I have encodes of a rare tv series Exosquad. I encoded them myself to x264/AAC from VHS recordings which are the best quality I've ever found them in. The problem is the audio is in stereo but sound only comes out through one channel. This is how it was in the source. Is there any way I can modify those aac files to mirror that channel? It's very distracting only having audio coming out through the left speaker.

Ouch. Your best option (although the most time consuming, as well!) would be to re-encode the series and convert the audio to mono prior to encoding. Assuming you used AviSynth or VirtualDub, each has the ability to do a stereo-to-mono conversion.

Barring that, you could extract the AAC from your muxed stream, transcode as mono with foobar2000, and re-mux.

Unfortunately I do not know of any way to losslessly mirror the channels without either re-encoding or transcoding.

- M.

Thanks. I found the 'encode to mono' option in my encoding app. Does anyone know how I can extract the aac files from the mkv files as their original .mp4 audio files? When I extract it with mkvmerge it extracts as a .mkv file which my encoding app doesn't take in. Manually changing the extension doesn't help.

Edit: Found a thread on how to do it on this forum. http://www.hydrogenaudio.org/forums/lofive...php/t35935.html

Edit2: I can't find a foobar version that lets you transcode so I ended up using a transcoder plug-in for Winamp. Really easy.

Use some player/codec with a matrix mixer. There, you can send arbitrary input channels into arbitrary output channels (you just set the matrix coefficients between 0.0 and 1.0). This way, you may mix multiple input channels into one or split one input channel into multiple output ones or do whatever channel mix you need.
AC3Filter has this, for example. You only have to set it up to handle the audio type you need.
This will not change the file itself, though.

Yea I know ffdshow has that capability. But switching this feature on and off dissuaded me.

I find it diffucult to believe that you never noticed this problem before encoding. What are very basic audio operations – cut, paste, multiply – become extremely difficult to do upon compressed data, even MP3.

??? Every foobar2000 version will let you transcode... but the program will warn you that doing so is generally a bad idea.

- M.

Btw, if the audio is in one channel only you should take it and discard the other. There is no point in mixing the noise from the other channel in the final encode.

Who said I didn't notice? I just didn't care back then.
Oh lol I just had to right click on the title of the song itself. I'm very new at this stuff.