4.0.0.2 - Numerous problems (caused by audio transcoding)

[uglymagoo 9]

Server: Debian Stretch, Emby 4.0.0.2

 

Input video: HEVC 4k, DTS, PGSSUB, mkv

 

Player1: Nvidia Shield TV 7.2.2, Emby 1.6.x beta
Player2: iPad Pro 10.5, Emby stable

 

Using any subtitle and an audio stream that is supported by the client and does not require transcoding, both clients direct play the video. However, if I select a audio stream that requires audio transcoding, also video is transcoded. That's a huge problem for some of my clients that require subs but do not have permission for video transcoding. In this case, subtitles are just not shown.

 

I really do not want software HEVC to H.264 transcoding if it's not required

 

Edit: The subtitle format does not seem to be of importance. As soon as audio transcoding is required and subs are enabled, Emby automatically also transcodes the video.

 

Here is the ffmpeg remux log.

 

Edit2: With remux and audio transcoding I also have a broken video stream, i.e. green screen or random pixels, on both clients   Remux log

 

Edit3: The docker image has the same issue.

Edited January 17, 2019 by uglymagoo

[chudak 23]

I’d like to reproduce the issue.

Any suggestion how to force audio transcoding?

[uglymagoo 9]

I’d like to reproduce the issue.

Any suggestion how to force audio transcoding?

 

Easy enough: play any movie with a TRUEHD audio track on mostly any device that's not connected to an AVR    My friend, who alerted me to this problem today, uses an Nvidia Shield TV directly connected to his Sony TV. I was able to reproduce this issue by putting my AVR into Standby and using HDMI pass through of my AVR to also tell the Emby Android TV Client only about the features of my old Samsung TV.

 

However, the TV of my friend is also not able to decode DTS, so any DTS track also triggers this issue in his case.

 

Additionally, the iOS Emby app on my iPad Pro 10.5 also triggers the same issue with any video with TRUEHD tracks.

Edited January 17, 2019 by uglymagoo

[chudak 23]

Easy enough: play any movie with a TRUEHD audio track on mostly any device that's not connected to an AVR My friend, who alerted me to this problem today, uses an Nvidia Shield TV directly connected to his Sony TV. I was able to reproduce this issue by putting my AVR into Standby and using HDMI pass through of my AVR to also tell the Emby Android TV Client only about the features of my old Samsung TV.

 

However, the TV of my friend is also not able to decode DTS, so any DTS track also triggers this issue in his case.

 

Additionally, the iOS Emby app on my iPad Pro 10.5 also triggers the same issue with any video with TRUEHD tracks.

How do I get THRUEHD track?

I remember seeing transcoding being used with some subtitles but can’t find any who could trigger it atm

 

If the video is small enough maybe you can attach it here

Edited January 17, 2019 by chudak

[uglymagoo 9]

How do I get THRUEHD track?

 

It's an audio codec used on BD. https://en.wikipedia.org/wiki/Dolby_TrueHD

[Happy2Play 8338]

Sorry as far as I know there are no clients that support psg (graphical) subtitles. 

 

As you see the subtitles are burn in causing a full transcode.  This will aways happen with graphical subs.

 

Transcode

Stream mapping:
  Stream #0:0 (hevc) -> overlay:main (graph 0)
  Stream #0:4 (pgssub) -> scale (graph 0)
  hwupload (graph 0) -> Stream #0:0 (h264_vaapi)
  Stream #0:1 -> #0:1 (truehd (native) -> ac3 (native))

 

Verse without subtitles the video stream is copied as is.

 

Audio track conversion

Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (truehd (native) -> ac3 (native))

[uglymagoo 9]

Sorry as far as I know there are no clients that support psg (graphical) subtitles. 

 

As you see the subtitles are burn in causing a full transcode.  This will aways happen with graphical subs.

 

That's just not true at all I have been using them for many months on my Shield TV in the Emby client. There is just a new bug triggered by audio transcoding.

 

Btw: these subs still direct play without any problem in my normal setup (Shield TV -> Marantz AVR -> Samsung TV) and are never burned in as long as my HDMI chain supports the audio codec.

Edited January 17, 2019 by uglymagoo

[Happy2Play 8338]

Okay sorry you appear to have a device that supports them as not many do.  But don't know how this appies to hevc though.

 

https://github.com/MediaBrowser/Wiki/wiki/Android%20TV#direct-play-media-formats

 

As for the audio it comes down to compatible hardware.

Edited January 17, 2019 by Happy2Play

[uglymagoo 9]

As for the audio it comes down to compatible hardware.

 

Of course. I just don't believe that it's the appropriate behavior of the server to turn on video transcoding just because audio transcoding is required. I mean, there is a special setting per user to enable audio transcoding but disable video transcoding. This does not make any sense if one triggers the other.

 

In my "perfect" setup, transcoding is never required.

 

However, using a TV that does not support e.g. truehd, the result is currently the following using the Shield TV Emby client:

 

video track #1: hevc, PGSSUB subs track #1, audio track #1: ac3 --> Direct Play

video track #1: hevc, PGSSUB subs track #1, audio track #2: truehd --> audio + video transcoding. Why is there video transcoding?

 

And please do not focus on the graphical subs. It's the same with SRT and also the same behavior on iOS. Something is broken.

Edited January 17, 2019 by uglymagoo

[Happy2Play 8338]

Someone proficient on the client will have to respond by to me your setup does not support TrueHD.

 

You would need to post a log to support srt subtitles producing the same results.  But as always no two devices have the same capabilities.

[uglymagoo 9]

Ok. You are correct, there were still some details missing / wrong in my report. I have come up with the following four experiments. It's always Shield TV directly connected to TV (AVR in HDMI pass through):

 

OK:

1. video track #1: hevc, SRT subs, audio track #1: ac3 --> Direct Play

2. video track #1: hevc, PGSSUB subs, audio track #1: ac3 --> Direct Play

 

Problem:

3. video track #1: hevc, PGSSUB subs, audio track #2: truehd--> audio + video transcoding. No pixel errors, wrong tone mapping (as expected)

4. video track #1: hevc, SRT subs, audio track #2: truehd --> audio transcoding, video direct play, video completely broken, see following photo:

 

Edited January 17, 2019 by uglymagoo

[uglymagoo 9]

Sorry I have not gotten back to this post. So, small feedback to the two above issues.

 

(1) The broken output when remuxing was most likely caused by a broken file. I re-encoded the file in question and everything is well now.

 

(2) My current understanding is that Emby does not support image based subtitles without burning them in, when transcoding is required (HLS stream), even when only audio is transcoded. My workaround is to use MrMC on those clients (Nvidia Shield TV).

 

So, everything is good Please let me know if I am wrong about (2) and the official Emby Android TV app on the Shield TV should also support audio transcoding + image based subtitles without burning them in.

[Luke 37188]

Thanks for the feedback and that is correct about the subtitles. We can look at supporting them in a future update.