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• A Windows-compatible C IDE that will be able to compile FFmpeg ?

  6 décembre 2015, par Shimmy

  I want to set up an environment on my PC (Win7x64) that I will be able to combine these projects and compile them into one executable:

  • FFmpeg
  • AMV codec tools

  For this I need an environment that can compile/debug both the above projects (creating a Windows compatible exe).

  Any ideas?

• OpenGL (GLEW) + FFMPEG + VS2010 release build

  6 décembre 2015, par rickhik

  Currently I am working on a application that uses OpenGL (GLEW) and FFMPEG (libav's) in Visual Studio 2010. The GLEW libs are included as Additional Libraries. The libav is set via a header file with extern "c" and pragma comment lib.

  The application opens a OpenGL window which draws some quads with textures via FFMPEG. I want to use this application for my volunteer job at a TV station of a Childrens Hospital.

  The problem I have is building a release version of my project. When I am building a Debug version it all works fine. I get a OpenGL Window with the quads. When I change Debug into Release and start the Debugger, it gives me the message "entry point of procedure __GLEW_EXT_framebuffer_object not found in DLL avcodec-56.dll", which is a bit strange to me because of the fact that the GLEW is not part of the avcodec-56.dll?

  I can solve this issue by going to the project settings -> Linker -> Optimization and switch References from Yes(/OPT:REF) to No(/OPT:NOREF). I start the debugger to build the solution and it works as well. Now when I go to the Release folder of the project and start the build executable, the OpenGL Window stays black without giving me an error message.

  I hope you guys can help me out.

  @michael-iv I saw you had a similar issue

• how to change the frame rate and capturing image size from IP camera

  6 décembre 2015, par rockycai

  Now I have a IP camera and I want to capture image from it through RTSP.I use below code and it works well.But the camera's frame rate is 25/s.So I got a lot of images per second.I don't want it.And per image is 6.2MB.I also don't want need to get high quality image.What can I do to slower the frame rate and smaller the size of image?

  #ifndef INT64_C
  #define INT64_C(c) (c ## LL)
  #define UINT64_C(c) (c ## ULL)
  #endif
  
  #ifdef __cplusplus
  extern "C" {
  #endif
      /*Include ffmpeg header file*/
  #include avformat.h>
  #include avcodec.h>
  #include swscale.h>
  #include 
  #ifdef __cplusplus
  }
  #endif
  
  #include 
  
  
  static void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame);
  
  int main (int argc, const char * argv[])
  {
      AVFormatContext *pFormatCtx;
      int             i, videoStream;
      AVCodecContext  *pCodecCtx;
      AVCodec         *pCodec;
      AVFrame         *pFrame; 
      AVFrame         *pFrameRGB;
      AVPacket        packet;
      int             frameFinished;
      int             numBytes;
      uint8_t         *buffer;
  
      // Register all formats and codecs
      av_register_all();
  //  const char *filename="C:\libraries\gfjyp.avi";
      // Open video file
      //AVDictionary *options = NULL;
      //av_dict_set(&options,"rtsp_transport","tcp",0);
      if(av_open_input_file(&pFormatCtx, argv[1], NULL, 0, NULL)!=0)
          return -1; // Couldn't open file
  
      // Retrieve stream information
      if(av_find_stream_info(pFormatCtx)<0)
          return -1; // Couldn't find stream information
  
      // Dump information about file onto standard error
      dump_format(pFormatCtx, 0, argv[1], false);
  
      // Find the first video stream
      videoStream=-1;
      for(i=0; inb_streams; i++)
          if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO)
          {
              videoStream=i;
              break;
          }
          if(videoStream==-1)
              return -1; // Didn't find a video stream
  
          // Get a pointer to the codec context for the video stream
          pCodecCtx=pFormatCtx->streams[videoStream]->codec;
  
          // Find the decoder for the video stream
          pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
          if(pCodec==NULL)
              return -1; // Codec not found
  
          // Open codec
          if(avcodec_open(pCodecCtx, pCodec)<0)
              return -1; // Could not open codec
  
          // Hack to correct wrong frame rates that seem to be generated by some codecs
  
          if(pCodecCtx->time_base.num>1000 && pCodecCtx->time_base.den==1)
              pCodecCtx->time_base.den=1000;
  
          //pCodecCtx->time_base.den=1;
          //pCodecCtx->time_base.num=1;
          // Allocate video frame
          pFrame=avcodec_alloc_frame();
  
          // Allocate an AVFrame structure
          pFrameRGB=avcodec_alloc_frame();
          if(pFrameRGB==NULL)
              return -1;
  
          // Determine required buffer size and allocate buffer
          numBytes=avpicture_get_size(PIX_FMT_RGB24, pCodecCtx->width,
              pCodecCtx->height);
  
          //buffer=malloc(numBytes);
          buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
  
          // Assign appropriate parts of buffer to image planes in pFrameRGB
          avpicture_fill((AVPicture *)pFrameRGB, buffer, PIX_FMT_RGB24,
              pCodecCtx->width, pCodecCtx->height);
  
