diff --git a/media/libnbaio/AudioStreamOutSink.cpp b/media/libnbaio/AudioStreamOutSink.cpp
index c28d34d..0d5f935 100644
--- a/media/libnbaio/AudioStreamOutSink.cpp
+++ b/media/libnbaio/AudioStreamOutSink.cpp
@@ -43,7 +43,8 @@
         uint32_t sampleRate = mStream->common.get_sample_rate(&mStream->common);
         audio_channel_mask_t channelMask =
                 (audio_channel_mask_t) mStream->common.get_channels(&mStream->common);
-        mFormat = Format_from_SR_C(sampleRate, popcount(channelMask), streamFormat);
+        mFormat = Format_from_SR_C(sampleRate,
+                audio_channel_count_from_out_mask(channelMask), streamFormat);
         mFrameSize = Format_frameSize(mFormat);
     }
     return NBAIO_Sink::negotiate(offers, numOffers, counterOffers, numCounterOffers);