Y some video streams faster than others?

Discussion in 'Apple TV and Home Theater' started by aygwm, Nov 17, 2010.

  1. aygwm macrumors member

    Jul 4, 2008
    I'm sure we've all observed different pieces of video, (for example Netflix or video podcasts) aren't uniform in terms of when they start playing. For example, some video seems to start right away, others need as much as 1/3 of the content downloaded before the video starts.
    I'm a clueless moron, so can someone enlighten the rest of us why this is so? I think it has something to do with the encoding process, and a preference telling the file how much to download before playing. Is that so? And is there anyway to override that preference? And for those who create and encode video, what's the best setting for start time, provided there is such a preference...
  2. waw74 macrumors 68030

    May 27, 2008
    the delay in the start is due to buffering.
    You video player starts the download, and it looks at the size of the file, and your speed.
    If it's a 45 minute video (typical hour long show without commercials), and the player thinks it will take 60 minutes to download, it will start playing after you've been downloading for about 15 minutes, so that the amount you've watched never catches up to the amount you've downloaded.

    If it's a lower quality video (smaller file) and your player thinks it will take 30 minutes to download, it will start up almost immediately. although it will get a bit ahead just in case of network congestion.

    if your watching did catch up to the downloading, you'd have to pause in the middle to let the download get ahead of you again, so probably not something you'd want to override.

    If you're on a cable modem, your available bandwidth probably changes over time, in the evening when everyone is just home from work, and on the computer, it will be slower, late at night, it will be faster. and everyone's internet connection is different speeds, so the start time is not really a set thing.
  3. aygwm thread starter macrumors member

    Jul 4, 2008
    That sounds logical...but...
    Assuming the speed is constant, I find many one hour videos load instantly, others take forever. It's clear some are programmed/encoded to only start after a certain percentage has been buffered. Some seem to require 1/3, others not.

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