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• FFMPEG DASH Exemple

  23 janvier 2021, par Diogo Crava

  Would anyone be able to provide me an example of an FFMPEG command converting a simple .mp4 file into DASH format but with segmentation for each resolution (480, 720 and 1080). I found some examples but none of them had segmentation.

  


  Can you also indicate to me which field allows me to do that ?

  


  I would also appreciate it if you gave me an FFMPEG tutorial besides the documentation alone.

  


• FFMpeg RGB32 to NV12 using SWScale

  28 avril 2016, par KevinA

  I’m trying to convert RGB32 frames to NV12 Frames to feed into an encoder.

  m_iWidthIn = 1920;
  
  m_iHeightIn = 1080;
  
  m_iWidthOut = (((iWidthIn  + 31) >> 5) << 5) //32bit align
  
  m_heightOut = (((iHeightIn + 31) >> 5) << 5) //32bit align
  
  m_outputPixelFormat = AV_PIX_FMT_NV12;
  
  
  
  // allocate and fill buffers
  
  
  
  m_sws = ::sws_getContext(m_iWidthIn, m_iHeightIn, AV_PIX_FMT_RGB32, m_iWidthOut, m_iHeightOut, m_outputPixelFormat, SWS_FAST_BILINEAR, nullptr, nullptr, nullptr);
  
  AVFrame* frameOut = av_frame_alloc();
  
  frameOut->height = m_iHeightOut;
  
  frameOut->width = m_iWidthOut;
  
  frameOut->format = m_outputPixelFormat;
  
  av_frame_get_buffer(frameOut, 32);
  
  int linesize[1] = { m_iWidthIn * 4 };
  
  uint8_t * data[1] = { m_inputBuffer  };
  
  if (m_bFlip)
  
  {
  
      data[0] += linesize[0] * (m_iHeightIn - 1);
  
      linesize[0] = -linesize[0];
  
  }
  
  ::sws_scale(m_sws, data, linesize, 0, m_iHeightIn, frameOut->data, frameOut->linesize);
  
  ::av_image_copy_to_buffer(pOutputBuffer, lDataLen, frameOut->data, frameOut->linesize, m_outputPixelFormat, m_iWidthOut, m_iHeightOut, 32);

  If I make m_outputPixelFormat AV_PIX_FMT_RGB32 and use a DMO colorspace converter, the video comes out correctly. However if I change it to NV12, I end up with a slanted video with missing data at the bottom.
  I know this is caused by me copying the data incorrectly out of the buffer, but I’m unsure what I’m doing incorrectly.

• FFMpeg muxing h264 to mp4 resultant file is not running

  11 mars 2016, par M.Taha

  I am writing code to mux h264 file into mp4 by using latest FFMPEG 3.0. Muxing is working but the resultant mp4 file is not showing vedio, only the time is running when i play the resultant mp4 file. Kindly try to help to solve this. Please tell me what i am missing. Here is my code :

  int main()
  
  {   
  
      avcodec_register_all();
  
  
  
      av_register_all();
  
  
  
      // define AVOutputFormat
  
      AVOutputFormat *avoutputFormat = NULL;
  
      avoutputFormat = av_guess_format("mp4", NULL, NULL);
  
      if (!avoutputFormat) {
  
      fprintf(stderr, "Could not find suitable output format\n");
  
      return 1;
  
      }
  
  
  
      AVFormatContext *avoutFmtCtx = NULL;
  
      /*Below initialize AVFormatContext.*/
  
      avformat_alloc_output_context2(&avoutFmtCtx, avoutputFormat, NULL, NULL);
  
  
  
      avoutFmtCtx->oformat = avoutputFormat;
  
      sprintf_s(avoutFmtCtx->filename, "%s", "Out.mp4");  /*Filling output file name..*/
  
  
  
      if (avoutputFormat->video_codec == AV_CODEC_ID_NONE) 
  
      printf("\n Unsupported format...");
  
  
  
      AVStream * avoutStrm = avformat_new_stream(avoutFmtCtx, 0);
  
  
  
      if (!avoutStrm) {
  
      _tcprintf(_T("FFMPEG: Could not alloc video stream\n"));        
  
      }
  
  
  
      AVCodecContext *c = avoutStrm->codec;
  
      c->codec_id     = avoutputFormat->video_codec;
  
      c->codec_type   = AVMEDIA_TYPE_VIDEO;
  
      c->bit_rate     = 2000*1000;
  
      c->width        = 1920; 
  
      c->height       = 1080; 
  
      AVRational avr;
  
      avr.den = 30;
  
      avr.num = 1;
  
  
  
      avoutStrm->time_base = c->time_base = av_add_q(avoutStrm->codec->time_base, avr);
  
  
  
      // Some formats want stream headers to be separate
  
      if(avoutFmtCtx->oformat->flags & AVFMT_GLOBALHEADER)
  
      c->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  
  
      // Open the output container file
  
      if (avio_open(&avoutFmtCtx->pb, avoutFmtCtx->filename, AVIO_FLAG_WRITE) < 0)
  
      {
  
      _tcprintf(_T("FFMPEG: Could not open '%s'\n"), avoutFmtCtx->filename);      
  
      }
  
  
  
      m_pExtDataBuffer = (uint8_t*)av_malloc(1000 + 1000);
  
      if(!m_pExtDataBuffer) {
  
      _tcprintf(_T("FFMPEG: could not allocate required buffer\n"));
  
  
  
      }
  
  
  
      uint8_t SPSbuf[1000];
  
      uint8_t PPSbuf[1000];
  
      memcpy(m_pExtDataBuffer, SPSbuf, 1000);             
  
      memcpy(m_pExtDataBuffer + 1000, PPSbuf, 1000);  
  
  
  
      /* Codec "extradata" conveys the H.264 stream SPS and PPS info (MPEG2: sequence header is housed in SPS buffer, PPS buffer is empty)*/
  
      c->extradata        = m_pExtDataBuffer;
  
      c->extradata_size   = 1000 + 1000;
  
  
  
      if(avformat_write_header(avoutFmtCtx,NULL)) {
  
      _tcprintf(_T("FFMPEG: avformat_write_header error!\n"));
  
  
  
      }
  
  
  
      /* Here do writing data in loop...*/
  
      int m_nProcessedFramesNum = 0;
  
  
  
      while(1)
  
      {
  
      ++m_nProcessedFramesNum;
  
      AVPacket pkt;
  
      av_init_packet(&pkt);
  
  
  
      AVCodecContext *c = avoutStrm->codec;
  
      avoutStrm->pts.val = m_nProcessedFramesNum;
  
      pkt.stream_index    = avoutStrm->index;
  
  
  
      pkt.data            = /*Filling h.264 data from here... This is valid h264 data*/
  
      pkt.size            = /*Filling valid h264 data size here...*/
  
      av_new_packet(&pkt,pkt.size);
  
      pkt.pts = m_nProcessedFramesNum*512;
  
      pkt.dts = m_nProcessedFramesNum*512;
  
      pkt.duration = 512;
  
  
  
      // Write the compressed frame in the media file
  
      if (av_interleaved_write_frame(avoutFmtCtx, &pkt)) {
  
      _tcprintf(_T("FFMPEG: Error while writing video frame\n"));         
  
      }/*End of loop.*/
  
  
  
      av_free_packet(&pkt);       
  
  
  
      }   
  
      av_write_trailer(avoutFmtCtx);
  
      avio_close(avoutFmtCtx->pb);
  
      avformat_free_context(avoutFmtCtx);
  
  }