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• Files created with a direct stream copy using FFmpeg's libavformat API play back too fast at 3600 fps

  2 octobre 2013, par Chris Ballinger

  I am working on a libavformat API wrapper that converts MP4 files with H.264 and AAC to MPEG-TS segments suitable for streaming. I am just doing a simple stream copy without re-encoding, but the files I produce play the video back at 3600 fps instead of 24 fps.

  Here are some outputs from ffprobe https://gist.github.com/chrisballinger/6733678, the broken file is below :

  r_frame_rate=1/1
  
  avg_frame_rate=0/0
  
  time_base=1/90000
  
  start_pts=0
  
  start_time=0.000000
  
  duration_ts=2999
  
  duration=0.033322

  The same input file manually sent through ffmpeg has proper timestamp information :

  r_frame_rate=24/1
  
  avg_frame_rate=0/0
  
  time_base=1/90000
  
  start_pts=126000
  
  start_time=1.400000
  
  duration_ts=449850
  
  duration=4.998333

  I believe the problem lies somewhere in my setup of libavformat here : https://github.com/OpenWatch/FFmpegWrapper/blob/master/FFmpegWrapper/FFmpegWrapper.m#L349 where I repurposed a bunch of code from ffmpeg.c that was required for the direct stream copy.

  Since 3600 seems like a "magic number" (60*60), it could be as simple as me not setting the time scale properly, but I can't figure out where my code diverges from ffmpeg/avconv itself.

  Similar question here, but I don't think they got as far as I did : Muxing a H.264 Annex B & AAC stream using libavformat with vcopy/acopy

• How to concat two/many mp4 files(Mac OS X Lion 10.7.5) with different resolution, bit rate [on hold]

  3 septembre 2013, par praveen

  I have to concat different mp4 files into single mp4 file. i am using following ffmpeg command but this command is only working if both file is same(copy, or if all video property is same(codec, resolution,bitrate....) ) other wise result is unexpected video. (I am working on Mac OS X Lion 10.7.5)

  ffmpeg commad :

  ffmpeg -i images/1/output.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts intermediate1.ts
  
  ffmpeg -i images/1/Video2.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts intermediate2.ts
  
  ffmpeg -i "concat:intermediate1.ts|intermediate2.ts" -c copy -bsf:a aac_adtstoasc output2.mp4

  console output :

  [mpegts @ 0x7f8c6c03d800] max_analyze_duration 5000000 reached at 5000000 microseconds
  
  
  
  Input #0, mpegts, from 'concat:intermediate1.ts|intermediate2.ts':
  
  Duration: 00:00:16.52, start: 1.400000, bitrate: 1342 kb/s
  
  Program 1 
  
  Metadata:
  
  service_name    : Service01
  
  service_provider: FFmpeg
  
  Stream #0:0[0x100]: Video: h264 (Main) ([27][0][0][0] / 0x001B), yuv420p, 1024x768 [SAR   1:1 DAR 4:3], 25 fps, 25 tbr, 90k tbn, 50 tbc
  
  Stream #0:1[0x101](und): Audio: aac ([15][0][0][0] / 0x000F), 48000 Hz, stereo, fltp, 101 kb/s
  
  
  
  
  
  
  
  Output #0, mp4, to 'output2.mp4':
  
  Metadata:
  
  encoder         : Lavf54.63.104
  
  Stream #0:0: Video: h264 ([33][0][0][0] / 0x0021), yuv420p, 1024x768 [SAR 1:1 DAR 4:3],      q=2-31, 25 fps, 90k tbn, 90k tbc
  
  Stream #0:1(und): Audio: aac ([64][0][0][0] / 0x0040), 48000 Hz, stereo, 101 kb/s
  
   Stream mapping:
  
  Stream #0:0 -> #0:0 (copy)
  
  Stream #0:1 -> #0:1 (copy)
  
  Press [q] to stop, [?] for help
  
   frame=  586 fps=0.0 q=-1.0 Lsize=    2449kB time=00:00:20.11 bitrate= 997.4kbits/s    
  
   video:2210kB audio:225kB subtitle:0 global headers:0kB muxing overhead 0.578335%

  Please help

• Generate video from bitmap images using FFMPEG

  29 juin 2013, par Pferd

  I'm trying to encode a bunch of images into a video using FFMPEG in visual studio. However I couldnt get it. Can some one please tell me where am I going wrong. please find the attached code here !

  void Encode::encodeVideoFromImage(char* filename){
  
  
  
  
  
    // gET THE encoder here. ~ try with mpeg1Video as a start!
  
    int i;
  
    AVCodec* codec = avcodec_find_encoder(CODEC_ID_MPEG1VIDEO); 
  
  //AVCodec* codec = avcodec_find_encoder(CODEC_ID_MPEG4); 
  
  //AVCodec* codec = avcodec_find_encoder(CODEC_ID_MPEG2VIDEO);
  
  
  
  if (!codec) 
  
  { 
  
      MessageBox(_T("can't find codec"), _T("Warning!"), MB_ICONERROR | MB_OK);
  
