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• FFmpeg mux video use libavformat avcodec but output couldn't be played

  10 août 2017, par tqn

  I’m trying write a app that take an input video and crop it to square video and ignore audio stream. Because bad performance if using command, I’m trying to use libavcodec and libavformat to do it. But the output isn’t playable by any video player and duration is 0 although I wrote all frame. Here are my code.

  void convert_video(char* input) {
  
      AVFormatContext *pFormatCtx = NULL;
  
      int             i, videoStreamIndex;
  
      AVCodecContext  *pCodecCtx = NULL;
  
      AVCodec         *pCodec = NULL;
  
      AVFrame         *pFrame = NULL;
  
      AVFrame         *pFrameSquare = NULL;
  
      AVPacket        packet, outPacket;
  
      int             frameFinished;
  
      int             numBytes;
  
      uint8_t         *buffer = NULL;
  
      AVCodec         *pEncodec = NULL;
  
      AVFormatContext *poFormatCxt = NULL;
  
      MuxOutputStream    videoStream = {0}, audioStream = {0};
  
      int tar_w, tar_h;
  
  
  
      const enum AVPixelFormat pic_format = AV_PIX_FMT_YUV420P;
  
      const enum AVCodecID codec_id = AV_CODEC_ID_H264;
  
      AVDictionary    *optionsDict = NULL;
  
      char output[50];
  
      sprintf(output, "%soutput.mp4", ANDROID_SDCARD);
  
  
  
      // Register all formats and codecs
  
      av_register_all();
  
  
  
      // Open video file
  
      if(avformat_open_input(&pFormatCtx, input, NULL, NULL)!=0)
  
          return; // Couldn't open file
  
      avformat_alloc_output_context2(&poFormatCxt, NULL, NULL, output);
  
  
  
      // Retrieve stream information
  
      if(avformat_find_stream_info(pFormatCtx, NULL)<0)
  
          return; // Couldn't find stream information
  
  
  
      // Find the first video stream
  
      videoStreamIndex=-1;
  
      for(i=0; inb_streams; i++)
  
          if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO) {
  
              videoStreamIndex=i;
  
              break;
  
          }
  
      if(videoStreamIndex==-1)
  
          return; // Didn't find a video stream
  
  
  
      // Get a pointer to the codec context for the video stream
  
      pCodecCtx = pFormatCtx->streams[videoStreamIndex]->codec;
  
      tar_w = pCodecCtx->width > pCodecCtx->height ? pCodecCtx->height : pCodecCtx->width;
  
      tar_h = tar_w;
  
  
  
      // Find the decoder for the video stream
  
      pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
  
      pEncodec = avcodec_find_encoder(codec_id);
  
  
  
      add_stream_mux(&videoStream, poFormatCxt, &pEncodec, codec_id, tar_w, tar_h);
  
      videoStream.st[0].time_base = pFormatCtx->streams[videoStreamIndex]->time_base;
  
      videoStream.st[0].codec->time_base = videoStream.st[0].time_base;
  
      videoStream.st[0].codec->time_base.den *= videoStream.st[0].codec->ticks_per_frame;
  
  //    add_stream(&audioStream, poFormatCxt, &)
  
      open_video(poFormatCxt, pEncodec, &videoStream, optionsDict);
  
      int ret = avio_open(&poFormatCxt->pb, output, AVIO_FLAG_WRITE);
  
  
  
      // Open codec
  
      if(avcodec_open2(pCodecCtx, pCodec, &optionsDict) < 0)
  
          return; // Could not open codec
  
  
  
      ret = avformat_write_header(poFormatCxt, &optionsDict);
  
      if (ret != 0) {
  
          ANDROID_LOG("Died");
  
      }
  
  
  
      // Allocate video frame
  
      pFrame=av_frame_alloc();
  
      pFrame->format = videoStream.st->codec->pix_fmt;
  
      pFrame->width = pCodecCtx->width;
  
      pFrame->height = pCodecCtx->height;
  
      av_frame_get_buffer(pFrame, 32);
  
  
  
      // Allocate an AVFrame structure
  
      pFrameSquare=av_frame_alloc();
  
      if(pFrameSquare==NULL)
  
          return;
  
  
  
      // Determine required buffer size and allocate buffer
  
      numBytes=avpicture_get_size(pic_format, tar_w,
  
                                  tar_h);
  
      buffer = (uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
  
  
  
