笔者酷爱在Debian5.02下用mplayer看电影，平时都好好的，突然有一天，命令行下出现如下提示：

MPlayer interrupted by signal 11 in module: filter_video - MPlayer crashed by bad usage of CPU/FPU/RAM.   Recompile MPlayer with --enable-debug and make a 'gdb' backtrace and   disassembly. Details in DOCS/HTML/en/bugreports_what.html#bugreports_crash. - MPlayer crashed. This shouldn't happen.   It can be a bug in the MPlayer code _or_ in your drivers _or_ in your   gcc version. If you think it's MPlayer's fault, please read   DOCS/HTML/en/bugreports.html and follow the instructions there. We can't and   won't help unless you provide this information when reporting a possible bug.  [ This binary of MPlayer in Debian is currently compiled with    '--enable-debug'; the debugging symbols are in the package    'mplayer-dbg'.]

Oh My God！(当时是说粗口，这里用这句代替一下，毕竟要和谐)

0) 第一阶段探索，使用Debian提供的二进制包机制

$ sudo apt-get install mplayer-dbg $ pwd /home/c-aries/source/debian $ apt-get source mplayer $ cd mplayer-1.0~rc2/ $ gdb mplayer ... #使用gdb调试 (gdb) run -vo fbdev ~/video/拥抱春天.flv ... #因为我没开X，所以调试是在终端下的jfbterm工作，视频必需显示在framebuffer上，所以为 -vo fbdev Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 0xb5c136d0 (LWP 18529)] read_font_desc_ft (fname=0x8ae0800 "/usr/share/fonts/truetype/unifont/unifont.ttf", movie_width=320, movie_height=33124) at font_load_ft.c:797 797    font_load_ft.c: No such file or directory.     in font_load_ft.c (gdb) list 792    in font_load_ft.c (gdb)

此时提示在read_font_desc_ft()里出现Segmentation fault
说明mplayer出错和font(字体)有关

1) 第二阶段探索，使用Debian提供的源码包机制

$ sudo apt-get remove mplayer $ pwd /home/c-aries/source/debian/mplayer-1.0~rc2 $ sudo apt-get build-dep mplayer $ ./configure --prefix=/usr --enable-debug --codecsdir=/usr/lib/codecs/ --enable-fbdev --disable-dvdnav --disable-dvdread --disable-dvdread-internal --enable-mencoder && make ... #我的GNU小本没有光驱，所以--disable-dvd*，其间报错，mencoder无法正常生成 $ gdb ./mplayer ... #学 0) 中的调试方法，发现视频可正常播放，我还想用gdb调试一下mplayer看哪里出错了啊 : (

2) 第三阶段探索，使用自己下载的包

由于 1) 中的mencoder编译失败，不爽，所以亲手下载官网的包，重新编译

$ pwd /home/c-aries/source/mplayer $ cat url http://www.mplayerhq.hu/MPlayer/releases/MPlayer-1.0rc1.tar.bz2 http://www.mplayerhq.hu/MPlayer/releases/MPlayer-1.0rc2.tar.bz2 http://www.mplayerhq.hu/MPlayer/releases/codecs/essential-20071007.tar.bz2 http://www.mplayerhq.hu/MPlayer/releases/codecs/all-20071007.tar.bz2 http://www.mplayerhq.hu/MPlayer/releases/fonts/font-arial-iso-8859-7.tar.bz2 http://www.mplayerhq.hu/MPlayer/skins/Blue-1.7.tar.bz2 http://www.mplayerhq.hu/MPlayer/patches/asmrules_fix_20061231.diff http://www.mplayerhq.hu/MPlayer/patches/cddb_fix_20070605.diff http://www.linuxfromscratch.org/patches/blfs/6.3/MPlayer-1.0rc1-ext_ffmpeg-1.patch $ wget -c -i url ... #根据url中的文件列表下载文件，省略 $ pwd /home/c-aries/source/mplayer/MPlayer-1.0rc2 $ ./configure --prefix=/usr --enable-debug --codecsdir=/usr/lib/codecs/ --enable-fbdev --disable-dvdnav --disable-dvdread --disable-dvdread-internal --enable-mencoder && make

结果mplayer和mencoder编译成功，视频播放正常

3) 第四阶段探索，为什么Debian官方包的mplayer不能正常使用?

