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Videos recorded on the iPhone are huge. I don't know where I'm supposed to store those videos. Even with 1TB of storage, I'd run out of space if I regularly recorded & stored these huge files. Also, they're cumbersome to transfer and stream.

Why are they so big anyway, and is there anything that can be done about that?

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  • a full HD movie is > 500 Mb, more like 1GB and up. So what file size do you have. The video size depends also on Video format type, ia the Flash Video is smallest file size.
    – Ruskes
    Sep 18, 2014 at 16:40
  • Yeah, I was probably wrong in specifying the exact length of the video...4-minute is just a random number. I'll edit.
    – M.K. Safi
    Sep 18, 2014 at 16:42
  • If you now (2+ years after your question) have an iphone 6 or 7 running at least iOS 9, then you can go into settings and reduce the default video quality to 720p and thus reduce the file sizes significantly
    – MilkyTech
    Jan 27, 2017 at 21:39

4 Answers 4

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The answer boils down to how much work the compression algorithm can do to squeeze the file down, and how much quality loss you are willing to tolerate.

Dark Knight on Blu-ray uses VC-1 encoding at 24Mbps, and it's around 27GB on disk. Good thing BDs have so much room! The goal is to give really good quality.

The iPhone encodes things around 17Mbps (according to the file I just checked) using h.264 with the [email protected] profile. It has to encode things in real-time because it can't stream the raw video to flash. Doing things in real-time limits the amount of work the compressor can do and results in higher file size than slower compression. The iPhone could probably choose to degrade the quality of the video in order to get smaller files, but since you can never get quality back, it makes sense to keep quality there at the beginning.

The BD rips you're talking about have two things in their favor. One is that people are willing to accept a much lower quality than the BD in order to shrink the file size. Also, they have plenty of time to compress the files, so they can easily compress at half or quarter real time. That lets the compression algorithms find a lot more ways to shrink the file size without degrading quality.

If you want to store the iPhone videos yourself for later viewing, you can certainly transcode them yourself and shrink them. You probably would not want to use the results for a television ad but they would be perfectly good for keeping memories.

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  • A two minute video of mine recording a computer screen is over 200 MB? That makes video basically unusable.
    – Anthony
    Mar 27, 2016 at 1:08
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HD Videos take up lot's of space. iPhone 5 Video's are going to be in the neighborhood of 120MB - 180MB per minute (depending on compression). Some apps will allow you to record at lower resolution then 1080i if space is an issue.

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  • Okay, but a movie like the Dark Knight for example is 152 minutes long. If the full HD version of the movie had the same compression as the iPhone it would be around 18GB, but you can actually download a Blu-ray rip that is only 3GB. Why can't the iPhone have compression like this?
    – M.K. Safi
    Sep 18, 2014 at 16:38
  • The "Blu-ray rip" is likely highly compressed. If you'd like to compress your iPhone videos, you may, just download Handbrake or some other compression utility, and shrink your video as much as you want.
    – sdmeyers
    Sep 19, 2014 at 14:18
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I believe the answer he is looking for lies in the amount of processing power that an iPhone or other device would need in order to:

  1. capture video
  2. compress the captured video in realtime to a format and settings that would result in those smaller "compressions"
  3. write it to disk

The iPhone has plenty of processing power to capture the video and write it to disk, but it would be difficult, if not impossible for it to capture video, compress it to an extremely efficient, and small file size, and write it to disk in realtime.

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just FYI, one workaround I've discovered for sharing large videos direct from the iphone: Don't start at the video. Just write and email. When ready, hold your finger down in the body of email. instead of copy and paste, go to the options to the right, and you'll have "insert photo or video" . then you can go to your camera roll, and pop any video in, and it will be compressed to %10 of it's original size, and fine for viewing on tiny screens.

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