我想删除 pt-br 音频并将英语 DTS 转换为 AC3，我正在使用以下命令：
ffmpeg -i input.mkv -c:v copy -c:s copy -c:a ac3 -ac 2 -map 0:0 -map 0:2 -map 0:3 -aspect 16:9 test.mkv
ffmpeg version N-63968-g73d820e Copyright (c) 2000-2014 the FFmpeg developers
built on Jun 15 2014 00:52:21 with gcc 4.8.3 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack …