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Add SDL_ConvertAudioSamples() helper function

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This commit is contained in:
Sylvain 2023-01-23 08:24:49 +01:00 committed by Sam Lantinga
parent 7b50bae524
commit 052b14eb65
8 changed files with 124 additions and 57 deletions
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1
WhatsNew.txt
View file

@ -24,3 +24,4 @@ General:
* Added SDL_aligned_alloc() and SDL_aligned_free() to allocate and free memory with a given alignment
* Added SDL_GetRenderVSync() to get vsync of the given renderer
* Added SDL_PlayAudioDevice() to start audio playback
* Added SDL_ConvertAudioSamples() to convert audio samples from one format to another

27
docs/README-migration.md
View file

@ -54,29 +54,28 @@ SDL_PauseAudioDevice() is only used to pause audio playback. Use SDL_PlayAudioDe
SDL_FreeWAV has been removed and calls can be replaced with SDL_free.
SDL_AudioCVT interface is removed, SDL_AudioStream can be used instead.
SDL_AudioCVT interface is removed, SDL_AudioStream interface or SDL_ConvertAudioSamples() helper function can be used.
Code that used to look like this:
```c
SDL_AudioCVT cvt;
SDL_BuildAudioCVT(&cvt, spec.format, spec.channels, spec.freq, spec.format, cvtchans, cvtfreq);
cvt.len = len;
cvt.buf = (Uint8 *) SDL_malloc(len * cvt.len_mult);
SDL_memcpy(cvt.buf, data, len);
SDL_BuildAudioCVT(&cvt, src_format, src_channels, src_rate, dst_format, dst_channels, dst_rate);
cvt.len = src_len;
cvt.buf = (Uint8 *) SDL_malloc(src_len * cvt.len_mult);
SDL_memcpy(cvt.buf, src_data, src_len);
SDL_ConvertAudio(&cvt);
do_something(cvt.buf, cvt.len_cvt);
```
should be changed to:
```c
SDL_AudioStream *stream = SDL_CreateAudioStream(spec.format, spec.channels, spec.freq, spec.format, cvtchans, cvtfreq);
int src_samplesize = (SDL_AUDIO_BITSIZE(spec.format) / 8) * spec.channels;
int src_len = len & ~(src_samplesize - 1); // need to be rounded to samplesize
SDL_PutAudioStreamData(stream, data, src_len);
SDL_FlushAudioStream(stream);
int dst_len = expected_dst_len & ~(dst_samplesize - 1); // need to be rounded to samplesize
Uint8 *dst_buf = (Uint8 *)SDL_malloc(dst_len);
int real_dst_len = SDL_GetAudioStreamData(stream, dst_buf, dst_len);
do_something(dst_buf, real_dst_len);
Uint8 *dst_data = NULL;
int dst_len = 0;
if (SDL_ConvertAudioSamples(src_format, src_channels, src_rate, src_len, src_data
dst_format, dst_channels, dst_rate, &dst_len, &dst_data) < 0) {
/* error */
}
do_something(dst_data, dst_len);
SDL_free(dst_data);
```

31
include/SDL3/SDL_audio.h
View file

@ -1113,6 +1113,37 @@ extern DECLSPEC void SDLCALL SDL_UnlockAudioDevice(SDL_AudioDeviceID dev);
*/
extern DECLSPEC void SDLCALL SDL_CloseAudioDevice(SDL_AudioDeviceID dev);
/**
* Convert some audio data of one format to another format.
*
* \param src_format The format of the source audio
* \param src_channels The number of channels of the source audio
* \param src_rate The sampling rate of the source audio
* \param src_len The len of src_data
* \param src_data The audio data to be converted
* \param dst_format The format of the desired audio output
* \param dst_channels The number of channels of the desired audio output
* \param dst_rate The sampling rate of the desired audio output
* \param dst_len Will be filled with the len of dst_data
* \param dst_data Will be filled with a pointer to converted audio data, which should be freed with SDL_free().
*
* \returns 0 on success or a negative error code on failure. On error, *dst_data will be NULL and so not allocated.
*
* \since This function is available since SDL 3.0.0.
*
* \sa SDL_CreateAudioStream
*/
extern DECLSPEC int SDLCALL SDL_ConvertAudioSamples(SDL_AudioFormat src_format,
Uint8 src_channels,
int src_rate,
int src_len,
Uint8 *src_data,
SDL_AudioFormat dst_format,
Uint8 dst_channels,
int dst_rate,
int *dst_len,
Uint8 **dst_data);
/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}

