https://github.com/alessiomaffeis/xmpng

XMPNG (Differential Motion PNG) is a simple lossless video codec, particularly well-suited for high quality screencasts and screen sharing applications
https://github.com/alessiomaffeis/xmpng

codec lossless video video-codec

Last synced: 11 months ago
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XMPNG (Differential Motion PNG) is a simple lossless video codec, particularly well-suited for high quality screencasts and screen sharing applications

• Host: GitHub
• URL: https://github.com/alessiomaffeis/xmpng
• Owner: alessiomaffeis
• License: mit
• Created: 2015-06-16T16:55:22.000Z (about 11 years ago)
• Default Branch: master
• Last Pushed: 2017-02-21T21:14:38.000Z (over 9 years ago)
• Last Synced: 2025-04-03T22:24:39.906Z (about 1 year ago)
• Topics: codec, lossless, video, video-codec
• Language: C#
• Homepage:
• Size: 3.91 KB
• Stars: 3
• Watchers: 0
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# XMPNG

XMPNG (Differential Motion PNG) is a simple lossless video codec, particularly well-suited for high quality screencasts and screen sharing applications. This is a quick, proof of concept C#/.NET implementation from an old academic project.

The concept is pretty straightforward: the encoder writes the initial **I** frame as a full PNG image, then it writes each subsequent **P** frame as the PNG encoded XOR "difference" with respect of its preceding frame (i.e. P2 = Frame 2 XOR Frame 1).

This method allows to greatly reduce both the inter-frame temporal redundancy, by means of the fast and effective XOR "difference", and the intra-frame spatial redundancy, thanks to PNG's own 2D prediction filter.

![alt tag](http://i.imgur.com/SaEqSrQ.png)

Then, the decoder can reconstruct the exact, original frames by making a XOR operation between each **P** frame and the previous reconstructed frame (e.g. Frame 2 = P2 XOR Frame 1)

![alt tag](http://i.imgur.com/4eBBzYL.png)