Transcoded quality is really bad on some files?

General Discussions
1

Hi,

Lately i have been getting some quality issues with files that are transcoded, both when i play them on my samsung tv with the plex app and when i sync them to my android phone.
If i play the file in a browser (chrome) the file is fine, as far as i can see it is not transcoding when i use a browser.
The files are also fine if i just use VLC on pc.

VLC gives me this information about the codec.
Codec: H264 - MPEG-4 AVC (part 10) (avc1)
Frame rate: 23.976000
Decoded format: Planar 4:2:0 YUV

My plexserver (Version 1.10.1.4602 - i know there is a newer version, but i have had this problem for a long time now, and have already upgraded 3 times meanwhile) is installed on a Qnap NAS (TS-879 Pro running QTS 4.3.3.0299).

please let me know if there is any more information you need, i can also upload a sample file if you send me directions on were to do so.

The files are really unwatchable, so I am currently using handbrake to reencode my files so that plex can play them without the quality issues, and that is of cause a timeconsuming task that i don’t want to have to do :slight_smile:

I don’t know if this is a setup issue or a plex issue. I already tried changing a lot of settings with no result. Any pointers would be great!

Thanks in advance!
Simon

2

Hi again,

i upgraded to Version 1.12.0.4829 - just to be sure.
i will check if there are still problems with quality later when i get home.

br
Simon

3

Here is how it looks on my tv and synced to my phone.

and here is how the file looks on the pc

Please advice!

Thanks!

4

Apparently, the hardware transcoder in your unit is producing garbage.
Settings - Server - Transcoder - ‘Show Advanced’ - “Use hardware acceleration when available” = OFF

Are you using files which are already very low in bitrate?
Post the Plex XML info of your example movie please.

5

Hi,
it IS a low bitrate file. Here is the XML:

<MediaContainer size="1" allowSync="1" identifier="com.plexapp.plugins.library" librarySectionID="2" librarySectionTitle="AutoSeries" librarySectionUUID="70e98080-e0e0-4c9a-b6c5-9c5690f6cf83" mediaTagPrefix="/system/bundle/media/flags/" mediaTagVersion="1519709664">
<Video ratingKey="106519" key="/library/metadata/106519" parentRatingKey="106508" grandparentRatingKey="106507" guid="com.plexapp.agents.thetvdb://325517/1/3?lang=en" librarySectionTitle="AutoSeries" librarySectionID="2" librarySectionKey="/library/sections/2" type="episode" title="na" grandparentKey="/library/metadata/106507" parentKey="/library/metadata/106508" grandparentTitle="Salvation" parentTitle="Sæson 1" contentRating="TV-14" summary="It's a race against time as Darius must accelerate his plan to stop the asteroid before the Pentagon shuts him down. Also, Grace has to make difficult decisions that could have life or death consequences for millions of people, and Liam and Jillian reunite under surprising circumstances.
 " index="3" parentIndex="1" rating="8.5" viewOffset="324000" viewCount="1" lastViewedAt="1521140529" year="2017" thumb="/library/metadata/106519/thumb/1518940696" art="/library/metadata/106507/art/1516814672" parentThumb="/library/metadata/106508/thumb/1516814671" grandparentThumb="/library/metadata/106507/thumb/1516814672" grandparentArt="/library/metadata/106507/art/1516814672" duration="2629451" originallyAvailableAt="2017-07-26" addedAt="1516814545" updatedAt="1518940696">
<Media videoResolution="480" id="120474" duration="2629451" bitrate="717" width="854" height="480" aspectRatio="1.78" audioChannels="2" audioCodec="aac" videoCodec="h264" container="mp4" videoFrameRate="24p" optimizedForStreaming="1" audioProfile="lc" has64bitOffsets="0" videoProfile="high">
<Part accessible="1" exists="1" id="139172" key="/library/parts/139172/1516791184/file.mp4" duration="2629451" file="/share/CACHEDEV1_DATA/Multimedia/AutoSeries/Salvation/Season 1/03/Salvation s01e03.mp4" size="235793700" audioProfile="lc" container="mp4" has64bitOffsets="0" optimizedForStreaming="1" videoProfile="high">
<Stream id="168282" streamType="1" default="1" codec="h264" index="0" bitrate="555" bitDepth="8" chromaSubsampling="4:2:0" frameRate="23.976" hasScalingMatrix="0" height="480" level="30" profile="high" refFrames="2" streamIdentifier="1" width="854"/>
<Stream id="168283" streamType="2" selected="1" default="1" codec="aac" index="1" channels="2" bitrate="162" audioChannelLayout="stereo" profile="lc" samplingRate="44100" streamIdentifier="2"/>
<Stream id="168293" key="/library/streams/168293" streamType="3" codec="srt" language="Dansk" languageCode="dan"/>
<Stream id="168292" key="/library/streams/168292" streamType="3" selected="1" codec="srt" language="English" languageCode="eng"/>
</Part>
</Media>
<Director id="28646" filter="director=28646" tag="Stuart Gillard"/>
<Writer id="28644" filter="writer=28644" tag="Gavin Johannsen"/>
<Writer id="28645" filter="writer=28645" tag="Dennis Saldua"/>
<Extras size="0"></Extras>
</Video>
</MediaContainer>
6

555 kbps for video is already near “garbage” quality. Sending this through a transcoding process again, will inevitably produce garbage.
You can only direct-play this.

Since you have a subtitle selected, Plex has no choice but to transcode when syncing this file to your phone.