在Linux环境下看了一电影，黎明骑士（AVI格式），觉得片头曲超棒，只是不知道名字，后来从片尾滚动字幕里找到了名字
wayfaring stranger
是一首经典的乡村民谣，不知道谁是原唱，不过电影里是george canyon唱的，超沧桑。
网上找了一番，都不是很满意，音质低，而且没有多少沧桑感，所以就从电影里直接提取声音了MP3。
很简单，一条指令搞定
@linux:~$ mplayer -dumpaudio DAWN.RIDER.2012.480p.BRRip.XviD.AC3-PTpOWeR.avi -dumpfile linuxidc.mp3
MPlayer2 UNKNOWN (C) 2000-2011 MPlayer Team
mplayer: could not connect to socket
mplayer: No such file or directory
Failed to open LIRC support. You will not be able to use your remote control.
Playing DAWN.RIDER.2012.480p.BRRip.XviD.AC3-PTpOWeR.avi.
Detected file format: AVI format (libavformat)
[mpeg4 @ 0x7f79aa26c300]Invalid and inefficient vfw-avi packed B frames detected
[lavf] stream 0: video (mpeg4), -vid 0
[lavf] stream 1: audio (ac3), -aid 0
VIDEO: [MP4V] 720x304 24bpp 23.976 fps 0.0 kbps ( 0.0 kbyte/s)
dump: 235714100 bytes written (~78.0%)
dump: 301267343 bytes written to 'linuxidc.mp3'.
Stream dump complete.
Exiting... (End of file)
@linux:~$