if it's just an mp4 or webm and you have a direct link you can get it so long as the site doesn't ask for credentials or anything. if they stream you any of the data there's a way to get the file somewhere besides you browser's temp directory. if they really didn't want you to have the data, the page wouldn't give you a link and they wouldn't send you any data to begin with. actual strong copy protection is on media where you already have the files because the IP owner has to restrict you locally- that's why HDMI and Displayport can be such bitches to deal with.
plenty of sites exclusively stream things (TS/HLS etc), in which case you can download or write a browser extension. one example is video downloadhelper (and its optional companion program) for firefox but I can't guarantee its safety cause I didn't write it. this extension will let you download any videos that will play on your browser. if your browser has an option to show networking or memory per-page you'll also see that the stream comes in as a bunch of files and those can be individually downloaded and edited together but don't waste your time doing that manually.
also you complained about quality degredation which is pretty stupid. after the camera sensor gets the light, image quality is butched several times before the file ever reaches you. first, almost every camera on the market has a compression scheme favoring luminance (color data is thrown out, usually 2:1:1 or something), second, porn studios don't capture video in raw formats (except maybe for still images) they'll use a reasonably heavy compression like everyone else that doesn't have a bunch of tape drives for storage (actually big porn studios might use tape drives for backup but my guess is they'll buy cloud storage cause they're shooting enough data to be uploaded. this is a guess though don't base your thesis on it…) third, you're not seeing the original files anyway, the porn studio edits everything to length and probably did some basic levels and if you don't have a premium account with them they're 99% serving you a lower resolution file than the source, maybe even lower framerate. once their video guy renders the web version they've just stripped maybe 90% of the filesize off. THEN fourth the host website might have compression of their own to even further reduce how much data they have to send. then fifth, depending on the parameters in the file link you might accidentally be requesting a lower quality version of the file (dunno if this happens with video but for images you'll notice there can be a resolution in the link and if you remove that from the link you'll DL the source). so yeah your ugly tattoo whore has been wrung through compression several times, enjoy wanking to the visible compression between 8x8 pixel blocks and if you zoom in a bit, you'll clearly see the horizontal and vertical content cause over 2/3 of the AC values in the quantization matrix (from the bottom right) are 0. heck, in the OP image I bet any blocks within any of those color stripes on the wall are just a few AC values, maybe even just the DC! not sure how the priority works for video though, I mostly know about jpg.
I don't do anything related to this as a professional and haven't actually studied the literature so I don't actually know what the fuck I'm talking about but hopefully enough info is accurate enough to help/be interesting.
also brave is shit and no accessible browser actually respects your privacy
