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• How to mention real image instead of dummy image in ffmpeg api-example.c

  2 mars 2013, par Mohan

  I am using video_encode_example function from api-example.c of FFmpeg,
  which basically creates 25 dummy images and encodes into a one second video.
  How ever i am unable to mention real images instead of dummy ones.
  If any one know how to do this for xcode objective C, pl submit a reply.
  Below is the function

  /*
  
   * Video encoding example
  
   */
  
  static void video_encode_example(const char *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");
  
  }

• Stream real-time video flux in HTML video tag

  26 septembre 2018, par c.censier

  I want to stream a real-time video flux that come from udp into a HTML video tag.
  I made some research but I got a lot of informations and I struggle to have a clear overview of what I can do and what I can’t.

  The video flux use H.264 and AAC codecs, MP4 container and has a 3840x2160 (4K) resolution. I’d like to play it on Chrome (latest version).

  As I understand from now, HTML video tag can natively read H.264/AAC videos. I made it work with the video direclty on my server (I’m using Meteor JS + React).

  I learnt to use FFmpeg to stream an udp flux read by VLC player, and then I used FFserver (I know it’s deprecated) to create an HTTP flux also read by VLC but not by the HTML video tag.

  So... my question is : is HTML video can natively read video stream from HTTP ?

  I’ve seen a lot of discussions about HLS and DASH, but I didn’t understand if (and why) they’re mandatory.

  I read a post about someone creating a HLS m3u8 using only FFmpeg, is it a viable solution ?

  FFserver configuration

  HTTPPort                        8090
  
  HTTPBindAddress                 0.0.0.0
  
  MaxHTTPConnections              20
  
  MaxClients                      10
  
  MaxBandwidth                    100000
  
  
  
  <feed>
  
    File                          /tmp/feed.ffm
  
    FileMaxSize                   1g
  
    ACL allow                     127.0.0.1
  
  </feed>
  
  
  
  <stream>
  
    Feed                          feed.ffm
  
    Format                        mpeg
  
    AudioCodec                    aac
  
    AudioBitRate                  256
  
    AudioChannels                 1
  
    VideoCodec                    libx264
  
    VideoBitRate                  10000      // Total random here
  
    VideoBitRateRange             5000-15000 // And here...
  
    VideoFrameRate                30
  
    VideoQMin                     1
  
    VideoQMax                     50
  
    VideoSize                     3840x2160
  
    VideoBufferSize               20000      // Not sure either
  
    AVOptionVideo                 flags +global_header
  
  </stream>

  I had to specify QMin and QMax to avoid error message but I don’t really understand what is it.

  FFmpeg command line

  ffmpeg -re -i bbb_sunflower_2160p_30fps_normal.mp4 -strict -2 -r 30 -vcodec libx264 http://localhost:8090/feed.ffm

  This work with VLC. I’m working with a file on my computer before moving to an udp stream.

• Split Audio nad Video, or redirect audio to virtual sound card, on real time stream

  26 décembre 2012, par Inferius

  I have a semi-profi camera, and recived stream through FireWire, but this device call in windows how simultaneous A/V device. Ffmpeg or other in C# not recording audio, only video (This finded only video stream A/V). How split realtime audio from video, or record audio from video ?