[Solved] AAC 5.1 plays back as 2.0 (1 Viewer)

[whatisk]

I fairly recently rebuilt my HTPC with Win7 x64 as I got a SSD drive.
I have some movies with AAC 5.1 sound that when using XP played fine, however, with the new install, they only play back as 2.0 (stereo). I've tried LAV as well as FFDShow with no luck. They play as stereo both through MP as well as media player. When I installed FFDShow, I unticked AAC in LAV and have also tried setting FFDShow to top prioroty in Filmerit. I'm assuming the files have AAC sound as that's the icon that shows in Moving Pictures. So, I can only assume it's a codec thing. I'm using optical connection from HTPC to amp.

Does anyone have any suggestions of what I could try? Or what I need to provide to help troubleshoot.

 

[DoXer]

I have the same problem. Any suggestions are welcome

 

[corcy]

There are at least three ways to solve the problem you have. The easiest would be to re-encode to AC3 in FFDShow audio, there is a setting in the output where you can choose that only 5.1 pcm will be re-encoded (S/PDIF encode mode). You might have to resample to 48000 Hz if your source signal has a different original sample rate.

Another way would be to use the lav audio mixer and to downmix to stereo using a dolby prologic filter.

Third way is what I actually use myself. If you are using mp 1.3 alpha or beta you should use the mediaportal audio renderer, set the speaker configuration to 5.1 (or 7.1) depending on your actual speaker setup, you can also choose the option to re-encode to AC3 but it is not really necessary. If you are still on mp 1.23 it is also possible to use mp audio renderer, you will have to obtain a copy of mpaudiorenderer.ax (a beta version is available here in the forum) and register it manually (ex with a filter manager) then choose it as the main audio renderer in the codec setup section for video. I hope I was able to help you.

 

[DoXer]

I will check at weekend.

 

[whatisk]

There are at least three ways to solve the problem you have. The easiest would be to re-encode to AC3 in FFDShow audio, there is a setting in the output where you can choose that only 5.1 pcm will be re-encoded (S/PDIF encode mode). You might have to resample to 48000 Hz if your source signal has a different original sample rate.

Thanks. I will have a look in the FFDShow audio config for that option. In MP config, I then set the AAC decoder to FFDShow? Or would that not really matter?

Third way is what I actually use myself. If you are using mp 1.3 alpha or beta you should use the mediaportal audio renderer, set the speaker configuration to 5.1 (or 7.1) depending on your actual speaker setup, you can also choose the option to re-encode to AC3 but it is not really necessary. If you are still on mp 1.23 it is also possible to use mp audio renderer, you will have to obtain a copy of mpaudiorenderer.ax (a beta version is available here in the forum) and register it manually (ex with a filter manager) then choose it as the main audio renderer in the codec setup section for video. I hope I was able to help you.

I'm currently using 1.2.3, but may look into this also. I'm not sure how I got it working fine under XP...

 

[corcy]

In MP config, I then set the AAC decoder to FFDShow?

This is correct if you are going for the first option.

 

[whatisk]

In MP config, I then set the AAC decoder to FFDShow?

This is correct if you are going for the first option.

Thanks. I had a quick play with option 1 and didn't have much luck. Set FFDShow as audio decoder in MP setup. Had a look at the output options in FFDShow audio decoder and did what I think is right according to your directions, but no joy.
I downloaded GraphStudioOne (equivalent of GraphEdit I believe) and opened a file in that. The graph showed that for audio decoding Microsoft DTV-DVD Audio Decoder is being used. This is despite FFDShow having a higher merit. In Filmerit I am unable to change the merit of the MS audio decoder. I'm also not sure where it's come from - whether it's part of Win7, or came as part of the graphics driver I downloaded...
When I have more time or over the weekend I will plug in the old XP drive and see how I had things setup there and see if that gives me some idea as to what's happening.

Edit: Okay, looks as though for FFDShowre-encoding to work correctly I need to disable the MS audio decoder.

 

[corcy]

Did you choose aac in the ffdshow audio codec section? Also, don't forget about resampling to 48000Hz.

I use this little tool Win7DSFilterTweaker to deactivate all unnecessary Microsoft Codecs that I don't need and set the ones I want to use. It works well with ffdshow and/or LAV Filter. Then you don't have to mess around with setting merits manually.

 

[whatisk]

Did you choose aac in the ffdshow audio codec section? Also, don't forget about resampling to 48000Hz.

I use this little tool Win7DSFilterTweaker to deactivate all unnecessary Microsoft Codecs that I don't need and set the ones I want to use. It works well with ffdshow and/or LAV Filter. Then you don't have to mess around with setting merits manually.

Got it working. I set FFDShow to just decode AAC. Set MP to use FFDShow for AAC. I then used the tool you mentioned to disable the MS audio decoder and I now get AAC5.1!! I didn't need to set any resampling.
Thanks for the help corcy.

 

[corcy]

You are welcome.