[MPlayer-users] Problems downmixing to lower number of channels

[Bryan Donlan]

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