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• conversion from cv::mat to avframe, encode in h264 dont writing correctly [on hold]

  15 novembre 2014, par danics

  i create a method for converting between cv::mat to avframe with PIX_FMT_YUV420P format (oframe format) but _convCtx always return null, whats wrong ? thanks in advance ! ((i solve this)) but i have another probelm in end of this question please

  void processToFrame(cv::Mat* _mat, AVFrame* oframe)
  
    {
  
        // Create and allocate the conversion frame.
  
        if (_oframe == nullptr) {
  
            _oframe = avcodec_alloc_frame();  
  
            if (_oframe == nullptr)
  
                throw std::runtime_error("Matrix Converter: Could not allocate the output frame.");
  
  
  
            avpicture_alloc(reinterpret_cast(_oframe), 
  
                PIX_FMT_BGR24, _mat->cols, _mat->rows);             
  
        }
  
  
  
        avpicture_fill(reinterpret_cast(_oframe),
  
            (uint8_t *)_mat->data,
  
            AV_PIX_FMT_BGR24,
  
            _mat->cols,
  
            _mat->rows);
  
  
  
        // Convert the image from its native format to BGR.
  
        if (_convCtx == nullptr) {
  
            _convCtx = sws_getContext(
  
                oframe->width, oframe->height, (enum AVPixelFormat) oframe->format, 
  
                _oframe->width, _oframe->height, PIX_FMT_BGR24, 
  
                SWS_BICUBIC, nullptr, nullptr, nullptr);
  
        }
  
        if (_convCtx == nullptr)
  
            throw std::runtime_error("Matrix Converter: Unable to initialize the conversion context.");   
  
  
  
        // Scales the source data according to our SwsContext settings.
  
        if (sws_scale(_convCtx,
  
            _oframe->data, _oframe->linesize, 0, _oframe->height,
  
            oframe->data, oframe->linesize) < 0)
  
            throw std::runtime_error("Matrix Converter: Pixel format conversion not supported.");
  
    }

  create oframe

  void createVideoFile(const char* filename, int w, int h, int codec_id, int fps)
  
    {
  
        /* find the mpeg1 video encoder */
  
        if(codec == nullptr) 
  
        {
  
            /* find the mpeg1 video encoder */
  
            codec = avcodec_find_encoder((AVCodecID)codec_id);
  
            if (!codec) {
  
                throw std::runtime_error("codec not found\n");
  
            }
  
        }
  
  
  
        if(c == nullptr)
  
        {
  
            c = avcodec_alloc_context3(codec);
  
            if(!c)
  
            {
  
                throw std::runtime_error("Could not allocate video codec context\n");
  
            }
  
            /* put sample parameters */
  
            c->bit_rate = 400000;
  
            /* resolution must be a multiple of two */
  
            c->width = 2 * (w / 2);
  
            c->height = 2 * (h / 2);
  
            /* frames per second */
  
            AVRational ar;
  
            ar.den = 1;
  
            ar.num = fps;
  
  
  
            c->time_base= ar; //(AVRational){1,25};
  
            c->gop_size = 10; /* emit one intra frame every ten frames */
  
            c->max_b_frames=1;
  
            c->pix_fmt = PIX_FMT_YUV420P;
  
  
  
            if(codec_id == AV_CODEC_ID_H264)
  
                av_opt_set(c->priv_data, "preset", "slow", 0);
  
  
  
            /* open it */
  
            if (avcodec_open2(c, codec, NULL) < 0) {
  
                throw std::runtime_error("Could not open codec\n");
  
            }
  
  
  
            f = fopen(filename, "wb");
  
            if (!f) {
  
                throw std::runtime_error("could not open file\n");
  
            }
  
  
  
            frame = avcodec_alloc_frame();
  
            if (!frame) {
  
                throw std::runtime_error("Could not allocate video frame\n");
  
            }
  
            frame->format = c->pix_fmt;
  
            frame->width  = c->width;
  
            frame->height = c->height;
  
  
  
            /* the image can be allocated by any means and av_image_alloc() is
  
             * just the most convenient way if av_malloc() is to be used */
  
  
  
            int ret = av_image_alloc(frame->data, frame->linesize, c->width, c->height, c->pix_fmt, 32);
  
  
  
            if (ret < 0) {
  
                throw std::runtime_error("Could not allocate raw picture buffer\n");
  
            }
  
        }
  
  }

  read mat images

  void video_encode_example(const cv::Mat& fin)
  
  {
  
      AVPacket pkt;
  
      /* encode 1 second of video */
  
      av_init_packet(&pkt);
  
      pkt.data = NULL;    // packet data will be allocated by the encoder
  
      pkt.size = 0;
  
  
  
      fflush(stdout);
  
