FFmpeg流映射不'；我不再工作了

例如，我很难从MKV文件中获取第一个流。奇怪的是，我的脚本曾经在旧的Debian上工作，而相同的代码在Debian8上不工作。我也检查了手册，有相同的：

ffmpeg-i输入-映射0:1 out.wav

你知道怎么了吗

多谢各位

    tommy@reco1:/home/www/media/20$ ffmpeg -i /home/www/media/21/21.mkv -map 0:1 /var/www/vids/21/new.mkv  
ffmpeg version 2.6.8 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 4.9.2 (Debian 4.9.2-10)
  configuration: --prefix=/usr --extra-cflags='-g -O2 -fstack-protector-strong -Wformat -Werror=format-security ' --extra-ldflags='-Wl,-z,relro' --cc='ccache cc' --enable-shared --enable-libmp3lame --enable-gpl --enable-nonfree --enable-libvorbis --enable-pthreads --enable-libfaac --enable-libxvid --enable-postproc --enable-x11grab --enable-libgsm --enable-libtheora --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libx264 --enable-libspeex --enable-nonfree --disable-stripping --enable-libvpx --enable-libschroedinger --disable-encoder=libschroedinger --enable-version3 --enable-libopenjpeg --enable-librtmp --enable-avfilter --enable-libfreetype --enable-libvo-aacenc --disable-decoder=amrnb --enable-libvo-amrwbenc --enable-libaacplus --libdir=/usr/lib/x86_64-linux-gnu --disable-vda --enable-libbluray --enable-libcdio --enable-gnutls --enable-frei0r --enable-openssl --enable-libass --enable-libopus --enable-fontconfig --enable-libpulse --disable-mips32r2 --disable-mipsdspr1 --disable-mipsdspr2 --enable-libvidstab --enable-libzvbi --enable-avresample --disable-htmlpages --disable-podpages --enable-libutvideo --enable-libfdk-aac --enable-libx265 --enable-libiec61883 --enable-vaapi --enable-libdc1394 --disable-altivec --shlibdir=/usr/lib/x86_64-linux-gnu
  libavutil      54. 20.100 / 54. 20.100
  libavcodec     56. 26.100 / 56. 26.100
  libavformat    56. 25.101 / 56. 25.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 11.102 /  5. 11.102
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  3.100 / 53.  3.100
Guessed Channel Layout for  Input Stream #0.1 : mono
Guessed Channel Layout for  Input Stream #0.2 : mono
Guessed Channel Layout for  Input Stream #0.3 : mono
Guessed Channel Layout for  Input Stream #0.4 : stereo
Input #0, matroska,webm, from '/home/www/media/21/21.mkv':
  Metadata:
    MINOR_VERSION   : 0
    COMPATIBLE_BRANDS: mp42isom
    MAJOR_BRAND     : mp42
    ENCODER         : Lavf56.25.101
  Duration: 00:01:30.16, start: 0.000000, bitrate: 3512 kb/s
    Stream #0:0(und): Video: h264 (Main), yuv420p(tv), 1024x576 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 1k tbn, 50 tbc (default)
    Stream #0:1: Audio: pcm_s16le, 16000 Hz, 1 channels, s16, 256 kb/s
    Metadata:
      ENCODER         : Lavc56.56.101 pcm_s16le
    Stream #0:2: Audio: pcm_s16le, 16000 Hz, 1 channels, s16, 256 kb/s
    Metadata:
      ENCODER         : Lavc56.56.101 pcm_s16le
    Stream #0:3: Audio: pcm_s16le, 16000 Hz, 1 channels, s16, 256 kb/s
    Metadata:
      ENCODER         : Lavc56.56.101 pcm_s16le
    Stream #0:4(und): Audio: pcm_s16le, 16000 Hz, 2 channels, s16, 512 kb/s (default)
    Metadata:
      LANGUAGE        : und
      ENCODER         : Lavc56.56.101 pcm_s16le
/var/www/vids/21/new.mkv: No such file or directory

---

此消息：

/var/www/vids/21/new.mkv:没有这样的文件或目录是明确的。您正在写入的目录：
/var/www/vids/21
显然不存在。尝试创建它并查看它的功能。
它的功能是，输入文件位于同一文件夹中。drwxr-xr-x 2 tommy lab 4096 May 5 16:15 21`您正在源文件夹中执行ls-l？你没有显示结果吗？请检查确切的路径，因为显然有一个文件夹无法访问。哦，天哪，我是瞎子。对不起，是真的，走错了路。。。我现在感觉不舒服（哈哈，别那么做。很高兴你找到了它！：-）