Recherche avancée

Sur d’autres sites (5022)

• Grab partial .mp4 video from onlline source

  28 juillet 2016, par Flemingjp

  I want to be able to grab a partial mp4 file from an online source so I can produce quick thumbnails.

  My idea was to pull a patial mp4 file from a http request using the header

  Range: 'bytes=1000-'

  However when I parse the data it doesn’t have the mp4 container therefore is corrupt. In Firefox it handles this easily as seeking to an unloaded part of the video is very quick.

  How can I pull partial mp4 clips ? For example from here I could get a clip that is 0:28-0:30

• ffmpeg Could not find input stream [closed]

  17 avril 2013, par Peter Walker

  I've seen lot's of post on streaming video feeds to ffserver but still haven't found what I wanted.

  I use not only on the mp4 file but avi and other formats as well.

      ffmpeg -i test5.mp4 http://localhost:8090/feed1.ffm

  I keep finding this error.

      Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'test5.mp4':
  
      Metadata:
  
             major_brand     : isom
  
             minor_version   : 512
  
             compatible_brands: isomiso2mp41
  
             encoder         : Lavf53.21.1
  
      Duration: 00:05:00.00, start: 0.000000, bitrate: 278 kb/s
  
      Stream #0.0(und): Video: mpeg4 (Simple Profile), yuv420p, 640x320 [PAR 1:1 DAR     2:1], 277 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
  
      Incompatible sample format '(null)' for codec 'mp2', auto-selecting format 's16'
  
      Last message repeated 1 times
  
      Output #0, ffm, to 'http://localhost:8090/feed1.ffm':
  
      Stream #0.0: Video: [0][0][0][0] / 0x0000, yuv420p, q=0-0, 1000k tbn
  
      Stream #0.1: Video: mpeg1video, (null), 32622x226393720, q=2-31, pass 1, pass 2,     226393 kb/s, 1000k tbn
  
      Stream #0.2: Audio: mp2, 22050 Hz, 1 channels, s16, 226391 kb/s
  
      Stream #0.3: Video: msmpeg4, yuv420p, 352x240, q=2-31, 226391 kb/s, 1000k tbn, 15  tbc
  
      Could not find input stream matching output stream #0.2
  
      *** glibc detected *** ffmpeg: free(): invalid pointer: 0x0000000000a53d00 ***
  
      ======= Backtrace: =========
  
      /lib/x86_64-linux-gnu/libc.so.6(+0x7e626)[0x7f6e0d4af626]
  
      /usr/lib/x86_64-linux-gnu/libavformat.so.53(avformat_free_context+0xb0)    [0x7f6e0f2c9c70]
  
      ffmpeg[0x4089bf]
  
      ffmpeg[0x40a52f]
  
      ffmpeg[0x407a04]
  
      /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xed)[0x7f6e0d45276d]

  The config file I used for the ffserver is

      Port 8090
  
      RTSPPort 7654
  
      BindAddress 0.0.0.0
  
      MaxHTTPConnections 2000
  
      MaxClients 1000
  
      MaxBandwidth 500000
  
      CustomLog -
  
      NoDaemon
  
      <feed>
  
              File /tmp/feed1.ffm
  
              FileMaxSize 5M
  
      #       NoAudio
  
      </feed>
  
  
  
      <stream>
  
              Feed feed1.ffm
  
              Format rtp
  
      #       NoAudio
  
              VideoFrameRate 30
  
      </stream>

  Can anyone help me figure out some something or something to look for ?
  I tried googling but almost everyone uses video feeds instead or it just works well for them.
  Any clue or direction/suggestion would help. Thank you so much in advance.

• Encoding a screenshot into a video using FFMPEG

  2 juillet 2013, par mohM

  I'm trying to get the pixels from the screen, and encode the screenshot into a video using ffmpeg. I've seen a couple of examples but they either assume you already have the pixel data, or use image file input. It seems like whether I use sws_scale() or not (which is included in the examples I've seen), or whether I'm typecasting a HBITMAP or RGBQUAD* it's telling me that the image src data is bad and is encoding a blank image rather than the screenshot. Is there something I'm missing here ?

