diff --git a/media/libnbaio/AudioStreamInSource.cpp b/media/libnbaio/AudioStreamInSource.cpp
index ae8fac8..ca7b8e0 100644
--- a/media/libnbaio/AudioStreamInSource.cpp
+++ b/media/libnbaio/AudioStreamInSource.cpp
@@ -49,6 +49,7 @@
                     (audio_channel_mask_t) mStream->common.get_channels(&mStream->common);
             mFormat = Format_from_SR_C(sampleRate, popcount(channelMask));
             mBitShift = Format_frameBitShift(mFormat);
+            mFrameSize = Format_frameSize(mFormat);
         }
     }
     return NBAIO_Source::negotiate(offers, numOffers, counterOffers, numCounterOffers);