      // Assign appropriate parts of buffer to image planes in pFrameSquare
  
      // Note that pFrameSquare is an AVFrame, but AVFrame is a superset
  
      // of AVPicture
  
      ret = avpicture_fill((AVPicture *)pFrameSquare, buffer, pic_format,
  
                     tar_w, tar_h);
  
      if (ret < 0) {
  
          ANDROID_LOG("Can't fill picture");
  
          return;
  
      }
  
  
  
      // Read frames and save first five frames to disk
  
      i=0;
  
      ret = av_read_frame(pFormatCtx, &packet);
  
      while(ret >= 0) {
  
          // Is this a packet from the video stream?
  
          if(packet.stream_index == videoStreamIndex) {
  
              // Decode video frame
  
  //            av_packet_rescale_ts(&packet, videoStream.st->time_base, videoStream.st->codec->time_base);
  
              avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished,
  
                                    &packet);
  
  //            while (!frameFinished) {
  
  //                avcodec_decode_video2(videoStream.st->codec, pFrame, &frameFinished, NULL);
  
  //            }
  
              ANDROID_LOG("Trying to decode frame %d with result %d", i, frameFinished);
  
              ret = av_picture_crop((AVPicture*) pFrameSquare, (AVPicture*) pFrame, pic_format, 0, 0);
  
              if (ret < 0) {
  
                  ANDROID_LOG("Can't crop image");
  
              }
  
  //            av_frame_get_best_effort_timestamp(pFrame);
  
  //            av_rescale_q()
  
  
  
              if(frameFinished) {
  
  
  
                  // Save the frame to disk
  
                  av_init_packet(&outPacket);
  
  //                av_packet_rescale_ts(&outPacket, videoStream.st->codec->time_base, videoStream.st->time_base);
  
                  pFrameSquare->width = tar_w;
  
                  pFrameSquare->height = tar_h;
  
                  pFrameSquare->format = pic_format;
  
                  pFrameSquare->pts = ++videoStream.next_pts;
  
                  ret = avcodec_encode_video2(videoStream.st->codec, &outPacket, pFrameSquare, &frameFinished);
  
  
  
  //                int count = 0;
  
  //                while (!frameFinished && count++ < 6) {
  
  //                    ret = avcodec_encode_video2(videoStream.st->codec, &outPacket, NULL, &frameFinished);
  
  //                }
  
                  if (frameFinished) {
  
                      ANDROID_LOG("Writing frame %d", i);
  
                      outPacket.stream_index = videoStreamIndex;
  
                      av_interleaved_write_frame(poFormatCxt, &outPacket);
  
                  }
  
                  av_free_packet(&outPacket);
  
              }
  
          }
  
  
  
          // Free the packet that was allocated by av_read_frameav_free_packet(&packet);
  
          ret = av_read_frame(pFormatCtx, &packet);
  
      }
  
  
  
      ret = av_write_trailer(poFormatCxt);
  
      if (ret < 0) {
  
          ANDROID_LOG("Couldn't write trailer");
  
      } else {
  
          ANDROID_LOG("Video convert finished");
  
      }
  
  
  
      // Free the RGB image
  
      av_free(buffer);
  
      av_free(pFrameSquare);
  
  
  
      // Free the YUV frame
  
      av_free(pFrame);
  
  
  
      // Close the codec
  
      avcodec_close(pCodecCtx);
  
  //    avcodec_close(pEncodecCtx);
  
  
  
      // Close the video file
  
      avformat_close_input(&pFormatCtx);
  
  
  
      return;
  
  }

  Helper

  #define STREAM_DURATION   10.0
  
  #define STREAM_FRAME_RATE 25 /* 25 images/s */
  
  #define STREAM_PIX_FMT    AV_PIX_FMT_YUV420P /* default pix_fmt */
  
  
  
  /* Add an output stream. */
  
  void add_stream_mux(MuxOutputStream *ost, AVFormatContext *oc,
  
                         AVCodec **codec,
  
                         enum AVCodecID codec_id, int width, int heigh)
  
  {
  
      AVCodecContext *codecCtx;
  
      int i;
  
      /* find the encoder */
  
      *codec = avcodec_find_encoder(codec_id);
  
      if (!(*codec)) {
  
          fprintf(stderr, "Could not find encoder for '%s'\n",
  
                  avcodec_get_name(codec_id));
  
          exit(1);
  
      }
  
      ost->st = avformat_new_stream(oc, *codec);
  
      if (!ost->st) {
  
          fprintf(stderr, "Could not allocate stream\n");
  
          exit(1);
  
      }
  
      ost->st->id = oc->nb_streams-1;
  
      codecCtx = ost->st->codec;
  
      switch ((*codec)->type) {
  
          case AVMEDIA_TYPE_AUDIO:
  
              codecCtx->sample_fmt  = (*codec)->sample_fmts ?
  
