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audio: Calculate a legitimate SDL_AudioSpec::silence in SDL_LoadWAV_RW().

This commit is contained in:
Ryan C. Gordon 2020-01-21 15:49:37 -05:00
parent 55afc281fa
commit dbe5c14b33
3 changed files with 22 additions and 15 deletions
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34
src/audio/SDL_audio.c
View File

@ -1664,24 +1664,28 @@ SDL_NextAudioFormat(void)
return format_list[format_idx][format_idx_sub++];
}
Uint8
SDL_SilenceValueForFormat(const SDL_AudioFormat format)
{
switch (format) {
// !!! FIXME: 0x80 isn't perfect for U16, but we can't fit 0x8000 in a
// !!! FIXME: byte for memset() use. This is actually 0.1953 percent off
// from silence. Maybe just don't use U16.
case AUDIO_U16LSB:
case AUDIO_U16MSB:
case AUDIO_U8:
return 0x80;
default: break;
}
return 0x00;
}
void
SDL_CalculateAudioSpec(SDL_AudioSpec * spec)
{
switch (spec->format) {
case AUDIO_U8:
// !!! FIXME: 0x80 isn't perfect for U16, but we can't fit 0x8000 in a
// !!! FIXME: byte for memset() use. This is actually 0.1953 percent off
// from silence. Maybe just don't use U16.
case AUDIO_U16LSB:
case AUDIO_U16MSB:
spec->silence = 0x80;
break;
default:
spec->silence = 0x00;
break;
}
spec->silence = SDL_SilenceValueForFormat(spec->format);
spec->size = SDL_AUDIO_BITSIZE(spec->format) / 8;
spec->size *= spec->channels;
spec->size *= spec->samples;

1
src/audio/SDL_audio_c.h
View File

@ -52,6 +52,7 @@ extern SDL_AudioFormat SDL_FirstAudioFormat(SDL_AudioFormat format);
extern SDL_AudioFormat SDL_NextAudioFormat(void);
/* Function to calculate the size and silence for a SDL_AudioSpec */
extern Uint8 SDL_SilenceValueForFormat(const SDL_AudioFormat format);
extern void SDL_CalculateAudioSpec(SDL_AudioSpec * spec);
/* Choose the audio filter functions below */

2
src/audio/SDL_wave.c
View File

@ -2081,6 +2081,8 @@ WaveLoad(SDL_RWops *src, WaveFile *file, SDL_AudioSpec *spec, Uint8 **audio_buf,
break;
}
spec->silence = SDL_SilenceValueForFormat(spec->format);
/* Report the end position back to the cleanup code. */
if (RIFFlengthknown) {
chunk->position = RIFFend;