Write the original H.264 SPS if it required no fixups

app/streaming/video/ffmpeg.cpp

@@ -1781,6 +1781,7 @@ void FFmpegVideoDecoder::writeBuffer(PLENTRY entry, int& offset)
 
         // Fixup the SPS to what OS X needs to use hardware acceleration
         // This is also critical for decoding latency on the Pi 2.
+        if (stream->sps->num_ref_frames != 1 || stream->sps->vui.max_dec_frame_buffering != 1) {
             stream->sps->num_ref_frames = 1;
             stream->sps->vui.max_dec_frame_buffering = 1;
 
@@ -1808,6 +1809,14 @@ void FFmpegVideoDecoder::writeBuffer(PLENTRY entry, int& offset)
             // Copy the NALU prefix over from the original SPS
             memcpy(&m_DecodeBuffer.data()[initialOffset], entry->data, nalStart);
             offset += nalStart;
+        }
+        else {
+            // Write the SPS as-is if it required no modification
+            memcpy(&m_DecodeBuffer.data()[offset],
+                   entry->data,
+                   entry->length);
+            offset += entry->length;
+        }
 
         h264_free(stream);
     }