annotate docs/man3/SDL_AudioCVT.3 @ 3099:82e60908fab1

Date: Mon, 23 Mar 2009 09:17:24 +0200 From: "Mike Gorchak" Subject: New QNX patches Please apply patch qnx4.diff, which is attached. What has been done: 1)Added back OpenGL ES renderer for QNX target. Added few corrections to OpenGL ES renderer to let it work under QNX. OpenGL ES renderer do not support textures under QNX, so I think some additional work must be done. 2) Added GL_OES_query_matrix extension to SDL_opengles.h header file, which required by OpenGL ES 1.1 specification. 3) Added attribute clearing at the entrance of function SDL_GL_GetAttribure(). Added error checking into the function SDL_GL_GetAttribure(), because some attributes can't be obtained in OpenGL ES 1.0. 4) Porting testdyngles to OpenGL ES 1.0 (1.1 has glColor4ub() and glColor4f() functions, but 1.0 has glColor4f() only). 5) Added error checking after obtaining attributes using SDL_GL_GetAttribute() function to the testgl2 and testgles. 6) Small correction to testmultiaudio with printing errors. 7) Added software and accelerated OpenGL ES 1.0 support into the QNX GF driver. Please remove ./src/audio/nto directory - it will not be used anymore. Please create ./src/audio/qsa directory and add content of the archive qsa.tar.gz into this directory. I rewrote some sound code, added support for multiple audio cards, enumeration, etc. Added initial support for capture. As far as I can understand SDL 1.3 is not supporting audio capture right now ? Sam, Am I right ? Or audio capture must be supported through the PlayDevice routine ? And last, please put file SDL_gf_opengles.c to the ./src/video/qnxgf directory. It is OpenGL ES 1.1 emulation layer for some functions, which are not supported by OpenGL ES 1.0.
author Sam Lantinga <slouken@libsdl.org>
date Tue, 24 Mar 2009 10:33:12 +0000
parents 546f7c1eb755
children 1238da4a7112
rev   line source
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1 .TH "SDL_AudioCVT" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference"
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2 .SH "NAME"
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3 SDL_AudioCVT \- Audio Conversion Structure
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4 .SH "STRUCTURE DEFINITION"
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5 .PP
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6 .nf
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7 \f(CWtypedef struct{
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8 int needed;
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9 Uint16 src_format;
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10 Uint16 dest_format;
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11 double rate_incr;
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12 Uint8 *buf;
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13 int len;
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14 int len_cvt;
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15 int len_mult;
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16 double len_ratio;
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17 void (*filters[10])(struct SDL_AudioCVT *cvt, Uint16 format);
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18 int filter_index;
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19 } SDL_AudioCVT;\fR
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20 .fi
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21 .PP
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22 .SH "STRUCTURE DATA"
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23 .TP 20
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24 \fBneeded\fR
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25 Set to one if the conversion is possible
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26 .TP 20
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27 \fBsrc_format\fR
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28 Audio format of the source
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29 .TP 20
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30 \fBdest_format\fR
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31 Audio format of the destination
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32 .TP 20
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33 \fBrate_incr\fR
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34 Rate conversion increment
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35 .TP 20
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36 \fBbuf\fR
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37 Audio buffer
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38 .TP 20
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39 \fBlen\fR
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40 Length of the original audio buffer in bytes
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41 .TP 20
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42 \fBlen_cvt\fR
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43 Length of converted audio buffer in bytes (calculated)
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44 .TP 20
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45 \fBlen_mult\fR
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46 \fBbuf\fR must be \fBlen\fR*\fBlen_mult\fR bytes in size(calculated)
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47 .TP 20
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48 \fBlen_ratio\fR
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49 Final audio size is \fBlen\fR*\fBlen_ratio\fR
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50 .TP 20
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51 \fBfilters[10](\&.\&.)\fR
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52 Pointers to functions needed for this conversion
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53 .TP 20
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54 \fBfilter_index\fR
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55 Current conversion function
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56 .SH "DESCRIPTION"
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57 .PP
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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\&.
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59 .PP
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60 Many of the fields in the \fBSDL_AudioCVT\fR structure should be considered private and their function will not be discussed here\&.
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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\&.
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62 .IP "\fBint\fP \fBlen\fR" 10This is the length of the original audio data in bytes\&.
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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\&.
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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\&.
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65 .SH "SEE ALSO"
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66 .PP
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67 \fI\fBSDL_BuildAudioCVT\fP\fR, \fI\fBSDL_ConvertAudio\fP\fR, \fI\fBSDL_AudioSpec\fR\fR
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68 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58