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• Hung out to dry

  31 mai 2013, par Mans — Law and liberty

  Outrage was the general reaction when Google recently announced their dropping of XMPP server-to-server federation from Hangouts, as the search giant’s revamped instant messaging platform is henceforth to be known. This outrage is, however, largely unjustified ; Google’s decision is merely a rational response to issues of a more fundamental nature. To see why, we need to step back and look at the broader instant messaging landscape.

  A brief history of IM

  The term instant messaging (IM) gained popularity in the mid-1990s along with the rise of chat clients such as ICQ, AOL Instant Messenger, and later MSN Messenger. These all had one thing in common : they were closed systems. Although global in the sense of allowing access from anywhere on the Internet, communication was possible only within each network, and only using the officially sanctioned client software. Contrast this with email, where users are free to choose any service provider as well as client software, inter-server communication over open protocols delivering messages to their proper destinations.

  The email picture has, however, not always been so rosy. During the 1970s and 80s a multitude of incompatible email systems (e.g. UUCP and X.400) were in more or less widespread use on various networks. As these networks gave way to the ARPANET/Internet, so did their mail systems to the SMTP email we all use today. A similar consolidation has yet to occur in the area of instant messaging.

  Over the years, a few efforts towards a cross-domain instant messaging have been undertaken. One early example is the Zephyr system created as part of Project Athena at MIT in the late 1980s. While it never saw significant uptake, it is still in use at a few universities. A more successful story is that of XMPP. Conceived under the name Jabber in the late 1990s, XMPP is an open standard specified in a set of IETF RFCs. In addition to being open, a distinguishing feature of XMPP compared to other contemporary IM systems is its decentralised nature, server-to-server connections allowing communication between users with accounts on different systems. Just like email.

  The social network

  A more recent emergence on the Internet is the social network. Although not the first of its kind, Facebook was the first to achieve its level of penetration, both geographically and across social groups. A range of messaging options, including email-style as well as instant messaging (chat), are available, all within the same web interface. What it does not allow is communication outside the Facebook network. Other social networks operate in the same spirit.

  The popularity of social networks, to the extent that they for many constitute the primary means of communication, has in a sense brought back fragmented networks of the 1980s. Even though they share infrastructure, up to and including the browser application, the social networks create walled-off regions of the Internet between which little or no exchange is possible.

  The house that Google built

  In 2005, Google launched Talk, an XMPP-based instant messaging service allowing users to connect using either Google’s official client application or any third-party XMPP client. Soon after, server-to-server federation was activated, enabling anyone with a Google account to exchange instant messages with users of any other federated XMPP service. An in-browser chat interface was also added to Gmail.

  It was arguably only with the 2011 introduction of Google+ that Google, despite its previous endeavours with Orkut and Buzz, had a viable contender in the social networking space. Since its inception, Google+ has gone through a number of changes where features have been added or reworked. Instant messaging within Google+ was until recently available only in mobile clients. On the desktop, the sole messaging option was Hangouts which, although featuring text chat, cannot be considered instant messaging in the usual sense.

  With a sprawling collection of messaging systems (Talk, Google+ Messenger, Hangouts), some action to consolidate them was a logical step. What we got was a unification under the Hangouts name. A redesigned Google+ now sports in-browser instant messaging similar the the Talk interface already present in Gmail. At the same time, the standalone desktop Talk client is discontinued, as is the Messenger feature in mobile Google+. All together, the changes make for a much less confusing user experience.

  The sky is falling down

  Along with the changes to the messaging platform, one announcement stoked anger on the Internet : Google’s intent to discontinue XMPP federation (as of this writing, it is still operational). Google, the (self-described) champions of openness on the Internet were seen to be closing their doors to the outside world. The effects of the change are, however, not quite so earth-shattering. Of the other major messaging networks to offer XMPP at all (Facebook, Skype, and the defunct Microsoft Messenger), none support federation ; a Google user has never been able to chat with a Facebook user.

  XMPP federation appears to be in use mainly by non-profit organisations or individuals running their own servers. The number of users on these systems is hard to assess, though it seems fair to assume it is dwarfed by the hundreds of millions using Google or Facebook. As such, the overall impact of cutting off communication with the federated servers is relatively minor, albeit annoying for those affected.

  A fragmented world

  Rather than chastising Google for making a low-impact, presumably founded, business decision, we should be asking ourselves why instant messaging is still so fragmented in the first place, whereas email is not. The answer can be found by examining the nature of entities providing these services.

