[FFmpeg-devel] FATE Sub-CC Test

Chris Landry chris.landry at vidyard.com
Wed Jan 4 19:16:37 EET 2017

I submitted a patch that failed a FATE test a while back. The patch changed
the time position of subtitles.

I have finally been able to take a look at the test (fate-sub-cc), and I
believe the test is incorrect.

It is looking for the following cues:

Dialogue: 0,0:00:12.36,0:00:40.83,Default,,0,0,0,,{\an7}{\pos(38,44)}({\i1}
inaudible radio chatter{\i0} )
Dialogue: 0,0:00:40.83,0:00:59.07,Default,,0,0,0,,{\an7}{\pos(38,28)}({\i1}
inaudible radio chatter{\i0} )\N{\an7}{\pos(38,44)}>> Safety remains our
number one

So the captions would be visible from 0:00:12.36 - 0:00:40.83 and
0:00:40.84 - 0:00:59.07.

With my patch, these timings are significantly changed to 0:00:00.83 -
0:00:02.97 and 0:00:02.97 - 0:00:04.34.

I ran the same video through ccextractor -- which produced correct captions
on videos that produced incorrect timings on captions without my fix -- and
the timings were not close to the ones we are currently testing for:
0:00:01.033 - 0:00:04.399 and 0:00:04.401 - 0:00:05.198.

Before I update the test and resubmit my patch, I wanted to know if anyone
had a reason for the difference here. I don't want to just assume the test
is wrong when I might just have a misunderstanding.


More information about the ffmpeg-devel mailing list