MpegMetadata

For editing metadata of HDHomeRun programme (.mpg) file.

The first 12032 bytes appear to be given over to 64 x 188 byte frames which contain JSON formatted metadata.

Each frame starts with a four-byte delimter and these are slotted into the JSON, so we need to:

• strip out the frame delimiters
• strip off the 0xFF padding characters
• Convert to string (ASCII? UTF8?)
• deserialise JSON

Assembly is reverse of disassembly!

The frame delimiters seem to incorporate a sequence counter in fourth byte (last 4 bits?) that starts at 0x10, counts up to 0x1F and repeats.

Diagrammatically, it sort of looks a bit like this:

[xxx0] [...json...js]
[xxx1] [on...json...]
[xxx2] [json...json.]
[xxx4] [..jsonFFFFFF]
[xxx5] [FFFFFFFFFFFF]
...up to 12032 bytes, then rest of file...