Extract audio from mp4

Garageband? and delete the video file that might work

QuickTime Pro will do this.. Export audio.

audio hijack will work too. simply play the mp4 and record the audio..most popular formats outputted as well.

Hi, sorry for re-activating this old discussion. However, I found it on google and thought it would be more appropriate to add my question here.

I have a few videos in the MP4 format and want to get the audio track saved to a seperate audio file. As the audio track is already AAC there should be no reencoding required. Unfortunetely, when I simply remove the video track using QuickTime Pro and save the remaing audio track a .mov is created. Using the export function won't be losslessly writing the data from the audio track to the disk but reencoding it as I guess.
I believe GarageBand will do just the same, not sure about Audio HiJack.

Isn't there a tool with which I can just take the audio track of a video file and save it to disk as a seperate file without reencoding it? Any ideas?

You don't need QT Pro! In QT, click File>Export and where it says export, chose Sound to AIFF. AIFF is the highest quality of sound export avaiable. This should help.

Regards,
David

Thanks for the hint FCP.guru.guy. However, I was already aware of this possibility. And you're right, exporting the Audio into the AIFF format should't lower the quality but at the same time also increases the file size dramatically though not needed at all. I just hoped it would there would be a possibility to simply take the raw data of the audio track in AAC format and write it to directly to disk into an AAC file. Without any reencoding or reformating. Ain't there some tools out there for lossless audio editing that should also handle things like that?

Well, if your final destination is iTunes, you can make an AAC version and pitch the original AIFF one in the Trash (don't forget to empty once and a while) This will create a file that is the size that it should be as an AAC. If your final destination is something other than iTunes, just take the trip there for 1 minute. Add it to you library, make an AAC version, and delete both of them out of your library but KEEP THE FILES!!! When it asks you to move to Trash or keep files make sure you choose keep files other wise they will be moved to the Trash.

David

I've tried this a million times with various formats and nothing works :\ AIFF files will be the length of the audio file, but blank. Exporting to MP3 creates a 1 second blank file

Is there anything I'm doing wrong?

Sorry, maybe I just don't get it or you don't actually understand what I intend to do.

If I understand you right, FCP.guru.guy, you tell me to convert the video to AIFF to just get the audio out and then convert it back to AAC for a smaller filesize. But this is definitely not lossless and its reencoding for two times.

What I am looking for is a direct way of splitting the audio from the video track and saving it to disk as is. In the same format. No reencoding.

I apologize honestly if I just didn't understand what you told me.

I was having the same problem as you (with the high file size produced from quicktime). But found this program free http://www.ffmpegx.com/

Basically once you have installed it, you drop the file into the left hand side screen, and then on the right hand side there is a list of presets including the rather nifty "Movie audio to mp3" function. This produces exactly what i was looking for, and most likely what you want: an mp3 file at 48000 Hz, 128 kbps, with a lowish file size.

Hope this helps

Dave

Hi macdave2,

Thanks for your reply. But your suggestions is not what I want. Your idea is to convert the audio twice (once to AIFF then to mp3). This can actually be done a lot easiert, just using iTunes, setting its import format to MP3 and then choose "Convert into 'MP3'…" from the "Advanced" menu while holding the option key pressed.

What I am looking for is a lossless way to just take audio track of a video and write the raw data in the same format it already is to the disk.

Sorry that you misunderstood me.
When you convert audio or video to a smaller file size, it is near impossible to make it lossless. It sounds like you just wanted the audio so that is what I was instructing you to do.

As I have described in an earlier post, use QT to export the only the audio in give AIFF which is a very high quality audio, this will be lossless if they were in the MPEG-4 format that you described them as. Then use iTunes or this app to convert the AIFF file to mp3. If you want an AAC file then you will have to google around to find a converter or use iTunes. This whole process should be lossless or have unnoticeable quality loss.

David

Hi FCP.guru.guy,

sorry but I fear we're both talking into different directions.

I do not want to convert anything as you try to teach me.

Please let's assume we have an MPEG4 file with a video track encoded in H.264 and an audio track encoded as an AAC. So the audio track is already in the format I finally want. Now I am looking for a way to get rid off the video track and keep the audio just in the same format without any conversion! Or on the other hand just take the raw data of the AAC audio track, write it to disk and put it into an .m4a container.

Maybe there is no way to do this. But if so I really wonder why because converting an audio file from one format to another to finally get what I already have seem strange to me.

I am very sorry for misunderstanding you so many times.

If I finally understand you, you are able to do this in GarageBand as a "Podcast". This will not take any converting! When in GarageBand, click on the movies tab and drag the video you want in. It has to be in the Movies folder in Finder though. Drag the movie onto the track. Click Replace with Movie if a window comes up. Then click on the movie track so it turns purple. Click Command>Delete. This will delete the video track. Delete any other tracks except for the audio track you want to save as an AAC. Then click Share>Export song to disk. Make the the compressing setting an AAC Encoder. And this should finally solve your problem! Hope I could finally help!

David

Hi,

thanks for trying to investigate this issue with me.

