as of today there is no multichannel audio specification in the OpenMax IL 1.1.2 standard.
I would like to have suggestion about doing following things in a multichannel decoder
1> how to configure an audio decoder for a required speaker layout.
i.e. to tell the decoder about expected output channels
2> how to enable the downmix algo present inside the decoder e.g. DTS & Dolby has there own downmixing algo.
3> how to configure an audio decoder for discarding LFE channel or downmixing it to front channels
4> how to configure decoder downmix algo for expected channel output
this is similar to first point.
5> how to configure an audio decoder for desired output pcm bits (16 / 24 / 32 (!) )

so far only mono/stereo decoders were there and it was quite easy for integrator.
but when multichannel decoders comes into play, there will be lot of requirements in terms of expected output.

i.e. some particular configuration at HDMI out
or stereo output at speakers or something else

integrator and component developer will be shuffling mails for months.

I think there can be a single structure, e.g. OMX_AUDIO_MULTICHANNELCONFIG , for giving all these parameters at the input port of the multichannel decoders to instruct the decoder about expected output and hence making it easier for integrator