Figure out why Plex is transcoding

General Discussions
1

My Plex Server is consistently transcoding some files that that seem to me to me in the correct format to use direct play.

Here’s the avprobe output for a file that directly streams:
Duration: 00:20:31.49, start: 0.000000, bitrate: 3406 kb/s
Stream #0:0(eng): Video: h264 (High), yuv420p(tv, bt709/unknown/unknown), 1280x720, SAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)

And here’s the output for one of the files that transcodes.
Duration: 00:20:51.38, start: 0.000000, bitrate: 3835 kb/s
Stream #0:0(eng): Video: h264 (High), yuv420p(tv, bt709/unknown/unknown), 1280x718, SAR 1:1 DAR 640:359, 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)

Is there a way to tell why Plex decided to transcode from the logs?

2

Yes
Set verbose debug on.
Start The video that is transcoding.
Look in the logs for lines that start with MDE
That will tell you why Plex thinks it needs to transcode.

3

@jjrjr1 said:
Set verbose debug on.
Look in the logs for lines that start with MDE

Actually, when you activate ‘verbose’, the log files you seek won’t start with MDE .
I recommend not to activate ‘Verbose’ logging, since the log files ‘rotate’ too fast and the logs get filled with useless chatter.

@tallerthenyou said:
Here’s the avprobe output for a file that directly streams:

could you post the Plex XML info from each file?
avprobe doesn’t give the full picture. it misses some cruicial video codec parameters, as well as infos about audio codec and subtitles.

4

@OttoKerner
I though I had read somewhere in the forum that in order to get MDE messages in the log was to have Verbose on??

If not true, I am glad to hear that and I learned something

Thanks.

5

I think I found the issue.

DEBUG - MDE: E05 - Thanksgiving: Direct Play is disabled
DEBUG - MDE: E05 - Thanksgiving: no direct play video profile exists for http/mkv/h264/ac3
DEBUG - Thanksgiving - video.refFrames limitation applies: 9 > 8

Here’s the XML for the stream

<Stream id="61774"
streamType="1"
default="1"
codec="h264"
index="0"
bitrate="3023"
language="English"
languageCode="eng"
bitDepth="8"
chromaSubsampling="4:2:0"
colorRange="tv"
colorSpace="bt709"
frameRate="23.976"
hasScalingMatrix="0"
height="720"
level="41"
profile="high"
refFrames="9"
requiredBandwidths="3474,3178,3178,3178,3178,3178,3178,3178"
scanType="progressive"
width="1280"/>
6

@tallerthenyou said:
I think I found the issue.
DEBUG - Thanksgiving - video.refFrames limitation applies: 9 > 8

refFrames="9"

Indeed. Your device can only handle 8 ‘Reference Frames.’ Your file uses 9.
This is most likely a hardware restriction of your client device.