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• iOS FFMPEG encode images to video

  10 avril 2013, par brad.roush

  I am trying to take a set of UIImages and create a video file out of them with FFMPEG. Seems there are lots of questions about this topic but non have been able to get this working correctly for me. This one was particularly helpful in giving me a starting point. This iFrameExtractor example was also very helpful but I want to do this in reverse, then add audio.

  This is the closest I have gotten and it creates a short silent video with flashing colors and no images :

  // Register all formats and codecs
  
  av_register_all();
  
  
  
  AVCodec *codec;
  
  AVCodecContext *c= NULL;
  
  
  
  int i, out_size, size, outbuf_size;
  
  FILE *file;
  
  AVFrame *picture;
  
  uint8_t *outbuf;
  
  
  
  NSLog(@"Video encoding");
  
  
  
  /* find the mpeg video encoder */
  
  codec = avcodec_find_encoder(CODEC_ID_MPEG2VIDEO);
  
  if (!codec) {
  
      fprintf(stderr, "codec not found\n");
  
      exit(1);
  
  }
  
  
  
  c= avcodec_alloc_context3(codec);
  
  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_open2(c, codec, nil) < 0) {
  
      fprintf(stderr, "could not open codec\n");
  
      exit(1);
  
  }
  
  
  
  // Put file in place
  
  
  
  NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
  
  NSString *docs_dir = [paths objectAtIndex:0];
  
  NSString *filePath = [docs_dir stringByAppendingPathComponent:@"test.mpeg"];
  
  
  
  // Seed file
  
  NSString *sourcePath = [[NSBundle mainBundle] pathForResource:@"test" ofType:@"mov"];
  
  NSError* error = nil;
  
  if (![[NSFileManager defaultManager] copyItemAtPath:sourcePath toPath:filePath error:&error]) {
  
      NSLog(@"Test Video creation failed:%@",[error userInfo]);
  
  } else NSLog(@"Test Video Created");
  
  
  
  const char *filename = [filePath UTF8String];
  
  file = fopen(filename, "wb");
  
  if (!file) {
  
      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;
  
  
  
  //#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);
  
  
  
  
  
  AVPacket packet;
  
  av_init_packet(&packet);
  
  
  
  
  
  //#pragma mark -
  
  for(i=1;i<50;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 imageWithContentsOfFile:[docs_dir stringByAppendingPathComponent:[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_RGB8, 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_RGB8,
  
                                                     c->width, c->height,
  
                                                     PIX_FMT_YUV420P,
  
                                                     SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  
  
      //perform the conversion
  
  
  
      sws_scale(fooContext, outpic->data, outpic->linesize,
  
                0, c->height, outpic->data, outpic->linesize);
  
      // Tried This but it didn't work
  
      //sws_scale(fooContext, picture->data, picture->linesize, 0, c->height, outpic->data, outpic->linesize);
  
  
  
  
  
      out_size = avcodec_encode_video(c, outbuf, outbuf_size, outpic);
  
      // Tried this but it didn't work
  
      //int test = 0;
  
      //out_size = avcodec_encode_video2(c, &packet, outpic, &test);
  
  
  
  
  
  
  
      printf("encoding frame %3d (size=%5d)\n", i, out_size);
  
      fwrite(outbuf, 1, out_size, file);
  
  
  
      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, file);
  
  }
  
  */
  
  
  
  /* 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, file);
  
  fclose(file);
  
  free(outbuf);
  
  
  
  avcodec_close(c);
  
  av_free(c);
  
  av_free(picture);
  
  printf("\n");

  Any ideas will be helpful here. If anyone knows of any other good objective-c examples, this would also be great.

• 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");

• Concat two mp4 files with ffmpeg without losing quality [migrated]

  13 juin 2013, par jenia

  i have now a problem with concatenating of 2 videos using ffmpeg.
  So, i am encoding the source mp4 files to ts with

     ffmpeg -i output1.mp4 -scodec copy -vbsf h264_mp4toannexb i0.ts

  but the file i get looks much worse, then the source file.

  here is the information about both the files

     Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'output1.mp4':
  
     Metadata:
  
     major_brand     : isom
  
     minor_version   : 1
  
     compatible_brands: isom
  
     creation_time   : 2013-06-13 15:40:36
  
     Duration: 00:00:15.72, start: 0.000000, bitrate: 2053 kb/s
  
     Stream #0.0(und): Video: h264 (High), yuv420p, 1280x720, 1931 kb/s, 25 fps, 25 tbr,   12800 tbn, 50 tbc
  
     Stream #0.1(und): Audio: aac, 44100 Hz, stereo, s16, 128 kb/s
  
  
  
    Input #0, mpegts, from 'i0.ts':
  
    Duration: 00:00:15.64, start: 1.400000, bitrate: 1382 kb/s
  
    Program 1 
  
    Metadata:
  
    service_name    : Service01
  
    service_provider: Libav
  
    Stream #0.0[0x100]: Video: mpeg2video (Main), yuv420p, 1280x720 [PAR 1:1 DAR 16:9], 104857 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
  
    Stream #0.1[0x101](und): Audio: mp2, 44100 Hz, stereo, s16, 128 kb/s

  So, how can i solve this problem ?
  Thanks in advance !