I'm trying to play back a 5.1 surround file with my 2-channel speakers. I've tried using -channels 2, but that just silences all but the front side channels. How can I get it to mix the back, center, and subwoofer channels into the front two channels? Mplayer output: $ mplayer -vo vesa -ao alsa -channels 2 -alang jpn -slang eng media.mkv MPlayer 1.0pre5-3.3.4 (C) 2000-2004 MPlayer Team CPU: Advanced Micro Devices Athlon MP/XP/XP-M Barton 2158 MHz (Family: 6, Stepping: 0) Detected cache-line size is 64 bytes MMX2 supported but disabled 3DNow supported but disabled 3DNowExt supported but disabled CPUflags: MMX: 1 MMX2: 0 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 0 Compiled for x86 CPU with extensions: MMX SSE Reading config file /usr/share/mplayer/mplayer.conf Reading config file /home/bdonlan/.mplayer/config Reading /home/bdonlan/.mplayer/codecs.conf: Can't open '/home/bdonlan/.mplayer/codecs.conf': No such file or directory Reading /usr/share/mplayer/codecs.conf: 73 audio & 180 video codecs font: can't open file: /home/bdonlan/.mplayer/font/font.desc Font /usr/share/mplayer/font/font.desc loaded successfully! (206 chars) Using usleep() timing Can't open input config file /home/bdonlan/.mplayer/input.conf: No such file or directory Input config file /usr/share/mplayer/input.conf parsed: 53 binds Playing media.mkv. [mkv] Track ID 1: video (V_MS/VFW/FOURCC), -vid 0 [mkv] Track ID 2: audio (A_AAC/MPEG4/LC/SBR), -aid 0, -alang jpn [mkv] Track ID 3: audio (A_VORBIS), -aid 1, -alang eng [mkv] Track ID 4: subtitles (S_TEXT/UTF8), -sid 0, -slang eng [mkv] Track ID 5: subtitles (S_TEXT/UTF8), -sid 1, -slang ger [mkv] Will play video track 1 [mkv] Will play audio track 2 [mkv] Will display subtitle track 4 Matroska file format detected. ========================================================================== Opening audio decoder: [faad] AAC (MPEG2/4 Advanced Audio Coding) FAAD: compressed input bitrate missing, assuming 128kbit/s! AUDIO: 44100 Hz, 6 ch, 16 bit (0x10), ratio: 16000->529200 (128.0 kbit) Selected audio codec: [faad] afm:faad (FAAD AAC (MPEG2/MPEG4 Audio) decoder) ========================================================================== ========================================================================== Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family Selected video codec: [ffodivx] vfm:ffmpeg (FFmpeg MPEG-4) ========================================================================== Checking audio filter chain for 44100Hz/6ch/16bit -> 44100Hz/2ch/16bit... AF_pre: af format: 2 bps, 6 ch, 44100 hz, little endian signed int AF_pre: 44100Hz 6ch Signed 16-bit (Little-Endian) alsa-init: got device=0, subdevice=0 alsa-init: 1 soundcard found, using: default alsa: 44100 Hz/2 channels/4 bpf/65536 bytes buffer/Signed 16 bit Little Endian AO: [alsa] 44100Hz 2ch Signed 16-bit (Little-Endian) (2 bps) Building audio filter chain for 44100Hz/6ch/16bit -> 44100Hz/2ch/16bit... Starting playback... VDec: vo config request - 704 x 480 (preferred csp: Planar YV12) VDec: using Planar YV12 as output csp (no 0) Movie-Aspect is 1.33:1 - prescaling to correct movie aspect. VO: [vesa] 704x480 => 704x528 Planar YV12 -- bd