                               (*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;
  
              codecCtx->bit_rate    = 64000;
  
              codecCtx->sample_rate = 44100;
  
              if ((*codec)->supported_samplerates) {
  
                  codecCtx->sample_rate = (*codec)->supported_samplerates[0];
  
                  for (i = 0; (*codec)->supported_samplerates[i]; i++) {
  
                      if ((*codec)->supported_samplerates[i] == 44100)
  
                          codecCtx->sample_rate = 44100;
  
                  }
  
              }
  
              codecCtx->channels        = av_get_channel_layout_nb_channels(codecCtx->channel_layout);
  
              codecCtx->channel_layout = AV_CH_LAYOUT_STEREO;
  
              if ((*codec)->channel_layouts) {
  
                  codecCtx->channel_layout = (*codec)->channel_layouts[0];
  
                  for (i = 0; (*codec)->channel_layouts[i]; i++) {
  
                      if ((*codec)->channel_layouts[i] == AV_CH_LAYOUT_STEREO)
  
                          codecCtx->channel_layout = AV_CH_LAYOUT_STEREO;
  
                  }
  
              }
  
              codecCtx->channels        = av_get_channel_layout_nb_channels(codecCtx->channel_layout);
  
              ost->st->time_base = (AVRational){ 1, codecCtx->sample_rate };
  
              break;
  
          case AVMEDIA_TYPE_VIDEO:
  
              codecCtx->codec_id = codec_id;
  
              codecCtx->bit_rate = 400000;
  
              /* Resolution must be a multiple of two. */
  
              codecCtx->width    = width;
  
              codecCtx->height   = heigh;
  
              /* timebase: This is the fundamental unit of time (in seconds) in terms
  
               * of which frame timestamps are represented. For fixed-fps content,
  
               * timebase should be 1/framerate and timestamp increments should be
  
               * identical to 1. */
  
              ost->st->time_base = (AVRational){ 1, STREAM_FRAME_RATE };
  
              codecCtx->time_base       = ost->st->time_base;
  
              codecCtx->gop_size      = 12; /* emit one intra frame every twelve frames at most */
  
              codecCtx->pix_fmt       = STREAM_PIX_FMT;
  
              if (codecCtx->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
  
                  /* just for testing, we also add B frames */
  
                  codecCtx->max_b_frames = 2;
  
              }
  
              if (codecCtx->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
  
                  /* Needed to avoid using macroblocks in which some coeffs overflow.
  
                   * This does not happen with normal video, it just happens here as
  
                   * the motion of the chroma plane does not match the luma plane. */
  
                  codecCtx->mb_decision = 2;
  
              }
  
              break;
  
          default:
  
              break;
  
      }
  
      /* Some formats want stream headers to be separate. */
  
      if (oc->oformat->flags & AVFMT_GLOBALHEADER)
  
          codecCtx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
  
  }
  
  static void open_video(AVFormatContext *oc, AVCodec *codec, MuxOutputStream *ost, AVDictionary *opt_arg)
  
  {
  
      int ret;
  
      AVCodecContext *c = ost->st->codec;
  
      AVDictionary *opt = NULL;
  
      av_dict_copy(&opt, opt_arg, 0);
  
      /* open the codec */
  
      ret = avcodec_open2(c, codec, &opt);
  
      av_dict_free(&opt);
  
      if (ret < 0) {
  
          fprintf(stderr, "Could not open video codec: %s\n", av_err2str(ret));
  
          exit(1);
  
      }
  
      /* allocate and init a re-usable frame */
  
      ost->frame = alloc_picture(c->pix_fmt, c->width, c->height);
  
      if (!ost->frame) {
  
          fprintf(stderr, "Could not allocate video frame\n");
  
          exit(1);
  
      }
  
      /* If the output format is not YUV420P, then a temporary YUV420P
  
       * picture is needed too. It is then converted to the required
  
       * output format. */
  
      ost->tmp_frame = NULL;
  
      if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
  
          ost->tmp_frame = alloc_picture(AV_PIX_FMT_YUV420P, c->width, c->height);
  
          if (!ost->tmp_frame) {
  
              fprintf(stderr, "Could not allocate temporary picture\n");
  
              exit(1);
  
