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• http: Reorder two code blocks

  10 novembre 2011, par Martin Storsjö

  http: Reorder two code blocks

• FFmpeg sample code for creating a video file from still images JNI Android

  21 juin 2012, par anish

  How i modify the following FFMPEG sample code for creating a video file from still images that i am having in my android phone. I am using JNI for invoking ffmpeg.

  JNIEXPORT void JNICALL videoEncodeExample((JNIEnv *pEnv, jobject pObj, jstring filename)
  
  
  
      {
  
       AVCodec *codec;
  
       AVCodecContext *c= NULL;
  
       int i, out_size, size, x, y, outbuf_size;
  
       FILE *f;
  
       AVFrame *picture;
  
       uint8_t *outbuf, *picture_buf;
  
  
  
       printf("Video encoding\n");
  
  
  
       /* find the mpeg1 video encoder */
  
       codec = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO);
  
       if (!codec) {
  
           fprintf(stderr, "codec not found\n");
  
           exit(1);
  
       }
  
  
  
       c= avcodec_alloc_context();
  
       picture= avcodec_alloc_frame();
  
  
  
       /* put sample parameters */
  
       c->bit_rate = 400000;
  
       /* resolution must be a multiple of two */
  
       c->width = 352;
  
       c->height = 288;
  
       /* frames per second */
  
       c->time_base= (AVRational){1,25};
  
       c->gop_size = 10; /* emit one intra frame every ten frames */
  
       c->max_b_frames=1;
  
       c->pix_fmt = PIX_FMT_YUV420P;
  
  
  
       /* open it */
  
       if (avcodec_open(c, codec) < 0) {
  
           fprintf(stderr, "could not open codec\n");
  
           exit(1);
  
       }
  
  
  
       f = fopen(filename, "wb");
  
       if (!f) {
  
           fprintf(stderr, "could not open %s\n", filename);
  
           exit(1);
  
       }
  
  
  
       /* alloc image and output buffer */
  
       outbuf_size = 100000;
  
       outbuf = malloc(outbuf_size);
  
       size = c->width * c->height;
  
       picture_buf = malloc((size * 3) / 2); /* size for YUV 420 */
  
  
  
       picture->data[0] = picture_buf;
  
       picture->data[1] = picture->data[0] + size;
  
       picture->data[2] = picture->data[1] + size / 4;
  
       picture->linesize[0] = c->width;
  
       picture->linesize[1] = c->width / 2;
  
       picture->linesize[2] = c->width / 2;
  
  
  
       /* encode 1 second of video */
  
       for(i=0;i<25;i++) {
  
           fflush(stdout);
  
           /* prepare a dummy image */
  
           /* Y */
  
           for(y=0;yheight;y++) {
  
               for(x=0;xwidth;x++) {
  
                   picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
  
               }
  
           }
  
  
  
           /* Cb and Cr */
  
           for(y=0;yheight/2;y++) {
  
               for(x=0;xwidth/2;x++) {
  
                   picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
  
                   picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
  
               }
  
           }
  
  
  
           /* encode the image */
  
           out_size = avcodec_encode_video(c, outbuf, outbuf_size, picture);
  
           printf("encoding frame %3d (size=%5d)\n", i, out_size);
  
           fwrite(outbuf, 1, out_size, f);
  
       }
  
  
  
       /* get the delayed frames */
  
       for(; out_size; i++) {
  
           fflush(stdout);
  
  
  
           out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
  
           printf("write frame %3d (size=%5d)\n", i, out_size);
  
           fwrite(outbuf, 1, out_size, f);
  
       }
  
  
  
       /* add sequence end code to have a real mpeg file */
  
       outbuf[0] = 0x00;
  
       outbuf[1] = 0x00;
  
       outbuf[2] = 0x01;
  
       outbuf[3] = 0xb7;
  
       fwrite(outbuf, 1, 4, f);
  
       fclose(f);
  
       free(picture_buf);
  
       free(outbuf);
  
  
  
       avcodec_close(c);
  
       av_free(c);
  
       av_free(picture);
  
       printf("\n");
  
      }

  Thanks and Regards
  Anish

• Why doesn't this FFmpeg code create a video from a series of images ?

  20 octobre 2011, par user551117

  I have successfully compiled the FFmpeg library for use in an iOS application. I would like to use it for encoding a video from a series of images, but I can't seem to make it work.

