWAV\fP\fR \fBsamples\fR is set to 4096\&.
    67 .SH "SEE ALSO"
    68 .PP
    69 \fI\fBSDL_OpenAudio\fP\fR, \fI\fBSDL_LoadWAV\fP\fR
    70 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58