Recherche avancée

Sur d’autres sites (4804)

• FFmpeg's trim filter to handle movie files with non-zero start_time for a transcoding task ?

  19 août 2014, par Drake

  For a movie file (ex, ooxx.mp4) with non-zero start_time in video stream, the negative start_time (ex, -0.5) can mean skipping first 0.5s frames, and the positive start_time (ex, 0.7s) can mean postponing the playback for 0.7s.

  I’m wondering if we can make use of FFmpeg’s trim filter (or something else) to strip out some video frames (for negative start_time) or put some empty (ex, black) frames ahead (for positive start_time) automatically ?

• 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 !!

• ChromaKey FLV Transparency

  1er décembre 2012, par Mr D

  I have over 20000 FLV's at the moment. They currently have no alpha channel and are all CGI generated text on a black background.

  My issue :
  I need to be able to remove the black background and make it transparent, so I can use these videos to layer over pictures in my flash project.

  It needs to be an automated process, that can go through the whole dir of videos and remove the backgrounds

  What I've tried ?

  I have spent the last three days pulling my hair out. Currently the option I see is to write a custom filter for ffmpeg.

  The end goal :

  Layer the flv videos over randomly generated videos in an adobe air application built in flex.