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Adam Strzelecki to SDL Since current DirectFB implementation is incomplete for YUV surfaces (actually causes segmentation faults when trying Lock and use YUV planar textures) I decided to fix it a bit. Here's a patch that should make DirectFB properly support YUV both packed and planar (3 planes). (1) Removed SDL_BYTESPERPIXEL at all in favor of DFB_BYTES_PER_PIXEL(SDLToDFBPixelFormat(fmt)) which does return always proper BPP for YUVs too, coz SDL_BYTESPERPIXEL returns incorrect values for FOURCCs (2) Fixed data->pixels allocation for planar YUVs in CreateTexture, it should allocate 150% more space (3) Copy other planes for planar YUVs in UpdateTexture (4) Moved checking if format is supported at all with DirectFB on CreateTexture at the beginning of the code Waiting for comments, -- Adam Strzelecki | nanoant.com
author Sam Lantinga <slouken@libsdl.org>
date Sun, 04 Oct 2009 04:03:37 +0000
parents 355632dca928
children
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>SDL_ConvertAudio</TITLE
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><H1
><A
NAME="SDLCONVERTAUDIO"
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>SDL_ConvertAudio</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN7048"
></A
><H2
>Name</H2
>SDL_ConvertAudio&nbsp;--&nbsp;Convert audio data to a desired audio format.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN7051"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN7052"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_ConvertAudio</B
></CODE
>(SDL_AudioCVT *cvt);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN7058"
></A
><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_ConvertAudio</TT
> takes one parameter, <TT
CLASS="PARAMETER"
><I
>cvt</I
></TT
>, which was previously initilized. Initilizing a <A
HREF="sdlaudiocvt.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_AudioCVT</SPAN
></A
> is a two step process. First of all, the structure must be passed to <A
HREF="sdlbuildaudiocvt.html"
><TT
CLASS="FUNCTION"
>SDL_BuildAudioCVT</TT
></A
> along with source and destination format parameters. Secondly, the <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>buf</I
></TT
> and <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>len</I
></TT
> fields must be setup. <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>buf</I
></TT
> should point to the audio data and <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>len</I
></TT
> should be set to the length of the audio data in bytes. Remember, the length of the buffer pointed to by <TT
CLASS="STRUCTFIELD"
><I
>buf</I
></TT
> show be <TT
CLASS="STRUCTFIELD"
><I
>len</I
></TT
>*<TT
CLASS="STRUCTFIELD"
><I
>len_mult</I
></TT
> bytes in length.</P
><P
>Once the <SPAN
CLASS="STRUCTNAME"
>SDL_AudioCVT</SPAN
>structure is initilized then we can pass it to <TT
CLASS="FUNCTION"
>SDL_ConvertAudio</TT
>, which will convert the audio data pointer to by <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>buf</I
></TT
>. If <TT
CLASS="FUNCTION"
>SDL_ConvertAudio</TT
> returned <SPAN
CLASS="RETURNVALUE"
>0</SPAN
> then the conversion was completed successfully, otherwise <SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> is returned.</P
><P
>If the conversion completed successfully then the converted audio data can be read from <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>buf</I
></TT
>. The amount of valid, converted, audio data in the buffer is equal to <SPAN
CLASS="STRUCTNAME"
>cvt</SPAN
>-&#62;<TT
CLASS="STRUCTFIELD"
><I
>len</I
></TT
>*<TT
CLASS="STRUCTFIELD"
><I
>cvt</I
></TT
>-&#62;<SPAN
CLASS="STRUCTNAME"
>len_ratio</SPAN
>.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN7093"
></A
><H2
>Examples</H2
><PRE
CLASS="PROGRAMLISTING"
>/* Converting some WAV data to hardware format */
void my_audio_callback(void *userdata, Uint8 *stream, int len);

SDL_AudioSpec *desired, *obtained;
SDL_AudioSpec wav_spec;
SDL_AudioCVT  wav_cvt;
Uint32 wav_len;
Uint8 *wav_buf;
int ret;

/* Allocated audio specs */
desired = malloc(sizeof(SDL_AudioSpec));
obtained = malloc(sizeof(SDL_AudioSpec));

/* Set desired format */
desired-&#62;freq=22050;
desired-&#62;format=AUDIO_S16LSB;
desired-&#62;samples=8192;
desired-&#62;callback=my_audio_callback;
desired-&#62;userdata=NULL;

/* Open the audio device */
if ( SDL_OpenAudio(desired, obtained) &#60; 0 ){
  fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError());
  exit(-1);
}
        
free(desired);

/* Load the test.wav */
if( SDL_LoadWAV("test.wav", &#38;wav_spec, &#38;wav_buf, &#38;wav_len) == NULL ){
  fprintf(stderr, "Could not open test.wav: %s\n", SDL_GetError());
  SDL_CloseAudio();
  free(obtained);
  exit(-1);
}
                                            
/* Build AudioCVT */
ret = SDL_BuildAudioCVT(&#38;wav_cvt,
                        wav_spec.format, wav_spec.channels, wav_spec.freq,
                        obtained-&#62;format, obtained-&#62;channels, obtained-&#62;freq);

/* Check that the convert was built */
if(ret==-1){
  fprintf(stderr, "Couldn't build converter!\n");
  SDL_CloseAudio();
  free(obtained);
  SDL_FreeWAV(wav_buf);
}

/* Setup for conversion */
wav_cvt.buf = malloc(wav_len * wav_cvt.len_mult);
wav_cvt.len = wav_len;
memcpy(wav_cvt.buf, wav_buf, wav_len);

/* We can delete to original WAV data now */
SDL_FreeWAV(wav_buf);

/* And now we're ready to convert */
SDL_ConvertAudio(&#38;wav_cvt);

/* do whatever */
.
.
.
.
&#13;</PRE
></DIV
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><A
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></A
><H2
>See Also</H2
><P
><A
HREF="sdlbuildaudiocvt.html"
><TT
CLASS="FUNCTION"
>SDL_BuildAudioCVT</TT
></A
>,
<A
HREF="sdlaudiocvt.html"
><TT
CLASS="FUNCTION"
>SDL_AudioCVT</TT
></A
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