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• Cannot use FFmpeg in Xcode iOS Project (file .h not found)

  19 mars 2016, par BlackBox

  I followed almost step by step this guide.

  Almost because I downloaded, as a user suggested, ffmpeg ios library already built from here

  I followed from "Linking static libraries in Xcode" but I cannot import anyway the header files of ffmpeg. (So I got the .a files)

  For example

  #include "avformat.h"
  
  // or
  
  #import "libavformat/avformat.h"
  
  // or
  
  #import <libavformat></libavformat>avformat.h>

  Everything that I use does not work.

  I specify that those .a files are currently in my project directory, indeed, if I import the .a file, it doesn’t complain that it isn’t found, but when compiling, it complains about UTF-8 stuff because .a files are object libraries and cannot be imported that way.

  I put also the Header Search Paths for the project as it was suggested and the config.log file but nothing.

  Also I see libraries are missing from every project example of FFmpeg I was able to find on GitHub.

  Any ideas ?

• ffmpeg produces mp4 I cannot load on latest Safari on iOS

  28 mars 2016, par Michael Heuberger

  When I encode a video with these ffmpeg parameters (based on images), I cannot play that mp4 it produces on latest Safari (inside a tag) inside my iPhone 6s using the latest iOS too :

  ffmpeg 
  
  -r 15.279071668502123 
  
  -f image2 -thread_queue_size 64 
  
  -i /home/michael-heuberger/abcd/frames/%d.webp 
  
  -y 
  
  -an 
  
  -vcodec libx264 
  
  -vf scale=trunc(iw/2)*2:trunc(ih/2)*2 
  
  -crf 16 
  
  -preset fast 
  
  -profile:v baseline 
  
  -pix_fmt yuv420p 
  
  -loglevel warning 
  
  -movflags faststart 
  
  /home/michael-heuberger/abcd/videomail_good.mp4 

  I think the above parameters should be solid. I am adding baseline and yuv420p, yet no luck on Safari 9. Why ?

  This makes it difficult for me to play videomails recorded on www.videomail.io on iOS devices.

  Am I missing something here ? Already did lots of research and tried various combinations, no luck.

  If you want to reproduce that, easy : just record a video on www.videomail.io and after that, copy the link of the recorded video page to your iPhone or just download it for local investigation.

  Any clues very welcome !

• How should set the video & audio's timestamp when using ffmpeg to publish rtmp stream to nginx-rtmp server

  8 juillet 2016, par user1190248

  Now I use ffmpeg to publish my av stream to nginx-rtmp server.
  My h264 stream is 30fps, AAC is 8khz stereo channels.
  In the packet sending function, I use following code to read frame,set audio & video’s timestamp.

  void RtmpLiveEncoder::Run()
  
  {
  
  AVBitStreamFilterContext* aacbsfc =  av_bitstream_filter_init("aac_adtstoasc");
  
  start_time = av_gettime();
  
  while(1)
  
  {
  
      do
  
      {
  
           int ret = 0;
  
           AVPacket pkt;
  
          av_init_packet(&pkt);
  
          ret = av_read_frame(ifmt_ctx,&pkt);
  
          if(ret<0 )
  
          {
  
              printf("read video frame failed\n");
  
              break;
  
          }
  
  
  
  
  
          if(pkt.pts==AV_NOPTS_VALUE)
  
          {
  
              if(_frameduration==0)
  
              {
  
                  pkt.dts = pkt.pts=(av_gettime()-start_time)/1000;
  
              }
  
              else
  
              {
  
                  pkt.dts = pkt.pts = _lastvideopts;
  
                  pkt.duration = _frameduration;
  
                  pkt.pos = -1;
  
                  _lastvideopts += _frameduration;
  
              }
  
  
  
          }
  
  
  
          if(av_write_frame(ofmt_ctx,&pkt)<0)
  
          {
  
             printf("write video frame failed\n");
  
          }
  
  
  
          av_packet_unref(&pkt);
  
      }while(0);
  
  
  
      do
  
      {
  
          if(!_hasaudio)
  
          {
  
              break;
  
          }
  
          if((_lastaudiopts-_lastvideopts)>0)
  
          {
  
              printf("the audio is faster than video, the audio pts is %d, the video pts is %d\n",_lastaudiopts,_lastvideopts);
  
              break;
  
          }
  
  
  
          int ret = 0;
  
          AVPacket audiopacket;
  
          av_init_packet(&audiopacket);
  
          ret = av_read_frame(aifmt_ctx,&audiopacket);
  
          if(ret<0)
  
          {
  
            break;
  
          }
  
  
  
          AVStream* out_stream = ofmt_ctx->streams[1];
  
          if(av_bitstream_filter_filter(aacbsfc, out_stream->codec, NULL, &audiopacket.data, &audiopacket.size, audiopacket.data, audiopacket.size, 0)<0)
  
          {
  
              printf("remove adts header failed\n");
  
          }
  
  
  
          if(av_bitstream_filter_filter(aacbsfc, out_stream->codec, NULL, &audiopacket.buf->data, &audiopacket.buf->size, audiopacket.buf->data, audiopacket.buf->size, 0)<0)
  
          {
  
             printf("remove adts header failed\n");
  
  
  
          }
  
  
  
          audiopacket.stream_index=1;
  
          audiopacket.dts = audiopacket.pts=_lastaudiopts;
  
          audiopacket.duration = (double)1024/out_stream->codecpar->sample_rate*1000;
  
          _lastaudiopts += audiopacket.duration;
  
          audiopacket.pos = -1;
  
  
  
  
  
          if(av_write_frame(ofmt_ctx,&audiopacket)<0)
  
          {
  
              printf("write audio failed.\n");
  
          }
  
  
  
          av_packet_unref(&audiopacket);
  
  
  
      }while(0);
  
  
  
  }
  
  av_write_trailer(ofmt_ctx);
  
  }

  as you can see, I set the audio&video’s pts by frameduration.
  Then I use vlc or iphone’s chrome to access the hls stream. At the first, the audio&video is synchronized.But as time goes on, the AV isn’t synchronized,the audio would be faster than video’s.
  So what’s wrong with it ?