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Issue playing HEVC encoded on iPhone6s

pahi78pahi78 Posts: 37Members, Plex Pass Plex Pass

Starting with iOS 4.23 I am unable to playback HEVC-encoded videos on my iPhone6s running iOS 11.2 from a (Linux) PMS 1.11.0.4666. The very same movie used to work prior to iOS 4.23.

The server does initiate a hw-transcode from HEVC to HEVC. The CPU is an Intel Kaby-Lake with 10-bit HEVC capability. Afaik the iPhone6s doesn't hold HEVC-capabilities.

Am I the only one with this kind of issue?

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Answers

  • jjrjr1jjrjr1 Posts: 1,931Members, Plex Pass Plex Pass

    Does the iPhone support DCA audio???

  • pahi78pahi78 Posts: 37Members, Plex Pass Plex Pass

    @jjrjr1 said:
    Does the iPhone support DCA audio???

    I'm pretty confident it doesn't, thus the transcode of audio isn't in question, but rather the transcode of the video stream. Imho PMS should've issued a transcode from HEVC (hw) to h264 (hw).

  • jjrjr1jjrjr1 Posts: 1,931Members, Plex Pass Plex Pass
    edited January 6

    That's the point..
    If Plex needs to re-encode audio for a HEVC file, it will always do a full transcode.

    I do understand that Plex is working on fixing that on some platforms.
    I do not know if it will be fixed for IOS.

    It's been an issue on Rokus for a long time as well,

  • jjrjr1jjrjr1 Posts: 1,931Members, Plex Pass Plex Pass

    Oh I missed something you said..
    the iPhone does not support HEVC since you expected a h264 transcode??

  • pahi78pahi78 Posts: 37Members, Plex Pass Plex Pass

    @jjrjr1 said:
    Oh I missed something you said..
    the iPhone does not support HEVC since you expected a h264 transcode??

    Correct. I expected the PMS to transcode both video- and audiostreams. The issue here is that PMS sends a HEVC-stream to the iOS-client, which with its hardware is incapable of playing it back.

    My guess is that the client presents itself to the server with HEVC-capabilities, but I haven't performed any deeper analysis yet. I just wanted to check if I was alone with the issue or if it's wide spread.

  • jjrjr1jjrjr1 Posts: 1,931Members, Plex Pass Plex Pass

    Yup that is what should happen..
    Maybe look at logs and look for entries with MDE as a tag.. Those entries should tell you why Plex is not transcoding,

    The easiest solution is NOT to transcode h265. Really a waste of resources for non 4K capable devices.

    Create h264 versions for NON-4K devices,

    I have been asking the question for long time and have not gotten any answer.
    Why create 4K media just to transcode???

  • pahi78pahi78 Posts: 37Members, Plex Pass Plex Pass

    Actually I just realized the server first tries to send a HEVC direct stream to the iPhone6s, before falling back to transcoding. Also, I just upgraded the phone to iOS 11.2.1. No change. Something is broken.

  • jjrjr1jjrjr1 Posts: 1,931Members, Plex Pass Plex Pass

    Should not work that way.
    Plex actually gets device capability from the Plex App on the device. (That is what you will see in those MDE log entries)
    As far as I know it does not attempt to play HEVC and wait to fail then change to h264..

  • jjrjr1jjrjr1 Posts: 1,931Members, Plex Pass Plex Pass

    Again..
    Why create HEVC media just to transcode??

  • pahi78pahi78 Posts: 37Members, Plex Pass Plex Pass

    @jjrjr1 said:
    Again..
    Why create HEVC media just to transcode??

    That's not the issue in question. I am well aware that there's always the option to save duplicates with a different quality setting. I have the hardware capable to transcode using hardware acceleration and I want to be able to use it. Performing transcode in hardware isn't ineffective. Storing duplicates, on the other hand is.

    Thank you for commenting. Although I'd rather have you verify my finding than debating transcode vs. storing duplicates.
    I will look for MDE-entries in the log file.

  • jjrjr1jjrjr1 Posts: 1,931Members, Plex Pass Plex Pass

    Just trying to help get it to work for you.
    If it is a software issue in Plex...
    Good luck seeing a fix for it any time soon.

    Really what you do is based on how long you can wait without a fix..

    Let me know what you see in the logs.

  • pahi78pahi78 Posts: 37Members, Plex Pass Plex Pass

    @jjrjr1 said:
    Just trying to help get it to work for you.

    Thank you very much. I do appreciate you taking your time. I just prefer to transcode using hw-acceleration prior to store dupes.

    Let me know what you see in the logs.

    It's clear according to the logs that it falls back to hw HEVC-encoding in the last line.
    Prior to iOS 4.23 it used to fallback to h264_vaapi. Now it picks hevc_vaapi, which clearly is wrong.

