View Issue Details

IDProjectCategoryView StatusLast Update
0001581DCP-o-matic[All Projects] Bugspublic2019-07-07 23:19
Reportercarl Assigned To 
PrioritynormalSeverityminorReproducibilityalways
Status resolvedResolutionopen 
Product Version 
Target Version2.16.0Fixed in Version 
Summary0001581: Burnt-in subtitles sometimes missing from DCP
Description

Content is a MKV and a SRT. MKV has subtitles but they are not being used.

MKV's subtitles finish about 16s before the end of the MKV (let's say at time t). After this point the MKV's decoder reports its position as t forever, since t is found by Decoder::position after it asks the TextDecoder where it is.

This means that the MKV is pass()ed instead of the SRT, so eventually there is a frame of video for which a sub from the SRT has not yet been received.

Additional Information

https://dcpomatic.com/forum/viewtopic.php?f=2&t=1340

TagsNo tags attached.
Branch
Estimated weeks required
Estimated work requiredUndecided

Activities

carl

2019-07-07 21:47

administrator   ~0003381

Can the TextDecoder know that it is "finished" i.e. no more subs will be emitted? I don't think so; here the problematic TextDecoder is being fed by subs muxed into a MKV.

carl

2019-07-07 21:50

administrator   ~0003382

Could FFmpegDecoder ignore subtitles when doing Decoder::position() in the hope that they will be "swept along" by the emissions from video/audio?

carl

2019-07-07 21:51

administrator   ~0003383

We could ignore unused subtitle streams in MKVs but this would just be a sticking plaster and it doesn't solve the underlying problem (and wouldn't solve the case when the MKV's subs were being used).

Issue History

Date Modified Username Field Change
2019-07-07 21:45 carl New Issue
2019-07-07 21:46 carl Description Updated View Revisions
2019-07-07 21:47 carl Note Added: 0003381
2019-07-07 21:50 carl Note Added: 0003382
2019-07-07 21:51 carl Note Added: 0003383
2019-07-07 23:19 carl Status new => resolved
2019-07-07 23:19 carl Target Version 2.14.x => 2.16.0