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Why Videos Are Clear on Your Phone and Blurry Online

Photo: Kim Kardashian West via Instagram

A quick question from social-media superstar Kim Kardashian West:

Great question! Kim is referring to the noticeable dip in video fidelity that happens when you upload a video file to a social-media platform like Facebook or Twitter. Videos often look, let’s say, muddier; less clear than the same video looks when playing the file on your phone.

The reason for this is because of lossy compression. Compression is that act of taking a file, and making it smaller. In lossless compression, the file is made smaller without reducing the quality of the media (there are various ways of doing this through technical wizardry that I won’t get into here). Lossy compression is essentially a compromise — that a slight dip in file quality is worth the smaller digital footprint.

The calculation that social-media platforms make is simple: If the files they are serving up to users are smaller, they will use less bandwidth, and that will keep costs down.

Obviously, smaller files download faster. The faster a service can serve media up to a user, the longer it can keep that user hooked. Even a couple of extra seconds of load time could make a user exit and head elsewhere online. Load times really matter, and platforms have determined that people are more likely to stick around if even low-quality video is already playing.

Compression is the main reason, but there are a couple others. For instance, a slower data connection might result in lower video quality. Most video platforms calculate your data speeds and adjust video quality on the fly. As such, you’ll usually get better video quality over Wi-Fi than you would over a mobile data connection like 4G, the former is usually faster than the latter. The video saved on your phone is stored locally — there’s no need to download anything — but the video you see on social media is streaming from a remote server, and thus, getting shoved through a metaphorical funnel.

And last but not least, there’s the freebooting issue. Freebooting is when someone rips a video and reuploads it themselves, and it’s a vital (and problematic) part of how digital content travels around the web. This leads to a cycle of video, image, and audio files getting compressed not just once, but multiple times. It’s the digital equivalent of copying a VHS so many times that it’s barely watchable.

Combine all of these aspects, and you get video that looks like crap.

Why Videos Are Clear on Your Phone and Blurry Online