Convert AAC 6ch to AAC 2ch w/ Dolby Pro Logic II Surround info

[SiegeX]

I have some .mp4 files which contain H264 video and 6channel AAC audio. Unfortunately, the XBox360 that I want to stream this to does not support AAC 5.1 audio so I must downsample this 6channel AAC to 2channel AAC; and I'd like to use Dolby Pro Logic II to keep the surround information.

I don't want to touch the video stream at all, so I intend to use YAMB to split the AAC file and then downsample with whatever tool you guys suggest for the job and then remux it back with YAMB again.

It would be nice if this same tool could also do the above downsampling plus repackage an .mkv with H264 video into an mp4 container. Right now I have XenonMKV for that but I'd like to use as few tools as possible.

Thanks for the help.

[SiegeX]

Update:

I heard good things about MeGUI so I installed it, imported the 6ch AAC file and used the following settings:

1. Nero AAC Encoder (needed neroAacEnc.exe)
2. AAC-LC profile
3. Downmix to Dolby Pro Logic II
4. VBR with Q=0.45
5. Checked "Force Decoding via Directshow" (heard this made the output volume closer to the original stream.)

This seemed to provide me the results I'm looking for. I'm curious if this is what most people would have suggested, and if Nero AAC was a better choice over FAAC.

Also I wonder if MeGUI will allow me to skip the YAMB demux/remux steps and just send it an MP4, tell it to downmix just the audio and leave the video as is.

[jman98]

[*]Downmix to Dolby Pro Logic II

You no longer have AAC audio after this step.

Instead of having to jump through this crazy hoop because of an Xbox limitation, you'd do well to consider getting a media player like one of the Western Digital models. No conversion necessary.

[SiegeX]

You no longer have AAC audio after this step.

Are you sure about that? Both mediainfo and YAMB say the audio is AAC 2channel.

Instead of having to jump through this crazy hoop because of an Xbox limitation, you'd do well to consider getting a media player like one of the Western Digital models. No conversion necessary.

Best comment evar! Wow, how come I didn't know about this sooner. That WD TV Live with network connectivity is everything I want! It even has a Toslink connector to pass DTS to my receiver. Guess I'll need to get one of those toslink selector boxes as my receiver only has one toslink input, but a small price to pay for what I get.

[jman98]

You no longer have AAC audio after this step.

Are you sure about that? Both mediainfo and YAMB say the audio is AAC 2channel.

Not 100% sure. Dolby Pro Logic II is oldish technology. If it gets muxed into an existing sound file instead of converting then I'm wrong. However, you should understand that 6 channels -> 2 channels -> 6 channels means that your final output is fake surround sound regardless.

Instead of having to jump through this crazy hoop because of an Xbox limitation, you'd do well to consider getting a media player like one of the Western Digital models. No conversion necessary.

Best comment evar! Wow, how come I didn't know about this sooner. That WD TV Live with network connectivity is everything I want! It even has a Toslink connector to pass DTS to my receiver. Guess I'll need to get one of those toslink selector boxes as my receiver only has one toslink input, but a small price to pay for what I get.

Thanks for listening. Sadly, most people in your situation would rather beat their head against the wall and try to make the Xbox work. I never stop being amazed at how many people place no value of any kind on their spare time and consider it worthwhile to change the audio like you were doing on every file they have rather than just pay over $100 to solve their problems once and for all. I make this kind of suggestion for the rare person like you who actually can benefit from it. The Xbox and PS3 have long been surpassed as media players with the Western Digital and similar media playing devices.

[SiegeX]

Ya, screw that. I have a 50" plasma and 5.1 audio w/DTS decoder for a reason, and it's not to play HD content with 2 channel stereo sound. I'm really fed up with this XBox360 not supporting 5.1 audio except for its own WMV format. It's almost like they added H264 support with 2channel audio out of spite. If I never reencode another video again it will be too soon.

I noticed that the WDTV only supports up to 24fps for 1080p and that sometimes movies are 29fps. So in those minor cases I'll have to reencode. Wondering what the fastest tool for that would be considering I just want to reduce the fps.