document fileformats

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+== TS FILES ==
+
+TS files are plain recordings, including PMT and PAT.
+
+They don't have a private header. 
+
+== .meta FILES ==
+
+.meta files have currently 4 lines:
+
+<service reference>
+<name>
+<description>
+<recording time>
+
+
+== .ap FILES ==
+
+Stored offsets and PTS values. They are collected while recording. Only 
+GOP starts are stored.
+
+File format is network-ordered (i.e. big endian), each entry contains
+two 64 bit values (PTS, offset).
+
+PTS values are not corrected (i.e. they aren't zero-based), offsets are
+relative to the beginning of the file (or first file, when we implement
+splitting)
+
+== .cut FILES ==
+
+Also network ordered, they contain a 64bit value (PTS) and 32bit value
+(type) for each cut. (If you want file offsets, use the .ap file to look up
+the PTS values.)
+
+Type is:
+
+0 - 'in' point
+1 - 'out' point
+2 - mark
+
+If the first 'out'-point is not preceeded by an 'in'-point, there is an 
+implicit 'in' point at zero.
+
+If the there is no final 'out' point, the end-of-file is an implicit
+'out'-point.
+