Could you turn on this option to use the old transcoder and try it?
Rebooting the firetv, switching back to the old transcoder and setting the content to transcoded at 720p 6mbps has it got it working again...
I am also on a synology nas with 8gb ram
I guess i just stick back on transcoded for now on firetv until there is a fix...
Can you try the new transcoder one more time? I’m very surprised it could make a difference in this case. The underlying encoder is the same for both.
Sure i will untick use old, reboot, leave it at 720p 6mb and will try it again
I also not that rate switching is not working.. 720p transcoded source and tv thinks 1080p 60
Weird.. seems to be working on the new transcoder after the reboot:
757.98 GB available
Activity
Watching recording Hairy Bikers Route 66 S01E04 2019-10-10-1957.mpg from 10.0.0.15 (Transcoder Running at 6mbps: 10m5s @ 2.69x (73.95fps)).
Previously it just said transcoder ready
Tried another recording and getting lots of interlacing artefacts and weirdly look like transcoder is doing nothing:
Watching recording The Jonathan Ross Show S15E05 2019-10-12-2204.mpg from 10.0.0.15 (Transcoder Ready).
And same again from another channel:
Watching recording Celebrity MasterChef S14E08 2019-09-18 2019-09-18-1957.mpg from 10.0.0.15 (Transcoder Ready).
I will try the same shows again on old transcoder..
Old transcoder:
Watching recording Hairy Bikers Route 66 S01E04 2019-10-10-1957.mpg from 10.0.0.15 (Running: 4m23s).
Watching recording The Jonathan Ross Show S15E05 2019-10-12-2204.mpg from 10.0.0.15 (Running: 5m24s @ 33.3x (73.07fps)).
Watching recording Celebrity MasterChef S14E08 2019-09-18 2019-09-18-1957.mpg from 10.0.0.15 (Running: 5m13s @ 37.4x (72.28fps)).
Not the no “transcoder ready” messages and there are no striping deinterlacing artifacts
So Eric it looks like there is a big difference between old and new transcoders..
With the new one, once it gets to the status transcoder ready.. the streamed video looks rubbish and has lots of artefacts (basically like if you choose original instead of 720p)
With old transcoder it never says transcoder ready and there are no artefacts but you do get audio sync issues occasionally after skipping - but least its watchable!
i have posted the logs to support email going back over the last 30 mins... lots of weirdness in there!
(nulls, errors, illegal reorderings, missing refs ertc)
i will stick with old transcoder for now at 720p 6mb and try not to skip too much as that results in a watchable stream internally on fireTv .... look forward to your thoughts
Ah! Thank you for your patience in helping me understand what is going on here.
The thing you're looking for is a way to tell the system "always transcode the video", but you aren't always getting that with the new transcoder.
I believe what we are seeing is a change that happened between the old transcoder and the new one. The change was to be smarter about the requested bitrate vs the source material bitrate and to not do transcoding when it is not necessary to meet the request. I am guessing that some of the content is more than the 6mbits/second that you are requesting and some of it is under that limit. When the status says (Transcoder Ready) it is saying that it is serving requests that can be sent without transcoding.
It seems that we may need to create a special setting for the FireTV to say "always force transcoding" until we can fix these underlying issues.
sounds good to me .. i will send some sample videos over now 
Hey Eric.. further thought.. its not just about forcing bitrate for transcoding (E.g. 6mbps).. i think we need to be able to force size too (e.g. 720p or 1080p etc)
Also if the stream is forced to 720p at say 6mps why does the firetv app not switch res from 1080 60p to 720p to match?
I believe we are sending at 720p so it appears there is a bug somewhere that isn’t switching the resolution like it should.
Regarding the 50hz issue, please click Submit Diagnostics in the app after trying to play 1080 at original.
Is your fire stick set to UK as the locale?
My fire tv is linked to my amazon uk account and the postcode is set correctly to my uk postcode and timezone is set to europe / british summer time (not seen an explicit setting where i can set country to UK though)
Diagnostics just submitted for video, crash and other
Have to say though, i dont think i have ever seen the firetv channels app change the resolution....