Thanks DiamondSW.
MrSW - I had asked diamondsw to take a look at this thread as he is more versed in chromecast than I am.
The last few screen shots/logs as well as information regarding your NW setup were helpful.
thanks guys - I love plex so really frustrating that it is playing up on me! it is 100% how i drive my TV’s in the house and my family use it as well for everything now.
But want to stress the point, when it does transcode, taping it to play origional quality always fixes it. I run everything through handbreak because 1) it reduces the files size by 2/3 or more saving disk space without losing any picture quality, and 2) putting it in the format that chrome cast can direct stream looks significantly higher quality than transcoding on a 75" screen… transcoding makes it look really bad at that size.
On the above question, we all use plex the same way… granb our tablet/phone… tap on plex… tap on the cast button (this turns the TV on) then select our media and hit play… more often than not it will direct stream and everything is great… but a lot of the time you see the picture is bad… tap gear cog, tap direct play and it fixes it…
OK as requested above, tried a movie and it worked first go direct played as expected
log attached
Working log.txt (248.4 KB)
Did you launch the working film and the non-working film you posted logs for earlier (The Boss Baby I think} from the same device?
Having just quicky looked at the logs it appears that when the Boss Baby was initially loaded it notified Plex that it has a maximum allowed bitrate of 2000kbps which is what triggered the transcode. The working movie loaded with a notification that the max bitrate was 20000kbps.
The working log was my on 75" TV + Chrome Cast Ultra, and i requested it on my Samsung Galaxy Tab S2… When i did the boss baby, i “might” have used my kids tablet which is a lenovo Tab3 (i think) but was with the same 75" TV and Chromecast… (It does incorrectly transcode on all our tablets/phones though it doesnt discriminate any device)
How is the bandwidth calculated? I’m assuming its between the chromecast and server not the tablet/phone? as the mobile device just brokers the deal, but the chrome cast fetches the data directly from the server so assuming speed test would be there?
The Access point i have is a 802.11ac 3x3, The Chromecast i think is only 1x1, from past experiance with my laptop which is 2x2 i can get about 30MB/s copy speeds from the same distance the TV is from the AP (5 meters), so with 1x1 it should get 15MB/s or 150mbps which is significantly higher than the 2mbps & 20mbps reported in the logs.
Any luck yet?
Have you pin pointed where the bug is yet?
I have been fairly busy this week with work so I haven’t had much time to look at the logs. I have pinged @diamondsw to see if he had found anything.
Can this be given a higher priority since it effects all chrome cast users and has been ignored for better part of a year?
I’ve likewise been busy (kids and work decided to hit at once). I don’t know that we’ve determined it’s a universal issue yet, but I’ll see if I can dig through my own files/logs and see if I run into similar issues. My apologies for not being more responsive; if I don’t manage to hit something immediately, it almost invariably gets shuffled off by the ongoing torrent of Things To Do.
OK i think i may have figured out why Plex stuffs up and starts transcoding with chromecast when its not needed.. I decided not to say anything for a good week or so while i wait to see if the problem comes back and so far it hasnt.
Looks like Google must have added a new option in Chromecast config which they turn on by default called “Video Smoothness” seems the chrome cast randomly seems to think the TV might not be able to handle the playback of the media and asks Plex to send it at a lower resolution.
By switching this from the default ON to Off instead, the problem has gone away. I’ve not seen plex transcode anything, this seems to have also worked for other people I know who were reporting the same issue to me.
Chuck - Solution above
So not Plex’s fault at all. Interesting and thank you.
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Thanks for the persistence @MrSW and sharing the information with the rest of the community.
Based on the description & what your logs were showing, my translation is that the Chromecast basically said “hey take the 1080i @ 30hz content and make it say 720p @ 60hz”… i.e. dropping resolution to increase frame rate (hence forcing the transcoding).
Most people’s TV’s are too small to be able to truly “see” 1080p from 10 feet away but they will definitely notice the choppiness of a large frame rate drop (especially when on mediocre wifi setups). So drop the resolution, which they really won’t typically see, and keep the frame rate higher.
Not quiet, TV hz is not the frame rate, its how many times it can draw the content per second. If you have a 25fps movie, modern TV’s now insert and make up new frames between the real frames to help smooth it out, which is how live sports can look smoother on 100hz… 100hz for games is better as it allows the game to insert 100fps
According to googles description if the TV doesnt support 60hz at 4K it drops it to 60hz at 1080p… but truth is the chrome cast is assuming it cant get 60hz at 4K when it can at random times, and not only does it drop it down to 1080p it also drops it to 720p
Google description is here,
https://support.google.com/chromecast/answer/7186055?hl=en-AU
Keeps whining for weeks, constantly repeats that the problem is surely with plex because he is SO smart, keeps being rude to people trying to help and turns out the problem isn’t with plex… The irony.
The fix is good and I appreciate it being shared but this is exactly NOT how to communicate a problem
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Not very nice of you Gentlemen 
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