Recherche avancée

Sur d’autres sites (6921)

• logos and subtitles in reverse using ffmpeg and OpenGL in iOS 5.0

  6 février 2012, par resident_

  I am using ffmpeg to play video on iOS 5.0. In my app with ffmpeg decoded video frames and use OpenGL to display it.

  But I have a problem I don't resolve it. Chains logos and subtitles of the video image is displayed in reverse. I think that is the problem of rendering OpenGL 2.0 or ffmpeg decoded.

  Can you tell me what is wrong ?, and How I can fix it ?

  Very thanks,

  Edit : I change my prepareTExture method with this :

  - (void) prepareTextureW: (GLuint) texW textureHeight: (GLuint) texH frameWidth: (GLuint) frameW frameHeight: (GLuint) frameH {
  
  
  
  float aspect = (float)frameW/(float)frameH;
  
  float minX=-1.f, minY=-1.f, maxX=1.f, maxY=1.f;
  
  float scale ;
  
  if(aspect>=(float)backingHeight/(float)backingWidth){
  
      // Aspect ratio will retain width.
  
      scale = (float)backingHeight / (float) frameW;
  
      maxY = ((float)frameH * scale) / (float) backingWidth;
  
      minY = -maxY;
  
  } else {
  
      // Retain height.
  
      scale = (float) backingWidth / (float) frameW;
  
      maxX = ((float) frameW * scale) / (float) backingHeight;
  
      minX = -maxX;
  
  }
  
  if(frameTexture) glDeleteTextures(1, &frameTexture);
  
  glEnable(GL_TEXTURE_2D);
  
  glGenTextures(1, &frameTexture);
  
  glBindTexture(GL_TEXTURE_2D, frameTexture);
  
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
  glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
  
  glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
  
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, texW, texH, 0, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, NULL);          
  
  
  
  
  
   verts[0] = maxX;           
  
    verts[1] = maxY;
  
    verts[2] = minX;      
  
    verts[3] = maxY;
  
    verts[4] = maxX;  
  
    verts[5] = minY;
  
    verts[6] = minX;    
  
    verts[7] = minY;
  
  
  
  float s = (float) frameW / (float) texW;
  
  float t = (float) frameH / (float) texH;             
  
  
  
  texCoords[0] = 0.f;        texCoords[1] = 1.f;
  
  texCoords[2] = 1;          texCoords[3] = 1.f;
  
  texCoords[4] = 0.f;        texCoords[5] =0;
  
  texCoords[6] = 1;          texCoords[7] =0;
  
  
  
  mFrameH = frameH;
  
  mFrameW = frameW;
  
  mTexH = texH;
  
  mTexW = texW;
  
  maxS = s;
  
  maxT = t;
  
  
  
  // Just supporting one rotation direction, landscape left.  Rotate Z by 90 degrees.
  
  matSetRotZ(&rot,M_PI_2);
  
  
  
  matMul(&mvp, &rot, &rot);
  
  [self setupShader];    

  }

  And now this is my result : link image

• How do i use libavfilter to deinterlace frames in my video player software

  19 juin 2014, par justanothercoder

  I’m using libavformat/libavcodec/libswscale/libavutil/libavfilter (ffmpeg related libraries) to make a video player.

  I’v gotten into issues with interlaced videos, it just pairs them incorrectly... It always draws the previous bottom frame with the current top frame. Which results in things I don’t want. And i’v tried messing about with the variables around this, it just won’t work. (I haven’t found a player which would play the videos I have correctly, no you can’t have them, i’m sorry)

  I managed to find a way around this, by re-encoding the video with the following command :

  ffmpeg -i video.mp4 -filter:v yadif -vcodec mpeg4 out.avi

  Now what i’d need is directions on how to do this with c++ code, inside my video player.

  I haven’t found any tutorials on the matter and the ffmpeg.c source code is just too alien to me.

  A link to a tutorial would be fine, i just haven’t found it..

  Edit :

  Also this example was worth checking out :

  https://github.com/krieger-od/imgs2video/blob/master/imgs2video.c

  It’s by a gentleman named Andrey Utkin

• FFMpeg Android Stagefright SIGSEGV error (h264 decode)

  19 avril 2013, par Sergey Ochkur

  I need to decode h264 file to YUV on Android 2.3+. As I understand I need to communicate with Stagefright, as it`s the only way now, after closing access with OpenMAX IL implementations. I have used FFmpeg 0.10 (and tried 0.9/0.9.1..) for this issue, compiled it with NDK7 (and also tried NDK6b with the same result) :

    ffmpeg version 0.10 Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Jan 28 2012 14:42:37 with gcc 4.4.3
  
    configuration: --target-os=linux --cross-prefix=arm-linux-androideabi- --arch=arm --cpu=armv7-a --sysroot=/home/grid/Android/Android_NDK/platforms/android-9/arch-arm --disable-avdevice --disable-decoder=h264 --disable-decoder=h264_vdpau --enable-libstagefright-h264 --prefix=build/stagefright/armeabi-v7a --extra-cflags='-Iandroid-source/frameworks/base/include -Iandroid-source/system/core/include -Iandroid-source/frameworks/base/media/libstagefright -Iandroid-source/frameworks/base/include/media/stagefright/openmax -I/home/grid/Android/Android_NDK/sources/cxx-stl/system/include -march=armv7-a -mfloat-abi=softfp -mfpu=neon' --extra-ldflags='-Wl,--fix-cortex-a8 -Landroid-libs -Wl,-rpath-link,android-libs' --extra-cxxflags='-Wno-multichar -fno-exceptions -fno-rtti'
  
    libavutil      51. 34.101 / 51. 34.101
  
    libavcodec     53. 60.100 / 53. 60.100
  
    libavformat    53. 31.100 / 53. 31.100
  
    libavfilter     2. 60.100 /  2. 60.100
  
    libswscale      2.  1.100 /  2.  1.100
  
    libswresample   0.  6.100 /  0.  6.100
  
  Hyper fast Audio and Video encoder
  
  usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...

  Hardware : Beagleboard-Xm + TI Android 2.3 (official)

  So, entering next command give me error with 480p :
  ffmpeg -i /sdcard/Video/480p.mp4

  Stopped (signal) ffmpeg -i /sdcard/Video/480p.mp4

  Full Android "answer" from ADB Logcat :
  http://pastebin.com/76JLgtXX

  Android-developers, does anybody know what this error means and how to deal with it ?
  I tried to make DSP window bigger, but with no luck.
  Commands like "stagefright /sdcard/Video/480p.mp4" works fine.

  P.S. Additionally I found that on some bigger files (720p) Android answers next :

  [libstagefright_h264 @ 0xd479b0] Decode failed : 80000000