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• getting black and white image after encoding

  16 mai 2012, par user1310596

  I am trying to encode image using ffmpeg library and objective c. I am using following code but I am getting black and white image as the result. Is there something to do with pixel format(PIX_FMT) ? Please help me so that I can get colored image.

  av_register_all();
  
  avcodec_init();
  
  avcodec_register_all();
  
  avformat_alloc_context();
  
  
  
  AVCodec *codec;
  
  AVCodecContext *ctx= NULL;
  
  int out_size, size, outbuf_size;
  
  AVFrame *picture;
  
  uint8_t *outbuf;
  
  unsigned char *flvdata = malloc(sizeof(unsigned char) * 30);
  
  
  
  
  
  outbuf_size = 200000;
  
  outbuf = malloc(outbuf_size);
  
  
  
  
  
  printf("Video encoding\n");
  
  
  
  codec = avcodec_find_encoder(CODEC_ID_FLV1);
  
  if (!codec) {
  
          fprintf(stderr, "codec not found\n");
  
          exit(1);
  
  }
  
  
  
  ctx= avcodec_alloc_context();
  
  picture= avcodec_alloc_frame();
  
  
  
  
  
  ctx->width = 320;
  
  ctx->height = 240;
  
  ctx -> sample_rate = 11025;
  
  ctx -> time_base.den = 1000;
  
  ctx -> time_base.num = 23976;
  
  ctx -> codec_id = CODEC_ID_FLV1;
  
  ctx -> codec_type = CODEC_TYPE_VIDEO;
  
  ctx->pix_fmt = PIX_FMT_YUV420P;
  
  
  
  if (avcodec_open(ctx, codec) < 0) {
  
          fprintf(stderr, "could not open codec\n");
  
          exit(1);
  
  }
  
  
  
  outbuf_size = 100000;
  
  outbuf = malloc(outbuf_size);
  
  size = ctx->width * ctx->height;
  
  
  
  AVFrame* outpic = avcodec_alloc_frame();
  
  int nbytes = avpicture_get_size(PIX_FMT_YUV420P, ctx->width, ctx->height);
  
  
  
  uint8_t* outbuffer = (uint8_t*)av_malloc(nbytes);
  
  
  
  fflush(stdout);
  
  
  
  int numBytes = avpicture_get_size(PIX_FMT_YUV420P, ctx->width, ctx->height);
  
  
  
  UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:@"0.jpg"]];
  
  CGImageRef newCgImage = [image CGImage];
  
  
  
  CGDataProviderRef dataProvider = CGImageGetDataProvider(newCgImage);
  
  CFDataRef bitmapData = CGDataProviderCopyData(dataProvider);
  
  long dataLength = CFDataGetLength(bitmapData);
  
  
  
  uint8_t *buffer = (uint8_t *)av_malloc(dataLength);
  
  buffer = (uint8_t *)CFDataGetBytePtr(bitmapData);
  
  
  
  for(int i = 0; i < dataLength; i++)
  
  {
  
          if((i + 1) % 16 == 1 && i != 1)
  
                  printf("\n");
  
          printf("%X\t",buffer[i]); // getting something different than the     actual hex value of the image
  
  }
  
  
  
  
  
  
  
  outpic -> pts = 0;        
  
  
  
  avpicture_fill((AVPicture*)picture, buffer, PIX_FMT_RGB8, ctx->width, ctx->height);
  
  
  
  avpicture_fill((AVPicture*)outpic, outbuffer, PIX_FMT_YUV420P, ctx->width, ctx->height);
  
  
  
  struct SwsContext* fooContext = sws_getContext(ctx->width, ctx->height, 
  
                                                         PIX_FMT_RGB8, 
  
                                                         ctx->width, ctx->height, 
  
                                                         PIX_FMT_YUV420P, 
  
                                                         SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  
  
  sws_scale(fooContext, picture->data, picture->linesize, 0, ctx->height, outpic->data, outpic->linesize);
  
  
  
  printf("abcdefghijklmnop");
  
  out_size = avcodec_encode_video(ctx, outbuf, outbuf_size, outpic);
  
  printf("\n\n out_size %d   outbuf_size %d",out_size,outbuf_size);

  Thanks in advance

• Remove white-xifish.png from makefile dependencies for spec ; it doesn’t appear to

  3 février 2012, par Monty

  Remove white-xifish.png from makefile dependencies for spec ; it doesn’t appear to
  reference it, and trying to install it twice is breaking make install.
  git-svn-id : http://svn.xiph.org/trunk/vorbis@18185 0101bb08-14d6-0310-b084-bc0e0c8e3800
  

  • [DH] doc/Makefile.am
  • [DH] doc/Vorbis_I_spec.html
  • [DH] doc/Vorbis_I_spec.pdf

• ffmpeg return black and white image

  16 décembre 2011, par njai

  Video capture device is kworld dvd maker 2 (em2861)
  It returns the image in "black and white" with green line at the bottom of screen ; but when I tested it with webcam, it worked properly.

  Here is 30s video. http://www.youtube.com/watch?v=7q2wFGVwGGI

  How can I convert it to color ?

  [root@localhost ~]# ffmpeg -f video4linux2 -i /dev/video0 -vcodec mpeg4 -y output.mp4
  
  ffmpeg version git-2011-11-05-5fd1a69, Copyright (c) 2000-2011 the FFmpeg developers
  
  built on Nov  5 2011 21:10:52 with gcc 4.4.4 20100726 (Red Hat 4.4.4-13)
  
  configuration: --enable-libx264 --enable-gpl --enable-libvpx
  
  libavutil    51. 23. 0 / 51. 23. 0
  
  libavcodec   53. 27. 0 / 53. 27. 0
  
  libavformat  53. 18. 0 / 53. 18. 0
  
  libavdevice  53.  4. 0 / 53.  4. 0
  
  libavfilter   2. 47. 0 /  2. 47. 0
  
  libswscale    2.  1. 0 /  2.  1. 0
  
  libpostproc  51.  2. 0 / 51.  2. 0
  
  [video4linux2,v4l2 @ 0x2a64780] Estimating duration from bitrate, this may be inaccurate
  
  Input #0, video4linux2,v4l2, from '/dev/video0':
  
  Duration: N/A, start: 1320637788.113946, bitrate: 165888 kb/s
  
  Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 720x576, 165888 kb/s, 25 tbr, 1000k tbn, 25 tbc
  
  Incompatible pixel format 'yuyv422' for codec 'mpeg4', auto-selecting format 'yuv420p'
  
  [buffer @ 0x2a63920] w:720 h:576 pixfmt:yuyv422 tb:1/1000000 sar:0/1 sws_param:
  
  [buffersink @ 0x2a63cc0] auto-inserting filter 'auto-inserted scale 0' between the filter    'src' and the filter 'out'
  
  [scale @ 0x2a64560] w:720 h:576 fmt:yuyv422 -> w:720 h:576 fmt:yuv420p flags:0x4
  
  Output #0, mp4, to 'output.mp4':
  
  Metadata:
  
  encoder         : Lavf53.18.0
  
  Stream #0:0: Video: mpeg4 ( [0][0][0] / 0x0020), yuv420p, 720x576, q=2-31, 200 kb/s, 25    tbn, 25 tbc
  
  Stream mapping:
  
  Stream #0.0 -> #0.0 (rawvideo -> mpeg4)
  
  Press [q] to stop, [?] for help
  
  frame=  969 fps= 25 q=31.0 Lsize=    1547kB time=00:00:38.76 bitrate= 327.0kbits/s    
  
  video:1538kB audio:0kB global headers:0kB muxing overhead 0.561411%