70
src/audio/SDL_audio.c
View file

@ -1662,3 +1662,73 @@ void SDL_CalculateAudioSpec(SDL_AudioSpec *spec)
spec->size *= spec->samples;
}
int SDL_ConvertAudioSamples(
SDL_AudioFormat src_format, Uint8 src_channels, int src_rate, int src_len, Uint8 *src_data,
SDL_AudioFormat dst_format, Uint8 dst_channels, int dst_rate, int *dst_len, Uint8 **dst_data)
{
int ret = -1;
SDL_AudioStream *stream = NULL;
int src_samplesize, dst_samplesize;
int real_dst_len;
if (src_len < 0) {
return SDL_InvalidParamError("src_len");
}
if (src_data == NULL) {
return SDL_InvalidParamError("src_data");
}
if (dst_len == NULL) {
return SDL_InvalidParamError("dst_len");
}
if (dst_data == NULL) {
return SDL_InvalidParamError("dst_data");
}
*dst_len = 0;
*dst_data = NULL;
stream = SDL_CreateAudioStream(src_format, src_channels, src_rate, dst_format, dst_channels, dst_rate);
if (stream == NULL) {
goto end;
}
src_samplesize = (SDL_AUDIO_BITSIZE(src_format) / 8) * src_channels;
dst_samplesize = (SDL_AUDIO_BITSIZE(dst_format) / 8) * dst_channels;
src_len &= ~(src_samplesize - 1);
*dst_len = dst_samplesize * (src_len / src_samplesize);
if (src_rate < dst_rate) {
const double mult = ((double)dst_rate) / ((double)src_rate);
*dst_len *= (int) SDL_ceil(mult);
}
*dst_len &= ~(dst_samplesize - 1);
*dst_data = (Uint8 *)SDL_malloc(*dst_len);
if (*dst_data == NULL) {
goto end;
}
if (SDL_PutAudioStreamData(stream, src_data, src_len) < 0 ||
SDL_FlushAudioStream(stream) < 0) {
goto end;
}
real_dst_len = SDL_GetAudioStreamData(stream, *dst_data, *dst_len);
if (real_dst_len < 0) {
goto end;
}
*dst_len = real_dst_len;
ret = 0;
end:
if (ret != 0) {
SDL_free(*dst_data);
*dst_len = 0;
*dst_data = NULL;
}
SDL_DestroyAudioStream(stream);
return ret;
}

1
src/dynapi/SDL_dynapi.sym
View file

@ -841,6 +841,7 @@ SDL3_0.0.0 {
SDL_PlayAudioDevice;
SDL_aligned_alloc;
SDL_aligned_free;
SDL_ConvertAudioSamples;
# extra symbols go here (don't modify this line)
local: *;
};

1
src/dynapi/SDL_dynapi_overrides.h
View file

@ -868,3 +868,4 @@
#define SDL_PlayAudioDevice SDL_PlayAudioDevice_REAL
#define SDL_aligned_alloc SDL_aligned_alloc_REAL
#define SDL_aligned_free SDL_aligned_free_REAL
#define SDL_ConvertAudioSamples SDL_ConvertAudioSamples_REAL

1
src/dynapi/SDL_dynapi_procs.h
View file

@ -913,3 +913,4 @@ SDL_DYNAPI_PROC(int,SDL_GetRenderVSync,(SDL_Renderer *a, int *b),(a,b),return)
SDL_DYNAPI_PROC(void,SDL_PlayAudioDevice,(SDL_AudioDeviceID a),(a),)
SDL_DYNAPI_PROC(void*,SDL_aligned_alloc,(size_t a, size_t b),(a,b),return)
SDL_DYNAPI_PROC(void,SDL_aligned_free,(void *a),(a),)
SDL_DYNAPI_PROC(int,SDL_ConvertAudioSamples,(SDL_AudioFormat a, Uint8 b, int c, int d, Uint8 *e, SDL_AudioFormat f, Uint8 g, int h, int *i, Uint8 **j),(a,b,c,d,e,f,g,h,i,j),return)

49
test/testresample.c
View file

@ -26,8 +26,7 @@ int main(int argc, char **argv)
int blockalign = 0;
int avgbytes = 0;
SDL_RWops *io = NULL;
int src_samplesize, dst_samplesize;
int src_len, dst_len, real_dst_len;
int dst_len;
int ret = 0;
/* Enable standard application logging */
@ -54,54 +53,18 @@ int main(int argc, char **argv)
goto end;
}
stream = SDL_CreateAudioStream(spec.format, spec.channels, spec.freq, spec.format, cvtchans, cvtfreq);
if (stream == NULL) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "failed to build audio stream: %s\n", SDL_GetError());
if (SDL_ConvertAudioSamples(spec.format, spec.channels, spec.freq, len, data,
spec.format, cvtchans, cvtfreq, &dst_len, &dst_buf) < 0) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "failed to convert samples: %s\n", SDL_GetError());
ret = 4;
goto end;
}
src_samplesize = (SDL_AUDIO_BITSIZE(spec.format) / 8) * spec.channels;
dst_samplesize = (SDL_AUDIO_BITSIZE(spec.format) / 8) * cvtchans;
src_len = len & ~(src_samplesize - 1);
dst_len = dst_samplesize * (src_len / src_samplesize);
if (spec.freq < cvtfreq) {
const double mult = ((double)cvtfreq) / ((double)spec.freq);
dst_len *= (int) SDL_ceil(mult);
}
dst_len = dst_len & ~(dst_samplesize - 1);
dst_buf = (Uint8 *)SDL_malloc(dst_len);
if (dst_buf == NULL) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Out of memory.\n");
ret = 5;
goto end;
}
/* Run the audio converter */
if (SDL_PutAudioStreamData(stream, data, src_len) < 0 ||
SDL_FlushAudioStream(stream) < 0) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Conversion failed: %s\n", SDL_GetError());
ret = 6;
goto end;
}
real_dst_len = SDL_GetAudioStreamData(stream, dst_buf, dst_len);
if (real_dst_len < 0) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Conversion failed: %s\n", SDL_GetError());
ret = 7;
goto end;
}
dst_len = real_dst_len;
/* write out a WAV header... */
io = SDL_RWFromFile(argv[2], "wb");
if (io == NULL) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "fopen('%s') failed: %s\n", argv[2], SDL_GetError());
ret = 8;
ret = 5;
goto end;
}
@ -126,7 +89,7 @@ int main(int argc, char **argv)
if (SDL_RWclose(io) == -1) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "fclose('%s') failed: %s\n", argv[2], SDL_GetError());
ret = 9;
ret = 6;
goto end;
}