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T0rn
Premium
join:2001-05-11
USA
1 edit |  [Tip] Automatically split an audio track with Audacity
Configuration for | 
Labels appear under the audio track | 
Configuration for | 
The final result; separate .mp3 files. |
So, I decided to play around with Audacity, and I discovered this extremely useful, yet much overlooked and simple solution. Introduced with Audacity version 1.3.x is a feature that allows you to automatically split an audio track every X number of seconds (or even splitting the track X number of times, based on its length.)
Now I am able "seek" to a certain part in the podcast episode by using the "next track" button in my car's CD player. For example, if I split a 60-minute audio track into 2 minute intervals, I am essentially able to "seek" within the episode every 2 minutes. (Part 0 starts at the 0:00:00 mark, part 1 starts at the 0:02:00 mark, part 2 starts at the 0:04:00 mark, and so on.)
Here is how it's done. Best of all, it's very simple and quick! (Make sure you have at least version 1.3.x of Audacity.)
1.) Launch Audacity. (Consult your system administrator, for this is a very difficult step and could possibly result in data loss, the CPU overheating, or a region-wide black out).
2.) Go to File > Open and browse for and select the audio file. (In my example, I am using a 20-minute podcast. It may take a while to import a large file.)
3.) Go to Analyze > Regular Interval Labels.
4.) Choose "Label interval" for "Label placement method" and then enter the interval (in seconds) for how the audio track should be split into separate files. (Or you may split with a specified number of files by selecting the "Number of labels" method and then entering the number of desired files/splits.) Make sure "Include final label" is set to "No". It does not matter what name you enter for the labels, as you will see why later on. After clicking "Okay", you will notice a bunch of label indicators underneath the audio track.
5.) Go to File > Export Multiple.
6.) Choose the "Export format" and configure it. (In my case, I use MP3, 128 kbps CBR).
7.) Choose "Labels" under "Split files based on". (Do not check "Include audio before first label".) Choose "Numbering consecutively" under "Name files" and type in a name that will be used for the .mp3 files.
8.) Click "Export".
9.) This next part I hate. You have to keep clicking "Okay" for every single audio track, since it wants you to enter tag information for every single file! (I found no way to skip this part and go straight to the exporting process.)
A.) Because 10.) would ruin the alignment on the left-hand side of this post.
B.) As it is exporting, it will keep popping up a different window for each separate file. Just let Audacity do its thing and try not to accidentally cancel the process. This can take a while, depending on the file size and track length of the original source.
C.) Browse to the folder where you saved the files to. You should see a bunch of files numbered sequentially and named according to your prior settings.
D.) Finally, just use you favorite disc burning application and burn the .mp3 files as a data CD. Make sure they are in the correct order before burning.
That's it! Enjoy your easy-to-seek podcast episodes on your CD-RW disc while driving in your car! This tip goes out to all of you! (Yes, all of you: all three of you who actually listen to podcasts with your car's CD player...)
* The drawback to this method is that it re-compresses the audio files, meaning you will get some quality loss, although it is not very noticeable. You might also hear a quick "skip" as it transitions from one track to the next. This should work with Audacity 1.3.x and greater on Windows, Mac, and Linux. If anyone knows of another cross-platform method (preferably quicker and/or does not require re-compression), please do share!
** Yes, I do know about mp3DirectCut, but this is a Windows-only application (unless you use Wine.) I have also heard about using cue sheets, but I think they only work with audio CDs, and not MP3 data CDs.
*** And before I even submitted this post, I found out about mp3splt-gtk, which is a cross-platform program (Windows, Mac, Linux) that is equivalent to mp3DirectCut! Might be something worth looking into, since it appears simple and straight-forward enough. | |
T0rn
Premium
join:2001-05-11
USA
| As a follow up, looks like mp3splt-gtk does a fantastic job! I even prefer its "Silence detection" feature over "normal intervals", since whenever the host of the podcast comes to a pause, it is the perfect time to split the audio track. It may yield more files in the end (same total file size), but it makes for great listening in the car!
The one benefit that the Audacity method brings is that you can convert the multiple audio tracks to a different format, on-the-fly. | |
howie
Premium,MVM
join:2003-04-08
Little Falls, NJ | reply to T0rn
Wow! Thanks for the very detailed and excellent presentation!
I'm sure many will find this useful!  | |
joe785
join:2009-07-13
| reply to T0rn
Very detailed. But it seems that the audio tracks can only be divided into several pieces equally. Recently, I am learning mandarin. I got some listening materials. And I want to split the materials according to the content, not time value. That is, I don't want to split each track into, like 3 pieces equally. Can anyone help? Thanks in advance! | |
T0rn
Premium
join:2001-05-11
USA
2 edits | said by joe785  :Very detailed. But it seems that the audio tracks can only be divided into several pieces equally. Recently, I am learning mandarin. I got some listening materials. And I want to split the materials according to the content, not time value. That is, I don't want to split each track into, like 3 pieces equally. Can anyone help? Thanks in advance! The only difference, in your case, would be to manually add the labels. After loading up the audio file, click on the beginning with your cursor (you can use the Left and Right arrow keys on your keyboard for precise movement of the selection), and then go to Tracks > Add Label At Selection. Keep doing this at the beginning of every section you wish to split.
After you're finished manually adding the labels, you can then proceed the same way as I posted above. It will ask you for tag information for every split file, which you can fill in for each one (or just use the defaults by clicking "Okay" every time it asks.) | |
Boricua65
join:2002-01-26
Puerto Rico
| reply to T0rn
Thanks for this write-up. I'll have to play around with this when I get home as I have one-hour remixes and three-hour remixes which I want to split up.
--
Illegal aliens have always been a problem in the United States. Ask any Indian. Robert Orben
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joe785
join:2009-07-13 |  reply to T0rn
Thanks a million!
Finally, I get a way of doing that. So happy! I will try it asap.
Thanks again! | |
Lou1
| reply to T0rn
This is brilliant, thank you muchly! | |
T0rn
Premium
join:2001-05-11
USA
4 edits | reply to T0rn
Just as an update, in my case, I had to change steps 6.) and D.) for a few reasons.
For step 6.) I prefer to use "WAV (Microsoft) signed 16 bit PCM" instead of "MP3". The reason is because using an MP3 data CD is not compatible with all CD players, and switching between tracks isn't as smooth as with an audio CD. Plus, having the WAV files ready (after exporting with Audacity) means that your burning program will not have to convert them (as opposed to the .mp3 files, which will need to be converted before burning as an audio CD.) The "export" process is also faster when using WAV instead of MP3. Finally, there will be no quality loss with this method.
For step 10.) I burn as an audio CD instead.
Make sure you select "Disc at Once" (DAO) and not "Track at Once" (TAO) in your CD burning program. DAO will place the WAV tracks side-by-side in such a manner that there will be no pause in between tracks. In other words, this is the equivalent to using a .cue sheet on a single track.
Of course, don't forget the delete the exported WAV files when you're all done. Every bit of saved space (even on today's hard drives) goes a long way!
EDIT: For some reason, the "comments" under the upload photos cut off. It might be due to a limited character length for this forum. | |
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