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• equivalent of QImage::bits() in C/C++

  17 février 2012, par JonnyCplusplus

  I am having an issue using ffmpeg. ffmpeg expects to read in a uint8_t and QImage::bits() is the only way I can generate valid images to feed to ffmpeg to get a valid video. The function ffmpeg(buf) will essentially generate the video I need. The issue is the buffers in each example print out very different results.

  My goad is to get the same result I get with QImage::bits() without using Qt at all. How can I duplicate that using C/C++

  Works:

  QImage getInfo("image");
  uint8_t *buf = getInfo.bits();
  ffmpeg(buff); // this will work great!
  

  This does not work:

  FILE *f;
  long lSize=0;
  uint8_t *buf;
  
  f = fopen ("image", "rb");
  
  fseek (f , 0 , SEEK_END);
  lSize = ftell (f);
  rewind (f);
  
  buf = (uint8_t*)malloc(lSize);
  fread (buf, 1, lSize, f);
  ffmpeg(buf);  //junk video!
  

• video frames render slow using opengl and ffmpeg in iphone

  17 février 2012, par resident_

  I'm developing an video player for iPhone. I'm using ffmpeg libraries to decode frames of video and I'm using opengl 2.0 to render the frames to the screen.

  But my app is very slow render the frames and some videos played slowly.

  I have played AVI, MOV, FLV, MP4 and WMV, and only several AVI files are correct played.

  I don't have much idea of ffmpeg and opengl, and I have used a tutorials and examples until now. But I think that the problem can be two things:

  1. The render method is very slowly. I don't use correctly the glTexSubImage2D function.

  2. I don't scale the frames correctly. I don't use correctly the sws_getContext function.

  I'm here parts of my code, to see if anyone can help me.

  So I use sws_getContext

   ctx->p_sws_ctx = sws_getContext(ctx->p_video_ctx->width, 
                                  ctx->p_video_ctx->height, 
                                  ctx->p_video_ctx->pix_fmt, 
                                  ctx->p_video_ctx->width, 
                                  ctx->p_video_ctx->height,
                                  PIX_FMT_RGB565, SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  
  
  
  // Framebuffer for RGB data
  ctx->p_frame_buffer = malloc(avpicture_get_size(PIX_FMT_RGB565,
                                                  ctx->p_video_ctx->width, 
                                                  ctx->p_video_ctx->height));
  
  avpicture_fill((AVPicture*)ctx->p_picture_rgb, ctx->p_frame_buffer, PIX_FMT_RGB565, 
                 ctx->p_video_ctx->width, 
                 ctx->p_video_ctx->height);
  

  My render method of opengl 2.0

  - (void) render: (uint8_t*) buffer
  

  { [EAGLContext setCurrentContext:context];

  glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebuffer);
  glViewport(0, 0, backingWidth, backingHeight);
  
  glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
  
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  
  // OpenGL loads textures lazily so accessing the buffer is deferred until draw; notify
  // the movie player that we're done with the texture after glDrawArrays.          
  glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, mFrameW, mFrameH, GL_RGB,GL_UNSIGNED_SHORT_5_6_5, buffer);
  
  glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
  
  
  [moviePlayerDelegate bufferDone];
  
  glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer);
  [context presentRenderbuffer:GL_RENDERBUFFER];
  

  }

  Someone, can I Help me?

  Thanks,

• compile opencv2.3.1 in ubuntu 11.10

  17 février 2012, par kyon

  Here is the tutorial I followed:http://thebitbangtheory.wordpress.com/2011/10/23/how-to-install-opencv-2-3-1-in-ubuntu-11-10-oneiric-ocelot-with-python-support/
  I think the problem is ffmpeg, the version I used is 0.8.10, and I installed it in /usr and enabled share, but when I complied opencv,the output was full of

  ./../lib/libopencv_highgui.so.2.3.1: undefined reference to av_codec_get_id' ../../lib/libopencv_highgui.so.2.3.1: undefined reference toav_seek_frame'
  ../../lib/libopencv_highgui.so.2.3.1: undefined reference to `avpicture_get_size

• How can I use ffmpeg avfilter without undefined reference

  17 février 2012, par Himiko

  I want to use the filters provided by ffmepeg in my own program to deal with the videos. And based on the sample provided in the file example of the usage of the filters, I changed into jni method, then compile it using android NDK r7, but there are many undefined reference errors while compiling, all from filters. I am sure that I include the needed headers and compiled the ffmpeg.so with

  --enable-avfilter
  

  I use

  System.loadLibrary("ffmpeg");
  

  and the Android.mk is like this

  
      LOCAL_PATH:= $(call my-dir)
      include $(CLEAR_VARS)
      PATH_TO_FFMPEG_SOURCE:=$(LOCAL_PATH)/ffmpeg
      LOCAL_C_INCLUDES += $(PATH_TO_FFMPEG_SOURCE)
      LOCAL_SHARED_LIBRARIES := -lffmpeg
      LOCAL_LDLIBS := -lffmpeg -lm -lz -ldl
      LOCAL_MODULE    := hello-jni
      LOCAL_SRC_FILES := hello-jni.c
      include $(BUILD_SHARED_LIBRARY)
      include $(LOCAL_PATH)/prebuilt/Android.mk

  I use prebuilt methods. Here are the errors I use ndk-build

  
      D:\Code\Android\hello-jni/jni/hello-jni.c:73: undefined reference to avfilter_get_by_name'
      D:\Code\Android\hello-jni/jni/hello-jni.c:74: undefined reference toavfilter_get_by_name'
      D:\Code\Android\hello-jni/jni/hello-jni.c:75: undefined reference to avfilter_inout_alloc'
      D:\Code\Android\hello-jni/jni/hello-jni.c:76: undefined reference toavfilter_inout_alloc'
      D:\Code\Android\hello-jni/jni/hello-jni.c:83: undefined reference to     avfilter_graph_create_filter'
      D:\Code\Android\hello-jni/jni/hello-jni.c:90: undefined reference toavfilter_graph_create_filter'
      D:\Code\Android\hello-jni/jni/hello-jni.c:108: undefined reference to avfilter_graph_parse'
      D:\Code\Android\hello-jni/jni/hello-jni.c:111: undefined reference toavfilter_graph_config'
      ./obj/local/armeabi/objs/hello-jni/hello-jni.o: In function cropFile':
      D:\Code\Android\hello-jni/jni/hello-jni.c:200: undefined reference toavfilter_graph_free'
  

• illegal text reloc to non_lazy_ptr error while building in xcode 4 with libav* libraries

  17 février 2012, par Oleg

  I'm trying to build a simple application that uses ffmpeg's libav* libraries in xcode 4 and getting the following error:

  ld: illegal text reloc to non_lazy_ptr from /ffmpeg/temp/ffmpeg-0.8/builduni/lib/libavcodec.a(ac3.o) in _ff_ac3_bit_alloc_calc_psd for architecture i386

  I've already tried to run ranlib -c libavcodec.a to fix this problem, but nothing happend. One more thing: my libav* libraries are fat binaries (i386 + x86_64).

  Any ideas what can it be?