CEA608 Closed Caption special characters are printed twice

[kvillnv]

[REQUIRED] Content description

Exoplayer has trouble with special characters in embeded CEA608 text track with Dash stream or .ts file.
Tested with exoplayer-demo with all default parameters.
Issue: Characters contained into exoplayer's CEA608Decoder.SPECIAL_CHARACTER_SET are printed in double
We are playing french content and observed the issue on all the Special characters we could test: "à", "â", "è", "ê", "î", "ô", "û"
FYI: Characters such as "é" and "ù" are not affected. I noticed they are not in SPECIAL_CHARACTER_SET array.

Example: "Allons voir où il nous mène." is printed "Allons voir où il nous mèène."

• I have played the same .ts video file in Kodi and other players, the subtitles are correct
• I have extracted the subtitles from the .ts video file and they are correctly written (no duplicated letters)
• Our packager also provides CMAF content to our iOS app which is correct as well

I was unable to create the same issue in any other player than Exoplayer.

[REQUIRED] Link to test content

To demonstrate the problem, I am sending by email a link where you can download:

• A .ts sample with embedded CEA608 closed caption.
• The extracted subtitles in .txt file, where you can see there is no typo.

[REQUIRED] Version of ExoPlayer being used

2.10.2 (bug was already here in previous versions)

[REQUIRED] Device(s) and version(s) of Android being used

Android N , O and P. Any device.

[REQUIRED] A full bug report captured from the device

No bug report

[tonihei]

Ça alors, c'est pas croyable :)

We'll provide a fix for that. The special control character gets repeated, but we don't check for repeated characters after handling it. So it's basically just a wrong execution order.

[kvillnv]

Merci!