    Jan 06, 2018 14:00:26.516 [0x7eff607fe700] DEBUG - MDE: Selected protocol hls; container: mp4
    Jan 06, 2018 14:00:26.516 [0x7eff607fe700] DEBUG - MDE: analyzing media item 450594
    Jan 06, 2018 14:00:26.517 [0x7eff607fe700] DEBUG - MDE: Movie: Direct Play is disabled
    Jan 06, 2018 14:00:26.517 [0x7eff607fe700] DEBUG - MDE: Movie: media must be transcoded in order to use the hls protocol
    Jan 06, 2018 14:00:26.517 [0x7eff607fe700] DEBUG - MDE: Movie: no direct play video profile exists for http/mkv/hevc
    Jan 06, 2018 14:00:26.517 [0x7eff607fe700] DEBUG - MDE: Movie: no direct play video profile exists for http/mkv/hevc/dca
    Jan 06, 2018 14:00:26.517 [0x7eff607fe700] DEBUG - MDE: Movie: Direct Streaming is disabled, so video stream will be transcoded
    Jan 06, 2018 14:00:26.517 [0x7eff607fe700] DEBUG - MDE: Movie: no remuxable profile found, so video stream will be transcoded
    Jan 06, 2018 14:00:26.517 [0x7eff70fff700] DEBUG - Completed: [192.168.xx.yyy:55193] 200 GET /status/sessions (11 live) TLS GZIP 6ms 4470 bytes (pipelined: 10)
    Jan 06, 2018 14:00:26.517 [0x7eff607fe700] DEBUG - Codecs: hardware transcoding: testing API vaapi
    Jan 06, 2018 14:00:26.518 [0x7eff607fe700] DEBUG - Scaled up video bitrate to 267354Kbps based on 4.500000x fudge factor.
    Jan 06, 2018 14:00:26.518 [0x7eff607fe700] DEBUG - MDE: Movie: Audio Direct Streaming is disabled, so video's audio stream will be transcoded
    Jan 06, 2018 14:00:26.518 [0x7eff607fe700] DEBUG - MDE: Movie: selected media 0 / 450594
    Jan 06, 2018 14:00:26.518 [0x7eff67bfe700] DEBUG - Killing job.
    Jan 06, 2018 14:00:26.518 [0x7eff607fe700] DEBUG - Streaming Resource: Session 0x7eff50091de0:73B43C34-0135-4A43-87F9-61BFEC88511E changed transcode slot usage to used. Used slots is now 1
    Jan 06, 2018 14:00:26.518 [0x7eff67bfe700] DEBUG - Signalling job ID 15833 with 9
    Jan 06, 2018 14:00:26.518 [0x7eff607fe700] DEBUG - Streaming Resource: Reached Decision id=156214 codes=(General=1001,Direct play not available; Conversion OK. Direct Play=3000,App cannot direct play this item. Direct play is disabled. Transcode=1001,Direct play not available; Conversion OK.) media=(id=450594 part=(id=450681 decision=transcode container=mp4 protocol=hls streams=(Video=(id=930072 decision=transcode bitrate=267354 encoder=hevc_vaapi width=3840 height=2160) Audio=(id=930073 decision=transcode bitrate=258 encoder=aac channels=2 rate=48000))))

  • jjrjr1jjrjr1 Posts: 1,931Members, Plex Pass Plex Pass

    You need to realize there is NO fallback.

    The way plex works is the client sends device capability to PMS.. The MDE in the server makes the decision as to how to handle the media.

    So either the problem is with the IOS app sending incorrect capability or the PMS MDE/Streaming Brain is broken.

    Plex has been messing with the Streaming Brain lot over the last year.

  • pahi78pahi78 Posts: 37Members, Plex Pass Plex Pass

    @jjrjr1 said:
    You need to realize there is NO fallback.

    You are correct. It was poor wording on my part.

    So either the problem is with the IOS app sending incorrect capability or the PMS MDE/Streaming Brain is broken.

    My guess is that the problem is with the IOS app, as the problem emerged today as I updated the IOS plex app last night to 4.23.

  • pahi78pahi78 Posts: 37Members, Plex Pass Plex Pass

    I just verified that the same movie works with iOS 4.22 on an iPhone6 (not 6s).
    The brain correctly picks h264_vaapi as encoder.

  • jjrjr1jjrjr1 Posts: 1,931Members, Plex Pass Plex Pass
    edited January 6

    Probably no way to re-install 4.22 on the 6s.

    Hopefully someone from Plex will chime in here. But, in my experience, do not hold your breath..

    If someone from Plex does chime in, lets hope that they will try to get it fixed..

    LOL

  • adamska46adamska46 Posts: 38Members, Plex Pass Plex Pass
    edited January 7

    With iOS 11, an iPhone 6S can decode HEVC 8 and 10 bit videos (and with HW acceleration like all A9 SoCs and later).
    However, it can't decode DTS audio, so transcoding to AAC or AC3 is necessary in this case.

    In a nutshell : ideally for an iPhone 6S, an HEVC video + DTS audio should imply transcoding of the audio stream only, without touching the video stream.

    What container is your file ? MKV ? MP4 ?

    PMS : NVIDIA Shield TV

  • pahi78pahi78 Posts: 37Members, Plex Pass Plex Pass

    @adamska46 said:
    With iOS 11, an iPhone 6S can decode HEVC 8 and 10 bit videos (and with HW acceleration like all A9 SoCs and later).

    I had no idea. Is that documented somewhere?

    However, it can't decode DTS audio, so transcoding to AAC or AC3 is necessary in this case.

    Right.

    What container is your file ? MKV ? MP4 ?

    MKV

  • jjrjr1jjrjr1 Posts: 1,931Members, Plex Pass Plex Pass

    As the last I knew Plex did not support h265 i MKV containers.
    They will always transcode as I understood

  • pahi78pahi78 Posts: 37Members, Plex Pass Plex Pass

    I just tried a BT.709 HEVC 720p encoded movie and it played right off. I also tried a BT.709 HEVC 1080p encoded movie which also worked without issue. I will do some debugging on the iPhone6s to see if I can fetch what's crashing Plex IOS while playing the BT.2020 HEVC 4k encoded movie.

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