Unfortunately I fear that's still not what I want. If I put an AAC audio file or a video file with an AAC audio track into GarageBand and then go to export I have to set compression settings. So the audio will quite probable be reencoded and recompressed.

I simply want to split audio from video track and save it in the format it already is but without changing any bit of the audio track data. I really wonder why I can't do this in QuickTime Pro! Open the movie in QT works fine, pressing Command-J and there extract the audio track and then saving this new track writes a .mov file to disk. Why not a an .m4a or .aac as the audio data already is in this format?

I understand your question completely and I'm afraid that QT Pro can't do this. You can try to uncheck the compress box but I'm not sure that this will export an AAC file. You could choose High Quality in the audio settings which will be lossless. I'm very sorry that this couldn't be solved without re-compressing and re-encoding but I do think that exporting with the Higher Quality setting will produce good results.

David

No, FCP.guru.guy, you really don't get what Canubis is trying to do.

Canubis, here's how I do what you're describing:
1. Get Rogue Amoeba's Fission
http://rogueamoeba.com/fission/
2. Open the movie file with Fission
3. Go to File > Save Audio and you will be able to save the audio track losslessly

i got it canubis

it took me HOURS but i finally found something that does it. i know exactly what ur trying 2 do canubis cuz ive been tryin 2 do it for days. extract audio "as is" no compressing or converting. in other words just open the mp4 container and take it out. ur absolutly right, makes no sense to recompress.

guru.guy, do some research youll see. technically ur losing quality even if its hard 2 tell the diffrence. what we want is 2 "eject" the cassette tape & take it with us rather than "dubbing" it.

go here:

http://www.afterdawn.com/guides/archive/how_to_edit_aac_mp4_audio_page_2.cfm

self explanatory except it says if you get the "yamb" u wont need to download "mp4box". for sum reason my yamb didnt install mp4box but i just downloaded it from this same page and end of story.

dont know if u know how 2 put the files in m4a containers cuz i sure dont. but u can set an option 2 extract them 2 mp4 containers which is fine unless u must have m4a for some reason. otherwise the default extracts them as raw aac files.

if u already found a way let me know if ur way is faster or better for whatever reason. "flvextract" does the same with flv (flash video) files in case u need it too. works in LITERALLY 2 seconds or less, maybe 1 second. compression is not done in 1 second so u know its lossless.

by the way

this is free, u have 2 pay with "fission" the above post by "halfthelaw" so thats why i didnt try that method so i dont know if it does what we want.

Yamb/mp4box

any ports to Mac OS? This is a Windows app.

halfthelaw said:

No, FCP.guru.guy, you really don't get what Canubis is trying to do.

Canubis, here's how I do what you're describing:
1. Get Rogue Amoeba's Fission
http://rogueamoeba.com/fission/
2. Open the movie file with Fission
3. Go to File > Save Audio and you will be able to save the audio track losslessly

Click to expand...

I think i have found a way to do this with SimpleMovieX. This is better than using Fission in that its free trial just makes you wait 12 seconds before it'll save, rather than altering it's output, meaning you can realistically use it for free, unlike fission.

To do this I added an MP4 (H.264 video/AAC audio) file to SimpleMovie X, then went Edit > Separate Tracks, then on the audio track I went File > Save As, then I renamed to file from MP4 to M4A. Once I added it to iTunes I could use it as any other M4A, and the file transfers to and plays on my iPod mini, which as far as I'm aware can't play MP4 so I'm pretty sure what SimpleMovieX is outputting is actually M4A even though it gives it a MP4 file extension.

The only thing with SimpleMovieX is it doesn't explicitly say it is doing this losslessly, but it implies it is on the page that I link to above, and once the 12 seconds has passed it saves the file so quickly it seems unlikely it is re-encoding it.

voodoofish said:

I think i have found a way to do this with SimpleMovieX. This is better than using Fission in that its free trial just makes you wait 12 seconds before it'll save, rather than altering it's output, meaning you can realistically use it for free, unlike fission.

To do this I added an MP4 (H.264 video/AAC audio) file to SimpleMovie X, then went Edit > Separate Tracks, then on the audio track I went File > Save As, then I renamed to file from MP4 to M4A. Once I added it to iTunes I could use it as any other M4A, and the file transfers to and plays on my iPod mini, which as far as I'm aware can't play MP4 so I'm pretty sure what SimpleMovieX is outputting is actually M4A even though it gives it a MP4 file extension.

The only thing with SimpleMovieX is it doesn't explicitly say it is doing this losslessly, but it implies it is on the page that I link to above, and once the 12 seconds has passed it saves the file so quickly it seems unlikely it is re-encoding it.

Click to expand...

It doesn't seem to work with a file that is video - H.264/MPEG-4 AVC, and audio - mp4a: MPEG-4 AAC LC. Any suggestions?

canubis... have you looked into what compressor can do? what about mpeg streamclip?

Open the file in Qt Pro, press command+J extract the audio (you know that already), save it as a mov file. When is done change the extension to m4a, mp4 or whatever you need without reencoding.

let me know if it works for you.

Greetings