GetChannel

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GetChannel(clip clip, int ch1 [, int ch2, ...])

GetLeftChannel(clip clip)

GetRightChannel(clip clip)

Prior to v2.5 GetLeftChannel returns the left and GetRightChannel the right channel from a stereo signal. GetChannel is present starting from v2.5 and it returns one or more channels of a multichannel signal. The ordening of the channels is determined by the ordening of the input file, because AviSynth doesn't assume any ordening. In case of stereo 2.0 WAV and 5.1 WAV files the ordening should be as follows:

WAV 2 ch (stereo):

1	left channel
2	right channel

WAV 5.1 ch:

1	front left channel
2	front right channel
3	front center channel
4	LFE (Subwoofer)
5	rear left channel
6	rear right channel

Examples:

# Removes right channel information, and return as mono clip with only left channel:
video = AviSource("c:\filename.avi")
stereo = WavSource("c:\afx-ab3_t4.wav")
mono = GetLeftChannel(stereo)
return AudioDub(video, mono)

# Using v2.5 this becomes:
video = AviSource("c:\filename.avi")
stereo = WavSource("c:\afx-ab3_t4.wav")
mono = GetChannel(stereo, 1)
return AudioDub(video, mono)

# You could also obtain the channels from the avi file itself:
video = AviSource("c:\filename.avi")
return GetChannel(video, 1)

# Converts avi with "uncompressed 5.1 wav" audio to a stereo signal:
video = AviSource("c:\divx_wav.avi")
audio = WavSource(c:\divx_wav.avi)
stereo = GetChannel(audio, 1, 2)
return AudioDub(video, stereo)

Remark1:

Every file format has a different channel ordening. The following table gives this ordening for some formats (useful for plugin writers :))

reference:	channel 1:	channel 2:	channel 3:	channel 4:	channel 5:	channel 6:
[5.1 WAV]	front left channel	front right channel	front center channel	LFE	rear left channel	rear right channel
[5.1 AC3]	front left channel	front center channel	front right channel	rear left channel	rear right channel	LFE
[5.1 DTS]	front center channel	front left channel	front right channel	rear left channel	rear right channel	LFE
[5.1 AAC]	front center channel	front left channel	front right channel	rear left channel	rear right channel	LFE
[5.1 AIFF]	front left channel	rear left channel	front center channel	front right channel	rear right channel	LFE

5.1 DTS: the LFE is on a separate stream (much like on multichannel MPEG2).
AAC specifications are unavailable on the internet (a free version)?

Remark2:

At the time of writing, BeSweet still has the [2GB barrier]. So make sure that the size of the 5.1 WAV is below 2GB, otherwise encode to six separate wavs or use HeadAC3he.

Remark3:

GetChannels is an alias to GetChannel and they can be used interchangeably. The syntax is the same for both.