Commit 93ff12ce8344cfdd81c5cb6fcc1e52432b6dd2d6
2016-10-07T17:23:20
Fixed bug 2952 - SDL_MixAudioFormat does not support audio format AUDIO_U16LSB/AUDIO_U16MSB Simon Sandstr?m As stated in Summary. The switch statement will execute the default case and set a SDL error message: "SDL_MixAudio(): unknown audio format". There are atleast two more problems here: 1. SDL_MixAudioFormat does not notify the user that an error has occured and that a SDL error message was set. It took me awhile to understand why I couldn't mix down the volume on my AUDIO_U16LSB formatted audio stream.. until I started digging in the SDL source code. 2. The error message is incorrect, it should read: "SDL_MixAudioFormat(): unknown audio format".
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diff --git a/src/audio/SDL_mixer.c b/src/audio/SDL_mixer.c
index b49c73d..e021939 100644
--- a/src/audio/SDL_mixer.c
+++ b/src/audio/SDL_mixer.c
@@ -202,6 +202,54 @@ SDL_MixAudioFormat(Uint8 * dst, const Uint8 * src, SDL_AudioFormat format,
}
break;
+ case AUDIO_U16LSB:
+ {
+ Uint16 src1, src2;
+ int dst_sample;
+ const int max_audioval = 0xFFFF;
+
+ len /= 2;
+ while (len--) {
+ src1 = ((src[1]) << 8 | src[0]);
+ ADJUST_VOLUME(src1, volume);
+ src2 = ((dst[1]) << 8 | dst[0]);
+ src += 2;
+ dst_sample = src1 + src2;
+ if (dst_sample > max_audioval) {
+ dst_sample = max_audioval;
+ }
+ dst[0] = dst_sample & 0xFF;
+ dst_sample >>= 8;
+ dst[1] = dst_sample & 0xFF;
+ dst += 2;
+ }
+ }
+ break;
+
+ case AUDIO_U16MSB:
+ {
+ Uint16 src1, src2;
+ int dst_sample;
+ const int max_audioval = 0xFFFF;
+
+ len /= 2;
+ while (len--) {
+ src1 = ((src[0]) << 8 | src[1]);
+ ADJUST_VOLUME(src1, volume);
+ src2 = ((dst[0]) << 8 | dst[1]);
+ src += 2;
+ dst_sample = src1 + src2;
+ if (dst_sample > max_audioval) {
+ dst_sample = max_audioval;
+ }
+ dst[1] = dst_sample & 0xFF;
+ dst_sample >>= 8;
+ dst[0] = dst_sample & 0xFF;
+ dst += 2;
+ }
+ }
+ break;
+
case AUDIO_S32LSB:
{
const Uint32 *src32 = (Uint32 *) src;
@@ -313,7 +361,7 @@ SDL_MixAudioFormat(Uint8 * dst, const Uint8 * src, SDL_AudioFormat format,
break;
default: /* If this happens... FIXME! */
- SDL_SetError("SDL_MixAudio(): unknown audio format");
+ SDL_SetError("SDL_MixAudioFormat(): unknown audio format");
return;
}
}