          }
  
      }
  
  }

  I’m afraid that I set wrong pts or time_base of frame, and also when decoding or encoding, I see that some first frame is lost, frameFinished is 0. See a post that I’ve to flush decoder by avcodec_decode_video2(videoStream.st->codec, pFrame, &frameFinished, NULL) but after try a few times, frameFinished still is 0, and with avcodec_encode_video2(videoStream.st->codec, &outPacket, NULL, &frameFinished) will throw error in next encode frame. So how I can get all frame that lost ? I’m using FFmpeg version 3.0.1

• Detect the type of an AVFrame instance

  23 octobre 2017, par stefk0

  Given a pointer pFrame to a structure of type AVFrame, is there a proper way to determine the type of the structure, i.e. either audio or video ?

  One way might be to check whether pFrame->nb_samples == 0 or not, but this doesn’t look right.

• How to complete your privacy policy with Matomo analytics under GDPR

  25 avril 2018, par InnoCraft

  Important note : this blog post has been written by digital analysts, not lawyers. The purpose of this article is to show you how to complete your existing privacy policy by adding the parts related to Matomo in order to comply with GDPR. This work comes from our interpretation of the UK privacy commission : ICO. It cannot be considered as professional legal advice. So as GDPR, this information is subject to change. We strongly advise you to have a look at the different privacy authorities in order to have up to date information. This blog post contains public sector information licensed under the Open Government Licence v3.0.

  Neither the GDPR official text or ICO are mentioning the words ‘privacy policy’. They use the words ‘privacy notice’ instead. As explained within our previous blog post about “How to write a privacy notice for Matomo”, the key concepts of privacy information are transparency and accessibility which are making the privacy notice very long.

  As a result, we prefer splitting the privacy notice into two parts :

  • Privacy notice : straight to the point information about how personal data is processed at the time of the data collection. This is the subject of the our previous blog post.
  • Privacy policy : a web page explaining in detail all the personal data you are processing and how visitors/users can exercise their rights. This is the blog post you are reading.

  Writing/updating your privacy policy page can be one of the most challenging task under GDPR.

  In order to make this mission less complicated, we have designed a template which you can use to complete the privacy policy part that concerns Matomo.

  Which information should your privacy policy include ?

  ICO is giving a clear checklist about what a privacy policy has to contain when the data is obtained from the data subject :

  1. Identity and contact details of the controller and where applicable, the controller’s representative and the data protection officer.
  2. Purpose of the processing and the legal basis for the processing.
  3. The legitimate interests of the controller or third party, where applicable.
  4. Any recipient or categories of recipients of the personal data.
  5. Details of transfers to third country and safeguards.
  6. Retention period or criteria used to determine the retention period.
  7. The existence of each of data subject’s rights.
  8. The right to withdraw consent at any time, where relevant.
  9. The right to lodge a complaint with a supervisory authority.
  10. Whether the provision of personal data part of a statutory or contractual requirement or obligation and possible consequences of failing to provide the personal data.
  11. The existence of automated decision-making, including profiling and information about how decisions are made, the significance and the consequences.

  So in order to use Matomo with due respect to GDPR you need to answer each of those points within your privacy policy.

  Matomo’s privacy policy template

  You will find below some examples to each point requested by GDPR. Those answers are just guidelines, they are not perfect, feel free to copy/paste them according to your needs.

  Note that this template needs to be tweaked according to the lawful basis you choose.

  1 – About Matomo

  Note : this part should describe the data controller instead, which is your company. But as you may already have included this part within your existing privacy policy, we prefer here to introduce what is Matomo.

  Matomo is an open source web analytics platform. A web analytics platform is used by a website owner in order to measure, collect, analyse and report visitors data for purposes of understanding and optimizing their website. If you would like to see what Matomo looks like, you can access a demo version at : https://demo.matomo.org.

  2 – Purpose of the processing

  Matomo is used to analyse the behaviour of the website visitors to identify potential pitfalls ; not found pages, search engine indexing issues, which contents are the most appreciated… Once the data is processed (number of visitors reaching a not found pages, viewing only one page…), Matomo is generating reports for website owners to take action, for example changing the layout of the pages, publishing some fresh content… etc.

