Add FIXMEs about audio_format_t assumption

Change-Id: I0d38241b61f70013573f4a0b9306547afe5f38ad
diff --git a/include/media/nbaio/NBAIO.h b/include/media/nbaio/NBAIO.h
index 4150a09..cdeb4ca 100644
--- a/include/media/nbaio/NBAIO.h
+++ b/include/media/nbaio/NBAIO.h
@@ -66,6 +66,7 @@
 size_t Format_frameBitShift(const NBAIO_Format& format);
 
 // Convert a sample rate in Hz and channel count to an NBAIO_Format
+// FIXME The sample format is hard-coded to AUDIO_FORMAT_PCM_16_BIT
 NBAIO_Format Format_from_SR_C(unsigned sampleRate, unsigned channelCount);
 
 // Return the sample rate in Hz of an NBAIO_Format
diff --git a/media/libnbaio/NBAIO.cpp b/media/libnbaio/NBAIO.cpp
index f630236..26ef8c4 100644
--- a/media/libnbaio/NBAIO.cpp
+++ b/media/libnbaio/NBAIO.cpp
@@ -24,11 +24,13 @@
 
 size_t Format_frameSize(const NBAIO_Format& format)
 {
+    // FIXME The sample format is hard-coded to AUDIO_FORMAT_PCM_16_BIT
     return Format_channelCount(format) * sizeof(short);
 }
 
 size_t Format_frameBitShift(const NBAIO_Format& format)
 {
+    // FIXME The sample format is hard-coded to AUDIO_FORMAT_PCM_16_BIT
     // sizeof(short) == 2, so frame size == 1 << channels
     return Format_channelCount(format);
 }