Enabling Subtitles Results in no HDR?

[cloudhill]

Is it expected that when you enable subtitles (PGS) in the Roku Jellyfin app that the video switches from HDR to SDR? 

With no subtitles the TV (LG) flashes the HDR indicator logo in the corner and the video definitely looks like HDR. However as soon as I enabled subtitles and the video reloads in a few seconds, the TV no longer flashes the HDR indicator logo. The video is also clearly looks like an SDR video.

Is this caused by a limitation of the Roku Jellyfin app or it likely a setting problem in Jellyfin? I'm using the 2023-09-12 release in a docker instance on an Unraid server.

[TheDreadPirate]

PGS subs aren't supported by some clients. It probably required that the sub be burned in, which requires transcoding. Transcoding will always convert HDR to SDR. SRT subs are more compatible and there are plugins to extract subs and convert them to SRT.

[cloudhill]

PGS subs aren't supported by some clients.  It probably required that the sub be burned in, which requires transcoding.  Transcoding will always convert HDR to SDR.  SRT subs are more compatible and there are plugins to extract subs and convert them to SRT.

I thought it was possible to transcode and keep HDR using tone mapping. I must have misunderstood what tone mapping was thinking it let you scale from 4k HDR to 1080p HDR.

[Deleted User]

PGS subs aren't supported by some clients.  It probably required that the sub be burned in, which requires transcoding.  Transcoding will always convert HDR to SDR.  SRT subs are more compatible and there are plugins to extract subs and convert them to SRT.

I thought it was possible to transcode and keep HDR using tone mapping. I must have misunderstood what tone mapping was thinking it let you scale from 4k HDR to 1080p HDR.

HDR->SDR only, use in cases where client does not support HDR

[thornbill]

HDR -> HDR transcoding is not currently supported by Jellyfin.