A 4 min 1080p30fps video taken with my phone camera is 518MB, While a 12 min 1080p30fps video ripped from youtube is 341MB, both are using mp4 h.264 as codec and the youtube one isnt of lower quality, so why this big difference?

  • tonyn
    link
    fedilink
    arrow-up
    30
    ·
    9 months ago

    Because you can compress video without reducing the resolution, codec, or frame rate. When a camera records two green pixels: it records (green pixel) (green pixel). When the video is compressed, it changes to (two green pixels) which takes up less storage space but retains the same information. Compression is computationally expensive, which is why cameras typically don’t do it on the fly.