  Ever since the commercialisation of the Internet started in the 1990s, email has been largely seen as being part of the Internet. Access to email was a major selling point for Internet service providers ; indeed, many still use the email facilities of their ISP. Instant messaging, by contrast, has never come as part of the basic offering, rather being a third-party service running on top of the Internet.

  Users wishing to engage in instant messaging have always had to seek out and sign up with a provider of such a service. As the IM networks were isolated, most would choose whichever service their friends were already using, and a small number of networks, each with a sustainable number of users, came to dominate. In the early days, dedicated IM services such as ICQ were popular. Today, social networks have taken their place with Facebook currently in the dominant position. With the new Hangouts, Google offers its users the service they want in the way they have come to expect.

  Follow the money

  We now have all the pieces necessary to see why inter-domain instant messaging has never taken off, and the answer is simple : the major players have no commercial incentive to open access to their IM networks. In fact, they have good reason to keep the networks closed. Ensuring that a person leaving the network loses contact with his or her friends, increases user retention by raising the cost of switching to another service. Monetising users is also better facilitated if they are forced to remain on, say, Facebook’s web pages while using its services rather than accessing them indirectly, perhaps even through a competing (Google, say) frontend. The users do not generally care much, since all their friends are already on the same network as themselves.

  While Google Talk was a standalone service, only loosely coupled to other Google products, these aspects were of lesser importance. After all, Google still had access to all the messages passing through the system and could analyse them for advert targeting purposes. Now that messaging is an integrated part of Google+, and thus serves as a direct competitor to the likes of Facebook, the situation has changed. All the reasons for Facebook not to open its network now apply equally to Google as well.

• How to reparse video with stable "overall bit rate" ? (FFmpeg)

  20 février 2018, par user3360601

  I have such code below :

  #include 
  
  #include 
  
  #include 
  
  
  
  extern "C"
  
  {
  
  #include <libavcodec></libavcodec>avcodec.h>
  
  #include <libavformat></libavformat>avformat.h>
  
  #include <libavfilter></libavfilter>buffersink.h>
  
  #include <libavfilter></libavfilter>buffersrc.h>
  
  #include <libavutil></libavutil>opt.h>
  
  #include <libavutil></libavutil>pixdesc.h>
  
  }
  
  
  
  static AVFormatContext *ifmt_ctx;
  
  static AVFormatContext *ofmt_ctx;
  
  
  
  typedef struct StreamContext {
  
      AVCodecContext *dec_ctx;
  
      AVCodecContext *enc_ctx;
  
  } StreamContext;
  
  static StreamContext *stream_ctx;
  
  
  
  static int open_input_file(const char *filename)
  
  {
  
      int ret;
  
      unsigned int i;
  
  
  
      ifmt_ctx = NULL;
  
      if ((ret = avformat_open_input(&amp;ifmt_ctx, filename, NULL, NULL)) &lt; 0) {
  
          av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n");
  
          return ret;
  
      }
  
  
  
      if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) &lt; 0) {
  
          av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n");
  
          return ret;
  
      }
  
  
  
      stream_ctx = (StreamContext *) av_mallocz_array(ifmt_ctx->nb_streams, sizeof(*stream_ctx));
  
      if (!stream_ctx)
  
          return AVERROR(ENOMEM);
  
  
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          AVStream *stream = ifmt_ctx->streams[i];
  
          AVCodec *dec = avcodec_find_decoder(stream->codecpar->codec_id);
  
          AVCodecContext *codec_ctx;
  
          if (!dec) {
  
              av_log(NULL, AV_LOG_ERROR, "Failed to find decoder for stream #%u\n", i);
  
              return AVERROR_DECODER_NOT_FOUND;
  
          }
  
          codec_ctx = avcodec_alloc_context3(dec);
  
          if (!codec_ctx) {
  
              av_log(NULL, AV_LOG_ERROR, "Failed to allocate the decoder context for stream #%u\n", i);
  
              return AVERROR(ENOMEM);
  
          }
  
          ret = avcodec_parameters_to_context(codec_ctx, stream->codecpar);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Failed to copy decoder parameters to input decoder context "
  
                  "for stream #%u\n", i);
  
              return ret;
  
          }
  
          /* Reencode video &amp; audio and remux subtitles etc. */
  
          if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO
  
              || codec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
  
              if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO)
  
                  codec_ctx->framerate = av_guess_frame_rate(ifmt_ctx, stream, NULL);
  
