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• hap : Decode using optimal slices sizes

  17 juillet 2015, par Luca Barbato

  hap : Decode using optimal slices sizes
  Enjoy some cache locality and use less threads.
  
  About 5x speedup (from 60ms to 12ms to decode a 4k frame).
  Signed-off-by : Luca Barbato <lu_zero@gentoo.org>
  

  • [DBH] libavcodec/hap.h
  • [DBH] libavcodec/hapdec.c

• ffmpeg H264 Encode Frame at a time for network streaming

  4 février 2017, par Richard Harrow

  I’m working on a remote desktop application, I would like to send an encoded H264 packet over TCP by using ffmpeg for the encoding. However I couldn’t find useful info for the particular case of encoding just one frame (already on YUV444) and get the packet.

  I have several issues, the first was that :

  avcodec_encode_video2

  Was not blocking, I found that most of the time you get the "delayed" frames at the end, however, since this is a real time streaming the solution was :

  av_opt_set(mCodecContext->priv_data, "tune", "zerolatency", 0);

  Now I got the frame, but several issues, it takes a while and even worse I got a gray with trash pixels video as result. My configuration for the Codec Context :

   m_pCodecCtx->bit_rate=8000000;
  
  m_pCodecCtx->codec_id=AV_CODEC_ID_H264;
  
  m_pCodecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
  
  m_pCodecCtx->width=1920;
  
  m_pCodecCtx->height=1080;
  
  m_pCodecCtx->pix_fmt=AV_PIX_FMT_YUV444P;
  
  m_pCodecCtx->time_base.num = 1;
  
  m_pCodecCtx->time_base.den = 25;
  
  m_pCodecCtx->gop_size = 1;
  
  m_pCodecCtx->keyint_min = 1;
  
  m_pCodecCtx->i_quant_factor = float(0.71);
  
  m_pCodecCtx->b_frame_strategy = 20;
  
  m_pCodecCtx->qcompress = (float)0.6;
  
  m_pCodecCtx->qmax = 51;
  
  m_pCodecCtx->qmin = 20;
  
  m_pCodecCtx->max_qdiff = 4;
  
  m_pCodecCtx->refs = 4;
  
  m_pCodecCtx->max_b_frames = 1;
  
  m_pCodecCtx->thread_count = 1;

  I would like to know how this could be done, how do I set the "I Frames" ? and, that would be the optimal for a "one at a time" encoding ? Also I’m not concerned right now with the quality, just need to be fast enough (under 16 ms).

  For the encoding part :

  nres = avcodec_encode_video2(m_pCodecCtx,&packet,m_pFrame,&framefinished);
  
  
  
  if(nres<0){
  
      qDebug() << "error encoding: " << nres << endl;
  
  }
  
  
  
  if(framefinished){
  
      m_pFrame->pts++;
  
       ofstream vidout("video.h264",ios::app);
  
       if(vidout.good()){
  
           vidout.write((const char*)&packet.data[0],packet.size);
  
       }
  
       vidout.close();
  
  
  
       av_packet_unref(&packet);
  
  
  
  }

  I’m not using a container, just a raw file, ffplay reproduce raw files if the packets are right, and that’s my principal issue. I’m planning to send the packet over tcp and decode on the client. Any help would be greatly appreciated.

• ffmpeg thumbnailer configure/make trouble in CentOS6

  16 décembre 2013, par Juneyoung Oh

  I am using CentOS 6.4 86x64.

  What I am planning to do is install ffmpegthumbnailer.

  I have downloaded at the link below.
  https://code.google.com/p/ffmpegthumbnailer/

  The problem is when I extract the tar.gz and command configure,

  It alway says like this.

  checking for FFMPEG... no
  
  configure: error: Package requirements (libavutil libavformat libavcodec >= 52.26.0 libswscale) were not met:
  
  
  
  No package 'libavutil' found
  
  No package 'libavformat' found
  
  No package 'libavcodec' found
  
  No package 'libswscale' found

  Of course, I already installed ffmpeg 1.2.

   /usr/lib64/libswscale.so.0.11.0
  
  /usr/lib64/libswscale.so.0

  and also have libswscale.so.

  What can I do to solve this ?

  Thanks:D

  ============I solved one and get another===============

  I solved(?) this with what console said.

  adjust PKG_CONFIG_PATH.

  I find my libavutil.pc and give that path to PKG_CONFIG_PATH, like below.

  export PKG_CONFIG_PATH=/usr/lib/pkgconfig/

  then It looks OK, but I got another one.

  ./configure works nice with suspected message.

  CONFIGURATION SUMMARY ----
  
  png support          : disabled
  
  jpeg support         : disabled
  
  gio support          : disabled
  
  register thumbnailer : disabled
  
  unittests            : disabled
  
  debug mode           : disabled

  anyway, configure was OK, and I have make files now.

  The problem is when I do make command, it shows error like below.

  /usr/bin/ld: /usr//lib/libavformat.a(allformats.o): relocation R_X86_64_32 against `ff_a64_muxer' can not be used when making a shared object; recompile with -fPIC
  
  /usr//lib/libavformat.a: could not read symbols: Bad value
  
  collect2: ld returned 1 exit status
  
  make[2]: *** [libffmpegthumbnailer.la] Error 1
  
  make[2]: Leaving directory `/home/guest/Downloads/ffmpegthumbnailer-2.0.8'
  
  make[1]: *** [all-recursive] Error 1
  
  make[1]: Leaving directory `/home/guest/Downloads/ffmpegthumbnailer-2.0.8'
  
  make: *** [all] Error 2

  Please, tell me that I have to do solve this:D