  The following is the code that I am using to encode this video :

  AVCodec *codec;
  
  AVCodecContext *c= NULL;
  
  int i, out_size, size, outbuf_size;
  
  FILE *f;
  
  AVFrame *picture;
  
  uint8_t *outbuf;
  
  
  
  printf("Video encoding\n");
  
  
  
  /// find the mpeg video encoder
  
  codec=avcodec_find_encoder(CODEC_ID_MPEG4);
  
  //codec = avcodec_find_encoder(CODEC_ID_MPEG4);
  
  if (!codec) {
  
      fprintf(stderr, "codec not found\n");
  
      exit(1);
  
  }
  
  
  
  c= avcodec_alloc_context();
  
  picture= avcodec_alloc_frame();
  
  
  
  // put sample parameters 
  
  c->bit_rate = 400000;
  
  /// resolution must be a multiple of two 
  
  c->width = 320;
  
  c->height = 480;
  
  //frames per second 
  
  c->time_base= (AVRational){1,25};
  
  c->gop_size = 10; /// emit one intra frame every ten frames
  
  c->max_b_frames=1;
  
  c->pix_fmt = PIX_FMT_YUV420P;
  
  
  
  //open it
  
  if (avcodec_open(c, codec) < 0) {
  
      fprintf(stderr, "could not open codec\n");
  
      exit(1);
  
  }
  
  
  
  f = fopen([[NSTemporaryDirectory() stringByAppendingPathComponent:filename] UTF8String], "w");
  
  if (!f) {
  
      fprintf(stderr, "could not open %s\n",[filename UTF8String]);
  
      exit(1);
  
  }
  
  
  
  // alloc image and output buffer
  
  outbuf_size = 100000;
  
  outbuf = malloc(outbuf_size);
  
  size = c->width * c->height;
  
  
  
  #pragma mark -
  
  AVFrame* outpic = avcodec_alloc_frame();
  
  int nbytes = avpicture_get_size(PIX_FMT_YUV420P, c->width, c->height);
  
  
  
  //create buffer for the output image
  
  uint8_t* outbuffer = (uint8_t*)av_malloc(nbytes);
  
  
  
  #pragma mark -  
  
  for(i=1;i<48;i++) {
  
      fflush(stdout);
  
  
  
      int numBytes = avpicture_get_size(PIX_FMT_YUV420P, c->width, c->height);
  
      uint8_t *buffer = (uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
  
  
  
      UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:@"%d.png", i]];
  
      CGImageRef newCgImage = [image CGImage];
  
  
  
      CGDataProviderRef dataProvider = CGImageGetDataProvider(newCgImage);
  
      CFDataRef bitmapData = CGDataProviderCopyData(dataProvider);
  
      buffer = (uint8_t *)CFDataGetBytePtr(bitmapData);   
  
  
  
      avpicture_fill((AVPicture*)picture, buffer, PIX_FMT_RGB24, c->width, c->height);
  
      avpicture_fill((AVPicture*)outpic, outbuffer, PIX_FMT_YUV420P, c->width, c->height);
  
  
  
      struct SwsContext* fooContext = sws_getContext(c->width, c->height, 
  
                                                     PIX_FMT_RGB24, 
  
                                                     c->width, c->height, 
  
                                                     PIX_FMT_YUV420P, 
  
                                                     SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  
  
      //perform the conversion
  
      sws_scale(fooContext, picture->data, picture->linesize, 0, c->height, outpic->data, outpic->linesize);
  
      // Here is where I try to convert to YUV
  
  
  
      // encode the image
  
  
  
      out_size = avcodec_encode_video(c, outbuf, outbuf_size, outpic);
  
      printf("encoding frame %3d (size=%5d)\n", i, out_size);
  
      fwrite(outbuf, 1, out_size, f);
  
  
  
      free(buffer);
  
      buffer = NULL;      
  
  
  
  }
  
  
  
  // get the delayed frames
  
  for(; out_size; i++) {
  
      fflush(stdout);
  
  
  
      out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
  
      printf("write frame %3d (size=%5d)\n", i, out_size);
  
      fwrite(outbuf, 1, outbuf_size, f);      
  
  }
  
  
  
  // add sequence end code to have a real mpeg file
  
  outbuf[0] = 0x00;
  
  outbuf[1] = 0x00;
  
  outbuf[2] = 0x01;
  
  outbuf[3] = 0xb7;
  
  fwrite(outbuf, 1, 4, f);
  
  fclose(f);
  
  free(outbuf);
  
  
  
  avcodec_close(c);
  
  av_free(c);
  
  av_free(picture);
  
  printf("\n");

  What could be wrong with this code ?