mp3: dither an arbitrary number of channels

The mp3 plugin did not use the MAD_NCHANNELS() value correctly: when a stream was not stereo, it was assumed to be mono, although the correct number was passed to MPD. libmad doesn't support more than 2 channels, but this change allows gcc to optimize its inlining strategy.

mp3: dither an arbitrary number of channels
f41fe1e0 · Max Kellermann · bac13660 · f41fe1e0
Commit f41fe1e0 authored Oct 10, 2008 by Max Kellermann
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Showing with 3 additions and 6 deletions

mp3_plugin.c src/inputPlugins/mp3_plugin.c +3 -6

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--- a/src/inputPlugins/mp3_plugin.c
+++ b/src/inputPlugins/mp3_plugin.c
@@ -116,14 +116,11 @@ static unsigned dither_buffer(int16_t *dest0, const struct mad_synth *synth,
 			      unsigned int num_channels)
 {
 	int16_t *dest = dest0;
-	unsigned int i;
+	unsigned int i, c;

 	for (i = start; i < end; ++i) {
-		*dest++ = audio_linear_dither(synth->pcm.samples[0][i],
-					      dither);
-
-		if (num_channels == 2)
-			*dest++ = audio_linear_dither(synth->pcm.samples[1][i],
+		for (c = 0; c < num_channels; ++c)
+			*dest++ = audio_linear_dither(synth->pcm.samples[c][i],
 						      dither);
 	}