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Subtitles synchronization problem when transcoding is on

PostPosted: Sat Sep 04, 2021 1:06 pm
by Snaily
Hi, i have Samsung UE65TU7160UXRU and i have problem with subtitles if i have to use transcoding, DTS audio track inside mkv container for example.
It works fine unless i interrupt it in some way, for example If I start video from where I left off last time, the subtitles would still play from the beginning. I belive i also had problems if i pause\ff, but i can't reproduce it rn.
Is it a serviio or TV problem? I'll provide logs in first case.

Re: Subtitles synchronization problem when transcoding is on

PostPosted: Sun Sep 05, 2021 2:41 am
by atc98092
Are the subtitles within the MKV container, or are they in an external file, such as an SRT file? If I had to guess, it's likely a TV issue, not Serviio. I base that on my experience with DLNA playback with numerous Samsung TVs. They simply don't put much effort in DLNA playback.

I gave up using the Samsung TV interface a long time ago, instead preferring to use external players. I've used Sony media players and Blu Ray players, many models of Roku players and TVs, and the Nvidia Shield. Even with my latest, LG Nano 85 TV, I much prefer using an external player. My favorite is the Shield, as it plays everything without transcoding, and also plays all captions. Roku players work well, unless you're trying to play ripped UHD movies, in which case they can't keep up with the video bitrate. Roku devices also only have a limited number of supported containers and codecs, so transcoding is often required, although sometimes it's only a remux and doesn't take much computer power.

Re: Subtitles synchronization problem when transcoding is on

PostPosted: Sun Sep 05, 2021 9:43 am
by Snaily
Are the subtitles within the MKV container, or are they in an external file, such as an SRT file?

It was embedded in mkv. Extracted them as .srt, turned off embedded subtitles in serviio, no effect, problem is still there.
instead preferring to use external players

Ty for the list, getting external player is my plan b, I still have hopes to fix it programmatically.
I wonder how protocol works, are subtitles streamed to TV or TV just gets file at the start?
Also there is "Enable burned-in subtitles" option in serviio, I assume it should render subs into picture, but it looks like it does nothing for me - i can still see subs on TV side, i mean i can turn them off so they are definetly not in the picture.

Re: Subtitles synchronization problem when transcoding is on

PostPosted: Sun Sep 05, 2021 7:26 pm
by atc98092
Subs embedded in the container are sent through for the player to decode. SRT files are included as a separate stream to my understanding, and the player (if it supports SRT files) then merges the captions into the video. To my knowledge, Samsung supports SRT files. Note that the SRT file must be named accurately for Serviio to include it in the stream. I'm including a link to the page that explains subtitle support further.

https://www.serviio.org/index.php?optio ... icle&id=33

Embedding subtitles via Serviio "burns" the subs into the video stream. This requires the video to be transcoded, even if the media is supported by the player. But again, the subtitle file must be named correctly for Serviio to use it.

Re: Subtitles synchronization problem when transcoding is on

PostPosted: Thu Sep 23, 2021 11:59 am
by Snaily
Sorry for the late reply.
Subs embedded in the container are sent through for the player to decode. SRT files are included as a separate stream to my understanding, and the player (if it supports SRT files) then merges the captions into the video

Well if thats the case it looks like serviio should be responsible for streaming subs from a certain point(i.e. moment i stoped watching last time), but subs allways start from the beginning if video is transcoded, it works fine without transcoding.
To my knowledge, Samsung supports SRT files.

Thats true, i have no problem with srt files.
Note that the SRT file must be named accurately for Serviio to include it in the stream. I'm including a link to the page that explains subtitle support further.
https://www.serviio.org/index.php?optio ... icle&id=33

I've already read this before asking on forum, unfortunately there is nothing that can help me.
And again
Also there is "Enable burned-in subtitles" option in serviio, I assume it should render subs into picture, but it looks like it does nothing for me - i can still see subs on TV side, i mean i can turn them off so they are definetly not in the picture.

The idea was "if it is tv's falt, then if subtitles would be burned into the picture problem should be solved", but it looks like this option doesn't work at all, i mean if subs would be part of the video stream i won't be able to turn them off on tv side. Only checked this option with transcodig on tho, may be "Enable burned-in subtitles" do not work together with transcoding, but I haven't seen that it was mentioned somewhere.