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• PHP and FFMPEG - Performing intelligent video conversion

  24 décembre 2012, par Andrew

  I have an oddly difficult task to perform. I thought it would be easy, but all my efforts have been fruitless.

  I'm converting videos uploaded to a php script from various formats (.avi, .mpg, .wmv, .mov, etc.) to a single .flv format. The conversion is working great but what I'm having trouble with is the resolution of the videos.

  This is the command I'm currently running (with PHP vars) :

  ffmpeg -i $original -ab 96k -b 700k -ar 44100 -s 640x480 -acodec mp3 $converted

  Both $original and $converted contain the full paths to those files. My problem is that this always converts to 640x480 (like I'm telling it to) even when the source is smaller. Obviously, this is a waste of disk space and bandwidth when the video is downloaded. Also, this doesn't account for input videos being in any aspect ratio other than 4:3, resulting in a "squished" conversion if I upload a 16:9 video.

  There are 3 things I need to do :

  1. Determine the aspect ratio of the original video.
  2. If not 4:3, pad top and bottom with black bars.
  3. Convert to 640x480 if either dimension of the original is larger or a 4:3 aspect ratio relating to the width/height of the original (whichever is closer to 640x480).

  I've run ffmpeg -i on a few videos, but I don't see a consistent format or location to find the original's resolution from. Once I'm able to figure that out, I know I can "do the math" to figure out the right size and specify padding to fix the aspect ratio with -padttop, -padbottom, etc.

• Writing Live-Multimedia-Application using OpenGL & Co. saving output to disc [closed]

  21 janvier 2013, par user1997286

  I want to write an application that does the following thing :

  • Getting Commands via ArtNET (DMX over Ethernet, a Control Protocol) for each object (called Layer)
  • each Layer could be one of the following : Live Camera Stream, Movie, Image
  • each layer could be translated, rotated or stretched
  • on each layer I can set filters (Like a Kaleidoscope Effect, Blur, Color Correction, etc.)
  • the rsulting video-stream is in the 3d-space
  • I want to display each part of the image on one Projector (in total up to 3 ones) using a TripleHead2GO (3 Projectors display a different region of my DVI-Output). Each Projecector-Image should have own Soft-Edge and Keystone parameters.
  • the resulting image will also be shown on a Preview-Screen with some Information overlay.

  I think all that should be possible with opengl and openal (for the movie audio)

  I think I'll use C++, OpenGL for Graphics, OpenAL for Audio, if needed ffmpeg for Video conversion, Ubuntu/Debian as OS.

  The software is used to do Multimedia-Shows on Concerts including Cameras & Co.

  All that should happen Live (On a FullHD output), Having i7 3770, GLX 670 and 16GB of Ram for at least 8 Layers. (4 Live-Images at once + Some Overlays like the Actors Name and some Logos)

  But now comes the question.

  Is it also Posible to do the following with that setting :

  • Writing the output Image with all the 3d translations to a Movie File (To Master a DVD later) with Audio
  • Mixing Audio from different Inputs & Files (Ambience Mics, Signal from the Sound Mixer, Playbacks from my own application) to more than one Mix (eg. one Mix for the Recording, one Mix for Live)
  • Stream that Output Complete or in Parts (e.g. the left Part of the Image) over the Network (For example, Projector 1 is near the Server, so I connect it using DVI, Projector 2+3 is connected to a Computer that receives the streams for that two projectors (with soft edge on each stream) and Screen 4 is outside the Concert Hall and shows the complete Live-Stream.
  • What GUI-Framework should I use for that ?
  • is it perhaps event performant enough to use Java for that ?
  • is it posible to use that mechanism for just rendering (eg. I have stored the cut points on Disc and saved every single camera stream to change some errors later or cut out some parts)

• image mime type detection failed.

  24 février 2013, par Grandt

  image mime type detection failed.
  Rev. 2.11 - 2013-02-24
  
  * Fixed : image mimetype detection failed if EXIF was not installed on
  
  the PHP server.