user12511: I would like to "convert" audio to video visualisation (oscilloscope or waveform) sort of like some media players have. 
I read this thread on how to do so with ffmpeg: How do I turn audio into video (that is, show the waveforms in a video)?
I have never used ffmpeg before and having read the previous thread I am still very confused with how to do it. As far as I know, ffmpeg does not have a GUI, so its a bit hard to understand. 
I tried the following code:
ffmpeg -i audio.mp3 -filter_complex "[0:a]avectorscope=s=1080x1080,format=yuv420p[vid]" -map "[vid]" -map 0:a -codec:v libx264 -crf 18 -preset fast -codec:a aac -strict -2 -b:a 192k output.mp4

But the result i get is just a vertical line (the avectorscope does not spread out).

I have made sure that the audio is in stereo and has a high amplitude. I guess there is something I am missing in the code...
Also I would really like to know how I can change the background color from black to something custom.

user12531: The following command shows a video with a waveform of the corresponding audio:
ffmpeg -i input.mp4 -filter_complex "[0:a]showwaves=s=1280x720,format=yuv420p[vid]" -map "[vid]" -map 0:a -codec:v libx264 -crf 18 -preset fast -codec:a aac -strict -2 -b:a 192k output.mp4

I replaced avectorscope with showwaves: avectorscope is for showing the difference between stereo pairs.
Try showcqt,showfreqs,showspectrum for other visualization effects.

12511: <p>I would like to "convert" audio to video visualisation (oscilloscope or waveform) sort of like some media players have. </p>

<p>I read this thread on how to do so with ffmpeg: <a href="https://video.stackexchange.com/q/9644">How do I turn audio into video (that is, show the waveforms in a video)?</a></p>

<p>I have never used ffmpeg before and having read the previous thread I am still very confused with how to do it. As far as I know, ffmpeg does not have a GUI, so its a bit hard to understand. </p>

<p>I tried the following code:</p>

<pre><code>ffmpeg -i audio.mp3 -filter_complex "[0:a]avectorscope=s=1080x1080,format=yuv420p[vid]" -map "[vid]" -map 0:a -codec:v libx264 -crf 18 -preset fast -codec:a aac -strict -2 -b:a 192k output.mp4
</code></pre>

<p>But the result i get is just a vertical line (the avectorscope does not spread out).</p>

<p><a href="https://i.stack.imgur.com/eaO6O.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/eaO6O.png" alt="enter image description here"></a></p>

<p>I have made sure that the audio is in stereo and has a high amplitude. I guess there is something I am missing in the code...</p>

<p>Also I would really like to know how I can change the background color from black to something custom.</p>
 12531: <p>The following command shows a video with a waveform of the corresponding audio:</p>

<pre><code>ffmpeg -i input.mp4 -filter_complex "[0:a]showwaves=s=1280x720,format=yuv420p[vid]" -map "[vid]" -map 0:a -codec:v libx264 -crf 18 -preset fast -codec:a aac -strict -2 -b:a 192k output.mp4
</code></pre>

<p>I replaced avectorscope with showwaves: avectorscope is for showing the difference between stereo pairs.
Try showcqt,showfreqs,showspectrum for other visualization effects.</p>
