Streaming platforms break content into small 2 to 10 second chunks, each encoded at several quality levels. Your player watches your connection speed and switches tiers in real time — dropping resolution when bandwidth falls, climbing back when it recovers.

This is adaptive bitrate streaming, and it is why Netflix rarely stalls on a shaky connection. The encoding matters even more: modern codecs like H.265 compress video by up to 50% versus older formats while keeping the picture sharp, which saves enormous amounts of bandwidth.