trying to run rpos in raspberry pi 4

Question

trying to run rpos in raspberry pi 4

Opened this issue 9 months ago · 20 comments

Hi,
I am newbie trying to run the rpos in raspberry pi 4.Not able to get the rtsp working.
Initially got the following errror
_rtspServer error: Error: spawn ./bin/rtspServer ENOENT
at Process.ChildProcess.handle.onexit (internal/child_process.js:268:19)
at onErrorNT (internal/child_process.js:470:16)
at processTicksAndRejections (internal/process/task_queues.js:84:21) {
errno: 'ENOENT',
code: 'ENOENT',
syscall: 'spawn ./bin/rtspServer',
path: './bin/rtspServer',
spawnargs: [Array]
}

changed to option 3 in rposConfig.json...still not able to get the rtsp working..any method to run the same
{
"NetworkAdapters" : ["awdl0","eth0", "wlan0", "en0"],
"IpAddress" : "10.35.62.102",
"ServicePort" : 8081,
"Username" : "admin",
"Password" : "admin",
"CameraType" : "picam",
"RTSPAddress" : "10.35.62.102",
"//": "Normally left blank. Used to set RTSP Server Address",
"RTSPPort" : 8554,
"RTSPName" : "h264",
"MulticastEnabled" : false,
"RTSPMulticastName" : "h264m",
"MulticastAddress" : "224.0.0.1",
"MulticastPort" : "10001",
"RTSPServer" : 3, "RtspServerComment" : "## Select RTSP Server > 1:RPOS RTSP Server 2:V4L2 RTSP Server by mpromonet (auto selected if MulticastEnabled=true)",
"PTZDriver" : "none", "PTZDriverComment": "## valid values are none,tenx,pelcod,visca and pan-tilt-hat",
"PTZOutput" : "none", "PTZOutputComment": "## values are none (eg Tenx), serial and tcp",
"PTZSerialPort" : "/dev/ttyUSB0",
"PTZSerialPortSettings" : { "baudRate":2400, "dataBits":8, "parity":"none", "stopBits":1 },
"PTZOutputURL": "127.0.0.1:9999",
"PTZCameraAddress": 1,
"DeviceInformation" : {
"Manufacturer" : "Raspberry Pi",
"Model" : "4 B",
"HardwareId" : ""
},
"logLevel" : 3, "logLevelComment": "## LogLevels are > 1:Error 2:Warning 3:Info 4:Debug",
"logSoapCalls" : false

Let me know if you have any chnages here.
Thanks
Ravi

Answer 1 · 2023-12-20T03:47:44.000Z

What is the source of your rtsp stream? How is the rtsp path look like?
If your rtsp stream is not from picam and also not provided by V4L2 RTSP Server by mpromonet, then you have to use the "rposConfig.sample-proxy.json" template.

Also, the "RTSPAddress" : "hostname_of_remote_rtsp_server", "//":"Normally left blank. Used to set RTSP Server Address", should be at same line.

Answer 2 · 2023-12-22T11:04:01.000Z

Hi,
My rtsp source is form pi cam as I am using raspiberry Pi 4 ...but still not able to get the rtsp server started.
I am working in one of the image where rtsp stream is working...but when I download and start afresh I am not able to get the stream...I even made the rtsp address same line and tried still not working.
regards
Ravi

Answer 3 · 2023-12-22T11:11:58.000Z

current json
{
"NetworkAdapters" : ["awdl0","eth0", "wlan0", "en0"],
"IpAddress" : "192.168.29.174",
"ServicePort" : 8081,
"Username" : "admin",
"Password" : "admin",
"CameraType" : "picam",
"RTSPAddress" : "", "//":"Normally left blank. Used to set RTSP Server Address",
"RTSPPort" : 8554,
"RTSPName" : "h264",
"MulticastEnabled" : false,
"RTSPMulticastName" : "h264m",
"MulticastAddress" : "224.0.0.1",
"MulticastPort" : "10001",
"RTSPServer" : 3, "RtspServerComment" : "## Select RTSP Server > 1:RPOS RTSP Server 2:V4L2 RTSP Server by mpromonet (auto selected if MulticastEnabled=true)",
"PTZDriver" : "none", "PTZDriverComment": "## valid values are none,tenx,pelcod,visca and pan-tilt-hat",
"PTZOutput" : "none", "PTZOutputComment": "## values are none (eg Tenx), serial and tcp",
"PTZSerialPort" : "/dev/ttyUSB0",
"PTZSerialPortSettings" : { "baudRate":2400, "dataBits":8, "parity":"none", "stopBits":1 },
"PTZOutputURL": "127.0.0.1:9999",
"PTZCameraAddress": 1,
"DeviceInformation" : {
"Manufacturer" : "Raspberry Pi",
"Model" : "2 B",
"HardwareId" : ""
},
"logLevel" : 3, "logLevelComment": "## LogLevels are > 1:Error 2:Warning 3:Info 4:Debug",
"logSoapCalls" : false
}
where I have changed rtspserver to 3 but still gives following error
_rtspServer: /home/rasppi1/onvif/rpos/./python/gst-rtsp-launch.py:60: PyGIDeprecationWarning: GObject.MainLoop is deprecated; use GLib.MainLoop instead
self.mainloop = GObject.MainLoop()

