Dear all, I use mplayer to play some music an network stream to test the its audio effect. Finally, I find that it's better to use '-ao oss' for the music "AUDIO: 44100 Hz", and use '-ao alsa' for the music with "AUDIO: 48000 Hz". Now, I use mplayer as a background program in my application. I setup mplayer as the following arguments: mplayer -ao oss -af volume=-5 -softvol -softvol-max 100 music.mp3 or mplayer -ao asla -af volume=-5 -softvol -softvol-max 100 music.mp3 Before I play the music, I can't get (maybe just I don't know how to get it) the media files "AUDIO" value. So I can't decide use "oss" or "asla" before I play it. Is there better way to solve that? Or mplayer can choose it automatically? Then how to solve it? My music output just like the following: music 1: ========================================================================== Forced audio codec: mad Opening audio decoder: [libmad] libmad mpeg audio decoder AUDIO: 44100 Hz, 2 ch, s16le, 128.0 kbit/9.07% (ratio: 16000->176400) Selected audio codec: [mad] afm: libmad (libMAD MPEG layer 1-2-3) ========================================================================== music 2: ========================================================================== Forced audio codec: mad Opening audio decoder: [libmad] libmad mpeg audio decoder AUDIO: 48000 Hz, 2 ch, s16le, 320.0 kbit/20.83% (ratio: 40000->192000) Selected audio codec: [mad] afm: libmad (libMAD MPEG layer 1-2-3) ========================================================================== network stream : ========================================================================== Forced audio codec: mad Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders AUDIO: 44100 Hz, 2 ch, s16le, 64.0 kbit/4.54% (ratio: 8003->176400) Selected audio codec: [ffwmav2] afm: ffmpeg (DivX audio v2 (FFmpeg)) ========================================================================== Thanks Kermit