用bat脚本和ffmpeg批量把bilibili App下载的视频文件转换为mp4

需要用到ffmpeg，脚本的运行层级就是App的下载目录：
Android/data/tv.danmaku.bili/download

@echo off
setlocal enabledelayedexpansion

set "target_folder=%~dp0"
echo target=%target_folder%
REM 设置序号变量，用于重命名
set "counter=1"
cd %target_folder%
REM 递归查找文件
for /D %%i in (!target_folder!) do (
    for /R %%f in (video.m4s) do (
        REM 获取文件所在的完整目录路径
        set "current=%%~dpf"
        if exist "%%f" (
            echo %%f            
            set "new_filename=!target_folder!\!counter!.mp4"
            REM 音视频合并
            ffmpeg.exe -i !current!\video.m4s -i !current!\audio.m4s -codec copy !new_filename!
            REM 仅视频转码
            REM ffmpeg.exe -i !current!\video.m4s -codec copy !new_filename!
            set /a "counter+=1"
        )
    )
)
echo Done.
endlocal