hadoop+ffmpeg 視頻轉碼

hadoop + ffmpeg 分佈式轉碼系統實踐
hadoop 安裝
ffmpeg 安裝
mkvtoolnix 安裝


一、分割視頻：
mkvmerge --split size:32m ./heihu01.mp4 -o ./heihu01.%05d.mp4


二、hdfs中創建存放分割後視頻的目錄
hadoop fs -mkdir movies


三、上傳分割後的視頻
for i in `ls heihu01.*.mp4`; do hadoop fs -put $i movies/; done


四、創建mapper輸入數據文件路徑
hadoop fs -mkdir movies_input


五、生成mapper數據文件，並上傳
cat > mapper_input.sh<<EOF
#!/bin/bash
pwd=\`pwd\`
tmp_file='movies_tmp.txt'
num=2   #TaskTracker數量
true > \${tmp_file}
hadoop fs -rm movies_input/movies_*
for i in \`ls *.[0-9][0-9][0-9][0-9][0-9].*\`;do  echo movies/\$i >> \${tmp_file};done
count="\$(wc -l \${tmp_file}|cut -d' ' -f1)"
if [ \$((\$count%\$num)) -eq 0 ];then
     rows="\$((\$count/\$num))"
else
     rows="\$((\$count/\$num+1))"
fi
split -l \$rows \${tmp_file} movies_
hadoop fs -put movies_[a-z0-9][a-z0-9] movies_input
EOF




chmod +x mapper_input.sh
./mapper_input.sh


六、創建轉換後視頻的上傳路徑
hadoop fs -mkdir movies_put


七、檢查Hadoop Streaming的執行身份與工作目錄
1、編寫腳本
cat > test_mapper.sh << EOF
#!/bin/bash
set -x
id="`whoami`"
mkdir -p /tmp/\$id
host=\`hostname\`
pwd=\`pwd\`
uid=\`whoami\`
put_dir='movies_put'


while read line; do
  input=\$line
  filename=\`basename \$input\`
  echo "\$uid@\$host:\$pwd> hadoop fs -get \$input /tmp/\$id/\$filename"
  echo "\$uid@\$host:\$pwd> ffmpeg -y -i /tmp/\$id/\$filename -s qcif -r 20 -b 200k -vcodec mpeg4 -ab 64k -ac 2 -ar 22050 -acodec libfaac output-\$filename.3gp"
  echo "\$uid@\$host:\$pwd> hadoop fs -put output-\$filename \${put_dir}"
done
rm -rf /tmp/\$id
EOF


chmod a+x test_mapper.sh


2、本地執行測試
cat movies_aa |./test_mapper.sh


3、hadoop streaming執行測試
hadoop jar /usr/local/hadoop/contrib/streaming/hadoop-streaming-1.0.2.jar -input movies_input -output movies_output -mapper test_mapper.sh -file test_mapper.sh


4、查看hadoop streaming執行結果
hadoop fs -cat /user/$(whoami)/movies_output/part-00000 | head


5、刪除測試輸出
hadoop fs -rmr movies_output    #刪除測試hadoop streaming的輸出


八、使用hadoop streaming執行轉碼
1、編寫腳本
cat > mapper.sh << EOF
#!/bin/bash
id="hduser"
mkdir -p /tmp/\$id
host=\`hostname\`
pwd=\`pwd\`
uid=\`whoami\`
put_dir='movies_put'
cd "/tmp/\$id"
true > a


while read line; do
  input=\$line
  filename=\`basename \$input\`
  echo "\$uid@\$host> hadoop fs -get \$input /tmp/\$id/\$filename"
  /usr/local/hadoop/bin/hadoop fs -get \$input /tmp/\$id/\$filename 2>&1
  echo "\$uid@\$host> ffmpeg -y -i /tmp/\$id/\$filename -s qcif -r 20 -b 200k -vcodec mpeg4 -ab 64k -ac 2 -ar 22050 -acodec libfaac output-\$filename.3gp"
  ffmpeg -y -i /tmp/\$id/\$filename -s 320*240 -r 20 -b 200k -vcodec mpeg4 -ab 64k -ac 2 -ar 22050 -qscale 5 -acodec libfaac  output-\$filename.3gp < a 2>&1
  /usr/local/hadoop/bin/hadoop fs -put output-\$filename.3gp \${put_dir} 2>&1
  echo "\$uid@\$host> hadoop fs -chown \$id \${put_dir}/output-\$filename.3gp"
  /usr/local/hadoop/bin/hadoop fs -chown \$id \${put_dir}/output-\$filename.3gp 2>&1
 
done
rm -f a
rm -rf /tmp/\$id
EOF


chmod a+x mapper.sh


2、本地執行測試
cat movies_aa | ./mapper.sh
hadoop fs -rm movies_put/*      #刪除本地執行的遺留文件


