Fix transcoded videos playback for Samsung 2016 UHD TVs

[sad-spirit]

I own a UE55KS7000 model and hit the same problem that is described in these forum posts
https://www.universalmediaserver.com/forum/viewtopic.php?t=12700
https://www.universalmediaserver.com/forum/viewtopic.php?t=13367

The TV did not play any transcoded videos showing an extremely unhelpful "Unknown error" message.

The logs showed a "Connection reset" exception:

DEBUG 2023-12-02 13:07:22.815 [jupnp-netty-worker 23] Caught exception: Connection reset
TRACE 2023-12-02 13:07:22.815 [jupnp-netty-worker 23] 
java.net.SocketException: Connection reset
	at java.base/sun.nio.ch.SocketChannelImpl.throwConnectionReset(SocketChannelImpl.java:394)
	at java.base/sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:426)
	at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:64)
	at org.jboss.netty.channel.socket.nio.AbstractNioWorker.process(AbstractNioWorker.java:108)
	at org.jboss.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:337)
	at org.jboss.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:89)
	at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:178)
	at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108)
	at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at java.base/java.lang.Thread.run(Thread.java:840)

which immediately followed that server response

HTTP/1.1 206 Partial Content (non-chunked)

HEADER:
  Content-Type: video/vnd.dlna.mpeg-tts
  Content-Range: bytes 0-9223372034707292158/9223372034707292159
  ContentFeatures.DLNA.ORG: DLNA.ORG_PN=AVC_TS_NA_ISO;DLNA.ORG_OP=11;DLNA.ORG_CI=0;DLNA.ORG_FLAGS=01700000000000000000000000000000
  Accept-Ranges: bytes
  Connection: keep-alive
  Server: Linux-amd64-6.1.0-0.deb11.13-amd64, UPnP/1.0 DLNADOC/1.50, UMS/13.8.0

As I suspected that the TV was not amused by the above Content-Range header, I added

TranscodedVideoFileSize = 1000000

to a custom .conf file based on Samsung-UHD.conf and transcoded videos immediately started playing.

Also changing

SeekByTime = true

to

SeekByTime = exclusive

actually allowed seeking.

I can create a PR for these changes, what should be the correct approach:

• Just fix Samsung-UHD.conf
  or
• Create a new higher-priority .conf with these changes that applies only to models of 2016 and before?

Another question is whether it is reasonable to use an Exabyte-sized Content-Range header in the first place?

[sad-spirit]

A followup:

ChunkedTransfer = true

also helps.

I think using chunked transfer encoding is a better way according to HTTP spec: it is specifically designed for content of unknown length.

[SubJunk]

@sad-spirit a PR would be great, thank you.
I can see that the TranscodedVideoFileSize hack is already in a lot of the Samsung configs. Do you need both ChunkedTransfer and TranscodedVideoFileSize, or just one of them?

[sad-spirit]

@SubJunk

Do you need both ChunkedTransfer and TranscodedVideoFileSize, or just one of them?

Just one of them, I'd suggest ChunkedTransfer as a lesser hack.

PIease give me guidance on PR, see above:

what should be the correct approach:

• Just fix Samsung-UHD.conf
  or
• Create a new higher-priority .conf with these changes that applies only to models of 2016 and before?

I suspect that just fixing the config will not break anything as it only applies to pre-2019 TVs but obviously I don't have TVs to test the changes with.

[SubJunk]

@sad-spirit I agree with you, you can just change it in that UHD file

[SubJunk]

@sad-spirit thank you for the PR