merging audio and video of different length

[Freelife2345]

Hi there, I extracted an audio file from a MP4 file into a mka file using mkv merge gui. I plan to merge this extracted mka file with another mp4. However, the audio length is different from the video. My video starts like around 2 min and audio starts around at 3 min. Which application can I use out there that is free to help me to adjust the audio so that my video and audio will be in sync when I merge it with mkv verge gui? I know I can cut the audio file but it might still be slightly off by a bit and I don't know how to make it exact. Please let me know if there is a way

[jman98]

Audacity is free and can do this kind of thing, but I don't know what they call it. I use an old commercial product called Cool Edit to do something like what you describe and it's called something like "pitch shift" under it. If there's a difference of more than just a few seconds between your audio and video, you won't be able to get them in sync with this method, and in your case that seems to be what is happening. But if you want to try, Audacity is your program.

[Cornucopia]

2min to 3min is a 150% expansion (a 66.66% slowdown). That is a HUGE difference. There is some difference depending upon the program material, but in general if you go >~4-8% it will be noticeable and if you go > ~10-25% it will be comical/bothersome and much more would be unbearable. This is regardless of pitch correction or not.

Never say never, but IIWY I'd look for a different copy that fits...

Scott
(I, too, have thoroughly used/enjoyed CoolEdit and Audition after it).

[Freelife2345]

I tried audacity. I don't know why when i install it, it always in another language likeChinese. I can't get it to be in English. Another thing is when I try importing the file, it's gives me this error message and I think it requires me to download some additional file like ffmeg?

I went to the below site and download according to the icon there. But, when I opened ffmeg, I get a bunch of text files and nothing to install. Did I download the right file? Help!!

http://ffmpeg.org/download.html

[videobruger]

Audacity language Edit -> Preference -> Interface -> Language.

FFMpeg http://manual.audacityteam.org/o/man/faq_installation_and_plug_ins.html#ffdown

[Freelife2345]

Audacity language Edit -> Preference -> Interface -> Language.

FFMpeg http://manual.audacityteam.org/o/man/faq_installation_and_plug_ins.html#ffdown

Thanks videobruger. I changed the language successfully and I managed to import the file as raw and got around from downloading ffmeg. But after I import the file, I don't hear anything other that static or sharp squeaky noises. Is the audio file corrupted or does audacity not recognize mka files extracted from mkv verge?

[videobruger]

Use MKVExtractGUI2 to extract the audio from .mka. Probably .aac format.

[Freelife2345]

Use MKVExtractGUI2 to extract the audio from .mka. Probably .aac format.

I tried mkv extract but I think it's only limited to mkv files ? Actually some of my files are in MP4 and rmvb and mkv merge actually work with MP4, and rmvb files when extracting audio files. Is there any other rmvb and MP4 programs out there that will do the job well when extracting audio files for audacity to recognize ?

[videobruger]

MKA is a MKV file with Audio only. If you have problems using it just rename it to .MKV. For your MP4 files you could de-mux the audio with My MP4BoxGUI.

[Freelife2345]

MKA is a MKV file with Audio only. If you have problems using it just rename it to .MKV. For your MP4 files you could de-mux the audio with My MP4BoxGUI.

When I tried downloading ffmeg from your above link, it led me to this blank page that says 403 forbidden.
When I tried downloading mkvextract, I got this message that says put me in mkvtooldir and after I click on ok, it led me to

https://www.bunkus.org/videotools/mkvtoolnix/win32/

I downloaded one of the mkvtoolsnix file there and I when I imported my mkv file it says error creating chilg process. I can try another mkvextract mirror download if you have another good one. There is too many mirror ones in this site it becomes overwhelming finding which one that works.

When I tried to download mymp4box gui, it said I need to have .netframework.

I am feeling a bit despair with all the failures in downloading these programs.

For now, I think if I can edit the extracted audio in audacity, I should be fine. However, I just need a way to get the sound to come up instead of just hearing static or weird squeaky noises. If I am able to download ffmeg and able to solve that problem, please let me know where else can I get another version mirror download.

Also, I wonder is there such a way to merge the dialogue audio by following the timing in my subtitle text? If so, that can get the video and audio in sync easily than just me cutting the audio by trial and error to get things exact. Just something I am curious about if the above method fails with cutting the audio with audacity.

[poisondeathray]

The ffmpeg import/export plugin for audacity is different than ffmpeg.exe

(The link you downloaded from earlier http://ffmpeg.org/download.html , is not for audacity)

The plugin for audacity enables you to open the audio from various video container formats directly in audacity. Follow these instructions

http://manual.audacityteam.org/o/man/faq_installation_and_plug_ins.html#How_do_I_downl...ort_Library.3F

Direct download link (it works, link isn't dead)
http://lame3.buanzo.com.ar/ffmpeg-win-2.2.2.exe

[Freelife2345]

The ffmpeg import/export plugin for audacity is different than ffmpeg.exe

(The link you downloaded from earlier http://ffmpeg.org/download.html , is not for audacity)

The plugin for audacity enables you to open the audio from various video container formats directly in audacity. Follow these instructions

http://manual.audacityteam.org/o/man/faq_installation_and_plug_ins.html#How_do_I_downl...ort_Library.3F

Direct download link (it works, link isn't dead)
http://lame3.buanzo.com.ar/ffmpeg-win-2.2.2.exe

I clicked on your download link and again it just led me to this page that says 403 forbidden. Am I supposed to right click and save it? If so, I tried that too.

[poisondeathray]

Maybe you have firewall /security settings that prevent you from downloading?

I upload a mirror here in a zip version in case "*.exe" is triggering your security software

Note this 2.2.2 version is for audacity 2.0.6 , won't work for older versions

EDIT: sorry it's not the correct version, I uploaded the zip version from that page, but it's actually not correct version, only the .exe version is

just a sec... I'll zip up the .exe version. OK, it works now. It should be a single .exe when you unzip it. It is the binary installer

[Freelife2345]

Thank you so much poisondeathray. I got the audio to be playing now. I will play around to see how I can edit out the first two min. But I do notice sometimes the audio makes some funny wave sound when I raise the volume. Also, is there any precise way to get the extracted audio to line up with the video or do I really have to go through trial and error editing that min or two. I have a feeling it will still come off to be a second or two out of sync. I'm just wondering can I make just the "dialagoue" part to follow the exact timing of one of my subtitle text file because all I care is really replacing the original audio with the dubbed audio. Is there a way I can do that with audacity or I'm just asking audacity too much ?

[videobruger]

One suggetion to sync the audio:

Open the MP4 you want to sync to with AviDemux. You can step through it frame by frame to get the time you want the audio to start. Use that for editing in Audacity.

[Freelife2345]

I have a piece of the audio in the beginning and middle around 20 min I need to edit out and then merge the file back together. I used split cut or delete and then join but it looks strange because I still see a gap. Am I doing it correctly? Or is there another approach I should consider in audacity ?

Is there Instructions on how to use avi demux to do the syncing? Basically do I just click on shift under audio output and will do the syncing? Don't I have to merge my new audio file I edit in audacity with this MP4 before using avi demux?