ChannelInterpretation

ChannelInterpretation type specifies how input channels are mapped out to output channels when the number of them are different.

Acceptable values:

• speakers

  Use set of standard mapping rules for all combinations of common input and output setups.

• discrete

  Covers all other cases. Mapping depends on relationship between number of input channels and number of output channels.

Channels mapping table

speakers

Number of input channels	Number of output channels	Mixing rules
1 (Mono)	2 (Stereo)	output.L = input.M output.R = input.M
1 (Mono)	4 (Quad)	output.L = input.M output.R = input.M output.SL = 0 output.SR = 0
1 (Mono)	6 (5.1)	output.L = 0 output.R = 0 output.C = input.M output.LFE = 0 output.SL = 0 output.SR = 0
2 (Stereo)	1 (Mono)	output.M = 0.5 * (input.L + input.R)
2 (Stereo)	4 (Quad)	output.L = input.L output.R = input.R output.SL = 0 output.SR = 0
2 (Stereo)	6 (5.1)	output.L = input.L output.R = input.R output.C = 0 output.LFE = 0 output.SL = 0 output.SR = 0
4 (Quad)	1 (Mono)	output.M = 0.25 * (input.L + input.R + input.SL + input.SR)
4 (Quad)	2 (Stereo)	output.L = 0.5 * (input.L + input.SL) output.R = 0.5 * (input.R + input.SR)
4 (Quad)	6 (5.1)	output.L = input.L output.R = input.R output.C = 0 output.LFE = 0 output.SL = input.SL output.SR = input.SR
6 (5.1)	1 (Mono)	output.M = 0.7071 * (input.L + input.R) + input.C + 0.5 * (input.SL + input.SR)
6 (5.1)	2 (Stereo)	output.L = input.L + 0.7071 * (input.C + input.SL) output.R = input.R + 0.7071 * (input.C + input.SR)
6 (5.1)	4 (Quad)	output.L = input.L + 0.7071 * input.C output.R = input.R + 0.7071 * input.C output.SL = input.SL output.SR = input.SR

discrete

Number of input channels	Number of output channels	Mixing rules
x	y where y > x	Fill each output channel with its counterpart(channel with same number), rest of output channels are silent channels
x	y where y < x	Fill each output channel with its counterpart(channel with same number), rest of input channels are skipped