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[SOLVED] Exceeding the estimated network speed

Posted: Wed Nov 09, 2022 10:02 am
by rhayy
Hi,

One of my video files has these following attributes:
- Overall bit rate: 24.7 Mb/s
- Format: DTS XLL.

Because of the audio codec not supported, it is transcoded. Very good.

The issue is that UMS estimates the network speed as 19 Mb/s (whereas my tv set displays 100/130 Mb/s; I can actually play the non transcoded video smoothly but with no sound) which leads ffmpeg to transcode the video as well (with the options -bufsize 19000k -maxrate 18000k).

I would like to bypass this speed limitation.

The MaxVideoBitrateMbps parameter has no effect.

Adding the line CustomFFmpegOptions = -bufsize 35000k -maxrate 30000k makes those two options appear twice in the ffmpeg process:

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/opt/ums/linux/ffmpeg -y -loglevel info -i /xxxxx/xxxxx/1HCF-RiCK.mkv -bufsize 19000k -maxrate 18000k -crf 23 -ab 320k -c:a aac -c:v libx264 -tune zerolatency -preset ultrafast -level 31 -pix_fmt yuv420p -f mpegts -bufsize 35000k -maxrate 30000k /tmp/UMS-ums/ffmpegvideo_44_1667945473361
How can I do it ? Thanks
The ideal solution would be to be able to remove these options.

Re: Exceeding the estimated network speed

Posted: Wed Nov 09, 2022 3:00 pm
by mik_s
If you turn off "Use automatic maximum bandwidth" and set maximum bandwidth to 0 then UMS will not try to limit transcoding to fit the bandwidth.
However if there is only 19Mb/s to your renderer then the video will probably hitch and stutter if it exceeds this.

That speed measurement might be low due to other reasons. It may be something else on the network was slowing it down, the connection type on the renderer may be limited/interference on WiFi etc. Best to try a wired connection to your router with both your computer and renderer and see if the speed improves.

Re: Exceeding the estimated network speed

Posted: Wed Nov 09, 2022 11:14 pm
by rhayy
This is spot on.

In UMS.conf file:

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automatic_maximum_bitrate = false
Optionnally, one can add (unit is Mb/s):

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maximum_bitrate = 100
Thank you.