Sound output is always stereo

[arifi]

Since a couple of days ago i installed the newest version of Mediacoder.
And then the audio output began.Whenever i try to convert an MKV to MKV just to hardcode subtitles in it,the 5.1 sound always gets converted ti stereo.
Even when i click "copy audio".The encoder i used was Ffmpeg or just leave it on "auto select".Then i tried Mencoder.The result is the same.
During conversion i put my mouse on the Ffdshow audio decoder and next to "output" there is always "PCM,stereo,48000 Hz,16-bit integer"
A couple of days ago i had another version of Mediacoder.I just forgot what version it was exactely.
And the problem did not occur on that version.
The versions i experienced this problem with are "MediaCoder2011-x64-R9-5196" and "MediaCoder2011-x64-R9-5196".
Both 64 bit.

I tried looking in the Mediacoder forum but could not find a clear answer.
I hope someone has an answer.
Thanks in advance.

[meRobs]

I checked this out using the settings for MKV in the Encoding Guide, under Tips & Guides, below.
This leaves the setting for Channels on the Sound tab at the default (Stereo).

In build 5196, a conversion from a VOB with 5.1 channels gave stereo as expected.
Changing Sound > Channels to 5.1 Channels gave Error 15 (Muxer error) whether Muxer is set as Auto or MKVmerge.

In build 5191, the same as 5196.

In build 5175, Channels = 5.1 channels gave "No file output"

NOTE: the above had audio as MP3 by FFmpeg as encoder. I shall try another.

[meRobs]

Looks as if the above "MP3" doesn't include MP3-surround (FFmpeg encoder). So, I tried LAME MP3 encoder and it failed as well.

Then, I tried different audio formats, those that ought to suport 5.1 channel surround.

(1) AC3 via FFmpeg encoder with all else as per the above MKV settings: setting Channels = 5.1 channels worked!
(2) taking the MP4 settings in the Encoding Guide (AAC audio) and changing Channels to 5.1 channels: it worked.
(3) as for MP4, but simply changed the Container from MP4 to MKV: it worked (5.1 channels).

What were your settings?

[arifi]

Looks as if the above "MP3" doesn't include MP3-surround (FFmpeg encoder). So, I tried LAME MP3 encoder and it failed as well.

Then, I tried different audio formats, those that ought to suport 5.1 channel surround.

(1) AC3 via FFmpeg encoder with all else as per the above MKV settings: setting Channels = 5.1 channels worked!
(2) taking the MP4 settings in the Encoding Guide (AAC audio) and changing Channels to 5.1 channels: it worked.
(3) as for MP4, but simply changed the Container from MP4 to MKV: it worked (5.1 channels).

What were your settings?

Sorry for taking so long to respond.
I have mkv as the container.As source on the audio tab i had ´´default´´.That gave stereo as output.
I changed to ´´FFmpeg´´ and it gave 5.1.
But the weird thing is that during conversion,ffdshow still shows PCM and stereo on the output.
I check the .ac3 file in the working folder of Mediacoder during conversion with Mediainfo and it is 5.1.
Probably a bug or so.
Thanks for your help.