Tvheadend

I'm having trouble getting the ffmpeg pipe to work on my tvheadend, I'm running Tvheadend version 4.3-2064~gabcb0ea67 on Enigma2.

What happens is that if I run ffmpeg directly over ssh everything works perfectly, the command looks like this:

/usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 -filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts test.ts

Now if I run it on tvheadend via pipe, using the command like this:

pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 -filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1

My tvheadend log looks like this:

2022-12-15 00:46:26.999 mpegts: pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 -filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1 - tuning on IPTV #1
2022-12-15 00:46:27.009 subscription: 0009: "HTTP" subscribing to service "IPTV/pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 --filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1/TCM", weight: 100, adapter: "IPTV #1", network: "IPTV", mux: "pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 -filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1", 
2022-12-15 00:46:27.010 spawn: Executing "/usr/bin/ffmpeg" 
2022-12-15 00:46:27.030 iptv: stdin pipe 46 unexpectedly closed: No data
2022-12-15 00:46:43.009 subscription: 0009: service instance is bad, reason: No input detected
2022-12-15 00:46:43.009 mpegts: pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 -filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1 - tuning on IPTV #2
2022-12-15 00:46:43.020 subscription: 0009: "HTTP" subscribing to service "IPTV/pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 --filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1/TCM", weight: 100, adapter: "IPTV #2", network: "IPTV", mux: "pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 -filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1", 
2022-12-15 00:46:43.020 spawn: Executing "/usr/bin/ffmpeg" 
2022-12-15 00:46:43.040 iptv: stdin pipe 46 unexpectedly closed: No data
2022-12-15 00:46:47.820 webui: Stop streaming /stream/service/bed095263c541552f04ef73edf469970?ticket=f23fe58037ae1ccafb0a64a994bfb6d696527430, timeout waiting for packets
2022-12-15 00:46:47.820 subscription: 0009: "HTTP" unsubscribing, hostname="192.168.1.1", client="VLC/3.0.17.4 LibVLC/3.0.17.4" 
2022-12-15 00:46:47.830 mpegts: pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 -filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1 - tuning on IPTV #1
2022-12-15 00:46:47.841 subscription: 000A: "HTTP" subscribing to service "IPTV/pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 --filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1/TCM", weight: 100, adapter: "IPTV #1", network: "IPTV", mux: "pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 -filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1", 
2022-12-15 00:46:47.842 spawn: Executing "/usr/bin/ffmpeg" 
2022-12-15 00:46:47.862 iptv: stdin pipe 46 unexpectedly closed: No data
2022-12-15 00:47:03.831 subscription: 000A: service instance is bad, reason: No input detected
2022-12-15 00:47:03.831 mpegts: pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 -filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1 - tuning on IPTV #2
2022-12-15 00:47:03.842 spawn: Executing "/usr/bin/ffmpeg" 
2022-12-15 00:47:03.843 subscription: 000A: "HTTP" subscribing to service "IPTV/pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 --filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1/TCM", weight: 100, adapter: "IPTV #2", network: "IPTV", mux: "pipe:///usr/bin/ffmpeg -i http://192.168.1.55:9981/stream/channelnumber/659 -filter_complex "channelmap=map=FR-FL|FR-FR:channel_layout=stereo"  -c:v copy -c:a mp2 -mpegts_flags system_b -f mpegts pipe:1", 
2022-12-15 00:47:03.862 iptv: stdin pipe 46 unexpectedly closed: No data
2022-12-15 00:47:07.831 webui: Stop streaming /stream/service/bed095263c541552f04ef73edf469970?ticket=f23fe58037ae1ccafb0a64a994bfb6d696527430, timeout waiting for packets
2022-12-15 00:47:07.831 subscription: 000A: "HTTP" unsubscribing, hostname="192.168.1.1", client="VLC/3.0.17.4 LibVLC/3.0.17.4" 

You can understand better by reading:
https://tvheadend.org/boards/5/topics/48726