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Subtitles going out of sync when transcoding sound


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#1 psxlover OFFLINE  

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Posted 21 March 2020 - 10:23 AM

I have a series with DTS audio on which Emby (correctly) decides to transcode the audio when playing it on my Samsung TV through the app (although in dashboard it appears as direct streaming, not sure if that is intended).

 

Playback seems to be fine, until I seek forwards/backwards, which causes the subtitles (.srt) to go out of sync.

Also if I stop the video (not pause), and then resume from where I left of, the subtitles start out of sync as well.

When resuming, the subtitles seem to start counting time immediately when I resume, so they are ahead of the video based on how much time the loading wheel has being displayed.

If I start the video from the beginning the subtitles are in sync, no matter how much time the loading takes.

 

It doesn't happen 100% of the time, I may move a couple of times without the subs going out of sync, and while testing I saw that sometimes resuming may start with the subs in sync as well.

Also it may not be a subtitle issue per se, it seems when I stop the video, it stops to where the subtitles where and not where the video was, so i seems more like the app's time is out of sync with the video.

 

 

(Hope I didn't forget something, this is the second fourth time I post this, seems like the first time I tried the post was lost)

 

Emby server: 4.3.1.0

Samsung app: 1.0.76

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#2 psxlover OFFLINE  

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Posted 21 March 2020 - 10:24 AM

Seems like putting an image directly into the post I was being redirected to the top of the board with my post getting lost...

 

Edit: I put the image as an attachment

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Edited by psxlover, 21 March 2020 - 10:26 AM.


#3 FrostByte OFFLINE  

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Posted 21 March 2020 - 02:30 PM

When it says direct streaming it is converting audio only (video is not being converted).  So that is correct.  Direct play is when video and audio are not converted.


Edited by FrostByte, 21 March 2020 - 02:31 PM.


#4 psxlover OFFLINE  

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Posted 21 March 2020 - 02:55 PM

 

Direct streaming
The media is compatible with the device regarding resolution and media type (H.264, AC3, etc.), but is in an incompatible file container (.mkv, .avi, .wmv, etc.). The video will be re-packaged on the fly before streaming it to the device.


Direct Streaming a file uses very little processing power without any loss in video quality.

 

The text should be changed to reflect that then, since it seems to imply that when direct streaming the issue is the container, which is not the case here since the issue is the audio is being transcoded ;)


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#5 Luke OFFLINE  

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Posted 06 April 2020 - 02:17 PM

Yes we need to improve that display. Thanks for the feedback.



#6 psxlover OFFLINE  

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Posted 06 April 2020 - 02:20 PM

What about the original issue (the subtitles/video getting out of sync).

Were you able to reproduce it?



#7 Luke OFFLINE  

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Posted 13 April 2020 - 02:33 PM

Is it a full transcode or just a remux with a video stream copy?



#8 psxlover OFFLINE  

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Posted 13 April 2020 - 02:39 PM

It says it is direct streaming, and there is no buffering (the server usually can't handle transcoding), so I guess only the audio is modified, and the video is simply copied.



#9 Luke OFFLINE  

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Posted 13 April 2020 - 04:15 PM

Ok so yes i can confirm this is only when stream copying the video. It's just a consequence of the way we segment the video as part of the delivery process. Ultimately we're going to have to segment the .ass subtitles together with the video as part of the same process, but that will require new development to accomplish that. We already have this capability for plain text subtitles, but for .ass/.ssa it will be a new thing. We will get there.


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#10 psxlover OFFLINE  

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Posted 13 April 2020 - 04:58 PM

I run into this issue when using .srt subtitles, not .ass subtitles (don't have any video with DTS audio and .ass subs to check if the same issue happens there as well).



#11 Luke OFFLINE  

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Posted 13 April 2020 - 05:01 PM

Can you attach the ffmpeg log? thanks.



#12 psxlover OFFLINE  

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Posted 18 April 2020 - 12:10 PM

Sorry for the delay.

 

Not sure if it is visible, after a couple of minutes I skipped forward once, and after a few seconds I went backwards.

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#13 Luke OFFLINE  

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Posted 29 April 2020 - 10:53 PM

Ok thanks for the info.I know why this is happening.






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