Convert stereo ac3 with bad channel to mono ac3

[chipsndukes]

Hi,

I have an old show recorded from TV and authored at one time into a DVD.
The audio is left channel only, the audio is encoded in .ac3 stereo.

I would like to take the left channel and copy it to the right channel and have an ac3 stereo file with both channels working, albeit mono.

I can't find a program that will do what I want it to do, even though this seems to be the simplest of all possible tasks.

Here is a screenshot from BeLight, attached.

Here is the BeSweet command line:

BeSweet.exe -core( -input "F:\AUDIO.ac3" -output "F:\AUDIO_1.ac3" ) -azid( -s mono --maximize ) -ac3enc( -b 256 )

The file encodes fine, but still comes out with only the left channel working, no change.

If someone can suggest a change to the command line, I can type it in manually or run it in command prompt, I just want to fix the problem.

Thanks much for your help, gentlemen, I appreciate it!
Chipsndukes

[aedipuss]

you might convert it to wav, and then most audio editors like audacity will be able to delete a channel and duplicate the remaining one. then convert back to ac-3 if you wish.

[freebird73717]

you might convert it to wav, and then most audio editors like audacity will be able to delete a channel and duplicate the remaining one. then convert back to ac-3 if you wish.

I second that suggestion. You may need the ac3 acm decompressor for audacity to open the ac3 file.

[chipsndukes]

He guys, thanks a lot.
You caught me being a little lazy, I was hoping everything was to be done in an ac3 format, as it was I encoded to .wav with BeLight, edited with Audacity, then reencoded back to .ac3 with BeLight again.

Freebird, I downloaded the ac3 codec and installed it, but when I tried to open the ac3 directly in Audacity, it interpreted it as an .mp3 and it came out as garbage.

If you could help me get ac3 working with Audacity, that would be great, keep it everything in it's native format and save the encoding steps.

Thanks guys!
Chipsndukes

[freebird73717]

Well it seems that I was wrong about ac3 acm decompressor being able to open ac3 files in audacity. I thought that I had used it to do that at one time but I guess I didn't. I hardly ever have to edit ac3. I did some searching and found out that so far there is no way to edit ac3 directly in audacity. It must first be converted to wav.

One thing I did notice was that if you use the latest beta v1.36 audacity can export directly to ac3 instead of saving to another wav file.

finally you can export directly to AC3!
Use: "Export" and choose "Save as type: external program" and then
Options: put your command line to pipe output to.
I use aften, as this: "p:\aften\aften.exe -b 128 -s 1 -w 45 -dnorm 27 - "%f"
and it created an AC3 file. Much faster and more convenient than exporting to a huge wave file and converting.

You will need to download aften and change the directory appropriately in the command line. You could use besweet as well but I find that aften gets a better sound. Maybe that can somewhat help you shorten your process for you.

[chipsndukes]

I appreciate the comments, freebird, surprised also not to see something to edit ac3 directly. I think a Nero app can do it, guess not enough people interested in that format.
For my use, you guys solved the problem, though.
I appreciate that and thank you for it...

Chipsndukes

[Alex_ander]

I think a Nero app can do it...

Since you've already mentioned a commercial application, here's the one which can open/edit/save a 2-channel ac3: SoundForge9. For opening an ac3 file (2-channel only), rename its extension to .VOB or .mpg. Select/copy the healthy channel and paste it over the other one, save as ac3 (or ac3pro if you have that plugin registered, then bitrate is selectable instead of the default 192kbps).

[chipsndukes]

Hi Alexander, here is a link to the topic where I got the idea about the Nero app/AC3, it's apparently "Free" for Nero owners:

https://forum.videohelp.com/topic267482.html?highlight=nero%20ac3