Hi, let me elaborate a little on my previous post.
First I saw the video (thank you again, this brought back memories, I haven't heard this song in many years, likely decades, this was nice for nostalgia though I don't enjoy Indian music) and the bass you refer to is pretty high in frequency in my opinion, it is not "low". Now you say you want bass that isn't loud, so you can just lower the volume, then you add that you wish for it to be room filling. This makes me think maybe you want the bass in the song to be lower in frequency so that it "hurts" the ears less as lower bass tends to be softer on the ears in general and as you go lower in frequency we hear it as "less loud" subjectively. Also due to the subjective nature of low bass in can be perceived as room filling, along with any rumbling/resonating of the items in the room. So if we assume that this is what you want then let's see what we can do.
Now there are two ways that I can think of to make the bass in a source lower than it actually is. Before I get into that, please note that this will be altering the signal, you can't change the source but you can alter the signal output. So this will not be "accurate", just for your information. What you might be asking for is something that is not present in the source, please understand that might be the case. Now the first option is to use the subharmonic synthesizer like I mentioned, this should create notes below the fundamental if I remember it right. If I have it wrong hopefully somebody will correct this. The second option is to use a DSP, what you want to do here is to possibly limit the upper bandwidth of the sub, using a low LPF, say 60Hz and then bump the 30-50Hz region, maybe cut the 60-100Hz region. Further cuts could be made upstream in the midrange and HF to lessen the harshness of the sound/bass, based on the music I assume this will be preferable to make the sound smooth, sweet and less offensive. If the DSP can and you wish to experiment then altering the time aspect, in terms of delay and phase could yield more of what you want. Time distortion often has a unique sound and is something most people do not observe, even if they claim to be experts. You could use both the synthesizer and DSP in conjunction, I think this will give you what you want but it needs to be setup properly. Again this is all based on the hypothesis that you might want lower bass than is present in the source. Hope this helps and if I made a mistake or did not understand what you want, please let me know. Good luck.