无意中发现自己以前的笔记中，configure配置时有个 --confdir 参数

$ pwd /home/c-aries/source/mplayer/MPlayer-1.0rc2 $ ./configure --prefix=/usr --enable-debug --codecsdir=/usr/lib/codecs/ --enable-fbdev --disable-dvdnav --disable-dvdread --disable-dvdread-internal --enable-mencoder --confdir=/etc/mplayer && make $ gdb ./mplayer (gdb) run -vo fbdev ~/video/拥抱春天.flv ... #省略 Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 0xb6a808f0 (LWP 31599)] read_font_desc_ft (     fname=0xa454100 "/usr/share/fonts/truetype/unifont/unifont.ttf",     movie_width=320, movie_height=33124) at font_load_ft.c:797 797            charset[i] = charcode; (gdb) list 792    #ifdef HAVE_FREETYPE21 793        i = 0; 794        charcode = FT_Get_First_Char( face, &gindex ); 795        while (gindex != 0) { 796        if (charcode < 65536 && charcode >= 33) { // sanity check 797            charset[i] = charcode; 798            charcodes[i] = 0; 799            i++; 800        } 801        charcode = FT_Get_Next_Char( face, charcode, &gindex ); (gdb) backtrace #0  read_font_desc_ft (     fname=0xa454100 "/usr/share/fonts/truetype/unifont/unifont.ttf",     movie_width=320, movie_height=33124) at font_load_ft.c:797 #1  0x082361a7 in load_font_ft (width=320, height=182, fontp=0x87f7380,     font_name=0xa2fe680 "Sans") at font_load_ft.c:1164 #2  0x082326db in vo_update_osd (dxs=320, dys=182) at sub.c:1093 #3  0x08232c83 in vo_draw_text (dxs=320, dys=182,     draw_alpha=0x80ed570 <draw_alpha>) at sub.c:1228 #4  0x080edc84 in draw_osd () at vo_fbdev.c:1093 #5  0x0814a492 in control (vf=0xa409ed0, request=7, data=0x0) at vf_vo.c:94 #6  0x08142e54 in control (vf=0xa3ec538, request=7, data=0x0)     at vf_scale.c:449 #7  0x0811f685 in filter_video (sh_video=0xa3b0280, frame=0xa3ee710, pts=0)     at dec_video.c:415 #8  0x080a3460 in main (argc=4, argv=0xbfbf95c4) at mplayer.c:2046 (gdb)

发现视频不能正常播放，gdb定位到出现问题的代码 : )
试着和 0) 比较，list可以列出代码了

好玩，用gdb在mplayer的代码中游走，list一下，break一下，print一下探寻问题的症结

原来关键在于 /etc/mplayer/mplayer.conf 文件，Debian官方编译mpalyer时应该使用了 --confdir=/etc/mplayer 配置选项

3) 结论

将 /etc/mplayer/mplayer.conf 中的 'fontconfig=1' 注释掉，改成 '#fontconfig=1' 即可

这是个表面原因，临时的解决方法，不过修改完，Debian官方的mplayer就能正常工作了

以下是我的配置

$ cat /etc/mplayer/mplayer.conf ### mplayer DEBCONF AREA. DO NOT EDIT THIS AREA OR INSERT TEXT BEFORE IT. #video output driver #vo=xv,x11 #c-aries: 添加fbdev支持 vo=fbdev,xv,x11 #device for dvd #dvd-device=/dev/cdrom #truetype font, using fontconfig #fontconfig=1 #c-aries: fontconfig=1是mplayer产生bug的原因 font='Sans' #if you do not like this default, override it by adding #  a ao= line below this debconf area #ao=alsa,oss #c-aries: 默认为alsa，oss我不熟悉，没配置 ao=alsa ### END OF DEBCONF AREA.  PLACE YOUR EDITS BELOW; THEY WILL BE PRESERVED.

Debian mplayer官方包真正不能运行的原因，就留给大家学习gdb，一起找出真正的原因吧
有点得过且过，不过话说回来也要循序渐进

调试到现在，不管是用Debian官方包还是自己编译的包，我系统上的mplayer又可以用来看电影了 : )

gdb mplayer bug