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• best approach for extracting image sequence from video file in Java

  13 mai 2013, par Daniel Ruf

  Well, there is FFMPEG and some Java bindings and wrappers for it but I need to distribute for each specific platform the right binary file of FFMPEG.

  Isnt there any plain Java solution or library without any dependencies like FFMPEG for converting a video fle to an image sequence ?

  Solutions like FFMPEG, XUGGLER or JMF (abandoned) are not suitable. Is there really no pure Java solution for this ?

  Maybe for specific video codecs / files at least ?

  I just want to extract the images from the video file to jpeg / png files and save them to the disk

• Révision 20065 : image/jpg est parfois envoye par des serveurs mal programmes (http://www.cairn.i...

  27 décembre 2012, par Fil Up

• Encode image to video using ffmpeg (sws_scale)

  26 septembre 2012, par bahar_p

  I'm trying to encode an image to video using ffmpeg library.
  I have these global params :

  //Global params
  
  AVCodec         *codec;
  
  AVCodecContext  *codecCtx;
  
  uint8_t         *output_buffer;
  
  int             output_buffer_size;

  I divided the encoding to 3 methods :
  Initialize the encoder :

  jint Java_com_camera_simpledoublewebcams2_CameraPreview_initencoder(JNIEnv* env,jobject thiz){
  
  avcodec_register_all();
  
  avcodec_init();
  
  av_register_all();
  
  
  
  int fps = 30;
  
  
  
  /* find the H263 video encoder */
  
  codec = avcodec_find_encoder(CODEC_ID_H263);
  
  if (!codec) {
  
      LOGI("avcodec_find_encoder() run fail.");
  
      return -5;
  
  }
  
  
  
  //allocate context
  
  codecCtx = avcodec_alloc_context();
  
  
  
  /* put sample parameters */
  
  codecCtx->bit_rate = 400000;
  
  /* resolution must be a multiple of two */
  
  codecCtx->width = 176;
  
  codecCtx->height = 144;
  
  /* frames per second */
  
  codecCtx->time_base = (AVRational){1,fps};
  
  codecCtx->pix_fmt = PIX_FMT_YUV420P;
  
  codecCtx->codec_id = CODEC_ID_H263;
  
  codecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
  
  
  
  /* open it */
  
  if (avcodec_open(codecCtx, codec) < 0) {
  
      LOGI("avcodec_open() run fail.");
  
      return -10;
  
  }
  
  
  
  //init buffer
  
  output_buffer_size = 500000;
  
  output_buffer = malloc(output_buffer_size);
  
  
  
  return 0;

  }

  Encoding the image :

  jint Java_com_camera_simpledoublewebcams2_CameraPreview_encodejpeg(JNIEnv* env,jobject thiz,jchar* cImage, jint imageSize){
  
  int             out_size;
  
  AVFrame         *picture;
  
  AVFrame         *outpic;
  
  uint8_t         *outbuffer;
  
  
  
  //allocate frame    
  
  picture = avcodec_alloc_frame();    
  
  outpic = avcodec_alloc_frame();
  
  
  
  int nbytes = avpicture_get_size(PIX_FMT_YUV420P, codecCtx->width, codecCtx->height);
  
  outbuffer = (uint8_t*)av_malloc(nbytes);
  
  outpic->pts = 0;
  
  
  
  //fill picture with image
  
  avpicture_fill((AVPicture*)picture, (uint8_t*)cImage, PIX_FMT_RGBA, codecCtx->width, codecCtx->height);
  
  //fill outpic with empty image
  
  avpicture_fill((AVPicture*)outpic, outbuffer, PIX_FMT_YUV420P, codecCtx->width, codecCtx->height);
  
  
  
  //rescale the image 
  
  struct SwsContext* fooContext = sws_getContext(codecCtx->width, codecCtx->height, 
  
                                                         PIX_FMT_RGBA, 
  
                                                         codecCtx->width, codecCtx->height, 
  
                                                         PIX_FMT_YUV420P, 
  
                                                         SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  sws_scale(fooContext, picture->data, picture->linesize, 0, codecCtx->height, outpic->data, outpic->linesize);   
  
  
  
  //encode the image
  
  out_size = avcodec_encode_video(codecCtx, output_buffer, output_buffer_size, outpic);
  
  out_size += avcodec_encode_video(codecCtx, output_buffer, output_buffer_size, outpic);
  
  
  
  //release pictures
  
  av_free(outbuffer);
  
  av_free(picture);
  
  av_free(outpic);
  
  
  
  return out_size;

  }

  And closing the encoder :

  void Java_com_camera_simpledoublewebcams2_CameraPreview_closeencoder(JNIEnv* env,jobject thiz){
  
  free(output_buffer);
  
  avcodec_close(codecCtx);
  
  av_free(codecCtx);

  }

  When I send the first image, I get a result from the encoder. When I try to send another image the program crashes.
  I tried calling init once and then the images, then the close - didn't work.
  I tried calling the init and the close for every image - didn't work.

  Any suggestions ?

  Thanks !

  EDIT : After further research I found that the problem is at sws_scale method.
  Still don't know what is causing this issue...