2023 Samsung Tizen (QN90C) - flac or pcm tracks trigger audio transcode

[pip08 1]

I want to understand the root cause and see if there's a quick fix available.

 

Model Number: QN55QN90CAFXZC

Client Version: Emby for Samsung 1.9.9

Server Version 4.8.11.0  @SamES

embyserver.txtffmpeg-remux-5ba16733-1cce-4d03-ba16-7426663931fc_1.txtffmpeg-remux-715cfc1c-e201-4061-9b58-d454b4a4efe8_1.txt

[Luke 42077]

Hi, we recently had to change flac in video to trigger a transcode due to this:

 

[Luke 42077]

Your pcm example is not due to pcm, but rather, the app tried to direct play the file, but the Samsung video player had a problem with it. Then we automatically switched the playback method in order to allow it to play.

[FrostByte 5392]

Pretty sure FLAC isn't supported by any Samsung TV.  It sometimes played flakey on some models at best.

Digital playback tables from User manual:

https://developer.samsung.com/smarttv/develop/specifications/media-specifications/2023-tv-video-specifications.html

 

For the PCM file just guessing here, but possibly because of FHD HEVC level 4?  Looking at the manual it appears HEVC is only supported for 1080p at level 4.1 (123)

Have you tried turning off transcoding on the server to see if your files play direct?

 

 

 

 

Edited March 20, 2025 by FrostByte

[Luke 42077]

it's one of those things that even when the TV reports that it supports flac, it often doesn't play it very well. Similar to opus.

[pip08 1]

6 minutes ago, FrostByte said:

Pretty sure FLAC isn't supported by any Samsung TV.  It sometimes played flakey on some models at best.

Digital playback tables from User manual:

https://developer.samsung.com/smarttv/develop/specifications/media-specifications/2023-tv-video-specifications.html

 

For the PCM file just guessing here, but possibly because of FHD HEVC level 4?  Looking at the manual it appears HEVC is only supported for 1080p at level 4.1 (123)

Have you tried turning off transcoding on the server to see if your files play direct?

 

 

 

 

HEVC level is not an issue because it shows direct play for video stream.

I also tried the same HEVC encoder settings for other videos with ac3 audio tracks. Those can play without transcoding.

It plays with no sound when audio transcoding is disabled.

[Luke 42077]

Well there you go. Looks like the app is doing the right thing.

[pip08 1]

I tried the DLNA player on the TV.

It is able to play pcm or flac tracks without any issues or audio lags.

It's a show stopper anyway for me if flac is not supported on Samsung TV client.

I will look at other streaming devices.

Edited March 20, 2025 by pip08

[Luke 42077]

The TV's dlna player usually gives the same result but not always. Our conclusion from this is that it's not exactly the same video player that Samsung makes available for third party apps to utilize.

[SamES 1056]

On 21/03/2025 at 07:11, pip08 said:

It is able to play pcm or flac tracks without any issues or audio lags.

From ours and other user experience, some/many models play some/many variations of flac, but it is very inconsistent across models, even in the same manufacturing year.  I have flac files that play on older models but won't play on newer models and vice-versa.  Even files that appear to have the same codec specs, but one will play and the other will not on the same TV. We've even had cases where the file plays fine for a period of time, then drops out, breaks up or has other issues.  This is not unique to Samsung, we've seen the same issue on LG as well.

We would have to be so selective about which flac parameters work and which do not on every TV model, the only way we could ever do this would be trial and error, which would be near impossible for us and not worth the time and effort, particularly as the number of people that this impacts doesn't appear to be high.  It's not that we haven't tried, but over the years as the number of models in the range continues to expand and the variation of flac files that we see also grows, it was clear that this was not something we are ever going to get to be robust, particularly when some models don't even list flac support at all on their (very limited and not always accurate) codec matrix.