I am generating an animation in Matlab, composed of simple diagrams. The images are characterized by fine structures, strong contrasts and mostly discrete colors, e.g. there are few-pixels wide black lines, dots or small patches of uniform color, few-pixels high antialiased text, etc. Here's a screen shot of a typical frame:

enter image description here

What changes from frame to frame are the colored patches on the left, the time ("t = "), and the position of the black dot in the right panel.

Using a standard video codec on this which was designed for full-frame moving photographic imagery generates strong artefacts even with weak compression. Without compression however, the video file becomes unmanageably huge.

My question: Is there a video codec that is optimized for this kind of material? If possible, it would be optimal if an encoder is included in ffmpeg, and if there is a decoder (codec implementation) available for Windows.

  • Will need some details: what ffmpeg command did you use to generate the bad looking video? What is the target bitrate or file size you're aiming for? Do you need a codec whose decoder can be freely distributed or is a commercial solution Ok? – Gyan Aug 19 '15 at 5:37
  • @Mulvya, thanks for your comment. bad looking video: I tried H.264/mp4, and increasing the bitrate only helped when the compressed video got almost as large as the original file. file size: my uncompressed video has a size of 25 GB, which cannot e.g. conveniently transferred via internet. As size below 500 MB would be nice. Decoder: Optimally it would be something that can be freely distributed, e.g. something that VLC supports. – Apart from the problem I'm facing right now, I'd be interested in some general pointers in how to deal with this kind of material. – A. Donda Aug 19 '15 at 15:16
  • I made some progress myself and will post a tentative answer soon. I'd be very interested in comments on how to improve upon that. – A. Donda Aug 19 '15 at 15:16

I read up a bit and made some experiments with lossless codecs, getting decent results. I'd be interested in comments on this, especially if there are lossless or lossy alternatives that I overlooked.

I tried the following codecs / formats in ffmpeg:

  • Lossless Motion JPEG2000 / AVI

    ffmpeg -i test.avi -vcodec jpeg2000 -strict -2 -pred 1 test_jpeg2000.avi

    compression ratio 19.59%

  • Lossless VP9 / WebM

    ffmpeg -i test.avi -vcodec vp9 -lossless 1 test_vp9.webm

    compression ratio 0.52%

  • HuffYUV / AVI

    ffmpeg -i test.avi -vcodec huffyuv test_huffyuv.avi

    compression ratio 37.42%

  • Lossless H.264 / MP4

    ffmpeg -i test.avi -vcodec h264 -qp 0 -preset veryslow test_h264.mp4

    compression ratio 0.53%

Since HuffYUV did not perform well, I excluded it from further tests.

I then tested playback support on Linux and Windows, trying mplayer, xine, vlc, chrome, and firefox on Linux (Debian testing) and vlc, windows media player, chrome, and firefox on Windows (8.1). I included browsers because WebM is specifically designed for web video. Results:

  • Lossless Motion JPEG2000 / AVI

    plays on Linux with mplayer

  • Lossless VP9 / WebM

    plays on Linux with vlc and chrome and on Windows with chrome and firefox

  • Lossless H.264 / MP4

    plays on Linux with mplayer, vlc, and chrome, and on Windows with vlc and chrome

That a video "plays" means it is supported by the player out of the box, and playback is correct. I found several cases where the video was "supported" but playback was buggy.

Though Lossless VP9 has the best compression ratio (by a tiny margin), for the time being I decided to use Lossless H.264 because it has better playback support.

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  • Have you looked into H.265 (aka x265)? I've never encoded with it, but the results look very promising. Animated video compresses about 50% more than H.264 (results will vary of course). The quality is sill phenomenal. Playback support will probably be worse, since its a newer codec. – Doug.McFarlane Aug 19 '15 at 19:11
  • I am having good results with .flv and codec On2 VP6 in Adobe Media Encoder. Roughly 200 Mb for 40 minutes of 640x480 1fs slideshow – Rho Phi Feb 27 '18 at 18:00
  • Probably not relevant anymore but what about the PNG-based formats APNG and MNG? And what about WebP? – Christian Dec 5 '19 at 0:40
  • I haven't really looked into any more it since then. If I remember correctly, I considered MNG, but it never really got off the ground. I hadn't heard about APNG. And I didn't know that WebP supports lossless animation. – A. Donda Dec 5 '19 at 2:15
  • @Christian, this littlesvr.ca/apng/gif_apng_webp5.html might interest you. If you happen to look into this further, I'd welcome an alternative answer! – A. Donda Dec 5 '19 at 2:16

If you're OK with formats requiring proprietary encoders, I suggest you check out RealVideo. I haven't been using this format for a while, but I remember 10 years ago I could compress DVD cartoons into < 500 MB RMVB files with very little quality loss, while XviD files of similar bitrate were extremely blocky.

I suppose your MATLAB animation will be similar to cartoons: few colors used, sharp borders between colors, only a small part of the frame actively changing, etc.

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