  
  
      cv::Mat res;
  
      cv::resize(fin, res, cv::Size(c->width, c->height));
  
  
  
      processToFrame(&res, frame);
  
      frame->pts = i;
  
  
  
      /* encode the image */
  
      int ret = avcodec_encode_video2(c, &pkt, frame, &got_output);
  
      if (ret < 0) {
  
      throw std::runtime_error("Error encoding frame\n");
  
      }
  
  
  
      if (got_output) {
  
          printf("Write frame %3d (size=%5d)\n", i, pkt.size);
  
          fwrite(pkt.data, 1, pkt.size, f);
  
          av_free_packet(&pkt);
  
      }
  
      i++;
  
  }

  update :

  i can solve the conversion problem by setting of _oframe.width = _mat.cols and _oframe.height = _mat.rows, avpicture_alloc dont set this value itself.

  now i have the other problem my videowriting class seems write ok because windows slideshow show one of frames, but i cant view video in my players, this is my release function, i dont know whats wrong endcoding or endcoder structure parameter like pts and else.

  void video_release()
  
      {
  
          /* get the delayed frames */
  
          for (got_output = 1; got_output; i++) {
  
              fflush(stdout);
  
  
  
              int ret = avcodec_encode_video2(c, &pkt, NULL, &got_output);
  
              if (ret < 0) {
  
                  throw std::runtime_error("Error encoding frame\n");
  
              }
  
  
  
              if (got_output) {
  
                  printf("Write frame %3d (size=%5d)\n", i, pkt.size);
  
                  fwrite(pkt.data, 1, pkt.size, f);
  
                  av_free_packet(&pkt);
  
              }
  
          }
  
  
  
          uint8_t endcode[] = { 0, 0, 1, 0xb7 };
  
  
  
          /* add sequence end code to have a real mpeg file */
  
          fwrite(endcode, 1, sizeof(endcode), f);
  
          fclose(f);
  
  
  
          avcodec_close(c);
  
          av_free(c);
  
          av_freep(&frame->data[0]);
  
          avcodec_free_frame(&frame);
  
  
  
          c = nullptr;
  
          codec = nullptr;
  
          frame = nullptr;
  
  
  
          if (_convCtx)
  
              sws_freeContext(_convCtx);
  
  
  
          if (_oframe) {
  
              //if (_oframe->data)
  
                  //av_free(_oframe->data[0]);
  
              av_free(_oframe);
  
          }
  
  
  
          _oframe = nullptr;
  
          _convCtx = nullptr;
  
      }

• Use ffmpeg to stream live content to azure media services

  9 juin 2016, par Dadicool

  I’ve been trying to stream content to azure media services using ffmpeg as it’s one of the options described here : http://azure.microsoft.com/blog/2014/09/18/azure-media-services-rtmp-support-and-live-encoders/

  My command is :

  ffmpeg -v verbose -i 300.mp4 -strict -2 -c:a aac -b:a 128k -ar 44100 -r 30 -g 60 -keyint_min 60 -b:v 400000 -c:v libx264 -preset medium -bufsize 400k -maxrate 400k -f flv rtmp://nessma-****.channel.mediaservices.windows.net:1935/live/584c99f5c47f424d9e83ac95364331e7

  I have made sure that the streaming endpoint has one active streaming unit, I also made sure that the channel is actually Ready and I even get it to start streaming (which makes a PublishURL available).

  When I execute the ffmpeg command to start streaming, I keep getting the following error :

  ffmpeg version 2.5.2 Copyright (c) 2000-2014 the FFmpeg developers
 built on Dec 30 2014 11:31:18 with llvm-gcc 4.2.1 (LLVM build 2336.11.00)
 configuration: --prefix=/Volumes/Ramdisk/sw --enable-gpl --enable-pthreads --enable-version3 --enable-libspeex --enable-libvpx --disable-decoder=libvpx --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-avfilter --enable-libopencore_amrwb --enable-libopencore_amrnb --enable-filters --enable-libgsm --enable-libvidstab --enable-libx265 --arch=x86_64 --enable-runtime-cpudetect
 libavutil      54. 15.100 / 54. 15.100
 libavcodec     56. 13.100 / 56. 13.100
 libavformat    56. 15.102 / 56. 15.102
 libavdevice    56.  3.100 / 56.  3.100
 libavfilter     5.  2.103 /  5.  2.103
 libswscale      3.  1.101 /  3.  1.101
 libswresample   1.  1.100 /  1.  1.100
 libpostproc    53.  3.100 / 53.  3.100
Routing option strict to both codec and muxer layer
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f9a0a002c00] overread end of atom 'colr' by 1 bytes
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f9a0a002c00] stream 0, timescale not set
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f9a0a002c00] max_analyze_duration 5000000 reached at 5003637 microseconds
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '300.mp4':
 Metadata:
   major_brand     : mp42
   minor_version   : 0
   compatible_brands: mp42isomavc1
   creation_time   : 2014-01-11 05:39:32
   genre           : Trailer
   artist          : Warner Bros.
   title           : 300: Rise of an Empire - Trailer 2
   encoder         : HandBrake 0.9.9 2013051800
   date            : 2014
 Duration: 00:02:33.24, start: 0.000000, bitrate: 7377 kb/s
   Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080 (1920x1088), 7219 kb/s, 23.98 fps, 23.98 tbr, 90k tbn, 47.95 tbc (default)
   Metadata:
     creation_time   : 2014-01-11 05:39:32
     encoder         : JVT/AVC Coding
   Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 157 kb/s (default)
   Metadata:
     creation_time   : 2014-01-11 05:39:32
   Stream #0:2: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 101x150 [SAR 72:72 DAR 101:150], 90k tbr, 90k tbn, 90k tbc
rtmp://nessma-****.channel.mediaservices.windows.net:1935/live/584c99f5c47f424d9e83ac95364331e7: Input/output error

