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• Progress with rtc.io

  12 août 2014, par silvia

  At the end of July, I gave a presentation about WebRTC and rtc.io at the WDCNZ Web Dev Conference in beautiful Wellington, NZ.

  

  Putting that talk together reminded me about how far we have come in the last year both with the progress of WebRTC, its standards and browser implementations, as well as with our own small team at NICTA and our rtc.io WebRTC toolbox.

  

  One of the most exciting opportunities is still under-exploited : the data channel. When I talked about the above slide and pointed out Bananabread, PeerCDN, Copay, PubNub and also later WebTorrent, that’s where I really started to get Web Developers excited about WebRTC. They can totally see the shift in paradigm to peer-to-peer applications away from the Server-based architecture of the current Web.

  Many were also excited to learn more about rtc.io, our own npm nodules based approach to a JavaScript API for WebRTC.

  

  We believe that the World of JavaScript has reached a critical stage where we can no longer code by copy-and-paste of JavaScript snippets from all over the Web universe. We need a more structured module reuse approach to JavaScript. Node with JavaScript on the back end really only motivated this development. However, we’ve needed it for a long time on the front end, too. One big library (jquery anyone ?) that does everything that anyone could ever need on the front-end isn’t going to work any longer with the amount of functionality that we now expect Web applications to support. Just look at the insane growth of npm compared to other module collections :

  

  For those that – like myself – found it difficult to understand how to tap into the sheer power of npm modules as a font end developer, simply use browserify. npm modules are prepared following the CommonJS module definition spec. Browserify works natively with that and “compiles” all the dependencies of a npm modules into a single bundle.js file that you can use on the front end through a script tag as you would in plain HTML. You can learn more about browserify and module definitions and how to use browserify.

  For those of you not quite ready to dive in with browserify we have prepared prepared the rtc module, which exposes the most commonly used packages of rtc.io through an “RTC” object from a browserified JavaScript file. You can also directly download the JavaScript file from GitHub.

  

  So, I hope you enjoy rtc.io and I hope you enjoy my slides and large collection of interesting links inside the deck, and of course : enjoy WebRTC ! Thanks to Damon, JEeff, Cathy, Pete and Nathan – you’re an awesome team !

  On a side note, I was really excited to meet the author of browserify, James Halliday (@substack) at WDCNZ, whose talk on “building your own tools” seemed to take me back to the times where everything was done on the command-line. I think James is using Node and the Web in a way that would appeal to a Linux Kernel developer. Fascinating !!

• Inconsistent Rotation of Output Video OpenCV

  27 avril 2021, par user530316

  I am reading in mobile videos shot on an iphone (.MOV format). When the video is shot upright, ffmpeg meta data states the video frames are rotated 90 clockwise. When I read the video in with opencv as a .MOV and then outwrite again with opencv as a .mp4, both the input and output videos appear upright. Note I display the video frames using opencv via a while loop :
 cap = cv2.VideoCapture("video.MOV")

  


  ret,frame=cap.read()

  


  while ret:
    cv2.imshow('',frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
    ret,frame = cap.read()
cap.release()
cv2.destroyAllWindows() 


  


  This is not the problem. The problem is that when the same video is run on another machine with the same os and same virtual environment, the videos come out rotated by 90 degrees. Any reason this should happen ?

  


  Both machines are using opencv-python version 4.5.1, ffmpeg 4.2.2, and ffmpeg-python 0.2.0.

  


• ffmpeg stuck in generating thumbnail of video [closed]

  10 décembre 2019, par user6121419

  I’m trying to create a thumbnail of a .mov video with ffmpeg, but it gets stuck.
  I tried the same command on 2 different machines and with different types of arguments, but nothing changed the result. The video itself can be viewed without a problem, so it shouldn’t be corrupted.
  The video was taken on an iphone at 4k 60fps.

  What I’ve tried :

  ffmpeg -i IMG_1001.MOV -ss 00:00:02 -vframes 1 thumbnail.jpg

  It gets stuck at the third last line frame= 0 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.00 bitrate=N/A speed=   0x and from then on, I stopped the process with ctrl+c

  Output :

  ffmpeg version 3.4.6-0ubuntu0.18.04.1 Copyright (c) 2000-2019 the FFmpeg developers
 built with gcc 7 (Ubuntu 7.3.0-16ubuntu3)
 configuration: --prefix=/usr --extra-version=0ubuntu0.18.04.1 --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
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'IMG_1001.MOV':
 Metadata:
   major_brand     : qt
   minor_version   : 0
   compatible_brands: qt
   creation_time   : 2019-11-xx
   com.apple.quicktime.make: Apple
   com.apple.quicktime.model: iPhone 8
   com.apple.quicktime.software: 13.2.2
   com.apple.quicktime.creationdate: 2019-11-xx
 Duration: 00:00:05.18, start: 0.000000, bitrate: 54961 kb/s
   Stream #0:0(und): Video: hevc (Main) (hvc1 / 0x31637668), yuv420p(tv, bt709), 3840x2160, 54851 kb/s, 60 fps, 60 tbr, 600 tbn, 600 tbc (default)
   Metadata:
     creation_time   : 2019-11-xx
     handler_name    : Core Media Data Handler
     encoder         : HEVC
   Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 94 kb/s (default)
   Metadata:
     creation_time   : 2019-11-xx
     handler_name    : Core Media Data Handler
   Stream #0:2(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
   Metadata:
     creation_time   : 2019-11-xx
     handler_name    : Core Media Data Handler
   Stream #0:3(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
   Metadata:
     creation_time   : 2019-11-xx
     handler_name    : Core Media Data Handler
Stream mapping:
 Stream #0:0 -> #0:0 (hevc (native) -> mjpeg (native))
Press [q] to stop, [?] for help
[swscaler @ 0x55d83a288940] deprecated pixel format used, make sure you did set range correctly
Output #0, image2, to 'thumbnail.jpg':
 Metadata:
   major_brand     : qt
   minor_version   : 0
   compatible_brands: qt
   com.apple.quicktime.creationdate: 2019-11-xx
   com.apple.quicktime.make: Apple
   com.apple.quicktime.model: iPhone 8
   com.apple.quicktime.software: 13.2.2
   encoder         : Lavf57.83.100
   Stream #0:0(und): Video: mjpeg, yuvj420p(pc), 3840x2160, q=2-31, 200 kb/s, 60 fps, 60 tbn, 60 tbc (default)
   Metadata:
     creation_time   : 2019-11-xx
     handler_name    : Core Media Data Handler
     encoder         : Lavc57.107.100 mjpeg
   Side data:
     cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
frame=    0 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.00 bitrate=N/A speed=   0x
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)

  Any idea on what it could be ? Am I missing something or could it be that the encoding can’t be read properly by ffmpeg ? Besides that I haven’t found any alternative to generate thumbnails from videos on linux