OK, apparently, there is also a problem with drop vs non-drop frame timecodes. Damn! It's even more difficult than I thought. But thanks again.
Here is the MediaInfo output about the subtitle streams for Thor 2. As you can see, the subtitle streams have a delay of 1001 ms. But all audio streams have no delay.
Code:
General
Complete name : G:\BDMV\PLAYLIST\00800.mpls
Format : Blu-ray Playlist
File size : 1.04 KiB
Duration : 1h 52mn
Overall bit rate mode : Variable
Overall bit rate : 1 bps
[...]
Text #1
ID : 4608 (0x1200)
Menu ID : 1 (0x1)
Format : PGS
Codec ID : 144
Duration : 834ms
Delay relative to video : 1s 1ms
Language : English
Source : 00939.m2ts
Text #2
ID : 4609 (0x1201)
Menu ID : 1 (0x1)
Format : PGS
Codec ID : 144
Duration : 834ms
Delay relative to video : 1s 1ms
Language : French
Source : 00939.m2ts
Text #3
ID : 4610 (0x1202)
Menu ID : 1 (0x1)
Format : PGS
Codec ID : 144
Duration : 834ms
Delay relative to video : 1s 1ms
Language : Spanish
Source : 00939.m2ts
Text #4
ID : 4611 (0x1203)
Menu ID : 1 (0x1)
Format : PGS
Codec ID : 144
Duration : 834ms
Delay relative to video : 1s 1ms
Language : Portuguese
Source : 00939.m2ts
Text #5
ID : 4612 (0x1204)
Menu ID : 1 (0x1)
Format : PGS
Codec ID : 144
Duration : 834ms
Delay relative to video : 1s 1ms
Language : English
Source : 00939.m2ts
Text #6
ID : 4613 (0x1205)
Menu ID : 1 (0x1)
Format : PGS
Codec ID : 144
Duration : 834ms
Delay relative to video : 1s 1ms
Language : French
Source : 00939.m2ts
Text #7
ID : 4614 (0x1206)
Menu ID : 1 (0x1)
Format : PGS
Codec ID : 144
Duration : 834ms
Delay relative to video : 1s 1ms
Language : Spanish
Source : 00939.m2ts
Text #8
ID : 4615 (0x1207)
Menu ID : 1 (0x1)
Format : PGS
Codec ID : 144
Duration : 834ms
Delay relative to video : 1s 1ms
Language : Portuguese
Source : 00939.m2ts
[...]
So, it is strange that you have no delay in your test of Thor2 at 1m25s. If MediaInfo is right, it should be one second and a couple ms.
I'm pretty sure that the drop-frame problem doesn't occur with all BDs, as there is no sync problem with all BDs that I have tried. Perhaps the problem occurs only when hardcoding the subtitles. Anyway, I'll do tests here when I'll have some time...