Amiga.org

The "Not Quite Amiga but still computer related category" => Alternative Operating Systems => Topic started by: TheMagicM on August 24, 2008, 03:40:43 AM

Title: mpeg audio editing
Post by: TheMagicM on August 24, 2008, 03:40:43 AM
I have a few videos I want to edit ("bleep") a few words out of.  I'm using SuSE 11 Linux.  Would I strip the audio from the mpeg, edit the audio and somehow merge the audio w/the video?

-Alex
Title: Re: mpeg audio editing
Post by: InTheSand on August 24, 2008, 07:41:49 AM
Hi,

Unless you can find a package that'll do this for you, you'll need to:
1. Demultiplex the audio and video
2. Load the audio into something like Audacity
3. Bleep out the bits required
4. Encode the audio back into MPEG format
5. Remultiplex the audio and video again

You could try mpgtx (http://mpgtx.sourceforge.net/), though that doesn't appear to have been updated for a while.

For all-in-one solutions that may work, have a look at Kdenlive (http://kdenlive.org/), Kino (http://www.kinodv.org/), LiVES (http://lives.sourceforge.net/) and Cinelerra (http://heroinewarrior.com/cinelerra.php3).

I must admit I usually "cheat" and drop back to Windoze for video-related work (mainly because I've paid for the editing software!), rather than doing it in Linux, but hopefully one of the above will be of use.

If I was in Windows doing this, I'd use TMPGEnc to demultiplex, then Audacity to bleep out, then TMPEGEnc to re-encode the audio, then TMPGEnc again to remultiplex.

Good luck!

 - Ali
Title: Re: mpeg audio editing
Post by: TiredOLife on August 24, 2008, 08:27:43 AM
Mpeg2Anim available at Aminet will split the video and sound into two files.

There are a few free packages there that will put them back together again.
Probably ffmpeg would do it.

Don't know much about editing sound though.
Title: Re: mpeg audio editing
Post by: bloodline on August 24, 2008, 11:51:29 AM
Quote

TheMagicM wrote:
I have a few videos I want to edit ("bleep") a few words out of.  I'm using SuSE 11 Linux.  Would I strip the audio from the mpeg, edit the audio and somehow merge the audio w/the video?

-Alex


Did I read that you have a MacMini in the house... Just use iMovie :)
Title: Re: mpeg audio editing
Post by: TheMagicM on August 24, 2008, 11:45:50 PM
yes.. its not here.. I ordered my son's macmini (intel) and fixing to trade my efika for a g4 mac mini so they're not here yet.  I'm partial to doing this on linux though.
Title: Re: mpeg audio editing
Post by: bloodline on August 24, 2008, 11:57:06 PM
Quote

TheMagicM wrote:
yes.. its not here.. I ordered my son's macmini (intel) and fixing to trade my efika for a g4 mac mini so they're not here yet.


To be honest I'd seriously avoid the G4.... It's so underpowered compared to the intel machines...

Quote

I'm partial to doing this on linux though.


Masochist!!! Just use the free tools tools that come with OSX :-)
Title: Re: mpeg audio editing
Post by: Wilse on August 25, 2008, 10:03:37 AM
Quote

bloodline wrote:
Quote

TheMagicM wrote:
yes.. its not here.. I ordered my son's macmini (intel) and fixing to trade my efika for a g4 mac mini so they're not here yet.


To be honest I'd seriously avoid the G4.... It's so underpowered compared to the intel machines...


True but it's more than capable of doing the job specified here and if he's getting it at a serious discount compared to the Macintel I'd say go for it. I've seen second-hand G4s for under a hundred quid - fantastic value for money.
I've also edited audio and video with iMovie on a G4 iBook and it was fine. Pretty straightforward too. Form memory, you'd just load the video into iMovie, separate the audio and export it to, e.g. Garageband. Then you make your alterations and re-import it to iMovie. Piece-a-pish. ;-)
Title: Re: mpeg audio editing
Post by: InTheSand on August 25, 2008, 11:50:00 AM
Quote

bloodline wrote:
Did I read that you have a MacMini in the house... Just use iMovie :)


Would iMovie do a full re-encode? Or would it be aware that only the audio part of the file had changed? May lose some video quality if a full encode takes place vs. the demux -> modify audio -> remux approach.

 - Ali
Title: Re: mpeg audio editing
Post by: bloodline on August 25, 2008, 12:04:44 PM
Quote

Wilse wrote:
Quote

bloodline wrote:
Quote

TheMagicM wrote:
yes.. its not here.. I ordered my son's macmini (intel) and fixing to trade my efika for a g4 mac mini so they're not here yet.


To be honest I'd seriously avoid the G4.... It's so underpowered compared to the intel machines...


True but it's more than capable of doing the job specified here and if he's getting it at a serious discount compared to the Macintel I'd say go for it. I've seen second-hand G4s for under a hundred quid - fantastic value for money.
I've also edited audio and video with iMovie on a G4 iBook and it was fine.


A G4 will work... but I'm finding my old 1.5Ghz G4 PowerBook increasingly pointless... I do try and use it just to justify keeping it around... but Soon I think I'll format it and put it in a cupboard and run it as a Home Server :-)

I don't think it's a good idea getting such an old machine now... an intel MacMini is just so much more useful..

Quote


Pretty straightforward too. Form memory, you'd just load the video into iMovie, separate the audio and export it to, e.g. Garageband. Then you make your alterations and re-import it to iMovie. Piece-a-pish. ;-)


Easier, just load the video in to iMove, then drop the audio envelope out at the required place... and put a Beep sound on a separate audio channel in the place if you want to have something there :-)

Piece-a-pish (tm)
Title: Re: mpeg audio editing
Post by: bloodline on August 25, 2008, 12:06:36 PM
Quote

InTheSand wrote:
Quote

bloodline wrote:
Did I read that you have a MacMini in the house... Just use iMovie :)


Would iMovie do a full re-encode? Or would it be aware that only the audio part of the file had changed? May lose some video quality if a full encode takes place vs. the demux -> modify audio -> remux approach.

 - Ali


Depends, if you set the project settings to that of the original file, no re-encode take place... I often change the format if I'm doing anything though, as I tend to use it to move stuff to my iPhone :-)