How to boost low audio at online videos

If this has been asked before, please point me to the appropriate thread.

I visit a TV station website and then browse the archive to find and watch the episodes of old series. The problem is that most old series of the 90's and 2000's were digitized and uploaded without any editing and the soundtrack audio level is below the middle. This means that it is difficult to hear the dialogues unless you turn up the volume too much. This would not be a problem when watching the episode, but any ad break is deafening loud.

My question is, is there any plugin or other way to automatically normalize the sound (boosting low levels) of online videos? If I download the video, I can then watch with Media Player Classic that has this feature, but I would prefer to watch it online.

PS: Enhanced tab is not available for HDMI audio (watching on TV), so I cannot use Loudness Normalisation. Any other ideas appreciated.

There seem to be clues that you can stream videos with VLC player - not tried it myself.
If so you can use its normalisation feature.

3 Ways to Normalize Sound Volume on Your PC
How To Normalize Volume in VLC

Otherwise:

If you’re watching Netflix or another type of movie streaming on your PC that can’t be watched through VLC, you can also take advantage of Windows’ inbuilt audio normaliser. Open the Control Panel on your PC, click through to Hardware and Sound and then select Manage Audio Devices under the Sound subheading. From here, select the device you’re using and click Properties, then under the Enhancement tab scroll down until you can check the box next to ‘Loudness Equalization’.

Classic Hacks: How To Fix Movies With Really Inconsistent Sound

Thank you for your reply.

There are other ideas in the links posted.

Also consider searching for a suitable browser add-on.
Here's an old one for FF.
vmo audio normalizer – Get this Extension for 🦊 Firefox (en-GB)

@hdmi - I've seen one reference to a 'normalise' button - but I've never actually seen one. (Yes, I've looked at all 3 possible GUIs for it).

Could you post a screenshot of where it actually is, or how normalisation can be done? Thanks.