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Loki Software to Open Source SDL Motion JPEG Library

Posted by Hemos on from the fun-with-graphics dept.

Loki Games has announced that they will be undertaking their 3rd Open Source project, the SDL Motion JPEG Library. SMJPEG creates and displays full motion video with a non-proprietary format created by Loki. It was developed while porting Railroad Tycoon II: Gold Edition. Check out their website for more details. Suffice to say that "among its many benefits, SMJPEG allows for arbitrary video sizes and frame-rates, user-tuneable compression levels, and facilities for frame-skipping and time synchronization," according to Loki.

2 of 55 comments (clear)

  1. Source already available by -+BlueSky+- · · Score: 5

    According to Linuxgames the source code has already been released.

    SMJPEG documentation

    SMJPEG source code

    BlueSky

  2. Re:Motion JPEG? by Paul+Johnson · · Score: 5
    but makes the files 10 times bigger, because you don't do inter-frame compression...

    Bigger yes, but not ten times bigger. I've done some experiments. A 600x400 image compresses down to 15k with some minor artifacts, and 24k with some almost-invisible artifacts. Reduce that to 300x200 and you are looking at 8 or 9k. My experience of watching compressed video is that the motion reduces the visual impact of the artifacts because they keep changing randomly, while the eye tends to track the image. So you should be able to get away with some 15k per frame. Maybe slightly less because these figures include picture headers that would be factored out of MJPEG.

    At 15k per frame and 25 fps that is 375k/sec, or 1.35Gb/hour, which is about twice MPEG-1. Plus sound of course. But radio quality sound only needs about 8k/sec, so we can ignore that for now.

    Has anyone tried doing this in real-time? It strikes me that we might have a DIY version of the TiVO here.

    Paul.

    --
    You are lost in a twisty maze of little standards, all different.