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• 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.

• how to build ffmpeg with librist ?

  9 janvier 2023, par SleepingBug

  how to build ffmpeg with librist ?

  


  I cannot find any useful thing to do it.

  


  I run a sh file in minGW on Windows as below :

  


  `./configure\
 --prefix=/home/source/ffmpeg/build/ffmepg-5.1\
 --arch=x86_64\
 --enable-shared\
 --enable-gpl\
 --enable-libfdk-aac\
 --enable-nonfree\
 --enable-libvpx\
 --enable-libx264\
 --enable-libx265\
 --enable-libmp3lame\
 --enable-librist\
 --extra-cflags="-I/home/source/build/libfdk-aac/include"\
 --extra-ldflags="-L/home/source/build/libfdk-aac/lib"\
 --extra-cflags="-I/home/source/build/libvpx/include"\
 --extra-ldflags="-L/home/source/build/libvpx/lib"\
 --extra-cflags="-I/home/source/build/libx264/include"\
 --extra-ldflags="-L/home/source/build/libx264/lib"\
 --extra-cflags="-I/home/source/build/libx265/include"\
 --extra-ldflags="-L/home/source/build/libx265/lib"\
 --extra-cflags="-I/home/source/build/libmp3lame/include"\
 --extra-ldflags="-L/home/source/build/libmp3lame/lib"\
 --extra-cflags="-I/home/source/librist/build/include"\
 --extra-cflags="-I/home/source/librist/include/librist"\
 --extra-cflags="-I/home/source/librist/include"\
 --extra-ldflags="-L/home/source/librist/build/"`


  


  the error is :
ERROR : librist >= 0.2.7 not found using pkg-config

  


  If you think configure made a mistake, make sure you are using the latest
version from Git. If the latest version fails, report the problem to the
ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.libera.chat.
Include the log file "ffbuild/config.log" produced by configure as this will help
solve the problem.

  


  ==================

  


  I have downloaded the latest librist source code !

  


  if I remove "—enable-librist" , everything is OK, but there is no librist in ffmpeg...

  


  build ffmpeg with librist

  


• How to convert a GIF to optimized mp4 video using FFMPEG on android ?

  6 novembre 2017, par Omar Hezi

  I successfully integrated FFMPEG as a library on android and I am using JNI to communicate my JAVA classes with C and C++ classes.

  Background and my question
  A chat app where GIFs can be sent, the issue is that one GIF could weigh up to 2MB, after a lot of research I found that the best solution is converting those gifs to mp4 (Something that Facebook messenger, whatsapp and telegram do).

  My question is, how can I convert a gif to mp4 in order to reduce its size, using ffmpeg (not in command line, in android) as Telegram mentions here ?

  What I have attempted

  • Understanding and implementing the gifvdeo.cpp from Telegram (it was extremely complicated and I could not understand it fully)
  • Converting the gif to frames of bitmaps, and compressing each bitmap and then converting those bitmaps to mp4 (I was not able to pass the bitmap object to C through JNI because of " Fatal signal 11 (SIGSEGV), code 1, fault addr 0x31f in tid 26952" which is another question)

  Research I have done

  • using ffmpeg to convert gif to mp4 , output doesn’t play on android
  • How to convert GIF to Mp4 is it possible ?
  • Convert GIF to Video in Android
  • https://unix.stackexchange.com/questions/40638/how-to-do-i-convert-an-animated-gif-to-an-mp4-or-mv4-on-the-command-line

  the problem with above questions is that they use command line FFMPEG which is not what I am doing, I am using JNI and direct access to c classes of mentioned library.