rtspServer: /home/rasppi1/onvif/rpos/./python/gst-rtsp-launch.py:78: PyGIDeprecationWarning: Since version 3.11, calling threads_init is no longer needed. See: https://wiki.gnome.org/PyGObject/Threading
GObject.threads_init()

rtspServer: INFO:root:StreamServer initialized

rtspServer: INFO:root:Video settings loaded from v4l2ctl.json
DEBUG:root:StreamServer.launch
DEBUG:root:( rpicamsrc preview=false bitrate=10000000 keyframe-interval=60 drc=3 image-effect=denoise shutter-speed=0 iso=0 brightness=50 contrast=0 saturation=0 sharpness=0 awb-mode=1 rotation=0 hflip=False vflip=False video-stabilisation=False ! video/x-h264, framerate=30/1, width=1280, height=720 ! h264parse ! rtph264pay name=pay0 pt=96 )
INFO:root:Starting service on port 8554 at url /h264

rtspServer: INFO:root:Running RTSP Server_
if I give as 1 then error posted at the start comes...so basically RTSP server is not accessible.
Let me know if there needs to be any change.
regards
Ravi

Answer 4 · 2024-01-01T08:49:34.000Z

Make sure the rtsp stream path is accessible. This can be done by open network stream via VLC Player.
I am using mediamtx as rtsp server for pi camera. It usually has rtsp stream path as "rtsp://ip-address:8554/stream"
Rename the "rposConfig.sample-proxy.json" to "rposConfig.json" and change some parameter as below:

{
"NetworkAdapters" : ["awdl0","eth0", "wlan0", "en0"],
"IpAddress" : "192.168.1.15",
"ServicePort" : 8081,
"Username" : "admin",
"Password" : "admin",
"CameraType" : "picam",
"RTSPAddress" : "", "//":"Normally left blank. Used to set RTSP Server Address",
"RTSPPort" : 8554,
"RTSPName" : "stream",
"MulticastEnabled" : false,
"RTSPMulticastName" : "h264m",
"MulticastAddress" : "224.0.0.1",
"MulticastPort" : "10001",
"RTSPServer" : 0, "RtspServerComment" : "## Select RTSP Server > 0:Use RTSP Server from 'RTSPAddress:' 1:RPOS RTSP Server 2:V4L2 RTSP Server by mpromonet (auto selected if MulticastEnabl>
"PTZDriver" : "none", "PTZDriverComment": "## valid values are none,tenx,pelcod,visca and pan-tilt-hat",
"PTZOutput" : "none", "PTZOutputComment": "## values are none (eg Tenx), serial and tcp",
"PTZSerialPort" : "/dev/ttyUSB0",
"PTZSerialPortSettings" : { "baudRate":2400, "dataBits":8, "parity":"none", "stopBits":1 },
"PTZOutputURL": "127.0.0.1:9999",
"PTZCameraAddress": 1,
"DeviceInformation" : {
"Manufacturer" : "RPiCam-3B",
"Model" : "RPi3B",
"HardwareId" : "1.0"
},
"logLevel" : 3, "logLevelComment": "## LogLevels are > 1:Error 2:Warning 3:Info 4:Debug",
"logSoapCalls" : false
}

By the way, I have node v12.22.12 and npm v6.14.16.

Answer 5 · 2024-01-11T12:43:56.000Z

Hi,
Thanks for your response.

