[FFmpeg-user] AAC conversion from 7.1 channel to 2 channel

[rohit a]

Hi,

For AAC conversion from 5.1 channels to 2 channels, ffmpeg code uses
surround_to_stereo() in libavcodec/Resample.c

In that the input data was packed in the format fl, fr, c, lfe, rl, rr
        fl = input[0];  // front left
        fr = input[1];  // front right
        c = input[2];   // center
        lfe = input[3]; // low frequency effects
        rl = input[4];  // rear left
        rr = input[5];  // rear right


I would like to convert AAC 7.1 channels to 2 channels.
But i have no idea about how the input data is packed.
Can anyone please tell me how the input data format is arranged for AAC 7.1
channels ?

Regards,
Rohit