Since last version, Transcoding happening but should not be needed - Why?

General Discussions
1

For some reason after the latest updates this video file is always being transcoded no matter what I do:

Media:

Video Resolution 1080p
Duration 1:20:51
Bitrate 2176 kbps
Width 1920
Height 1088
Aspect Ratio 1.78
Container MP4
Video Frame Rate 24p
Web Optimized Yes
Audio Profile lc
Has 64bit Offsets 0
Video Profile high

Video:

Codec H264
Bitrate 2050 kbps
Bit Depth 8
CABAC true
Chroma Subsampling 4:2:0
Duration 1:20:51
Frame Rate 23.976 fps
Frame Rate Mode cfr
Height 1088
Level 4.1
Pixel Format yuv420p
Profile high
Ref Frames 4
Scan Type progressive
Stream Identifier 1
Width 1920

My client is Android, last plex app version. Home Streaming is set as “Recommended”.
When the video is playing and i choose directly to play original quality it would transcode. The only thing different with other similar files is that the resolution for this file is 1920x1088 for others the height is always lower than 1080. Wondering if is a BUG.
H264 level is 5.2 so is not that.

Can anybody help me understand please?

Thanks in advance.

2

Tried with Home Streaming set as Maximum and the same. Movie is transcoded.

3

The new version has a setting called: Automatic Adjust Quality.
Maybe that one is playing tricks on you?

4

Please post the Plex XML info of this video file.
enclose the XML portion
within triple backticks ```

5

Could be the height of your video.

6

Thanks for your help. Responding inline:
Automatic Adjust Quality: This is disabled in my Android Tablet.
Could be the height of your video: Yes, that’s my theory. If it is … would it be a BUG?
@OttoKerner I sent you the xml in a private msg. Thanks.

7 
<Part accessible="1" exists="1" id="919879" key="/library/parts/919879/1474273036/file.mp4" duration="4851840" file="/share/media/irrelevant.mp4" size="1319458129" audioProfile="lc" container="mp4" has64bitOffsets="0" optimizedForStreaming="1" videoProfile="high">
<Stream id="1816644" streamType="1" default="1" codec="h264" index="0" bitrate="2050" bitDepth="8" cabac="1" chromaSubsampling="4:2:0" codecID="avc1" duration="4851806" frameRate="23.976" frameRateMode="cfr" hasScalingMatrix="0" height="1088" level="41" pixelFormat="yuv420p" profile="high" refFrames="4" scanType="progressive" streamIdentifier="1" width="1920" />
<Stream id="1816645" streamType="2" selected="1" default="1" codec="aac" index="1" channels="2" bitrate="123" audioChannelLayout="stereo" bitrateMode="cbr" codecID="40" duration="4851840" profile="lc" samplingRate="48000" streamIdentifier="2" />
<Stream id="1816658" key="/library/streams/1816658" streamType="3" selected="1" codec="srt" language="English" languageCode="eng" format="srt" />
</Part>

Can you repeat the playback test with the subtitle deactivated?

If that doesn’t change anything, then I assume it is indeed the height of your video, because it exceeds the boundary box of a compatible video for this client.

8

@OttoKerner you were right. If I play the video with a sub and then deselected it will continue transcoding but if, before playing the video i chose no sub it doesn’t transcode although in the overlay display it says transcoding.

Weird. Is this a BUG? Can you elaborate on the root cause?

Thanks a lot for your help.

9

@cesalo said:
i chose no sub it doesn’t transcode although in the overlay display it says transcoding.
Weird. Is this a BUG? Can you elaborate on the root cause?

I don’t know the Android app that well.
It may be, that on certain hardware SRT subtitles are not directly supported.
It may also depend on whether you are viewing it on a screen that is connected directly to the device vs. “flinging” the playback to a Chromecast or similar.

10

I just got told that the Android app has a preference to “burn” subs vs. not burning them.
The default should be to not burn them - but maybe that got changed somehow on your device?

11

I can reproduce the error in my phone, tablet and a fire HD tablet, all
Android. I have similar MP4 videos that play ok with subs, I actually use
subs all the time and avoid any transcoding decoding the files if needed so
I’m pretty sure this mp4 should not transcode. Subtitle configuration is to
burn automatically not always. I’ve checked and all the MP4 that work are
1080p but height is lower than 1080. It seems the issue is related with
that. For now I deleted the sub to avoid the issue. Thanks a lot for your
help.
Not sure if somebody from support should take a look and confirm or not if
is a bug.

12

Up until now we only made qualified guesses.
We can only be sure about what causes the transcoding by looking at the server log files.

  1. activate debug logging (not ‘verbose’!)
  2. quit Plex Server
  3. wait 1 minute
  4. start Plex Server
  5. wait 2 minutes
  6. play the movie for 1 minute
  7. wait 3 minutes
  8. fetch server log files and attach them here
13

I am experiencing the same issue. It is particularly problematic for me because I use a Drobo 5N as my Plex server and it is not powerful enough to transcode video on the fly. Ever since updating my PMS it tries to transcode high bitrate videos.