Raspbian - streaming avec raspivid - temps de latence

Bonjour,
J'utilise raspivid sous raspbian buster sur un raspberry pi 3B+ pour faire du streaming et ça fonctionne mais il y a plusieurs seconds de latence, c'est trop.

raspbian avec une adresse IP : 192.168.0.10 pour créer le flux
raspivid -n -t 0 -w 640 -h 480 -vf -hf -l -o tcp://0.0.0.0:1234

pour lire le flux
vlc avec interface graphique
tcp/h264://192.168.0.10:1234

vlc en ligne de commande
cvlc tcp/h264://192.168.0.10:1234

Les paramètres de raspivid sont les suivants :

"raspistill" Camera App (commit 7cbfbd38d982 Tainted)

Runs camera for specific time, and take JPG capture at end if requested

usage: raspistill [options]

Image parameter commands

-q, --quality : Set jpeg quality <0 to 100>
-r, --raw : Add raw bayer data to jpeg metadata
-l, --latest : Link latest complete image to filename <filename>
-t, --timeout : Time (in ms) before takes picture and shuts down (if not specified, set to 5s)
-th, --thumb : Set thumbnail parameters (x:y:quality) or none
-d, --demo : Run a demo mode (cycle through range of camera options, no capture)
-e, --encoding : Encoding to use for output file (jpg, bmp, gif, png)
-x, --exif : EXIF tag to apply to captures (format as 'key=value') or none
-tl, --timelapse : Timelapse mode. Takes a picture every <t>ms. %d == frame number (Try: -o img_%04d.jpg)
-fp, --fullpreview : Run the preview using the still capture resolution (may reduce preview fps)
-k, --keypress : Wait between captures for a ENTER, X then ENTER to exit
-s, --signal : Wait between captures for a SIGUSR1 or SIGUSR2 from another process
-g, --gl : Draw preview to texture instead of using video render component
-gc, --glcapture : Capture the GL frame-buffer instead of the camera image
-bm, --burst : Enable 'burst capture mode'
-dt, --datetime : Replace output pattern (%d) with DateTime (MonthDayHourMinSec)
-ts, --timestamp : Replace output pattern (%d) with unix timestamp (seconds since 1970)
-fs, --framestart : Starting frame number in output pattern(%d)
-rs, --restart : JPEG Restart interval (default of 0 for none)

GL parameter commands

-gs, --glscene : GL scene square,teapot,mirror,yuv,sobel,vcsm_square
-gw, --glwin : GL window settings <'x,y,w,h'>

Common Settings commands

-?, --help : This help information
-w, --width : Set image width <size>
-h, --height : Set image height <size>
-o, --output : Output filename <filename> (to write to stdout, use '-o -'). If not specified, no file is saved
-v, --verbose : Output verbose information during run
-cs, --camselect : Select camera <number>. Default 0
-md, --mode : Force sensor mode. 0=auto. See docs for other modes available
-gps, --gpsdexif : Apply real-time GPS information to output (e.g. EXIF in JPG, annotation in video (requires libgps.so.22)

Preview parameter commands

-p, --preview : Preview window settings <'x,y,w,h'>
-f, --fullscreen : Fullscreen preview mode
-op, --opacity : Preview window opacity (0-255)
-n, --nopreview : Do not display a preview window

Image parameter commands

-sh, --sharpness : Set image sharpness (-100 to 100)
-co, --contrast : Set image contrast (-100 to 100)
-br, --brightness : Set image brightness (0 to 100)
-sa, --saturation : Set image saturation (-100 to 100)
-ISO, --ISO : Set capture ISO
-vs, --vstab : Turn on video stabilisation
-ev, --ev : Set EV compensation - steps of 1/6 stop
-ex, --exposure : Set exposure mode (see Notes)
-fli, --flicker : Set flicker avoid mode (see Notes)
-awb, --awb : Set AWB mode (see Notes)
-ifx, --imxfx : Set image effect (see Notes)
-cfx, --colfx : Set colour effect (U:V)
-mm, --metering : Set metering mode (see Notes)
-rot, --rotation : Set image rotation (0-359)
-hf, --hflip : Set horizontal flip
-vf, --vflip : Set vertical flip
-roi, --roi : Set region of interest (x,y,w,d as normalised coordinates [0.0-1.0])
-ss, --shutter : Set shutter speed in microseconds
-awbg, --awbgains : Set AWB gains - AWB mode must be off
-drc, --drc : Set DRC Level (see Notes)
-st, --stats : Force recomputation of statistics on stills capture pass
-a, --annotate : Enable/Set annotate flags or text
-3d, --stereo : Select stereoscopic mode
-dec, --decimate : Half width/height of stereo image
-3dswap, --3dswap : Swap camera order for stereoscopic
-ae, --annotateex : Set extra annotation parameters (text size, text colour(hex YUV), bg colour(hex YUV), justify, x, y)
-ag, --analoggain : Set the analog gain (floating point)
-dg, --digitalgain : Set the digital gain (floating point)
-set, --settings : Retrieve camera settings and write to stdout


Notes

Exposure mode options :
off,auto,night,nightpreview,backlight,spotlight,sports,snow,beach,verylong,fixedfps,antishake,fireworks

Flicker avoid mode options :
off,auto,50hz,60hz

AWB mode options :
off,auto,sun,cloud,shade,tungsten,fluorescent,incandescent,flash,horizon

Image Effect mode options :
none,negative,solarise,sketch,denoise,emboss,oilpaint,hatch,gpen,pastel,watercolour,film,blur,saturation,colourswap,washedout,posterise,colourpoint,colourbalance,cartoon

Metering Mode options :
average,spot,backlit,matrix

Dynamic Range Compression (DRC) options :
off,low,med,high


Voilà, quelqu'un aurait une idée pour diminuer le temps de latence ?