I did try with mediamtx...but I am getting error

NF [path cam] [RPI Camera source] ready: 1 track (H264)
2024/01/11 18:06:14 INF [RTSP] [conn 10.35.62.103:60852] opened
2024/01/11 18:06:14 INF [RTSP] [conn 10.35.62.103:60852] closed: invalid URL (/h264)
My IP is 10.35.62.102 but I do not know why it is picking up 103...also I installed from following path
https://qengineering.eu/install-gstreamer-1.18-on-raspberry-pi-4.html
If you have clear steps for this kindly provide
2.Once you run the mediamtx..then try with rposProxy changes...then run node rpos.js ....you are saying ONVIF complaint can be achieved??
can you ellaborate on this??
also directly with onvif rpos ..I cannot get the rtsp running

_rtspServer: /home/rasppi1/onvif/rpos/./python/gst-rtsp-launch.py:60: PyGIDeprecationWarning: GObject.MainLoop is deprecated; use GLib.MainLoop instead
self.mainloop = GObject.MainLoop()

rtspServer: /home/rasppi1/onvif/rpos/./python/gst-rtsp-launch.py:78: PyGIDeprecationWarning: Since version 3.11, calling threads_init is no longer needed. See: https://wiki.gnome.org/PyGObject/Threading
GObject.threads_init()

rtspServer: INFO:root:StreamServer initialized

rtspServer: INFO:root:Video settings loaded from v4l2ctl.json

rtspServer: DEBUG:root:StreamServer.launch
DEBUG:root:( rpicamsrc preview=false bitrate=10000000 keyframe-interval=60 drc=3 image-effect=denoise shutter-speed=0 iso=0 brightness=50 contrast=0 saturation=0 sharpness=0 awb-mode=1 rotation=0 hflip=False vflip=False video-stabilisation=False ! video/x-h264, framerate=30/1, width=1280, height=720 ! h264parse ! rtph264pay name=pay0 pt=96 )

rtspServer: INFO:root:Starting service on port 8554 at url /stream
rtspServer: INFO:root:Running RTSP Server_

but not seeing anything in the vlc or any other streaming
Kindly let me know the steps..I am in right path
Thanks and regards
Ravi

Answer 6 · 2024-01-16T10:08:18.000Z

Hi ,
Any info on this error has any one tried running the same ...Kindly let me know for any pointers.
Thanks and regards
Ravi

Answer 7 · 2024-01-17T11:19:29.000Z

Hi,
still getting ffmpeg issue on RPI4 or on compute module when running RPOS...

ffmpeg exec error: Error: Command failed: ffmpeg -fflags nobuffer -probesize 256 -rtsp_transport tcp -i rtsp://127.0.0.1:8554/h264 -vframes 1 -r 1 -s 640x360 -y /dev/shm/snapshot.jpg
ffmpeg version 4.3.6-0+deb11u1+rpt5 Copyright (c) 2000-2023 the FFmpeg developers
built with gcc 10 (Debian 10.2.1-6)
configuration: --prefix=/usr --extra-version=0+deb11u1+rpt5 --toolchain=hardened --incdir=/usr/include/aarch64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --disable-mmal --enable-neon --enable-v4l2-request --enable-libudev --enable-epoxy --enable-sand --libdir=/usr/lib/aarch64-linux-gnu --arch=arm64 --enable-pocketsphinx --enable-libdc1394 --enable-libdrm --enable-vout-drm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
libavutil 56. 51.100 / 56. 51.100
libavcodec 58. 91.100 / 58. 91.100
libavformat 58. 45.100 / 58. 45.100
libavdevice 58. 10.100 / 58. 10.100
libavfilter 7. 85.100 / 7. 85.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 7.100 / 5. 7.100
libswresample 3. 7.100 / 3. 7.100
libpostproc 55. 7.100 / 55. 7.100

at ChildProcess.exithandler (child_process.js:308:12)
at ChildProcess.emit (events.js:314:20)
at maybeClose (internal/child_process.js:1022:16)
at Process.ChildProcess._handle.onexit (internal/child_process.js:287:5) {

killed: true,
code: null,
signal: 'SIGTERM',
cmd: 'ffmpeg -fflags nobuffer -probesize 256 -rtsp_transport tcp -i rtsp://127.0.0.1:8554/h264 -vframes 1 -r 1 -s 640x360 -y /dev/shm/snapshot.jpg'
}
Kindly help me out on this ...
Thanks
Ravi

Answer 8 · 2024-01-24T11:21:14.000Z

Make sure the rtsp stream path is accessible. This can be done by open network stream via VLC Player.
I am using mediamtx as rtsp server for pi camera. It usually has rtsp stream path as "rtsp://ip-address:8554/stream"

Rename the "rposConfig.sample-proxy.json" to "rposConfig.json" and change some parameter as below:

