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-rw-r--r--src/pcm_utils.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/src/pcm_utils.c b/src/pcm_utils.c
index 52f9294b7..cb6f93f63 100644
--- a/src/pcm_utils.c
+++ b/src/pcm_utils.c
@@ -385,6 +385,29 @@ pcm_convert_channels_2_to_1(int16_t *dest, const int16_t *src,
}
}
+static void
+pcm_convert_channels_n_to_2(int16_t *dest,
+ unsigned src_channels, const int16_t *src,
+ unsigned num_frames)
+{
+ unsigned c;
+
+ assert(src_channels > 0);
+
+ while (num_frames-- > 0) {
+ int32_t sum = 0;
+ int16_t value;
+
+ for (c = 0; c < src_channels; ++c)
+ sum += *src++;
+ value = sum / (int)src_channels;
+
+ /* XXX this is actually only mono ... */
+ *dest++ = value;
+ *dest++ = value;
+ }
+}
+
static const int16_t *
pcm_convertChannels(int8_t dest_channels,
int8_t src_channels, const int16_t *src,
@@ -406,6 +429,9 @@ pcm_convertChannels(int8_t dest_channels,
pcm_convert_channels_1_to_2(buf, src, num_frames);
else if (src_channels == 2 && dest_channels == 1)
pcm_convert_channels_2_to_1(buf, src, num_frames);
+ else if (dest_channels == 2)
+ pcm_convert_channels_n_to_2(buf, src_channels, src,
+ num_frames);
else {
ERROR("conversion %u->%u channels is not supported\n",
src_channels, dest_channels);