bash - 将 ffmpeg 应用于许多文件

Question

我写了一个简单的脚本:

#!/bin/bash
find . -name "*.m4a" | while read filename;
do
    new_filename=$(echo "$filename" | sed "s/^\(.*\)m4a$/\1flac/g");
    if [ ! -f "$new_filename" ]
    then
            #ffmpeg -i "$filename" -acodec flac "$new_filename" > /dev/null 2>&1;
            #wait $!;
            echo "$filename";
            echo "$new_filename";
    fi
done

它输出正确的结果:

./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/04 - Met.m4a
./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/04 - Met.flac
./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/02 - Nach Dem Winter.m4a
./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/02 - Nach Dem Winter.flac

如果取消注释 ffmpeg 并等待:

./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/04 - Met.m4a
./Equilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/04 - Met.flac
uilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/02 - Nach Dem Winter.m4a
uilibrium, ALAC [GER] viking.folk/2003 - Demo 2003, ALAC/02 - Nach Dem Winter.flac

而且还没有完成 flacs!

附言

#!/bin/bash
find . -name "*.m4a" | while read filename;
do
    new_filename=$(echo "$filename" | sed "s/^\(.*\)m4a$/\1flac/g");
    if [ ! -f "$new_filename" ]
    then
            ffmpeg -i "$filename" -acodec flac "$new_filename";
            echo "$filename";
            echo "$new_filename";
    fi
    sleep 5;
done

1) 编码开始但突然停止且没有错误信息

2) 由于“uilibrium”而不是“./Equilibrium”，编码无法启动

3) = 1)

4) = 2)

...

最后)正确

Answer 1

突然发现解决办法:

#!/bin/bash
find . -name "*.m4a" | while read filename;
do
        new_filename=$(echo "$filename" | sed "s/^\(.*\)m4a$/\1flac/g");
        if [ ! -f "$new_filename" ]
        then
                ffmpeg -i "$filename" -acodec flac "$new_filename" &
                wait $!;
        fi
done

我不知道为什么，但如果在后台启动进程 (&) 并等待它(等待 $!)一切正常!