  AVCodec* codec;
  
  AVCodecContext* c = NULL;
  
  AVFrame* inpic;
  
  uint8_t* outbuf, *picture_buf;
  
  int i, out_size, size, outbuf_size;
  
  HBITMAP hBmp;
  
  //int x,y;
  
  
  
  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);
  
  inpic = avcodec_alloc_frame();
  
  
  
  c->bit_rate = 400000;
  
  c->width = screenWidth;                                     // resolution must be a multiple of two
  
  c->height = screenHeight;
  
  c->time_base.num = 1;
  
  c->time_base.den = 25;
  
  c->gop_size = 10;                                           // emit one intra frame every ten frames
  
  c->max_b_frames=1;
  
  c->pix_fmt = PIX_FMT_YUV420P;
  
  c->codec_id = CODEC_ID_H264;
  
  //c->codec_type = AVMEDIA_TYPE_VIDEO;
  
  
  
  //av_opt_set(c->priv_data, "preset", "slow", 0);
  
  //printf("Setting presets to slow for performance\n");
  
  
  
  // 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 + 12*c->width*c->height;           // alloc image and output buffer
  
  //outbuf_size = 100000;
  
  outbuf = static_cast(malloc(outbuf_size));
  
  size = c->width * c->height;
  
  picture_buf = static_cast(malloc((size*3)/2));
  
  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");
  
  
  
  /*inpic->data[0] = picture_buf;
  
  inpic->data[1] = inpic->data[0] + size;
  
  inpic->data[2] = inpic->data[1] + size / 4;
  
  inpic->linesize[0] = c->width;
  
  inpic->linesize[1] = c->width / 2;
  
  inpic->linesize[2] = c->width / 2;*/
  
  
  
  
  
  //int x,y;
  
  // encode 1 second of video
  
  for(i=0;itime_base.den;i++) {
  
      fflush(stdout);
  
  
  
  
  
      HWND hDesktopWnd = GetDesktopWindow();
  
      HDC hDesktopDC = GetDC(hDesktopWnd);
  
      HDC hCaptureDC = CreateCompatibleDC(hDesktopDC);
  
      hBmp = CreateCompatibleBitmap(GetDC(0), screenWidth, screenHeight);
  
      SelectObject(hCaptureDC, hBmp);
  
      BitBlt(hCaptureDC, 0, 0, screenWidth, screenHeight, hDesktopDC, 0, 0, SRCCOPY|CAPTUREBLT);
  
      BITMAPINFO bmi = {0}; 
  
      bmi.bmiHeader.biSize = sizeof(bmi.bmiHeader); 
  
      bmi.bmiHeader.biWidth = screenWidth; 
  
      bmi.bmiHeader.biHeight = screenHeight; 
  
      bmi.bmiHeader.biPlanes = 1; 
  
      bmi.bmiHeader.biBitCount = 32; 
  
      bmi.bmiHeader.biCompression = BI_RGB;
  
      RGBQUAD *pPixels = new RGBQUAD[screenWidth*screenHeight];
  
      GetDIBits(hCaptureDC,hBmp,0,screenHeight,pPixels,&bmi,DIB_RGB_COLORS);
  
  
  
  inpic->pts = (float) i * (1000.0/(float)(c->time_base.den))*90;
  
      avpicture_fill((AVPicture*)inpic, (uint8_t*)pPixels, PIX_FMT_BGR32, c->width, c->height);                   // Fill picture with image
  
      av_image_alloc(inpic->data, inpic->linesize, c->width, c->height, c->pix_fmt, 1);
  
      //printf("Allocated frame\n");
  
      //SaveBMPFile(L"screenshot.bmp",hBmp,hDc,screenWidth,screenHeight);
  
      ReleaseDC(hDesktopWnd,hDesktopDC);
  
      DeleteDC(hCaptureDC);
  
      DeleteObject(hBmp);
  
  
  
      // encode the image
  
      out_size = avcodec_encode_video(c, outbuf, outbuf_size, inpic);
  
      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("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);
  
  free(picture_buf);
  
  free(outbuf);
  
  
  
  avcodec_close(c);
  
  av_free(c);
  
  av_free(inpic);
  
  printf("Closed codec and Freed\n");