代码片段如下
/**
* 创建并下载文件
* @param {String} fileName 文件名
* @param {String} content 文件内容
*/
function createAndDownloadFile(fileName, content) {
var aTag = document.createElement('a');
var blob = new Blob([content]);
aTag.download = fileName;
aTag.href = URL.createObjectURL(blob);
aTag.click();
URL.revokeObjectURL(blob);
}最近做一个项目，利用到Media Source Extensions 需要将普通的mp4文件转换问fragment格式的mp4文件，从https://www.bento4.com/downloads/ 下载对应的的二进制文件，对应的bin目录文件下有mp4fragment 可执行程序。教研的视频文件有120来个，打算使用shell脚本来执行这些程序
对应shell记录如下
#!/bin/sh
cd "/Users/vipkid/Downloads"
rm -rf fragmentDir
rm -rf cutMp4
## 创建 fragementDir
mkdir fragmentDir
## 创建 mp4
mkdir cutMp4
path="/Users/vipkid/Downloads/final_trail_videos_1215"
files=$(ls $path)
# 裁剪mp4
for FILE in $files
do
./ffmpeg -i $path"/"$FILE -filter:v "crop=720:540:560:200" -c:a copy "/Users/vipkid/Downloads/cutMp4/"$FILE
echo $FILE
done
# 转换格式
for FILE in $files
do
cd "/Users/vipkid/Downloads/Bento4-SDK-1-6-0-637.universal-apple-macosx/bin/"
./mp4fragment --verbosity 3 "/Users/vipkid/Downloads/cutMp4/"$FILE "/Users/vipkid/Downloads/fragmentDir/"$FILE
echo $FILE
done#!/bin/sh
## 裁剪文件 将文件裁剪成 320 240的 然后转换为fragment mp4
cd "/Users/vipkid/Downloads"
## 创建 fragementDir
mkdir cut320
mkdir fragmentDir320
path="/Users/vipkid/Downloads/cutMp4"
files=$(ls $path)
# 裁剪mp4
for FILE in $files
do
./ffmpeg -i $path"/"$FILE -vf scale=320:240 -acodec aac -vcodec h264 "/Users/vipkid/Downloads/cut320/"$FILE
echo $FILE
done
# 转换格式
for FILE in $files
do
cd "/Users/vipkid/Downloads/Bento4-SDK-1-6-0-637.universal-apple-macosx/bin/"
./mp4fragment --verbosity 3 "/Users/vipkid/Downloads/cut320/"$FILE "/Users/vipkid/Downloads/fragmentDir320/"$FILE
echo $FILE
done