          // Read frames and save first five frames to disk
          i=0;
          while(av_read_frame(pFormatCtx, &packet)>=0)
          {
              // Is this a packet from the video stream?
              if(packet.stream_index==videoStream)
              {
                  // Decode video frame
                  avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, 
                      &packet);
  
                  // Did we get a video frame?
                  if(frameFinished)
                  {
  
                      static struct SwsContext *img_convert_ctx;
  
  #if 0
                      // Older removed code
                      // Convert the image from its native format to RGB swscale
                      img_convert((AVPicture *)pFrameRGB, PIX_FMT_RGB24, 
                          (AVPicture*)pFrame, pCodecCtx->pix_fmt, pCodecCtx->width, 
                          pCodecCtx->height);
  
                      // function template, for reference
                      int sws_scale(struct SwsContext *context, uint8_t* src[], int srcStride[], int srcSliceY,
                          int srcSliceH, uint8_t* dst[], int dstStride[]);
  #endif
                      // Convert the image into YUV format that SDL uses
                      if(img_convert_ctx == NULL) {
                          int w = pCodecCtx->width;
                          int h = pCodecCtx->height;
  
                          img_convert_ctx = sws_getContext(w, h, 
                              pCodecCtx->pix_fmt, 
                              w, h, PIX_FMT_RGB24, SWS_BICUBIC,
                              NULL, NULL, NULL);
                          if(img_convert_ctx == NULL) {
                              fprintf(stderr, "Cannot initialize the conversion context!\n");
                              exit(1);
                          }
                      }
                      int ret = sws_scale(img_convert_ctx, pFrame->data, pFrame->linesize, 0, 
                          pCodecCtx->height, pFrameRGB->data, pFrameRGB->linesize);
  #if 0 
                      // this use to be true, as of 1/2009, but apparently it is no longer true in 3/2009
                      if(ret) {
                          fprintf(stderr, "SWS_Scale failed [%d]!\n", ret);
                          exit(-1);
                      }
  #endif
  
                      // Save the frame to disk
                      if(i++<=1000)
                          SaveFrame(pFrameRGB, pCodecCtx->width, pCodecCtx->height, i);
                  }
              }
  
              // Free the packet that was allocated by av_read_frame
              av_free_packet(&packet);
              //sleep(1);
          }
  
          // Free the RGB image
          //free(buffer);
          av_free(buffer);
          av_free(pFrameRGB);
  
          // Free the YUV frame
          av_free(pFrame);
  
          // Close the codec
          avcodec_close(pCodecCtx);
  
          // Close the video file
          av_close_input_file(pFormatCtx);
  
          return 0;
  }
  
  static void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame)
  {
      FILE *pFile;
      char szFilename[32];
      int  y;
  
      // Open file
      sprintf(szFilename, "frame%d.ppm", iFrame);
      pFile=fopen(szFilename, "wb");
      if(pFile==NULL)
          return;
  
      // Write header
      fprintf(pFile, "P6\n%d %d\n255\n", width, height);
  
      // Write pixel data
      for(y=0; ydata[0]+y*pFrame->linesize[0], 1, width*3, pFile);
  
      // Close file
      fclose(pFile);
  }
  

• Tainted canvas may not be exported. When trying to send it via ajax to php file

  6 décembre 2015, par romikette F

  I am trying to capture an image from a local video so I can make a thumb out of it. I am trying to avoid using video conversions (like ffmpeg) to save server resources and keep my videos in theyr original format. I'we been reading about tainted canvases and I understand I am trying to breach the browsers security protocols. But this article https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image#What_is_a_tainted_canvas said that I could pull an image if it were from a different source (something something). So far I have this:

  
  
  Capture 
  
  
  
   
  
  
  

  and:

  function capture(){
  var canvas = document.getElementById('mYcanvas');
  var video = document.getElementById('video');
  canvas.getContext('2d').drawImage(video, 0, 0, video.videoWidth, video.videoHeight);
  
  function getBase64() {
  var img = document.getElementById("mYcanvas");
  var canvas = document.createElement("canvas");
  canvas.width = img.width;
  canvas.height = img.width;
  var ctx = canvas.getContext("2d");
  ctx.drawImage(img, 0, 0);
  var dataURL = canvas.toDataURL("image/png");
  alert(dataURL.replace(/^data:image\/(png|jpg);base64,/, "")); 
  
  $.ajax({
      url: 'submit_image.php',
      type: 'POST',
      data: {
          imgdata: dataURL
      },
      success: function (res) {
              document.getElementById("response").innerHTML = res;
          }
  });
  }
  getBase64();
  
  }
  

  Never mind the php. It dose not receive anything.

• arm-linux-androideabi-gcc is unable to create an executable - compile ffmpeg for android armeabi devices

  6 décembre 2015, par Chaitanya Chandurkar

  I am trying to compile ffmpeg for android armeabi devices.
  I am following tutorial by roman10.net
  His given build script builds ffmpeg for armv7-a devices. I want to build it for armeabi.
  

  My ultimate aim is to run ffmpeg commands on android armeabi and armv7-a devices.