{ "NetworkAdapters" : ["awdl0","eth0", "wlan0", "en0"], "IpAddress" : "192.168.1.15", "ServicePort" : 8081, "Username" : "admin", "Password" : "admin", "CameraType" : "picam", "RTSPAddress" : "", "//":"Normally left blank. Used to set RTSP Server Address", "RTSPPort" : 8554, "RTSPName" : "stream", "MulticastEnabled" : false, "RTSPMulticastName" : "h264m", "MulticastAddress" : "224.0.0.1", "MulticastPort" : "10001", "RTSPServer" : 0, "RtspServerComment" : "## Select RTSP Server > 0:Use RTSP Server from 'RTSPAddress:' 1:RPOS RTSP Server 2:V4L2 RTSP Server by mpromonet (auto selected if MulticastEnabl> "PTZDriver" : "none", "PTZDriverComment": "## valid values are none,tenx,pelcod,visca and pan-tilt-hat", "PTZOutput" : "none", "PTZOutputComment": "## values are none (eg Tenx), serial and tcp", "PTZSerialPort" : "/dev/ttyUSB0", "PTZSerialPortSettings" : { "baudRate":2400, "dataBits":8, "parity":"none", "stopBits":1 }, "PTZOutputURL": "127.0.0.1:9999", "PTZCameraAddress": 1, "DeviceInformation" : { "Manufacturer" : "RPiCam-3B", "Model" : "RPi3B", "HardwareId" : "1.0" }, "logLevel" : 3, "logLevelComment": "## LogLevels are > 1:Error 2:Warning 3:Info 4:Debug", "logSoapCalls" : false }

By the way, I have node v12.22.12 and npm v6.14.16.

Thanks for the reply...I was able to get the mediamtx running on RPI4...Now I ran the rposConfig.JSON by changing the proxy.JSON...but I am not able to get the ONVIF going...I am getting ffmpeg issue

ffmpeg - starting
ffmpeg - finished
ffmpeg exec error: Error: Command failed: ffmpeg -fflags nobuffer -probesize 256 -rtsp_transport tcp -i rtsp://127.0.0.1:8554/stream -vframes 1 -r 1 -s 640x360 -y /dev/shm/snapshot.jpg
ffmpeg version 4.3.6-0+deb11u1+rpt5 Copyright (c) 2000-2023 the FFmpeg developers
built with gcc 10 (Debian 10.2.1-6)
configuration: --prefix=/usr --extra-version=0+deb11u1+rpt5 --toolchain=hardened --incdir=/usr/include/aarch64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --disable-mmal --enable-neon --enable-v4l2-request --enable-libudev --enable-epoxy --enable-sand --libdir=/usr/lib/aarch64-linux-gnu --arch=arm64 --enable-pocketsphinx --enable-libdc1394 --enable-libdrm --enable-vout-drm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
libavutil 56. 51.100 / 56. 51.100
libavcodec 58. 91.100 / 58. 91.100
libavformat 58. 45.100 / 58. 45.100
libavdevice 58. 10.100 / 58. 10.100
libavfilter 7. 85.100 / 7. 85.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 7.100 / 5. 7.100
libswresample 3. 7.100 / 3. 7.100
libpostproc 55. 7.100 / 55. 7.100
[rtsp @ 0x5586036000] method DESCRIBE failed: 404 Not Found
rtsp://127.0.0.1:8554/stream: Server returned 404 Not Found

any pointers for this error....I am running both the 2 different windows/sessions..let me know
--Thanks
Ravi

Answer 9 · 2024-01-24T11:23:22.000Z

why is RTSP method failed coming from....the method in which I am running is fine right??...kindly help me out.
--Ravi

Answer 10 · 2024-01-24T11:32:56.000Z

My ffmpeg conversion from .mp4 to mkv is working fine...do not know why specifically I am getting this error..
any changes need to be made in ffmpeg.??

Answer 11 · 2024-01-24T11:45:59.000Z

when setup for ONVIF is clicked ..ffmpeg is giving the error...any idea where the problem is ??

Answer 12 · 2024-01-27T02:46:54.000Z

Make sure you can play the rtsp stream by using VLC player or similar software.
If your rtsp stream need username and password in order for it to play?
ffmpeg exec error: Error: Command failed: ffmpeg -fflags nobuffer -probesize 256 -rtsp_transport tcp -i rtsp://127.0.0.1:8554/stream -vframes 1 -r 1 -s 640x360 -y /dev/shm/snapshot.jpg
Try change the rtsp path to the "absolute" rtsp path. If the rtsp need username and password, please supply that into the rtsp path also.

Answer 13 · 2024-01-27T02:50:30.000Z

The rtsp path gonna be edit here "rpos/services/media_service.ts" before compile them from .ts to .js.

