How to extract MP3 and AAC tracks from Youtube videos losslessly in Mac OS X, Windows

#1 04-16-2006, 04:09 AM

ffmpeg is a freeware command-line utility (Windows, Linux, Mac OS X). You can use it to extract MP3 and AAC tracks from downloaded Youtube videos.

Unlike converters the following tutorial allows to extract MP3 and AAC audio tracks from FLV and MP4 files losslessly, so you don't lose quality.

How to extract MP3 and AAC tracks from Youtube .FLV videos losslessly in Mac OS X, Windows, Linux using freeware ffmpeg

First of all find out what type of audio is used in the video file:

Code:

ffmpeg -i inputfile.flv

In case of an MP3 audio track you will get something like
Code:
```
Stream #0.1: Audio: mp3, 44100 Hz, mono, s16, 128 kb/s
```
Now you know that MP3 audio is used, so use the following command:
Code:
```
ffmpeg -i input.flv -vn -acodec copy output.mp3
```
In case of AAC audio track you will get something like
Code:
```
Stream #0.1: Audio: AAC, 44100 Hz, stereo, s16, 128 kb/s
```
Now you know that AAC audio is used, so use the following command to convert to M4A file (extract AAC track into M4A losslessly):
Code:
```
ffmpeg -i input.flv -vn -acodec copy output.m4a
```
or use the following command to convert to bookmarkable M4B file (extract AAC track into M4B losslessly):
Code:
```
ffmpeg -i input.flv -vn -acodec copy output.m4b
```