Dolby Digital Plus

apple-tv

#1

So I modified the tvOS.xml profile to have the server feed Dolby Digital Plus (eac3) to the Apple TV. And it mostly just works…in some cases!

Cases where it works:
1. Direct Playing. If the video is 8bit h264 with a single eAC3 5.1 track, I have gotten it to reliably work with multiple files.

Cases where it doesn't:
1. Direct Streaming both Video and Audio (i.e. remuxing from mkv to a container Apple TV likes).
2. If the server has to transcode the video and attempts to direct stream the audio: video plays as expected, but audio remains silent. Cases where the video track has to be transcoded: hevc, 10bit, ssa/ass subtitle display.
3. If the server has to transcode the audio (from flac, dts-hd, truehd, etc), it prefers to do so in ac3, even though eac3 has replaced it the tvOS.xml profile.

Basically if Plex needs to do anything to the file to get it to play, eAC3 playback fails.

I know that this is unsupported, but are any of the devs able to tell me why it is failing? Are there plans to address this/fully support Dolby Digital Plus? DD+ is more efficient, allows for more channels, and a higher bitrate so I am eager to be able to switch over to it for my ripping workflow. Since it seems mostly feasible and decoding is supported by both Apple TV's native AVPlayer stack and my AVR, I don't see why this shouldn't be implemented. I can only assume time was the limiting factor here since you had to ship this excellent 1.0 in such a short amount of time.

Thanks for your time!


#2

@rolyreyes We are currently investigating eac3 support and testing the ability to direct play/direct stream those tracks without conversion.

If you have some sample files that cover the cases where it doesn't work, it would be great if you could PM me a link to them.


#3

Thanks for the response! For me it fails in any case other than DirectPlay, essentially. I'll put together a zip of a few sample files and pm it to you.


#4

@chrisallen said:
rolyreyes We are currently investigating eac3 support and testing the ability to direct play/direct stream those tracks without conversion.

If you have some sample files that cover the cases where it doesn't work, it would be great if you could PM me a link to them.

http://s1.demo-world.eu/hd_trailers.php?filename=dolby_digital_plus_channel_check_lossless-DWEU.mkv

..from my thread here https://forums.plex.tv/discussion/comment/1053963#Comment_1053963

Mkv with eac3 track which gets transcoded to ac3


#5

Has anyone gotten EAC3 7.1 to work though the ATV4 and Plex yet? I got it working as an iTunes MP4 and as a Plex file, no transcoding, full 7.1 sound. Works fantastic, and running at 1024k bit rate.

I also noticed a few titles on iTunes are now coming through with DD+ 7.1 and they sound great. MI5 and Terminator Genisys. The biggest issue is encoding.


#6

@rolyreyes What are you using to encode eac3? ffmpeg will only encode the 5.1 core stream from what I can see. I am having great success and encoding to full 7.1 with adobe media encoder, 7.1 eac3 at 1024kb/s.


#7

Any update on EAC3 on AppleTV?


#8

Bump, I’m interested in EAC3 support as well.


#9

PMS 1.5.1 supports EAC3 encoding for the Apple TV


#10

For a 2 hour long 5.1 movie you save around 200MB vs regular DD so not a huge spacesaver.


#11

Not sure where to post this, but TRUEHD when converted to DD+ is out of sync. Is there a known fix for this?


#12

@tobztobztobz it’s a known issue that will be fixed in the next PMS release


#13

@chrisallen said:
@tobztobztobz it’s a known issue that will be fixed in the next PMS release

Sweet


#14

@chrisallen is there an ETA on when to expect the next PMS release?


#15

@chrisallen said:
PMS 1.5.1 supports EAC3 encoding for the Apple TV

What Bitrate will the EAC3 be transcoded at? will it be a improvement over 640bps AC3?


#16

The obvious improvement you will see at the same bitrate is in the compression of audio, for a ~10GB file ~200MB space save in audio (converting DTS 5.1 @ 1509.75 kbit/s). The big thing is 7.1 eac3 conversion from DTS-HD MA 7.1 or TrueHD 7.1 which I think plex can’t do by itself at the monent, you have to do it manually with a 3rd party app. But the support for eac3 7.1 is a start.


#17

Anyone figure out the bitrate used for eac3 conversion, from dts for example?


#18

DTS HD MA is transcoding to AC3 instead of EAC3. Was there an update that broke EAC3 transcoding support for DTS tracks?


#19

Hi, I am also trying to figure out why DTS transcodes to AC3 instead of EAC3.

Thanks.