Answer 14 · 2024-02-08T10:26:13.000Z

Hi ,
I modified under services media_service.js
var cmd = "ffmpeg -fflags nobuffer -probesize 256 -rtsp_transport tcp -i rtsp://10.35.62.108:".concat(_this.config.RTSPPort, "/").concat(_this.config.RTSPName
I gave the absolute path ...but _this.config.RTSPName ..need to change from stream to cam??
as my rtsp is working for rtsp://10.35.62.108:8554/cam

ffmpeg exec error: Error: Command failed: ffmpeg -fflags nobuffer -probesize 256 -rtsp_transport tcp -i rtsp://10.35.62.108:8554/stream -vframes 1 -r 1 -s 640x360 -y /dev/shm/snapshot.jpg
ffmpeg version 4.3.6-0+deb11u1+rpt5 Copyright (c) 2000-2023 the FFmpeg developers

rtsp://10.35.62.108:8554/stream: Server returned 404 Not Found
still getting ffmpeg error ...is the place in which I am modifying is correct..let me know.

rtsp is working...need to get the ONVIF going here.
Thanks
Ravi

Answer 15 · 2024-02-08T11:04:01.000Z

Hi,
Thanks for your reply...
Here is the following way in which I downloaded and started with the rpos

download from
git clone https://github.com/BreeeZe/rpos.git
cd rpos
npm install
do npx gulp
get the rpos.js
now use rposConfig.sample-picam.json to copy and create rposConfig.json..change the IP address here
"IpAddress" : "10.35.62.108",
4 "ServicePort" : 8081,
5 "Username" : "admin",
6 "Password" : "admin",
7 "CameraType" : "picam",
8 "RTSPAddress" : "", "//":"Normally left blank. Used to set RTSP Server Address",
9 "RTSPPort" : 8554,
10 "RTSPName" : "h264",
11 "MulticastEnabled" : false,
12 "RTSPMulticastName" : "h264m",
13 "MulticastAddress" : "224.0.0.1",
14 "MulticastPort" : "10001",
15 "RTSPServer" : 3, "RtspServerComment" : "## Select RTSP Server > 1:RPOS RTSP Server 2:V4L2 RTSP Server by mpromonet (auto selected if MulticastEnabled=true)",
I have used RTSPserver 3 here...with1 getting error
getting the ffmpeg error
ffmpeg exec error: Error: Command failed: ffmpeg -fflags nobuffer -probesize 256 -rtsp_transport tcp -i rtsp://127.0.0.1:8554/h264 -vframes 1 -r 1 -s 640x360 -y /dev/shm/snapshot.jpg
ffmpeg version 4.3.6-0+deb11u1+rpt5 Copyright (c) 2000-2023 the FFmpeg developers

Now any pointers let me know where the errors are so that I can make the changes
thanks
Ravi

Answer 16 · 2024-02-08T11:22:26.000Z

Hi ,
I tried downloading mediamtx and running rtsp...RTSP is running successfully.
but when I change the rposConfig.json under rpos I have this issue.
That's the update.

Answer 17 · 2024-02-11T07:31:28.000Z

When you are running MediMTX you need to
a) stop RPOS from launching a RTSP server
This requires "RTSPServer": 0

b) make sure MediaMTC knows the RTSP URL for the video stream
So if your MediaMTX is on the same computer as RPOS and if, for example, the MediaMTX URL was rtsp://hosrname:8554/stream
then you would set the folloiwng
"RTSPAddress" : "put the IP address of the device running Media MTX here"
"RTSPPort" : 8554,
"RTSPName" : "stream

You can try with "RTSPAddress": "127.0.0.1" but you probably want to put the actual IP address because that RTSPAddress forms part of FFMPEG being used to grab 1 frame of video and make a JPEG and also because ONVIF returns the RTSP URL back to the VMS or CCTV viewing software which will then be told to get video from 127.0.0.1 and not from a real IP address

Answer 18 · 2024-02-11T07:32:03.000Z

I should try and add an RTSPServer option 4 some time to make it launch MediaMTX automatically

Answer 19 · 2024-02-19T02:51:34.000Z

rtsp://10.35.62.108:8554/cam

If your rtsp stream working (verify by play it in VLC Player) with the above path, then in the rposConfig file, the "RTSPName" : "h264" has to change to "RTSPName" : "cam".

By the way, is the rtsp link below working as "rtsp://admin:admin@10.35.62.108:8554/cam"?
Or "rtsp://10.35.62.108:8554/cam" should work?
If "rtsp://10.35.62.108:8554/cam" is working, then in rposConfig file, the "Username" : "" & "Password" : "" gonna leave as is...don't put username and password on it.

Answer 20 · 2024-02-19T12:17:16.000Z

Hi ,
Thanks for all the suggestion ..mediamtx for RTSP and RPOS for ONVIF worked in raspberry pi
MediaMtx_RPOS_stepstoinstall.txt

Thanks for all your help.
--ravi