I want to write this blog post, showing you how you can archive MP3s from MP4s. So as an example, my live streams are
recorded via a screen capturing program that saves them in MP4 format, which is a video file format. Well I want to take these live streams and then extrapolate the audio from that video file.
Here is what I use to perform that task. I use what is called Bash on Ubuntu. It is a free tool that you can install on Windows 10.
I would recommend that you use Linux. It will be much faster. You need some type of Linux distribution, ie. Mint, Debian, Suse, etc.
Ubuntu is my preferred distrobution of Linux that's easy to use. So here is the command:
avconv -i example.mp4 -ac 1 -b:a 32k -ar 11025 example.mp3
What I want to do is I want to take the audio out of that mp4 video and then convert it into an mp3 podcast. This command will convert your mp4 video file into an mp3 file. It will extrapolate the audio track from this mp4 file.
You can use this avconv Linux tool for other video formats such as wmv, avi, flv, etc. The above example will create an mp3 file with one channel mono sound, 32 kilobits per second, and 11025 sample rate. You can adjust these parameters to your liking.
Since I mostly just talk on my livestreams, I don't necessarily need stereo sound and a higher sample rate. Also, I can keep my mp3 file sizes to a minimum. This avconv media converter runs much faster on a dedicated linux machine.
For stereo sound you would replace the number one above with a two, for two channels. Also, for stereo sound you would want to record at 128k instead of 32k. Finally, you can change the above sampling rate to 22050, 44100, 48000 or to whatever you would like.