Chrome, MSE increasing buffer?

Media Source Extensions is a standard for browser API that is implemented today in all the major browsers via JavaScript functions that are published by the browser.

You will find a good example of a minimal player in the webpage by Nick Desaulniers, and you may download the source for further study.

The major objects taking part in the video flow are best explained via the following diagram:

The major elements whose size you may wish to modify are the MediaSource and the SourceBuffer.

However, if you examined the API calls for both these functions, you would see that, astoundingly perhaps, there is nowhere to be found a buffer-size parameter. Actually, this is by design. Your only option is in your JavaScript player to ask the MediaSource object for buffers and to append them to the SourceBuffer buffer.

In the article Exceeding the buffering quota from 2019, Joseph Medley has examined the question of how much data can the SourceBuffer object contain before it gives an error. His findings per browser were:

Conclusion: The MSE internal cache is programmed into the browser and cannot be modified. The only option is for the JavaScript player to do the caching itself by asking for and appending more buffers to the SourceBuffer object. However, I haven't seen such an option in any of the web players I happened to use.

(The above discussion does not pertain to HTML5 video, for which there is also no parameter for buffer-size.)