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Direct Stream transcoding video if PGS subtitles are used


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#1 Xorp OFFLINE  

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Posted 03 January 2019 - 03:54 PM

Previously, if I played a Blu-ray mkv remux with PGS subtitles, the Emby Android app would direct stream everything (which it still does if I have no subtitles or SRT subtitles selected), but after a recent update it's transcoding the video if I turn on the PGS subtitles. It used to Direct Stream the PGS subtitles. This over a gigabit LAN to a Shield. Same thing is happening to a Roku.

 

Log: https://pastebin.com/nzL61MPh


Edited by Xorp, 03 January 2019 - 04:05 PM.


#2 ebr OFFLINE  

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Posted 03 January 2019 - 06:25 PM

Hi.  This is due to the audio being multi-channel FLAC.  That needs to be converted and, once that happens, the only thing we can do with PGS subs at this time is burn them in.



#3 Xorp OFFLINE  

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Posted 03 January 2019 - 09:29 PM

This is on my local LAN. The audio doesn't need to be converted since the receiver supports up to 24/192 PCM. The app used to decode and output to the receiver as PCM.


Edited by Xorp, 03 January 2019 - 11:52 PM.


#4 Luke OFFLINE  

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Posted 04 January 2019 - 01:04 AM

Can you please submit an in-app log? thanks.



#5 Xorp OFFLINE  

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Posted 08 January 2019 - 09:23 PM

Do you mean from the app on the Shield? How do I do that?

 

Here's the stats for nerds from the Shield:

 

jG33KnJ.png



#6 Luke OFFLINE  

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Posted 09 January 2019 - 12:16 AM

Instructions can be found at the bottom of this page here:

 

https://emby.media/c...port-a-problem/

 

Thanks !



#7 ebr OFFLINE  

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Posted 09 January 2019 - 11:34 AM

I already know why this is happening.  The player in the app does not support multi-channel FLAC in a video file right now.  So, it needs to convert that and, once that is the case, the only way to deliver the PGS subs is to burn them in.  External text-based subs or a compatible audio track (almost anything other than FLAC) would eliminate this issue.



#8 Xorp OFFLINE  

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Posted 09 January 2019 - 09:18 PM

This must be a new bug? I've been playing FLAC 5.1-7.1 / AVC / PGS / MKV files for over a year in the Emby Android app with no problem.


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#9 h.buckle OFFLINE  

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Posted 10 January 2019 - 05:06 AM

It was previously reported here https://emby.media/c...c-audio-broken/



#10 ebr OFFLINE  

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Posted 10 January 2019 - 12:20 PM

This must be a new bug? I've been playing FLAC 5.1-7.1 / AVC / PGS / MKV files for over a year in the Emby Android app with no problem.

 

Can you provide a sample file that you know used to direct play?



#11 thegrunge OFFLINE  

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Posted 17 February 2020 - 07:02 PM

I get the same problème when I used pgs subtitles the video is transcode and cut every 10 secondes. The audio format of my files are on AC3 5.1 and if I download others subtitles from emby that’s ok. I try the same file on my plex server and it’s direct play

 

EDIT: I unchecked Allow caption extraction on the fly and it works 100% better!

 

 


Edited by thegrunge, 17 February 2020 - 08:25 PM.


#12 Luke OFFLINE  

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Posted 17 February 2020 - 11:04 PM

That setting won't affect pgs because we don't extract pgs anyway.

#13 thegrunge OFFLINE  

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Posted 17 February 2020 - 11:08 PM

yet it changes everything for me into a roof case. I will send a comparison video but already we can see the difference in bitrate. I think he try to extract pgs and it fuck everything.

And thing to see is that the bitrate is constantly adjusting in transcoding. I send video tomorrow

Edited by thegrunge, 17 February 2020 - 11:25 PM.


#14 Luke OFFLINE  

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Posted 17 February 2020 - 11:31 PM

I can promise you it does not, but if you're happy, we're happy.

#15 thegrunge OFFLINE  

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Posted 18 February 2020 - 05:31 AM

I redid tests and indeed this function does not change anything. Simple circumstance which makes that the bitrate is higher than the days before in video transcoding caused by the PGS format. In any case even with a bitrate = to that of the video in transcoding, the video cuts every 10 seconds is a rather annoying problem.



#16 ebr OFFLINE  

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Posted 18 February 2020 - 11:57 AM

 In any case even with a bitrate = to that of the video in transcoding, the video cuts every 10 seconds is a rather annoying problem.

 

Hi. That would be an indication that your server just cannot transcode fast enough for smooth playback.  I see this in one of your images above (31fps).



#17 thegrunge OFFLINE  

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Posted 18 February 2020 - 01:22 PM

@ebr it is possible, however I have no reading problems if I do not put PGS subtitles and I force transcoding for example 2 mbps of a video file which normally in direct reading uses 15 mbps .. What would be the number of fps would be acceptable, because I can deactivate the regulation option in transcoding to see, otherwise the transcoding is done by hardware generally.



#18 ebr OFFLINE  

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Posted 18 February 2020 - 01:53 PM

Burning in graphical subs can be quite processor intensive.  You need to be able transcode faster than the video needs to be delivered.  Standard frame rate is about 30.



#19 thegrunge OFFLINE  

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Posted 18 February 2020 - 09:42 PM

@ebr Good here I made some test while playing with the profile of encoding and the crf and came to the conclusion that it was necessary to go as high as possible with the profile of encoding at the expense of a higher crf. this is the best way to have the best possible image as long as we have at least a fps of 20 and not below it otherwise we will be victim of video cutoff (We are always talking about a transcoded video playback because of the PGS subtitle format) In my case I had to set the encoding profile to medium and the crf to 24 to have a fps always above 20


Edited by thegrunge, 18 February 2020 - 09:43 PM.


#20 ebr OFFLINE  

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Posted 19 February 2020 - 11:03 AM

PGS subs by themselves do not require transcoding. It is only because some other factor of your media is not playable on the device.  My guess would be the audio track.  If you provide compatible audio tracks, or set the app to downmix to stereo, then transcoding will probably not be required at all.






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