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• python serve mp4 files securely [closed]

  4 June 2021, by mariam_gvikvarxar

  I am building video serving service on python (django framework). The main requirement is that users should not be able to see mp4 direct link.

  


  I was thinking about generating .ts files with subprocess using ffmpeg

  


  like this:

  


  import subprocess

infile = 'video.ts'
outfile = 'video.mp4'

subprocess.run(['ffmpeg', '-i', infile, outfile])


  


  but as I guess it will take a lot of resources (in a RAM) if multiple users try to watch videos

  


  How would you solve this problem if you were me?

  


  thanks in advance

  


• Streaming Webcam from Windows 10 to Ubuntu 18.04 via WSL2 and usbip [closed]

  15 June 2021, by Jacob Dallas

  Background
  
Alright so I was able to set up my Windows 10 desktop with WSL2 in order to run Ubuntu 18.04. I'm trying to get the webcam to be accessible and have picked and pieced together the following tutorials in order to get myself to where I am.

  


  

  • https://www.youtube.com/watch?v=IL7Jd9rjgrM

  


  • https://github.com/rpasek/usbip-wsl2-instructions

  


  • https://www.davecorder.org/windows-10/

  


  • https://www.reddit.com/r/bashonubuntuonwindows/comments/gcbjfi/module_usbcore_not_found_in_directory/

  


  • https://dmaiorino.com/?p=12

    

  


  


  The Why
  
"Why would you go through this painstaking effort? Seems dumb." you might be telling yourself. Well I think that it's dumb that WSL2 doesn't have a USB pass-through, so there's that. But I develop on Windows traditionally, and with a recent computer vision project I'm undertaking that incorporates the Nvidia Isaac SDK (only available on Ubuntu 18.04) I was hoping to continue to use Windows to develop, and then Ubuntu 18.04 to test. I'm trying to stay away from dual booting because switching back and forth between OSs is time-consuming.

  


  Current State
  
What I'm able to do is pass through the web camera using usbip from windows using the following commands
  
.\usbip.exe bind -b 1-189
  
.\usbipd.exe -d -4
  

  


  and then on the linux side I connect it by running
  
sudo usbip attach --remote=172.30.64.1 --busid=1-220
  
except that I put in my own remote address and busid

  


  What that results in is the ability to see that the camera is attached and seen by linux, but no matter what program/library I use, none of them are able to open the webcam

  


  Here are some outputs from different commands people have used to display camera information:
  

  


  ~$ v4l2-ctl --list-devices 
Logitech Webcam C930e (usb-vhci_hcd.0-1):
    /dev/video0
    /dev/video1

~$ v4l-info /dev/video0

### v4l2 device info [/dev/video0] ###
general info
    VIDIOC_QUERYCAP
    driver                  : "uvcvideo"
    card                    : "Logitech Webcam C930e"
    bus_info                : "usb-vhci_hcd.0-1"
    version                 : 4.19.84
    capabilities            : 0x84a00001 [VIDEO_CAPTURE,?,?,STREAMING,(null)]

standards

inputs
    VIDIOC_ENUMINPUT(0)
    index                   : 0
    name                    : "Camera 1"
    type                    : CAMERA
    audioset                : 0
    tuner                   : 0
    std                     : 0x0 []
    status                  : 0x0 []

video capture
    VIDIOC_ENUM_FMT(0,VIDEO_CAPTURE)
    index                   : 0
    type                    : VIDEO_CAPTURE
    flags                   : 0
    description             : "YUYV 4:2:2"
    pixelformat             : 0x56595559 [YUYV]
    VIDIOC_ENUM_FMT(1,VIDEO_CAPTURE)
    index                   : 1
    type                    : VIDEO_CAPTURE
    flags                   : 1
    description             : "Motion-JPEG"
    pixelformat             : 0x47504a4d [MJPG]
    VIDIOC_G_FMT(VIDEO_CAPTURE)
    type                    : VIDEO_CAPTURE
    fmt.pix.width           : 640
    fmt.pix.height          : 480
    fmt.pix.pixelformat     : 0x56595559 [YUYV]
    fmt.pix.field           : NONE
    fmt.pix.bytesperline    : 1280
    fmt.pix.sizeimage       : 614400
    fmt.pix.colorspace      : SRGB
    fmt.pix.priv            : 4276996862

