add ffmpeg build script

+#!/bin/bash
+
+ff_current_dir=$(pwd -P)
+ff_build_dir="${ff_current_dir}/_build"
+ff_release_dir="${ff_current_dir}/_release"
+echo "start to build the tools for transcode system:"
+echo "current_dir: ${ff_current_dir}"
+echo "build_dir: ${ff_build_dir}"
+echo "release_dir: ${ff_release_dir}"
+
+mkdir -p ${ff_build_dir}
+mkdir -p ${ff_release_dir}
+
+# yasm for libx264
+ff_yasm_bin=${ff_release_dir}/bin/yasm
+if [[ -f ${ff_yasm_bin} ]]; then 
+    echo "yasm is ok"
+else
+    echo "build yasm-1.2.0"
+    cd $ff_current_dir &&
+    rm -rf yasm-1.2.0 && unzip -q ../../3rdparty/yasm-1.2.0.zip &&
+    cd yasm-1.2.0 && ./configure --prefix=${ff_release_dir} &&
+    make && make install
+    ret=$?; if [[ 0 -ne ${ret} ]]; then echo "build yasm-1.2.0 failed"; exit 1; fi
+fi
+
+# libaacplus
+if [[ -f ${ff_release_dir}/lib/libaacplus.a ]]; then
+    echo "libaacplus is ok"
+else
+    echo "build yasm-1.2.0"
+    cd $ff_current_dir &&
+    rm -rf libaacplus-2.0.2 && unzip -q ../../3rdparty/libaacplus-2.0.2.zip &&
+    cd libaacplus-2.0.2 && cp ../../../3rdparty/libaacplus-patch-26410-800.zip src/26410-800.zip &&
+    bash autogen.sh && ./configure --prefix=${ff_release_dir} --enable-static && make && make install
+    ret=$?; if [[ 0 -ne ${ret} ]]; then echo "build libaacplus-2.0.2 failed"; exit 1; fi
+fi
+
+# lame-3.99
+if [[ -f ${ff_release_dir}/lib/libmp3lame.a ]]; then
+    echo "libmp3lame is ok"
+else
+    echo "build lame-3.99.5"
+    cd $ff_current_dir &&
+    rm -rf lame-3.99.5 && unzip -q ../../3rdparty/lame-3.99.5.zip &&
+    cd lame-3.99.5 && ./configure --prefix=${ff_release_dir} --enable-static && make && make install
+    ret=$?; if [[ 0 -ne ${ret} ]]; then echo "build lame-3.99.5 failed"; exit 1; fi
+fi
+
+# x264 core.138
+if [[ -f ${ff_release_dir}/lib/libx264.a ]]; then
+    echo "x264 is ok"
+else
+    echo "build x264"
+    cd $ff_current_dir &&
+    rm -rf x264-snapshot-20131129-2245-stable && unzip -q ../../3rdparty/x264-snapshot-20131129-2245-stable.zip &&
+    cd x264-snapshot-20131129-2245-stable && ./configure --prefix=${ff_release_dir} --bit-depth=10 --enable-static && make && make install
+    ret=$?; if [[ 0 -ne ${ret} ]]; then echo "build x264 failed"; exit 1; fi
+fi
+
+# ffmpeg-2.1.1
+if [[ -f ${ff_release_dir}/bin/ffmpeg ]]; then
+    echo "ffmpeg-2.1.1 is ok"
+else
+    echo "build ffmpeg-2.1.1"
+    cd $ff_current_dir &&
+    rm -rf ffmpeg-2.1.1 && unzip -q ../../3rdparty/ffmpeg-2.1.1.zip &&
+    echo "remove all so to force the ffmpeg to build in static" &&
+    rm -f ${ff_release_dir}/lib/*.so* &&
+    echo "export the dir to enable the build command canbe use." &&
+    export ffmpeg_exported_release_dir=${ff_release_dir} &&
+    cd ffmpeg-2.1.1 && 
+    ./configure \
+        --enable-gpl --enable-nonfree \
+        --yasmexe=${ff_yasm_bin} \
+        --prefix=${ff_release_dir} --cc= \
+        --enable-static --disable-shared --disable-debug \
+        --extra-cflags='-I${ffmpeg_exported_release_dir}/include' \
+        --extra-ldflags='-L${ffmpeg_exported_release_dir}/lib -lm' \
+        --disable-ffplay --disable-ffprobe --disable-ffserver --disable-doc \
+        --enable-postproc --enable-bzlib --enable-zlib --enable-parsers \
+        --enable-libx264 --enable-libmp3lame --enable-libaacplus \
+        --enable-pthreads --extra-libs=-lpthread --enable-encoders --enable-decoders --enable-avfilter --enable-muxers --enable-demuxers && 
+    make && make install
+    ret=$?; if [[ 0 -ne ${ret} ]]; then echo "build x264 failed"; exit 1; fi
+fi