Chapters Previews Missing for Some Episodes

[Grimmer 15]

Here is an interesting one for you...

Some episodes are missing the chapter previews (so you can't start playing at the chapter directly).

vs

I see this entry in the Emby Log:

However, there is no chapter that exists outside the runtime (00:43:36.65)...

The end time of chapter 12 is 00:43:36.572, which is still within the runtime.

At first, I was planning to delete the offending chapters, but when I looked into it there were none.  Maybe I can just delete the last chapter?  Is there a better way to fix the error so Emby can acquire the chapter previews normally?

 

 

[Luke 42077]

Hi, yea we’ll have to add more logging to see what values those are being based on.

[Grimmer 15]

One thought I had was it being a rounding issue when converting frames to seconds (or vicevesa).  As it turns out, the video is 23.98 fps.  If you add 1 frame (displayed twice), the end time becomes 43:36.655 seconds, which to a computer is out of bounds if ffprobe is reporting it as 43:36.650 and dropping the trailing 0 (it appears from the other numbers it is using 3 digits of precision).  However, the end of the chapter is 2616.572, so there shouldn't be an extra frame unless it is a "starts at 0" vs "starts at 1" issue in the chapter image extraction routines.

(2/23.98) + 36.572 = 36.655

[Grimmer 15]

Using ffmpeg, I updated the end point of the last chapter for the offending episodes by subtracting 83ms.  They all successfully pulled the chapter images.  Seems it was likely choking on the end point of the last chapter for those few episodes.