Editing .mka file on audacity

[Audacity_Beginner]

Hi,

I am new to editing and just trying to learn how to edit some audio; I am trying to edit 5.1 eac3 audio of a video file (.mkv). I used MKVToolNix to extract the eac3 file as .mka so I can edit a part of the file and replace it with another audio.

I have edited and replaced the parts of the audio file using Audacity (the length of audio is still same as original 2hours 27mins), the original length of the video is 2 hours 27mins. When I try to export the file from Audacity to .ac3 file the resulting exported audio length is now more than 13 hours . I have set "Use advanced mixing options" in the audacity preferences settings.

Is there a way to export the file to .ac3 to the original length of 2:27mins or any settings that I am missing to achieve this?

Any help would be greatly appreciated. Thank you

[johns0]

You can load the video right into audacity and edit it and output the audio and merge it to the video with mkvmerge,see if that fixes the length issue.

[Audacity_Beginner]

Thank you for the reply, I did try that first and it still outputs the audio file to 13 hours. No luck

[johns0]

Have got the newest audacity with the newest ffmeg for audacity installed?

[Audacity_Beginner]

Yes, I have got the newest version and installed ffmpeg installed as well.

I tried to export it to .mp3 to see if that works and exporting to .mp3 works well (length is 2 hours 27mins). .ac3 is the issue.

[johns0]

Unless you need to authorize the video you can output the audio as 5.1 aac.

[Audacity_Beginner]

Okay, will try the 5.1 aac output now. I just want to clarify this - So I have 6 tracks (5.1 master) in that .mka that I extracted out of MKVToolNix, when exporting to .aac in the last step it shows "Advanced Mixing Options" dialog should I keep the number of channels as default like this?


[Attachment 67866 - Click to enlarge]

[johns0]

Yes.Also make sure you give a bitrate of 448 for the aac output.

[Audacity_Beginner]

I cannot enter more than 320 kbps in the window. Is there anywhere else that I can enter more than 320?


[Attachment 67867 - Click to enlarge]

[johns0]

320 is the limit for aac which is better than the output limit for ac3,

[Audacity_Beginner]

Thank you for the help. At the moment I have exported the audio as .aac.

I still would like to know is there a reason why exporting to .ac3 export does not work as expected. Any ideas or any other software which I can try and see if I face the same issues? Could you please recommend some other software?

[Ennio]

Try eac3to. You can let Audacity losslessly export as a multichannel FLAC intermediate. Which you then load in eac3to to convert.

Download with GUI here: https://www.videohelp.com/download/eac3to336-UsEac3to133.zip

Is there a specific reason you want AC3 output?

[netmask56]

If you extract the original EAC3 audio track from the MKV file using MKVCleaver it will output the file as "Name.undefined". Audacity will recognise it and load the 5 tracks. A long bow but maybe the conversion to MKA is messing with the file ?

[johns0]

Op already tried loading the video directly into audacity with the same issue so it isn't a mka effect.I had that issue before with audacity really stretching out ac3 files,had to use eac3to but since then audacity has been good with ac3 files.