Sunday, September 23, 2018

Fully Decoded UTSC Packet

I released some UTSC packets for people to try and decode, to see if my format could be followed by other people. They contained a still image (instead of video since I don't have a VP9 encoder yet), music, an EPG, and some filecasts containing Bitcoin Cash blocks.

Tech2025 was able to extract the EPG but couldn't get any further. There was another guy, Jess, who he introduced to the format. I was pinged on Discord and asked to share some details. I brought Jess up to speed and provided him with the packets and the format documentation.

To be honest, I did help him a little, like with getting set up with a hex editor and explaining some of the byte structure. However, I let him do most of it so that we could honestly say he decoded it. The deal was that once someone decoded it, I would publish all the details of what was in the packets. I'm going to show what was in the first packet. This post will just describe the first one because the others are similar.

Recall that UTSC packets contain just 1 second of content.
The music is from Golden Alley, created by Nicolai Heidlas and Francesco Rea.

The EPG was a file called EPG0.json. It was contained within a 7-Zip archive compressed with PPMD.

Note: the EPG format is not defined so these are just suggested parameters.

The filecasts were split 7-Zip archives of the latest 3 Bitcoin Cash blocks at the time I created the packets. They were compressed with LZMA2. There is no need for me to share them here.

Finally, I wrote a UTSC parser in Liberty BASIC to show and extract all the information quickly. I didn't release it until after Jess had finished extracting everything.

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