[MEncoder-users] Determining number of channels in an audio stream ?

[Plexxus]

Hello,
I'm trying to encode a movie with dolby surround, recorded from
satellite (NRJ12 on Hotbird)
mplayer gives:
==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
dec_audio: allocation 4608 + 65536 = 70144 octets comme tampon de sortie
mp3lib: using generic C decore!
MP3lib: init layer2&3 finished, tables done
MPEG 1.0, Layer II, 48000 Hz 320 kbit Stereo, BPF: 960
Channels: 2, copyright: Yes, original: Yes, CRC: Yes, emphasis: 0
AUDIO: 48000 Hz, 2 ch, s16le, 320.0 kbit/20.83% (ratio: 40000->192000)
ID_AUDIO_BITRATE=320000
ID_AUDIO_RATE=48000
ID_AUDIO_NCH=2
Selected audio codec: [mp3] afm: mp3lib (mp3lib MPEG layer-2, layer-3)
==========================================================================

How can I be sure of the number of channels in this stream ?
Then I can force with -af channels=???


Are parameters like "-oac faac -faacopts quality=100" a good way to keep
surround effects ?

TIA