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Posted: 03 Mar 2018, 17:34 

I haven't said anything here in the last month, but I've been busy. I found the new TBC app like the old one failed pretty badly at a lot of real-world signals I tried to throw at it. Originally I started working on improving the code, but I found it seemed to be entirely based around expected values from the NTSC signal specs, and was quite rigid and hard to adapt from that point to be more tolerant of other signals that didn't conform to its expectations. I ended up heading in a different direction and writing something new from scratch. It's still early days, and there isn't any repair process in place yet for really badly damaged sync events, but I've got a workable program now that can take raw composite video signals (such as the one output by lddecode.py) and identify sync events, group into frames, and synchronise lines. There's no colour decoding yet, but here's the kind of raw frame output I get right now on the Fantasia sample I used before:
http://preview.ibb.co/eVVrYS/image.png

And here's a frame of progressive video from Sonic 2, which I couldn't decode previously:
http://preview.ibb.co/jXWgYS/image.png

The next big thing is adding colour decoding, which I'm not really looking forward to, but I'll give it a shot sometime soon. I've put the code up on github at https://github.com/RogerSanders/avtoolkit .

Some of the main advantages this has over the previous decoder are as follows:
-Universal format support (Can decode signals with any number of lines, any line/sync timing, progressive or interlaced)
-Supports any sample type (templated code allows any data type to be used)
-Supports any sample rate (adaptive processing algorithms scale to the length of detected events in the data stream)
-Extensive source comments and cleaner code structure
-Better performance (Efficient algorithms and multithreaded processing gives over 5x speedup on my PC)
-Cross-platform code with no external dependencies (Only Visual Studio projects provided right now for Windows compilation. I'll add a makefile soon for Linux compilation.)

It's far from perfect yet, but the elements are there to build from. If my interest keeps up, I'll split the core processing work out to a library, so a set of thin tools can grow around the common set of code. I'd like to get this to the point where it can decode basically any analog video signal.

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Posted: 26 Apr 2018, 15:18 

=> Updated the list in the first post with info from this thread: best laserdisc players for analog audio?

Julien
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