Opened 6 years ago

Closed 5 years ago

#10584 closed Bug Report - General (Fixed)

mpeg2 seektable generators are inconsistent

Reported by: J.Pilk@… Owned by: beirdo
Priority: minor Milestone: 0.26.1
Component: MythTV - General Version: 0.25
Severity: medium Keywords:
Cc: Ticket locked: no

Description

mythtv-0.25-283_v0.25_rc_156_g02216ca.el6.rpm fromATrpms

Seektables generated during recording, or by mythcommflag --rebuild, or by mythtranscode --mpeg2 --buildindex, are not the same. I demonstrated this by making MythArchives? of a short recording 'raw' and after running each command, and examining the .xml files created. The mythcommflag version does not include a mark=0 entry and the offsets (byte positions) from both commflag and transcode are then consistently 188 bytes greater than the 'raw' value. Maybe a within-packet offset got counted twice?

This was a recording from dvb-t. I'll check to see if HD dvb-t2 recordings show a similar raw/mythcommflag discrepancy.

raw <recordedseek>

<mark offset="188" type="9" mark="0"/> <mark offset="461164" type="9" mark="30"/>

mythcommflag <recordedseek>

<mark offset="461352" type="9" mark="30"/> <mark offset="812724" type="9" mark="60"/>

mythtranscode <recordedseek>

<mark offset="376" type="9" mark="0"/> <mark offset="461352" type="9" mark="30"/>

Change History (6)

comment:1 Changed 6 years ago by J.Pilk@…

With dvb-t2 HD recording: here the discrepancy in frame numbering is a complete keyframe interval. FWIW the recording was started mid-programme, from the EPG screen.

raw:

<channel callsign="Channel 4 HD" channum="52" chanid="1052" name="Channel 4 HD"/> <recordedseek>

<mark offset="376" type="9" mark="0"/> <mark offset="427512" type="9" mark="24"/> <mark offset="1044904" type="9" mark="48"/> <mark offset="1654400" type="9" mark="72"/> <mark offset="2244720" type="9" mark="96"/>

commflag:

<channel callsign="Channel 4 HD" channum="52" chanid="1052" name="Channel 4 HD"/>

<recordedseek>

<mark offset="1044904" type="9" mark="24"/> <mark offset="1654400" type="9" mark="48"/> <mark offset="2244720" type="9" mark="72"/> <mark offset="2847636" type="9" mark="96"/> <mark offset="3454312" type="9" mark="120"/>

comment:2 Changed 6 years ago by beirdo

Owner: set to beirdo
Status: newassigned

I'll take a look at this.

comment:3 Changed 6 years ago by J.Pilk@…

Thanks for that. This is relevant too. http://code.mythtv.org/trac/ticket/10606#comment:4

comment:4 Changed 6 years ago by sphery

FWIW, we should probably remove one or both of mythtranscode --buildindex and mythcommflag --rebuild (if removing both, the functionality would go into mythutil, instead--since rebuilding the seek data is neither transcoding the recording nor flagging commercials).

comment:5 Changed 6 years ago by J.Pilk@…

comment:6 Changed 5 years ago by Jim Stichnoth

Milestone: unknown0.26.1
Resolution: Fixed
Status: assignedclosed

This is most likely fixed as a result of commits related to #11328. If there are still problems in 0.26 related to the recorder seektable, then it is probably a dup of #11459.

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