Disabling transcoding on MKV files causes some to have no video.

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Acxelion
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Joined: Thu Nov 19, 2020 9:27 pm

Disabling transcoding on MKV files causes some to have no video.

Post by Acxelion »

I was tinkering with UMS after being unable to do playback/seeking. Some research informed me that this is due to transcoding because it generates each second of the video and outputs it, not the actual video file(for reasons I didn't look into). Learning this, I disabled transcoding for the file type I generally use and saw playback/seeking was working. However, some videos had no video. The only workaround I've found is to go into the TRANSCODE folder and find the video I'm looking for in there. Depending on the renderer I'm using, this is inconvenient because the TRANSCODE folder has a separate video for each subtitle language of the MKV and the easiest way to read them when they have long names is the thumbnail. But I've used some players that do not show the thumbnail. So, I'd like to take steps ahead of time to handle this. Does anyone have a solution?
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mik_s
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Re: Disabling transcoding on MKV files causes some to have no video.

Post by mik_s »

Instead of disabling transcoding of MKV files it is better to make sure the conf for that renderer is correct so UMS will only transcode files that are unsupported on it. Also disabling transcoding for one filetype effect all devices that are connected to UMS.
MKV is just a container and there are many codecs used for video and audio that may not all be able to be played nativity on your device.

If a file plays with no video or no audio it is a sign that it is not supported so has to be transcoded. If something is being transcoded when you think it shouldn't you can play from the #--TRANSCODE--# folder and select "No transcoding", If it works then you can update the conf so UMS will not transcode that in the future.

The #--TRANSCODE--# folder can be a bit overwhelming if a file has many subs and audio tracks as only one audio track and one subtitle can be transcoded each combination has to be selectable. You can tidy this up a bit by turning off all transcoding engines bar one (like FFmpeg)

Some renderers cannot handle seeking with transcoded video as since the file is being created as it is played, it cannot know the full file size to move to a specific point.
The upcoming version 11 has support for HLS which works differently and might solve the seeking problem if your device supports it.

A workaround to go to a certain time in a transcoded video is to enable chapters at set intervals, then you can start watching from a point close to where you want.

If you need help changing the conf so UMS does not transcode a file that can play without transcoding I'll be able to help if you post trace logs (see the section in red above).
Depending on how old your device is there is probably a better conf that it could be using or maybe just needs a little tweak.
Logs are important for us to help, Please follow This Link before asking for support. Just a forum cleaner, Will help if I can but no expert.
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