How do I calculate maximum video size to be streamed smoothly on a limited bandwidth

1

I mean, I'm gonna put up a video on my website, but the target audience will probably have slow internet connections (500kbps to 2mbps). So my video editor allows me to tweak the video's quality in order to reduce size, but I don't want to lose any more quality than what is really necessary.

The video is 5 minutes long, if I set it to maximum quality the file goes over 260 megabytes, if it's 50% quality, the file is surprisingly 82 megabytes, if I keep on reducing quality the file size drops dramaticaly. Assuming a 1mbps download speed, what would be the maximum file size that the video could have in order for it to run entirely at once, no freezing, if the whole bandwith is available for the video.

How can I calculate that based on file size, the video's duration and the download speed?

Delta

Posted 2013-10-26T22:51:14.130

Reputation: 145

1"Assuming a 1mbps download speed..." -- I'd guess a video file size around 37MB transmitted over 5 minutes would have an average bitrate of 1Mb/sec. You need to find a tool or video player that reports actual bitrates. – sawdust – 2013-10-26T23:03:40.060

I'll look into that – Delta – 2013-10-27T02:54:57.793

Answers

2

First, there is a difference between quality and resolution. Be sure you adjust both independently (you don't need to stream a 4K video at 10% quality; you'd be much better to stream a 480p video at 80% quality).

Second, depending on the compression or video container you're using, the quality and/or resolution could vary significantly. You're best to decide on a modern container/encoding or offer up multiple versions of your video (e.g. an .mp4 streaming in HTML5 and a flash-based .flv video, or at least the HTML5 stream).

Last, it's extremely inefficient to determine the resolution/compression based on percentage calculation. Most modern video editors (Final Cut, Adobe Premiere) allow you to export at a target bitrate, and will let you adjust both resolution and compression to meet that target bitrate.

  • Video tutorial for Premiere Pro adjusting quality/bitrate
  • Final Cut Pro will have similar tutorials hanging around the internet; a simple google search should find the information for you.
  • If you're not using those two, you should still be able to search for targeting a particular export bitrate.

brandonscript

Posted 2013-10-26T22:51:14.130

Reputation: 536

Yes, I'm using camtasia 8. There is a slide bar labeled "quality" I'm really not sure what it does exactly in order to reduce size, but I do notice a smaller resolution, like the video got stretched, though the actual resolution remains the same. The video is mp4 but I was gonna put it on a flash app to play. I'll check if camtasia has this bitrate option. Thanks – Delta – 2013-10-27T02:58:09.200

1

This should show you how to do that with Camtasia: http://support.brightcove.com/en/video-cloud/docs/exporting-high-quality-source-file-using-camtasia-mac

– brandonscript – 2013-10-27T03:19:31.683

Asked: 2013-10-26T22:51:14.130

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Active: 2013-10-26T22:58:47.070