Tvheadend

Hi to all and sorry for my poor english. I try to explaine my problem.
I install and use Tvheadend without any problem to record some tv programs to my hard disk. I'm using mini-itx pc with slow intel cpu, and for this reason I'm using the "pass" profile without any compression or transcode process, but is not this the problem.
I need to impress on video a timestamp and I seen that it's possible via ffmpeg command.
At first I need to use ffmeg to stream the channels and I'm trying to use this pipe command into "command line" box when I create a spawn/built-in profile in unstable version 4.3.963:

pipe:///usr/bin/ffmpeg -loglevel fatal -i http://localhost:9981/stream/channelnumber/1
-vcodec copy -acodec copy -metadata service_provider=RAI -metadata service_name=RAI 1 -f mpegts -tune zerolatency pipe:1

but but I certainly make some mistakes in the compilation. I'm not a ubuntu expert (I'm using ubuntu 17.10), so be pity I want to stream without any transcoding, just like the default "pass"profile does, only using ffmpeg.
Can someone tell me exactly how to fill in the command?
then I should integrate the command for timestamp cee should be "drawtext".

From the tvheadend logs, when I try to see the movie streaming with the new profile created, I read this:
2018-01-12 16:48:24.073 pass: Unable to start pipe pipe' pipe: ////usr/bin/ffmpeg -loglevel fatal -i' http://localhost:9981/stream/channelnumber/1' http://localhost:9981/stream/channelnumber/1'.
-vcodec copy -acodec copy -metadata service_provider=RAI
-metadata service_name=RAI 1 -f mpegts -tune zerolatency pipe: 0' (wrong executable?)

2018-01-12 16:48:25.738 subscription: 005B:"HTTP" subscribing on channel "Rai 1", weight: 100, adapter:"Philips TDA10046H DVB-T #0: DVB-T #0", network:"GECA", mux:"205.5MHz ", provider:" RAI ", service:" Rai 1 ", profile=" test ", hostname=" 127.0.0.0.1 ", client=" NSPlayer/7.10.0.3059 "," NSPlayer/7.10.0.3059 "," NSPlayer/7.10.3059 ".

2018-01-12 16:48:25,738 subscription: 005B:"HTTP" unsubscribing from "Rai 1", hostname="127.0.0.0.1", client="NSPlayer/7.10.0.3059".

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