Fire TV subtitles at wrong time after resume

[fuzzthekingoftrees 10]

When I play this file from the beginning the subtitles are fine. When I resume then the subtitles are out of sync. The subtitles appear a couple of seconds ahead of the audio.

This only happens on the Fire TV, no problem on my Shield.

I've seen this with other files I think only when ffmpeg is involved. Usually stopping and starting the video fixes the sync but in this case it's consistently out.

 

I've attached log files. I only played the file once but there are two ffmpeg remux logs. I've also uploaded debug logs from the app username fuzz.

 

embyserver-63665911430.txt

ffmpeg-remux-130d87c8-bdad-4bc6-98b9-cef0c2e9ba47.txt

ffmpeg-remux-999f4e03-6954-4941-875d-dc2cc325ae64.txt

[ebr 14913]

I'm not sure what is falling down here.  It is an external subtitle stream that we are having our server feed directly to the player.  Perhaps the timestamps in the video are incorrect when we seek it..?

[Luke 37071]

Yea if you play from the start, and then seek, does this also happen?

[fuzzthekingoftrees 10]

If I start the video at the beginning and the seek the subtitles stay in time as long as the location I'm seeking to has already been transcoded. If I start the video at the beginning and then jump to near the end I get the same issue with the subs being out.

I tried resuming the video and then pausing. Then I located the same timestamp within the file in mpc-hc and it was a different frame. The timestamp indicated in the Fire TV app is out which is why the subtitles are out.

I also set my max bitrate low to force emby to do a full transcode. This time the subtitles were in sync.

 

So to summarise

The issue occurs because the timestamp the Fire TV app sees is incorrect

The issue only occurs when the video stream is copied and the audio is transcoded

The issue only occurs when ffmpeg is asked to skip to a position in the video