The video file is 54min 31s long. And Adobe Encore shows it is 00:54:28:08 (hh:mm:ss:ff, whereas f=frames, not milliseconds)
This is the subtitle information outside Adobe Encore (just to clear the difference), as expected the .srt has 3-decimal miliseconds behind the collon, and the Encore Text Script with 2-decimal frames behind the semicolon:
subtitle.srt VS subtitle.txt (Adobe Encore Text Script (*txt)
1
00:01:01,725 --> 00:01:03,526 1 00;01;01;17 00;01;03;13 Brother?
Brother?
2
00:02:25,763 --> 00:02:28,230 2 00;02;25;18 00;02;28;06 Did you send the raven?
Did you send the raven?
499 499 00;52;47;17 00;52;52;06 I'm Barristan Selmy.
00:52:47,693 --> 00:52:52,263 Kingswatcher from your Father.
I'm Barristan Selmy.
Kingswatcher from your Father.
500 500 00;52;52;09 00;52;57;20 Allow me to accompany your kingswatch
00:52:52,363 --> 00:52:57,834 and I won't let you down.
Allow me to accompany your kingswatch
and I won't let you down.
And now the information how far off the subtitles are by the end of the movie:
Like I said, they start off in sync, so Line 1 and 2 from above are in sync.
But when I get to line 499 and line 500:
Line 499 Is spoken at 00:52:44:20, but shows at 00:52:47:17. (A difference of almost 3 seconds)
Line 500 Is poken at 00:52:49:08, but shows at 00:52:52:10. (A difference of slightly more than 3 seconds)
And here is some information about the videofile. While I doubt that has something to do with this problem...
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.0
Format settings, CABAC : Yes
Format settings, ReFrames : 4 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 54mn 31s
Bit rate mode : Variable
Bit rate : 5 102 Kbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Variable
Frame rate : 23.976 fps
Minimum frame rate : 23.810 fps
Maximum frame rate : 24.390 fps