controls
    VIDIOC_QUERYCTRL(BASE+0)
    id                      : 9963776
    type                    : INTEGER
    name                    : "Brightness"
    minimum                 : 0
    maximum                 : 255
    step                    : 1
    default_value           : 128
    flags                   : unknown
    VIDIOC_QUERYCTRL(BASE+1)
    id                      : 9963777
    type                    : INTEGER
    name                    : "Contrast"
    minimum                 : 0
    maximum                 : 255
    step                    : 1
    default_value           : 128
    flags                   : unknown
    VIDIOC_QUERYCTRL(BASE+2)
    id                      : 9963778
    type                    : INTEGER
    name                    : "Saturation"
    minimum                 : 0
    maximum                 : 255
    step                    : 1
    default_value           : 128
    flags                   : unknown
    VIDIOC_QUERYCTRL(BASE+12)
    id                      : 9963788
    type                    : BOOLEAN
    name                    : "White Balance Temperature, Auto"
    minimum                 : 0
    maximum                 : 1
    step                    : 1
    default_value           : 1
    flags                   : unknown
    VIDIOC_QUERYCTRL(BASE+19)
    id                      : 9963795
    type                    : INTEGER
    name                    : "Gain"
    minimum                 : 0
    maximum                 : 255
    step                    : 1
    default_value           : 0
    flags                   : unknown
    VIDIOC_QUERYCTRL(BASE+24)
    id                      : 9963800
    type                    : MENU
    name                    : "Power Line Frequency"
    minimum                 : 0
    maximum                 : 2
    step                    : 1
    default_value           : 2
    flags                   : unknown
    VIDIOC_QUERYCTRL(BASE+26)
    id                      : 9963802
    type                    : INTEGER
    name                    : "White Balance Temperature"
    minimum                 : 2000
    maximum                 : 7500
    step                    : 1
    default_value           : 4000
    flags                   : INACTIVE
    VIDIOC_QUERYCTRL(BASE+27)
    id                      : 9963803
    type                    : INTEGER
    name                    : "Sharpness"
    minimum                 : 0
    maximum                 : 255
    step                    : 1
    default_value           : 128
    flags                   : unknown
    VIDIOC_QUERYCTRL(BASE+28)
    id                      : 9963804
    type                    : INTEGER
    name                    : "Backlight Compensation"
    minimum                 : 0
    maximum                 : 1
    step                    : 1
    default_value           : 0
    flags                   : unknown

~$ sudo ffmpeg -y -t 5 -f video4linux2  -i /dev/video0  out.mov
ffmpeg version 3.4.8-0ubuntu0.2 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
  configuration: --prefix=/usr --extra-version=0ubuntu0.2 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
/dev/video0: Input/output error

~$ ffmpeg -f v4l2 -video_size 640x480 -i /dev/video0 -frames 1 out.jpg
ffmpeg version 3.4.8-0ubuntu0.2 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
  configuration: --prefix=/usr --extra-version=0ubuntu0.2 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
/dev/video0: Input/output error


  

  


  I'm not sure if I don't have a specific library, driver, random other thing, but everything I've tried so far seems to not solve the problem.

  
Question
  
Linux sees the web camera, knows that it is a web camera, but is not processing the camera feed. What would you recommend I do to be able to process the video feed? I think this is an issue with my settings when I originally set up linux with menuconfig.
Any help would be appreciated :)

  


• How to use ffmpeg to encode isolated motion vectors (using codecview)

  22 July 2021, by Temmeh

  I have been successfully using this command to superimpose MPEG motion vectors onto a video:

  


  ffmpeg -v error -flags2 +export_mvs -i input.mp4 -vf codecview=mv=pf+bf+bb -y output.mp4

  


  Now I would like to be able to export an h264 mp4 of just the motion vector arrows, like in this example, without the original video layered underneath. I checked the codecview documentation and and did not find a flag or option to do this.

  


  Any help is appreciated!