  Matomo is processing the following personal data :

  Pick up the one you are using :

  • Cookies
  • IP address
  • User ID
  • Custom Dimensions
  • Custom Variables
  • Order ID
  • Location of the user

  And also :

  • Date and time
  • Title of the page being viewed
  • URL of the page being viewed
  • URL of the page that was viewed prior to the current page
  • Screen resolution
  • Time in local timezone
  • Files that were clicked and downloaded
  • Link clicks to an outside domain
  • Pages generation time
  • Country, region, city
  • Main Language of the browser
  • User Agent of the browser

  This list can be completed with additional features such as :

  • Session recording, mouse events (movements, content forms and clicks)
  • Form interactions
  • Media interactions
  • A/B Tests

  Pick up one of the two :

  1. The processing of personal data with Matomo is based on legitimate interests, or :
  2. The processing of personal data with Matomo is based on explicit consent. Your privacy is our highest concern. That’s why we will not process any personal data with Matomo unless you give us clear explicit consent.

  3 – The legitimate interests

  This content applies only if you are processing personal data based on legitimate interests. You need here to justify your legitimate interests to process personal data. It is a set of questions described here.

  Processing your personal data such as cookies is helping us identify what is working and what is not on our website. For example, it helps us identify if the way we are communicating is engaging or not and how we can organize the structure of the website better. Our team is benefiting from the processing of your personal data, and they are directly acting on the website. By processing your personal data, you can profit from a website which is getting better and better.

  Without the data, we would not be able to provide you the service we are currently offering to you. Your data will be used only to improve the user experience on our website and help you find the information you are looking for.

  4 – Recipient of the personal data

  The personal data received through Matomo are sent to :

  • Our company.
  • Our web hosting provider : name and contact details of the web hosting provider.

  Note : If you are using the Matomo Analytics Cloud by InnoCraft the web hosting provider is “InnoCraft, 150 Willis St, 6011 Wellington, New Zealand“.

  5 – Details of transfers to third country and safeguards

  Matomo data is hosted in Name of the country.

  If the country mentioned is not within the EU, you need to mention here the appropriate safeguards, for example : our data is hosted in the United States within company XYZ, registered to the Privacy Shield program.

  Note : The Matomo Analytics Cloud by InnoCraft is currently hosted in France. If you are using the cloud-hosted solution of Matomo, use “France” as name of the country.

  6 – Retention period or criteria used to determine the retention period

  We are keeping the personal data captured within Matomo for a period of indicate here the period.

  Justify your choice, for example : as our data is hosted in France, we are applying the French law which defines a retention period of no more than 13 months. You can set the retention period in Matomo by using the following feature.

  7 – The existence of each of the data subject’s rights

  If you are processing personal data with Matomo based on legitimate interest :

  As Matomo is processing personal data on legitimate interests, you can exercise the following rights :

  • Right of access : you can ask us at any time to access your personal data.
  • Right to erasure : you can ask us at any time to delete all the personal data we are processing about you.
  • Right to object : you can object to the tracking of your personal data by using the following opt-out feature :

  Insert here the opt-out feature.

  If you are processing personal data with Matomo based on explicit consent :

  As Matomo is processing personal data on explicit consent, you can exercise the following rights :

  • Right of access : you can ask us at any time to access your personal data.
  • Right to erasure : you can ask us at any time to delete all the personal data we are processing about you.
  • Right to portability : you can ask us at any time for a copy of all the personal data we are processing about you in Matomo.
  • Right to withdraw consent : you can withdraw your consent at any time by clicking on the following button.

  8 – The right to withdraw consent at any time

  If you are processing personal data under the consent lawful basis, you need to include the following section :

  You can withdraw at any time your consent by clicking here (insert here the Matomo tracking code to remove consent).

  9 – The right to lodge a complaint with a supervisory authority

  If you think that the way we process your personal data with Matomo analytics is infringing the law, you have the right to lodge a complaint with a supervisory authority.

  10 – Whether the provision of personal data is part of a statutory or contractual requirement ; or obligation and possible consequences of failing to provide the personal data

  If you wish us to not process any personal data with Matomo, you can opt-out from it at any time. There will be no consequences at all regarding the use of our website.

  11 – The existence of automated decision-making, including profiling and information about how decisions are made, the significance and the consequences

  Matomo is not doing any profiling.

   

  That’s the end of our blog post. We hope you enjoyed reading it and that it will help you get through the GDPR compliance process. If you have any questions dealing with this privacy policy in particular, do not hesitate to contact us.

  The post How to complete your privacy policy with Matomo analytics under GDPR appeared first on Analytics Platform - Matomo.