Direct play playback issues for certain videos

[thebnich 5]

Hello, I'm having an issue on Fire TV where a few videos have a particular playback problem: the video is choppy and sped up as if fast forwarding, and there is no audio. This happens only on direct play, so I'm guessing this is a Fire TV issue rather than an Emby issue, but I'm curious if someone can confirm exactly *why* these particular videos are incompatible.

 

The issue is reproducible on both 4.3.1.0 and 4.4.0.15-beta. If I force transcoding, everything works fine.

 

Here are all the logs:

 

Fire TV:

• I sent a log from playback of the first 15 seconds of the video. The file is called test.mkv (Test Movie).
• Time: 12:28PM, EST. 
• Username on server: B+B

Attachments:

• embyserver-direct.txt: Server log when the item is direct played (and doesn't play properly).
• ffmpeg-transcode.txt: Server ffmpeg log when the item is transcoded (and plays properly).
• mediainfo-linux.txt: Output of `mediainfo test.mkv`.
• mediainfo-emby.txt: Media info displayed on Emby web detail page for item.

 

Thanks!

embyserver-direct.txt

ffmpeg-transcode.txt

mediainfo-linux.txt

mediainfo-emby.txt

Edited February 22, 2020 by thebnich

[ebr 16169]

 If I enable transcoding, everything works fine.

 

Does that mean you've disabled transcoding on your server and, if you re-enable it, the item transcodes and plays properly?

[thebnich 5]

Sorry, that was unclear.

 

No -- transcoding is always enabled on the server. When I play this item, it plays directly by default. To "fix" it, I was forcing transcoding on the client by selecting a lower max bitrate during playback.

[ebr 16169]

Okay, can I please see the media info shown on our web detail page for this item and also the ffmpeg log created when you force the transcode?

 

Thanks.

[thebnich 5]

Sure; I updated the original post.

[ebr 16169]

My guess is it is the DD+ audio track causing the issue.  However, I would have expected the app to convert that in the first place (not allow it to direct play).  It must be allowing it because we don't know the bitrate.

[thebnich 5]

Yeah, that seems to be the culprit: I checked a few other videos with the same problem, and all of them use DD+. One of them even has both a DD+ and a regular DD track, and switching from DD+ to DD fixes the playback.

[thebnich 5]

You might know this already, but I found that if I go to Settings > Display & Sounds > Audio > Dolby Digital Output and change it to OFF, everything plays normally. In fact, Emby even shows the client is direct playing in the server console.

 

I tried each of the Dolby settings, and they seem to have different effects:

• Dolby Digital Plus Automatic: no audio, choppy video
• Dolby Digital Plus OFF: audio and video work as expected
• Dolby Digital Plus over HDMI: no audio, choppy video (same as Automatic)
• Dolby Digital over HDMI: audio works as expected, video choppy

[ebr 16169]

 

You might know this already, but I found that if I go to Settings > Display & Sounds > Audio > Dolby Digital Output and change it to OFF, everything plays normally. In fact, Emby even shows the client is direct playing in the server console.

 

Yes, that would be effectively the same as setting the app to downmix everything to stereo.

[thebnich 5]

So if the client itself is able to downmix DD+ streams to stereo, shouldn't Dolby Digital Plus Automatic be doing just that if my device doesn't support DD+? Does that mean this is a Fire TV bug, where Automatic is selecting the wrong mode?

Edited March 2, 2020 by thebnich

[ebr 16169]

So if the client itself is able to downmix DD+ streams to stereo, shouldn't Dolby Digital Plus Automatic be doing just that if my device doesn't support DD+? Does that mean this is a Fire TV bug, where Automatic is selecting the wrong mode?

 

I'm sorry, I don't really understand that question but you're talking about settings in the TV that affect what it tells the app is supported.  That is what the app will react to.

[thebnich 5]

Hi, sorry about that. Thanks for bearing with me.

 

My question was made on the assumption that my TV can't handle DD+, so the playback issues are a result of trying to play DD+ on a TV that doesn't support it. I was thinking the Fire TV is incorrectly trying to play DD+ content when the Dolby Digital setting is Automatic, assuming the correct Automatic behavior would be to force stereo (since that's the only setting that works). I might have made some bad assumptions.

 

So when you said before that "it is the DD+ audio track causing the issue", specifically what device/software along the chain has an issue with it?

[ebr 16169]

I think it is probably an oddly encoded DD+ track.  The app would not try to play it if the TV reported that it doesn't support it.

[thebnich 5]

I looked through my library and found that I have 21 x264 encoded items with DD+; 9 of these 21 have the video skipping/no audio issue. All 9 of these are listed as DD+ 8 ch in Emby, whereas the other 12 that work are all DD+ 6 ch.

 

So, from my limited data set, this appears to be a bug specific to 8-channel DD+ x264 videos.

[ebr 16169]

I looked through my library and found that I have 21 x264 encoded items with DD+; 9 of these 21 have the video skipping/no audio issue. All 9 of these are listed as DD+ 8 ch in Emby, whereas the other 12 that work are all DD+ 6 ch.

 

So, from my limited data set, this appears to be a bug specific to 8-channel DD+ x264 videos.

 

I suspect that, if Amazon ever updates their port of Exo (they say they are in process), we will see this solved as a similar issue was just solved on the Google platform.

[thebnich 5]

In the meantime, would it be possible to add a workaround in Emby that automatically downmixes 8-channel DD+ streams to Fire TV?

[ebr 16169]

In the meantime, would it be possible to add a workaround in Emby that automatically downmixes 8-channel DD+ streams to Fire TV?

 

If they don't update their port before our next release.

[thebnich 5]

If they don't update their port before our next release.

 

Hi, I'm still having this issue as of Emby server 4.4.0.40 stable/4.5.0.5 beta. When you said "next release", were you referring to Emby server or the Fire TV app?

[Luke 42077]

I believe he's referring to the Fire TV app.

[thebnich 5]

Ah, OK. I was hoping this might be a server-side workaround that would force-transcode DD8+ content to Fire TV clients -- the advantage being that Emby server updates are incrementally rolled out much more frequently, and the fix could be implemented/reverted quickly between beta releases. Is that not feasible?

[Luke 42077]

It just depends on which side the problem is. @@ebr can provide more detail. Thanks.

[ebr 16169]

Amazon has updated their port of Exoplayer.  Can you try the Amazon beta of the app?

[Hyp3rD 10]

@@ebr How can we get the beta app for Amazon without subcribe "always" to the beta app program?

[ebr 16169]

@@ebr How can we get the beta app for Amazon without subcribe "always" to the beta app program?

 

You could leave the program and re-install the release version I guess...

[Hyp3rD 10]

You can't do like you did with the "google" release in the testing area?