[mythtv] What is the value in the MARK field in recordedmarkup

[Chris Pinkham]

* On Tue Jan 30, 2007 at 05:49:24PM -0800, Michael Drons wrote:
> I am trying to understand the MARK field in
> recordedmarkup.  What does the value in the database
> represent?  I have searched high and low for what this
> value is, I assume it is an offset for the MPEG file,
> YES?

There are several different types in the recordedseek
table.  These are defined in libs/libmythtv/programinfo.h

Type 6 indicates that the mark is a GOP start
and the mark value is the keyframe number, so the first
keyframe in the recording is mark 1, the second is mark 2,
etc..  In order to know where to seek to, you need to know
the keyframe distance.  If you want to seek to frame 1502
and the keyframe distance is 15, then you need to seek
to the 100th keyframe and then go forward 2 frames.  This
is used for recordings made from ivtv cards.

Type 7 is for Myth's Nuppel .nuv files and is the keyframe
number as well.  These are treated similar to the type 6,
but they start at 0 instead of 1.

Type 9 is used for recordings made from the dvb, hdtv,
firewire, etc. recorders and for these records, the mark
field indicates an actual frame number.  The type 6
records will go away eventually as we are wanting to migrate
to using type 9 for the ivtv recorder as well.  These are
0-based as well.

Here's are a few samples from my recordedseek.

+--------+---------------------+------+---------+------+
| chanid | starttime           | mark | offset  | type |
+--------+---------------------+------+---------+------+
|   1032 | 2007-01-30 01:00:00 |    1 | 0       |    6 |
|   1032 | 2007-01-30 01:00:00 |    2 | 206848  |    6 |
|   1032 | 2007-01-30 01:00:00 |    3 | 376832  |    6 |
|   1032 | 2007-01-30 01:00:00 |    4 | 548864  |    6 |
|   1032 | 2007-01-30 01:00:00 |    5 | 718848  |    6 |

+--------+---------------------+------+---------+------+
| chanid | starttime           | mark | offset  | type |
+--------+---------------------+------+---------+------+
|   1008 | 2003-05-13 18:45:00 |    0 | 620     |    7 |
|   1008 | 2003-05-13 18:45:00 |    1 | 611555  |    7 |
|   1008 | 2003-05-13 18:45:00 |    2 | 1145067 |    7 |
|   1008 | 2003-05-13 18:45:00 |    3 | 1659270 |    7 |
|   1008 | 2003-05-13 18:45:00 |    4 | 2156282 |    7 |

+--------+---------------------+------+----------+------+
| chanid | starttime           | mark | offset   | type |
+--------+---------------------+------+----------+------+
|   2011 | 2007-01-16 20:00:00 |    0 | 0        |    9 |
|   2011 | 2007-01-16 20:00:00 |   15 | 462292   |    9 |
|   2011 | 2007-01-16 20:00:00 |   30 | 1090964  |    9 |
|   2011 | 2007-01-16 20:00:00 |   45 | 1821156  |    9 |
|   2011 | 2007-01-16 20:00:00 |   60 | 2542136  |    9 |

--
Chris