diff --git a/trunk/auto/depends.sh b/trunk/auto/depends.sh
index 6c2c753df..24a88efce 100755
--- a/trunk/auto/depends.sh
+++ b/trunk/auto/depends.sh
@@ -504,6 +504,8 @@ if [ $SRS_FFMPEG = YES ]; then
     if [ ! -f ${SRS_OBJS}/ffmpeg/bin/ffmpeg ]; then echo "build ffmpeg-2.1 failed."; exit -1; fi
 fi
 
+# whatever the FFMPEG tools, if transcode and ingest specified,
+# srs always compile the FFMPEG tool stub which used to start the FFMPEG process.
 __SRS_FFMPEG=NO
 if [ $SRS_TRANSCODE = YES ]; then __SRS_FFMPEG=YES; fi
 if [ $SRS_INGEST = YES ]; then __SRS_FFMPEG=YES; fi
diff --git a/trunk/auto/options.sh b/trunk/auto/options.sh
index 2576d4b57..65fa8831f 100755
--- a/trunk/auto/options.sh
+++ b/trunk/auto/options.sh
@@ -199,6 +199,7 @@ if [ $SRS_DEV = YES ]; then
     SRS_FFMPEG=YES
     SRS_TRANSCODE=YES
     SRS_INGEST=YES
+    SRS_HTTP_PARSER=YES
     SRS_HTTP_CALLBACK=YES
     SRS_HTTP_SERVER=YES
     SRS_HTTP_API=YES
@@ -222,9 +223,10 @@ if [ $SRS_PI = YES ]; then
     SRS_NGINX=NO
     SRS_SSL=YES
     if [ $SRS_FFMPEG = RESERVED ]; then SRS_FFMPEG=NO; fi
-    if [ $SRS_TRANSCODE = RESERVED ]; then SRS_TRANSCODE=NO; fi
-    if [ $SRS_INGEST = RESERVED ]; then SRS_INGEST=NO; fi
-    SRS_HTTP_CALLBACK=NO
+    if [ $SRS_TRANSCODE = RESERVED ]; then SRS_TRANSCODE=YES; fi
+    if [ $SRS_INGEST = RESERVED ]; then SRS_INGEST=YES; fi
+    SRS_HTTP_PARSER=YES
+    SRS_HTTP_CALLBACK=YES
     SRS_HTTP_SERVER=YES
     SRS_HTTP_API=YES
     SRS_LIBRTMP=NO