diff --git a/trunk/3rdparty/opus-1.3.1.tar.gz b/trunk/3rdparty/opus-1.3.1.tar.gz
new file mode 100644
index 000000000..1119371fc
Binary files /dev/null and b/trunk/3rdparty/opus-1.3.1.tar.gz differ
diff --git a/trunk/auto/depends.sh b/trunk/auto/depends.sh
index b2c69bbdb..786c8aef8 100755
--- a/trunk/auto/depends.sh
+++ b/trunk/auto/depends.sh
@@ -84,6 +84,13 @@ function Ubuntu_prepare()
         echo "The unzip is installed."
     fi
 
+    nasm -v >/dev/null 2>&1; ret=$?; if [[ 0 -ne $ret ]]; then
+        echo "Installing nasm."
+        require_sudoer "sudo apt-get install -y --force-yes nasm"
+        sudo apt-get install -y --force-yes nasm; ret=$?; if [[ 0 -ne $ret ]]; then return $ret; fi
+        echo "The nasm is installed."
+    fi
+
     if [[ $SRS_VALGRIND == YES ]]; then
         valgrind --help >/dev/null 2>&1; ret=$?; if [[ 0 -ne $ret ]]; then
             echo "Installing valgrind."
@@ -157,6 +164,13 @@ function Centos_prepare()
         echo "The unzip is installed."
     fi
 
+    nasm -v >/dev/null 2>&1; ret=$?; if [[ 0 -ne $ret ]]; then
+        echo "Installing nasm."
+        require_sudoer "sudo yum install -y nasm"
+        sudo yum install -y nasm; ret=$?; if [[ 0 -ne $ret ]]; then return $ret; fi
+        echo "The nasm is installed."
+    fi
+
     if [[ $SRS_VALGRIND == YES ]]; then
         valgrind --help >/dev/null 2>&1; ret=$?; if [[ 0 -ne $ret ]]; then
             echo "Installing valgrind."
@@ -373,7 +387,7 @@ if [[ $SRS_SSL == YES && $SRS_USE_SYS_SSL != YES ]]; then
             rm -rf ${SRS_OBJS}/openssl-1.1.0e && cd ${SRS_OBJS} &&
             unzip -q ../3rdparty/openssl-1.1.0e.zip && cd openssl-1.1.0e &&
             ${OPENSSL_CONFIG} --prefix=`pwd`/_release $OPENSSL_OPTIONS &&
-            make CC=${SRS_TOOL_CC} AR="${SRS_TOOL_AR} -rs" LD=${SRS_TOOL_LD} RANDLIB=${SRS_TOOL_RANDLIB} && make install_sw &&
+            make CC=${SRS_TOOL_CC} AR="${SRS_TOOL_AR} -rs" LD=${SRS_TOOL_LD} RANDLIB=${SRS_TOOL_RANDLIB} ${SRS_JOBS} && make install_sw &&
             cd .. && rm -rf openssl && ln -sf openssl-1.1.0e/_release openssl
         )
     fi
@@ -382,6 +396,27 @@ if [[ $SRS_SSL == YES && $SRS_USE_SYS_SSL != YES ]]; then
     if [ ! -f ${SRS_OBJS}/openssl/lib/libssl.a ]; then echo "Build openssl-1.1.0e failed."; exit -1; fi
 fi
 
+#####################################################################################
+# libopus, for WebRTC to transcode AAC with Opus.
+#####################################################################################
+if [ $SRS_EXPORT_LIBRTMP_PROJECT = NO ]; then
+    # cross build not specified, if exists flag, need to rebuild for no-arm platform.
+    if [[ -f ${SRS_OBJS}/opus/lib/libopus.a ]]; then
+        echo "The opus-1.3.1 is ok.";
+    else
+        echo "Building opus-1.3.1.";
+        (
+            rm -rf ${SRS_OBJS}/opus-1.3.1 && cd ${SRS_OBJS} &&
+            tar xf ../3rdparty/opus-1.3.1.tar.gz && cd opus-1.3.1 &&
+            ./configure --prefix=`pwd`/_release --enable-static --disable-shared && make ${SRS_JOBS} && make install
+            cd .. && rm -rf opus && ln -sf opus-1.3.1/_release opus
+        )
+    fi
+    # check status
+    ret=$?; if [[ $ret -ne 0 ]]; then echo "Build opus-1.3.1 failed, ret=$ret"; exit $ret; fi
+    if [ ! -f ${SRS_OBJS}/opus/lib/libopus.a ]; then echo "Build opus-1.3.1 failed."; exit -1; fi
+fi
+
 #####################################################################################
 # live transcoding, ffmpeg-4.1, x264-core157, lame-3.99.5, libaacplus-2.0.2.
 #####################################################################################
@@ -393,17 +428,9 @@ if [ $SRS_FFMPEG_TOOL = YES ]; then
     if [[ -f ${SRS_OBJS}/ffmpeg/bin/ffmpeg ]]; then
         echo "ffmpeg-4.1 is ok.";
     else
-        echo "build ffmpeg-4.1"; 
-        (
-            cd ${SRS_OBJS} && pwd_dir=`pwd` && 
-            rm -rf ffmepg.src && mkdir -p ffmpeg.src && cd ffmpeg.src &&
-            rm -f build_ffmpeg.sh && ln -sf ../../auto/build_ffmpeg.sh && . build_ffmpeg.sh &&
-            cd ${pwd_dir} && rm -rf ffmpeg && ln -sf ffmpeg.src/_release ffmpeg
-        )
+        echo "no ffmpeg-4.1 found, please run in docker ossrs/srs:dev";
+        exit -1;
     fi
-    # check status
-    ret=$?; if [[ $ret -ne 0 ]]; then echo "build ffmpeg-4.1 failed, ret=$ret"; exit $ret; fi
-    if [ ! -f ${SRS_OBJS}/ffmpeg/bin/ffmpeg ]; then echo "build ffmpeg-4.1 failed."; exit -1; fi
 fi
 
 #####################################################################################
@@ -417,7 +444,7 @@ if [[ $SRS_SRT == YES ]]; then
     if [[ -f ${SRS_OBJS}/srt/lib/libsrt.a ]]; then
         echo "libsrt-1.4.1 is ok.";
     else
-        echo "no libsrt, please use srs-docker or build from source https://github.com/ossrs/srs/issues/1147#issuecomment-577469119";
+        echo "no libsrt, please run in docker ossrs/srs:srt or build from source https://github.com/ossrs/srs/issues/1147#issuecomment-577469119";
         exit -1;
     fi
 fi