  The Azure blog post clearly states that this should be possible but I can’t find a working example anywhere.

  Environment :

  • MacOS Maverick
  • FFMPEG installed from official build
  • 300.mp4 : 1080p trailer of the latest 300 movie

• FFmpeg muxing to avi

  2 septembre 2015, par Uncia

  sI have program, that succefully shows h264 stream using SDL : I’m getting h264 frame, decode it using ffmpeg and draw using SDL.
  Also I can write frames to file (using fwrite) and play this file through ffplay.

  But I want to mux data to the avi and face some problems in av_write_frame.

  Here is my code :

  ...
  
  /*Initializing format context - outFormatContext is the member of my class*/
  
  AVOutputFormat *outFormat;
  
  outFormat = av_guess_format(NULL,"out.avi",NULL);
  
  outFormat->video_codec = AV_CODEC_ID_H264;
  
  outFormat->audio_codec = AV_CODEC_ID_NONE;
  
  avformat_alloc_output_context2(&outFormatContext, outFormat, NULL, "out.avi");
  
  AVCodec *outCodec;
  
  AVStream *outStream = add_stream(outFormatContext, &outCodec, outFormatContext->oformat->video_codec);
  
  avcodec_open2(outStream->codec, outCodec, NULL);
  
  av_dump_format(outFormatContext, 0, "out.avi", 1);
  
  if (avio_open(&outFormatContext->pb, "out.avi", AVIO_FLAG_WRITE) < 0) 
  
      throw Exception("Couldn't open file");
  
  if (avformat_write_header(outFormatContext, NULL) < 0)
  
      throw Exception("Couldn't write to file");
  
   //I don't have exceptions here - so there is 6KB header in out.avi.
  
   ...
  
  
  
  static AVStream *add_stream(AVFormatContext *oc, AVCodec **codec,
  
                          enum AVCodecID codec_id)
  
  {
  
  AVCodecContext *c;
  
  AVStream *st;
  
  /* find the encoder */
  
  *codec = avcodec_find_encoder(codec_id);
  
  if (!(*codec)) 
  
      throw("Could not find encoder");
  
  st = avformat_new_stream(oc, *codec);
  
  if (!st) 
  
      throw ("Could not allocate stream");
  
  st->id = oc->nb_streams-1;
  
  c = st->codec;
  
  c->bit_rate = 400000;
  
  /* Resolution must be a multiple of two. */
  
  c->width    = 1920;
  
  c->height   = 1080;
  
  c->pix_fmt  = PIX_FMT_YUV420P;
  
  c->flags = 0;
  
  c->time_base.num = 1;
  
  c->time_base.den = 25;
  
  c->gop_size      = 12; /* emit one intra frame every twelve frames at most */
  
  return st;
  
  }
  
  ...
  
  /* Part of decoding loop. There is AVPacket packet - h264 packet;
  
  int ret = av_write_frame(outFormatContext, &packet); //it return -22 code - Invadlid argument;
  
  if (avcodec_decode_video2(pCodecCtx, pFrame, &frameDecoded, &packet) < 0) 
  
      return;
  
  if (frameDecoded)
  
  {
  
     //SDL stuff
  
  }

  Also i tried to use avcodec_encode_video2 (encode pFrame back to the H264) next to the SDL stuff but encoding is not working - i’ve got empty packets :( It is the second problem.

  Using av_interleaved_write_frame causes acces violation.

  Code of the muxing part i copied from ffmpeg muxing example (https://www.ffmpeg.org/doxygen/2.1/doc_2examples_2muxing_8c-example.html)