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• Modifying CISCO openh264 to take image frames and out compressed frames

  16 mai 2017, par Khurram Amin

  Has anyone tried to modify the CISCO openh264 library to take JPEG images as input and compress them into P and I frames (output as frames, NOT video) and similarly to modify decoder to take compressed P and I frames and generate uncompressed-frames ?

  I have a camera looking at a static scene and taking pictures (1280x720p) every 30 second. The scene is almost static. Currenlty I am using JPEG compression to compress each frame individually and it is resulting in an image size of 270KB. This compressed frame is transferred via internet to a storage server. Since there is very little motion in the scene, the ’I’ frame size will be very small (I think it should be 20-50KB). So it will be very cost effective to transmit I frames over internet instead of JPEG images.

  Can anyone guide me to some project or about how to proceed with this task ?

• FFmpeg : use absolute path in "metadata=print:file="

  27 octobre 2022, par Axel Herrmann

  I'm using FFmpeg to extract frames of a video and therefore I want to print the metadata of the video to a text file first (to get the scene\ value of each frame).

  


  This already works for me with something like :

  


  ffmpeg -i input.mp4 -vf "select='gte(scene,0)',metadata=print:file=scenescores.txt" -an -f null -


  


  Because I'm using all this inside of a Java application I want to pass an absolute path (of an temp directory) to print:file= instead of the currently relative one which will write it to the root directory of the project.

  


  But when I try to specify an absolute path like D:\scenescores.txt I get the following error :

  


  [metadata @ 00000203282ff0c0] Unable to parse option value "scenescores.txt" as boolean
[metadata @ 00000203282ff0c0] Error setting option direct to value scenescores.txt.
[Parsed_metadata_1 @ 00000203269bdf00] Error applying options to the filter.
[AVFilterGraph @ 0000020328020840] Error initializing filter 'metadata' with args 'print:file=D:\scenescores.txt'


  


  Is there any way to achieve printing to an absolute path ? Am I missing some escape rules or something ?

  


• Loading shared libraries with Gradle 2.2.1

  12 février 2015, par Gabriel Furstenheim

  I’m trying to use a shared library, libavcodec-56.so, in my Android app and I can’t find the way. I’m using Gradle 2.2.1 and Android Studio 1.0. What I have done so far is the following :

  -I built libavcodec-56.so from source code using a NDK toolchain.

  -I copied libavcodec-56.so into src/main/jniLibs/armeabi

  -I’m able to create a .c file in the project and communicate with the java files using private native void nameOfTheNativeMethod()

  -I can load some external libraries like ldLibs "m"

  However, if I try to use #include <libavcodec></libavcodec>avcodec.h> I get the error

  No such file or directory
  
       #include <libavcodec></libavcodec>avcodec.h>

  My gradle file looks like :

  apply plugin: 'com.android.library'
  
  
  
  android {
  
      compileSdkVersion 21
  
      buildToolsVersion "21.1.2"
  
  
  
      defaultConfig {
  
          minSdkVersion 15
  
          targetSdkVersion 21
  
          versionCode 1
  
          versionName "1.0"
  
          ndk {
  
              moduleName "ffmpeg"
  
              cFlags "-std=c99"   
  
              ldLibs "log",  "m" 
  
          }
  
      }
  
  
  
      sourceSets.main {
  
          jni.srcDirs = ["src/main/jni"];
  
          //jniLibs.srcDirs = ['src/main/jniLibs'];
  
      }
  
  
  
  
  
      buildTypes {
  
          release {
  
              minifyEnabled false
  
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
  
          }
  
      }
  
  }
  
  
  
  dependencies {
  
      compile fileTree(dir: 'libs', include: ['*.jar'])
  
      compile 'com.android.support:appcompat-v7:21.0.3'
  
  
  
  }

  Any ideas ?

  Thanks in advance