3、使用hadoop執行腳本
hadoop jar /usr/local/hadoop/contrib/streaming/hadoop-streaming-1.0.2.jar -input movies_input -output movies_output -mapper mapper.sh  -file mapper.sh 


4、驗證結果
hadoop fs -cat movies_output/part-00000 |head
hadoop fs -ls movies_put
Found 6 items
-rw-r--r--   3 hduser supergroup   19584280 2012-05-28 13:53 /user/hduser/movies_put/output-heihu01.00001.mp4.3gp
-rw-r--r--   3 hduser supergroup   14872878 2012-05-28 13:54 /user/hduser/movies_put/output-heihu01.00002.mp4.3gp
-rw-r--r--   3 hduser supergroup   12052800 2012-05-28 13:55 /user/hduser/movies_put/output-heihu01.00003.mp4.3gp
-rw-r--r--   3 hduser supergroup   11174014 2012-05-28 13:53 /user/hduser/movies_put/output-heihu01.00004.mp4.3gp
-rw-r--r--   3 hduser supergroup   15713836 2012-05-28 13:55 /user/hduser/movies_put/output-heihu01.00005.mp4.3gp
-rw-r--r--   3 hduser supergroup   13084511 2012-05-28 13:56 /user/hduser/movies_put/output-heihu01.00006.mp4.3gp


5、reduce合併視頻
cat >reduce.sh <<EOF
#!/bin/bash
tmp_file="movies_tmp.txt"
id="hduser"
pwd=\`pwd\`
dir="/tmp/\${id}_merger"
mkdir \$dir
cd $dir
true > \${tmp_file}
hadoop fs -ls movies_put|awk '{print \$8}'|sed '/^$/d' >> \${tmp_file}


unset m
for i in \`cat \${tmp_file}\`
do
     hadoop fs -get \$i \$dir
     filename=\`basename \$i\`
     if [ ! -z \$m ];then
          filename="+\$filename"
     fi
     echo \$filename >> \$dir/files.txt
     m=\$((m+1))
done


mkvmerge -o \$dir/output.3gp \`cat \$dir/files.txt\`
hadoop fs -put \$dir/output.3gp movies_put/
rm -rf \$dir
EOF


chmod +x reduce.sh
6、本地執行測試
./reduce.sh    


7、使用hadoop執行腳本
hadoop jar /usr/local/hadoop/contrib/streaming/hadoop-streaming-1.0.2.jar -input movies_input -output movies_output -mapper mapper.sh -reducer reduce.sh -file reduce.sh -file mapper.sh


8、驗證結果
hadoop fs -ls movies_put
Found 7 items
-rw-r--r--   3 hduser supergroup   19584280 2012-05-29 14:15 /user/hduser/movies_put/output-heihu01.00001.mp4.3gp
-rw-r--r--   3 hduser supergroup   14872878 2012-05-29 14:16 /user/hduser/movies_put/output-heihu01.00002.mp4.3gp
-rw-r--r--   3 hduser supergroup   12052800 2012-05-29 14:17 /user/hduser/movies_put/output-heihu01.00003.mp4.3gp
-rw-r--r--   3 hduser supergroup   11174014 2012-05-29 14:15 /user/hduser/movies_put/output-heihu01.00004.mp4.3gp
-rw-r--r--   3 hduser supergroup   15713836 2012-05-29 14:16 /user/hduser/movies_put/output-heihu01.00005.mp4.3gp
-rw-r--r--   3 hduser supergroup   13084511 2012-05-29 14:17 /user/hduser/movies_put/output-heihu01.00006.mp4.3gp
-rw-r--r--   3 hduser supergroup   86175913 2012-05-29 14:17 /user/hduser/movies_put/output.3gp


hadoop fs -cat movies_output/part-00000




附：
hadoop streaming 調試
hadoop 的output 中只記錄正確輸出，因此調試錯誤需要將命令的輸出重定向到正確輸出
即在命令後加"2>&1"，如：
mkvmerge -o $dir/output.3gp `cat $dir/files.txt`  2>&1