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• First image not showing image to video using ffmpeg

  3 octobre 2014, par death_relic0

  I am very new to ffmpeg and trying to convert a series of images to a video.

  The command I am using (copied/modified from a tutorial)

  ffmpeg -framerate 1/5 -start_number 1 -i dog%01d.jpg -c:v libx264 -r 30 -pix_fmt rgb24 dog.mp4

  Basically, I have 4 images labelled dog1.jpg, dog2.jpg, dog3.jpg and dog4.jpg.

  The problem is the output video I get has image starting at "dog2.jpg" and ending at "dog4.jpg" meaning that it is missing the first image in the sequence (i.e dog1.jpg).

  I tried with different image combinations and the same behavior happened, the resulting video never had the first image in the sequence.

  Any ideas ?

• FFMpeg encoded video will only play in FFPlay

  8 novembre 2013, par mohM

  I've been debugging my program for a couple of weeks now with the output video only showing a blank screen (was testing with VLC, WMP and WMPClassic). I happened to try using FFPlay and lo and behold the video works perfectly. I've read that this is usually caused by an incorrect pixel format, and that switching to PIX_FMT_YUV420P will make it work universally...but I'm already using that pixel format in the encoding process. Is there anything else that is causing this ?

  AVCodec* codec;
  
  AVCodecContext* c = NULL;
  
  uint8_t* outbuf;
  
  int i, out_size, outbuf_size;
  
  
  
  avcodec_register_all();
  
  
  
  printf("Video encoding\n");
  
  
  
  // Find the mpeg1 video encoder
  
  codec = avcodec_find_encoder(CODEC_ID_H264);
  
  if (!codec) {
  
      fprintf(stderr, "Codec not found\n");
  
      exit(1);
  
  }
  
  else printf("H264 codec found\n");
  
  
  
  c = avcodec_alloc_context3(codec);
  
  
  
  c->bit_rate = 400000;
  
  c->width = 1920;                                        // resolution must be a multiple of two (1280x720),(1900x1080),(720x480)
  
  c->height = 1200;
  
  c->time_base.num = 1;                                   // framerate numerator
  
  c->time_base.den = 25;                                  // framerate denominator
  
  c->gop_size = 10;                                       // emit one intra frame every ten frames
  
  c->max_b_frames = 1;                                    // maximum number of b-frames between non b-frames
  
  //c->keyint_min = 1;                                        // minimum GOP size
  
  //c->i_quant_factor = (float)0.71;                      // qscale factor between P and I frames
  
  //c->b_frame_strategy = 20;
  
  //c->qcompress = (float)0.6;
  
  //c->qmin = 20;                                         // minimum quantizer
  
  //c->qmax = 51;                                         // maximum quantizer
  
  //c->max_qdiff = 4;                                     // maximum quantizer difference between frames
  
  //c->refs = 4;                                          // number of reference frames
  
  //c->trellis = 1;                                           // trellis RD Quantization
  
  c->pix_fmt = PIX_FMT_YUV420P;
  
  c->codec_id = CODEC_ID_H264;
  
  //c->codec_type = AVMEDIA_TYPE_VIDEO;
  
  
  
  // Open the encoder
  
  if (avcodec_open2(c, codec,NULL) < 0) {
  
      fprintf(stderr, "Could not open codec\n");
  
      exit(1);
  
  }
  
  else printf("H264 codec opened\n");
  
  
  
  outbuf_size = 100000 + c->width*c->height*(32>>3);//*(32>>3);           // alloc image and output buffer
  
  outbuf = static_cast(malloc(outbuf_size));
  
  printf("Setting buffer size to: %d\n",outbuf_size);
  
  
  
  FILE* f = fopen("example.mpg","wb");
  
  if(!f) printf("x  -  Cannot open video file for writing\n");
  
  else printf("Opened video file for writing\n");
  
  
  
  // encode 5 seconds of video
  
  for(i=0;iwidth, c->height);
  
      uint8_t* outbuffer = (uint8_t*)av_malloc(nbytes*sizeof(uint8_t));
  
  
  
      AVFrame* inpic = avcodec_alloc_frame();
  
      AVFrame* outpic = avcodec_alloc_frame();
  
  
  
      outpic->pts = (int64_t)((float)i * (1000.0/((float)(c->time_base.den))) * 90);
  
      avpicture_fill((AVPicture*)inpic, (uint8_t*)pPixels, PIX_FMT_RGB32, c->width, c->height);                   // Fill picture with image
  
      avpicture_fill((AVPicture*)outpic, outbuffer, PIX_FMT_YUV420P, c->width, c->height);
  
      av_image_alloc(outpic->data, outpic->linesize, c->width, c->height, c->pix_fmt, 1); 
  
  
  
      inpic->data[0] += inpic->linesize[0]*(screenHeight-1);                                                      // Flipping frame
  
      inpic->linesize[0] = -inpic->linesize[0];                                                                   // Flipping frame
  
  
  
      struct SwsContext* fooContext = sws_getContext(screenWidth, screenHeight, PIX_FMT_RGB32, c->width, c->height, PIX_FMT_YUV420P, SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
      sws_scale(fooContext, inpic->data, inpic->linesize, 0, c->height, outpic->data, outpic->linesize);
  
  
  
      // 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);
  
      delete [] pPixels;
  
      av_free(outbuffer);     
  
      av_free(inpic);
  
      av_free(outpic);
  
  }
  
  
  
  // get the delayed frames
  
  for(; out_size; i++) {
  
      fflush(stdout);
  
  
  
      out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
  
      printf("Writing 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);
  
  
  
  avcodec_close(c);
  
  free(outbuf);
  
  av_free(c);
  
  printf("Closed codec and Freed\n");

• FFMPEG not converting mp3 to ogg

  25 juillet 2013, par nbs189

  I have a php upload script that converts MP3 files after they have been uploaded. I am keeping the mp3 file which is why I am doing it afterwards. A copy is created and then that is converted to ogg. The problem i am having is with FFMPEG as it is just not doing anything. I have never used FFMPEG or a tool like it before, nor have I used PHP's exec() function so I really have no idea how to use it but I have had a thorough look around for my answer before I came here.

  exec("ffmpeg -i ".$target_path."".$hash_filename.".".$path_extension."  ".$hash_filename.".ogg");

  What the function could look like with data instead of variables :

  ffmpeg -i ../uploads/ee78d5deb564901626067cc0008456ed.mp3 ee78d5deb564901626067cc0008456ed.ogg

  I have checked with SSH and FFMPEG is located under the usual usr/bin/ffmpeg. I wondered if I should be targeting the file from where FFMPEG is or where the phpscript is but I have had no luck with either. Perhaps I am still targeting it from the wrong place ?

  I have checked and the codecs required for mp3 to ogg conversion are installed. I did also try adding those codecs into the command but the same thing happened. I understand FFMPEG automatically chooses which codecs to use so I ommited them.