  } 
  
  
  
  // Initialize codec
  
  
  
  AVCodecContext* c = avcodec_alloc_context(); 
  
  
  
  // Put sample parameters 
  
  c->bit_rate = 400000; 
  
  // Resolution must be a multiple of two 
  
  c->width = 800; 
  
  c->height = 600;  
  
  c->time_base.num = 1; 
  
  c->time_base.den = 25; 
  
  c->gop_size = 8; // Emit one intra frame every ten frames 
  
  c->max_b_frames=1; 
  
  c->pix_fmt = PIX_FMT_YUV420P; 
  
  
  
  // Open the codec. 
  
  if (avcodec_open(c, codec) < 0) 
  
  { 
  
     // fprintf(stderr, "could not open codec\n"); 
  
       MessageBox(_T("can't open codec"), _T("Warning!"), MB_ICONERROR | MB_OK); 
  
  } 
  
  
  
  
  
  // Open the output file 
  
  FILE* f = fopen(filename, "wb"); 
  
  if (!f) 
  
  { 
  
      // fprintf(stderr, "could not open %s\n", filename); 
  
       MessageBox(_T("Unable to open file"), _T("Warning!"), MB_ICONERROR | MB_OK);
  
  } 
  
  
  
  // alloc image and output buffer
  
  int in_width, in_height, out_width, out_height;
  
  
  
  //here, make sure inbuffer points to the input BGR32 data, 
  
  //and the input and output dimensions are set correctly.
  
  
  
  int out_size=1000000;
  
  
  
  in_width=c->width;
  
  out_width=c->width;
  
  in_height=c->height;
  
  out_height=c->height;
  
  
  
      //create ffmpeg frame structures.  
  
  AVFrame* inpic = avcodec_alloc_frame();
  
  AVFrame* outpic = avcodec_alloc_frame();
  
  
  
  // bytes needed for the output image
  
  int nbytes = avpicture_get_size(PIX_FMT_BGR32, out_width, out_height);
  
  
  
  //create buffer for the output image
  
  uint8_t* outbuffer = (uint8_t *)av_malloc(nbytes*sizeof(uint8_t));
  
  uint8_t* inbuffer = (uint8_t *)av_malloc(nbytes*sizeof(uint8_t));
  
  
  
  CImage capImage;
  
  CString pictureNumber;
  
  
  
  /* encode 1 frame of video */
  
  
  
  for(i=0;i<50;i++) {
  
       fflush(stdout);
  
       /* Use existing images */
  
       pictureNumber="";          
  
       pictureNumber.Format(_T("%d"),i+1);
  
  
  
  capImage.Load(_T("C:\\imageDump\\test")+pictureNumber+_T(".bmp")); // TBD from memory!
  
      //MessageBox(_T("C:\\imageDump\\test")+pictureNumber+_T(".bmp"), _T("Warning!"), MB_ICONERROR | MB_OK);
  
  inbuffer =  (uint8_t*)capImage.GetBits();
  
  
  
  
  
          // convert RGB to YUV 420 here! 
  
          //  RGBtoYUV420P(pBits,picture_buf,bpp,true,c->width,c->height,false); 
  
  //inbuffer=pBits;
  
  
  
  avpicture_fill((AVPicture*)inpic, inbuffer, PIX_FMT_BGR32, in_width, in_height);
  
  avpicture_fill((AVPicture*)outpic, outbuffer, PIX_FMT_YUV420P, out_width, out_height);
  
  
  
  //create the conversion context
  
  SwsContext* fooContext = sws_getContext(in_width, in_height, PIX_FMT_BGR32, out_width, out_height, PIX_FMT_YUV420P, SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  
  
  //perform the conversion
  
  sws_scale(fooContext, inpic->data, inpic->linesize, 0, in_height, outpic->data, outpic->linesize);
  
  
  
  out_size = avcodec_encode_video(c, outbuffer, out_size, inpic);
  
      //printf("encoding frame %3d (size=%5d)\n", i, out_size);
  
  fwrite(outbuffer, 1, out_size, f);
  
  capImage.Destroy();
  
  //free(inbuffer);
  
  } 
  
  
  
  // Get the delayed frames 
  
   for(; out_size; i++) {
  
       fflush(stdout);
  
  
  
       out_size = avcodec_encode_video(c, outbuffer, out_size, NULL);
  
       //printf("write frame %3d (size=%5d)\n", i, out_size);
  
       fwrite(outbuffer, 1, out_size, f);
  
   }
  
  
  
   /* add sequence end code to have a real mpeg file */
  
   outbuffer[0] = 0x00;
  
   outbuffer[1] = 0x00;
  
   outbuffer[2] = 0x01;
  
   outbuffer[3] = 0xb7;
  
   fwrite(outbuffer, 1, 4, f);
  
   fclose(f);
  
   free(inbuffer);
  
   free(outbuffer);
  
  
  
   avcodec_close(c);
  
   av_free(c);
  
   av_free(inpic);
  
   av_free(outpic);
  
   //printf("\n");

  }

  Thank you !