  So I change the script's CPU part from

  #arm v7vfpv3
  CPU=armv7-a
  OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfpv3-d16 -marm -march=$CPU "
  PREFIX=./android/$CPU
  ADDITIONAL_CONFIGURE_FLAG=
  build_one 
  

  to

  #arm v6
  CPU=armv6
  OPTIMIZE_CFLAGS="-marm -march=$CPU"
  PREFIX=./android/$CPU 
  ADDITIONAL_CONFIGURE_FLAG=
  build_one
  

  (I thought changing it to armv6 would build ffmpeg compatible with armeabi devices. m I wrong?)

  Doubt 1:
  Do I also have to change toolchain?
  i.e from arm-linux-androideabi-4.4.3 to arm-eabi-4.4.0 ?????

  Doubt 2:

  When I try running ./build.sh (without changing toolchain) it gives me following error:
  

  /home/chaitanya/android/android-ndk-r5b/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc is unable to create an executable file.
  C compiler test failed.
  
  If you think configure made a mistake,.. blaah blahh blaah
  

  after that I got lot of warnings saying:
  ‘sub_id’ is deprecated and many other function deprecated warnings.

  platform: ubuntu 11.10
  ffmpeg version: 0.11.2
  NDK : android-ndk-r5b

  Here is my build script:

  #!/bin/bash
  ######################################################
  # Usage:
  # put this script in top of FFmpeg source tree
  # ./build_android
  # It generates binary for following architectures:
  # ARMv6 
  # ARMv6+VFP 
  # ARMv7+VFM-ïd16 (Tegra2) 
  # ARMv7+Neon (Cortex-A8)
  # Customizing:
  # 1. Feel free to change ./configure parameters for more features
  # 2. To adapt other ARM variants
  # set $CPU and $OPTIMIZE_CFLAGS 
  # call build_one
  ######################################################
  NDK=~/android/android-ndk-r5b
  PLATFORM=$NDK/platforms/android-8/arch-arm/
  PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86
  function build_one
  {
  ./configure --target-os=linux \
      --prefix=$PREFIX \
      --enable-cross-compile \
      --extra-libs="-lgcc" \
      --arch=arm \
      #--cc=$PREBUILT/bin/arm-linux-androideabi-gcc \
      --cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \
      #--nm=$PREBUILT/bin/arm-linux-androideabi-nm \
      --sysroot=$PLATFORM \
      --extra-cflags=" -O3 -fpic -DANDROID -DHAVE_SYS_UIO_H=1 -Dipv6mr_interface=ipv6mr_ifindex -fasm -Wno-psabi -fno-short-enums -fno-strict-aliasing -finline-limit=300 $OPTIMIZE_CFLAGS " \
      --disable-shared \
      --enable-static \
      --extra-ldflags="-Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -nostdlib -lc -lm -ldl -llog" \
      --disable-everything \
      --enable-demuxer=mov \
      --enable-demuxer=h264 \
      --disable-ffplay \
      --enable-protocol=file \
      --enable-avformat \
      --enable-avcodec \
      --enable-decoder=rawvideo \
      --enable-decoder=mjpeg \
      --enable-decoder=h263 \
      --enable-decoder=mpeg4 \
      --enable-decoder=h264 \
      --enable-parser=h264 \
      --disable-network \
      --enable-zlib \
      --disable-avfilter \
      --disable-avdevice \
      $ADDITIONAL_CONFIGURE_FLAG
  
  make clean
  make  -j4 install
  $PREBUILT/bin/arm-linux-androideabi-ar d libavcodec/libavcodec.a inverse.o
  $PREBUILT/bin/arm-linux-androideabi-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib  -soname libffmpeg.so -shared -nostdlib  -z,noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffmpeg.so libavcodec/libavcodec.a libavformat/libavformat.a libavutil/libavutil.a libswscale/libswscale.a -lc -lm -lz -ldl -llog  --warn-once  --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/arm-linux-androideabi/4.4.3/libgcc.a
  }
  
  #arm v6
  CPU=armv6
  OPTIMIZE_CFLAGS="-marm -march=$CPU"
  PREFIX=./android/$CPU 
  ADDITIONAL_CONFIGURE_FLAG=
  build_one
  
  #arm v7vfpv3
  #CPU=armv7-a
  #OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfpv3-d16 -marm -march=$CPU "
  #PREFIX=./android/$CPU
  #ADDITIONAL_CONFIGURE_FLAG=
  #build_one
  
  #arm v7vfp
  #CPU=armv7-a
  #OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU "
  #PREFIX=./android/$CPU-vfp
  #ADDITIONAL_CONFIGURE_FLAG=
  #build_one
  
  #arm v7n
  #CPU=armv7-a
  #OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=neon -marm -march=$CPU -mtune=cortex-a8"
  #PREFIX=./android/$CPU 
  #ADDITIONAL_CONFIGURE_FLAG=--enable-neon
  #build_one
  
  #arm v6+vfp
  #CPU=armv6
  #OPTIMIZE_CFLAGS="-DCMP_HAVE_VFP -mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU"
  #PREFIX=./android/${CPU}_vfp 
  #ADDITIONAL_CONFIGURE_FLAG=
  #build_one
  

  How do I tackle this problem? what is going wrong?