subtitle burn-in conversion?

[Soundpool 2]

Hi,

 

I'm currently having issues with with subtitles on pretty much all content I have running.
I have Emby configured for auto conversion to HEVC, which in itself works perfectly, but it also strips any subtitles that are included.
External subtitles are fine, but if they are burned in, then they are removed by the conversion.

Is there a setting I'm overlooking that can preserve these subs? either externally (file) or internally (burned in, but not forced)
As far as I can see the Emby conversion doesn't offer any options besides codec, bitrate and audio format.

I do realize it can be achieved with external programs like Handbrake and Makemkv, but prefer to have it included due to automation (sonarr/radarr)
Any pointers?
 

[Soundpool 2]

Small update.

Tested it with an Episodes of Bleach.
The original has 2 PGSSUB stream, but the converted one has none.
Why would it remove those?

[rbjtech 5284]

Can you provide the ffmpeg conversion log ?

To note the subs you are referring to are 'internal' subs (PGS etc) as opposed to 'burned in' - as this means they are part of the Video stream.  'Burned in' subtitles would get converted automatically during the HEVC conversion as they are not recognised as subs at all.

[Soundpool 2]

Hi,

thanks for your input.
If internal subs don't get recognized as such, should they still be stripped off then?

Attached the log of the mentioned Bleach test episode.

 

ffmpeg-transcode-ecad66dc-8029-417b-84ad-9d15c8d3b970_1.txt

[rbjtech 5284]

That's a transcode log - is there not a 'conversion' log anywhere ?  (sorry it's been a while since I used this feature - but pretty sure it uses ffmpeg, so there should be a log somewhere ) ..

[rbjtech 5284]

ah sorry - it's in the main embyserver.txt log

So I did a quick test myself -

ProcessRun 'Encoding ca7596' Execute: C:\Emby-Server-Beta\system\ffmpeg.exe -loglevel +timing -y -print_graphs_file "C:\Emby-Server-Beta\programdata\logs\ffmpeg-transcode-ca7596cc-b887-4a3a-856c-7ebda4ce89b8_1graph.txt" -copyts -start_at_zero -f mp4 -c:v:0 h264 -i "C:\Test\A Touch of Frost (1992) [tvdbID=76247]\Season 1\A Touch of Frost - S01E01 - Care and Protection.mp4" -map 0:0 -map 0:1 -sn -c:v:0 libx264 -g:v:0 150 -maxrate:v:0 1403909 -bufsize:v:0 2807818 -sc_threshold:v:0 0 -keyint_min:v:0 150 -pix_fmt:v:0 yuv420p -preset:v:0 veryfast -profile:v:0 high -level:v:0 3.0 -x264opts:v:0 "subme=0:me_range=4:rc_lookahead=10:partitions=none" -crf:v:0 23 -c:a:0 copy -disposition:a:0 default -avoid_negative_ts disabled -map_metadata -1 -map_chapters -1 "C:\Emby-Server-Beta\programdata\sync\1\1\ca7596cc-b887-4a3a-856c-7ebda4ce89b8.mkv"

In answer to your question - emby is not using a -c:s:? copy in the command line above - this would have copied all the existing subtitle streams.

A Dev would need to answer why this was not included ...  ?

[Soundpool 2]

Hi,

Apologies, that was indeed the transcode one.
Unfortunately pretty much everything (except transcodes) gets logged in a single file, meaning it's a bit difficult to find.. well anything.

I have rotated the log and reran the encoding on the file, and could find something (see attachment).

I see you were faster than me in this regard and already located the ffmpeg command.
Forgot to mention, running Emby version 4.6.4.0, so this may be different in one of the beta versions. 

encode test.txt

[Luke 42083]

Currently the goal of the conversion feature is to produce a streaming friendly format that can play on a wide range of devices.

Since pgs is not widely supported it will either get burned into the output with transcoding, or dropped altogether depending on user subtitle preferences.

We plan to add more control over this in future updates. Thanks.

 

[Soundpool 2]

Hi,

If a specific format isn't supported, shouldn't it be transcoded to a format that does work on the playing device rather than be stripped out preemptively?

[rodainas 191]

Converting PGS Subs to SRT requires more power and is a slow process by itself, the "easier solution" would be having them burned in as previously said on the transcoded video file of course requiring more server power.

[rbjtech 5284]

I tend to agree with the OP - If you strip them out (without advising that you have done so..) then you have no options to play them back, burnt in via transcoding or otherwise ..    If you have chosen to overwrite the original file as part of the conversion process - then you may be in for a surprise .. 

 

[Soundpool 2]

Exactly what happened rbjtech,  well said

Wouldn't mind a bit more processing power or time requirement, as long as it can be automated without human intervention.

Edited September 23, 2021 by Soundpool