              /* Open decoder */
  
              ret = avcodec_open2(codec_ctx, dec, NULL);
  
              if (ret &lt; 0) {
  
                  av_log(NULL, AV_LOG_ERROR, "Failed to open decoder for stream #%u\n", i);
  
                  return ret;
  
              }
  
          }
  
          stream_ctx[i].dec_ctx = codec_ctx;
  
      }
  
  
  
      av_dump_format(ifmt_ctx, 0, filename, 0);
  
      return 0;
  
  }
  
  
  
  static int open_output_file(const char *filename)
  
  {
  
      AVStream *out_stream;
  
      AVStream *in_stream;
  
      AVCodecContext *dec_ctx, *enc_ctx;
  
      AVCodec *encoder;
  
      int ret;
  
      unsigned int i;
  
  
  
      ofmt_ctx = NULL;
  
      avformat_alloc_output_context2(&amp;ofmt_ctx, NULL, NULL, filename);
  
      if (!ofmt_ctx) {
  
          av_log(NULL, AV_LOG_ERROR, "Could not create output context\n");
  
          return AVERROR_UNKNOWN;
  
      }
  
  
  
  
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          out_stream = avformat_new_stream(ofmt_ctx, NULL);
  
          if (!out_stream) {
  
              av_log(NULL, AV_LOG_ERROR, "Failed allocating output stream\n");
  
              return AVERROR_UNKNOWN;
  
          }
  
  
  
          in_stream = ifmt_ctx->streams[i];
  
          dec_ctx = stream_ctx[i].dec_ctx;
  
  
  
          //ofmt_ctx->bit_rate = ifmt_ctx->bit_rate;
  
          ofmt_ctx->duration = ifmt_ctx->duration;
  
  
  
          if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO
  
              || dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
  
              /* in this example, we choose transcoding to same codec */
  
              encoder = avcodec_find_encoder(dec_ctx->codec_id);
  
              if (!encoder) {
  
                  av_log(NULL, AV_LOG_FATAL, "Necessary encoder not found\n");
  
                  return AVERROR_INVALIDDATA;
  
              }
  
              enc_ctx = avcodec_alloc_context3(encoder);
  
              if (!enc_ctx) {
  
                  av_log(NULL, AV_LOG_FATAL, "Failed to allocate the encoder context\n");
  
                  return AVERROR(ENOMEM);
  
              }
  
  
  
              /* In this example, we transcode to same properties (picture size,
  
              * sample rate etc.). These properties can be changed for output
  
              * streams easily using filters */
  
              if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO) {
  
                  enc_ctx->gop_size = dec_ctx->gop_size;
  
                  enc_ctx->bit_rate = dec_ctx->bit_rate;
  
                  enc_ctx->height = dec_ctx->height;
  
                  enc_ctx->width = dec_ctx->width;
  
                  enc_ctx->sample_aspect_ratio = dec_ctx->sample_aspect_ratio;
  
                  /* take first format from list of supported formats */
  
                  if (encoder->pix_fmts)
  
                      enc_ctx->pix_fmt = encoder->pix_fmts[0];
  
                  else
  
                      enc_ctx->pix_fmt = dec_ctx->pix_fmt;
  
                  /* video time_base can be set to whatever is handy and supported by encoder */
  
                  enc_ctx->time_base = av_inv_q(dec_ctx->framerate);
  
                  enc_ctx->framerate = av_guess_frame_rate(ifmt_ctx, in_stream, NULL);
  
              }
  
              else {
  
                  enc_ctx->gop_size = dec_ctx->gop_size;
  
                  enc_ctx->bit_rate = dec_ctx->bit_rate;
  
                  enc_ctx->sample_rate = dec_ctx->sample_rate;
  
                  enc_ctx->channel_layout = dec_ctx->channel_layout;
  
                  enc_ctx->channels = av_get_channel_layout_nb_channels(enc_ctx->channel_layout);
  
                  /* take first format from list of supported formats */
  
                  enc_ctx->sample_fmt = encoder->sample_fmts[0];
  
                  //enc_ctx->time_base = (AVRational){ 1, enc_ctx->sample_rate };
  
                  enc_ctx->time_base.num = 1;
  
                  enc_ctx->time_base.den = enc_ctx->sample_rate;
  
  
  
                  enc_ctx->framerate = av_guess_frame_rate(ifmt_ctx, in_stream, NULL);
  
              }
  
  
  
              /* Third parameter can be used to pass settings to encoder */
  
              ret = avcodec_open2(enc_ctx, encoder, NULL);
  
              if (ret &lt; 0) {
  
                  av_log(NULL, AV_LOG_ERROR, "Cannot open video encoder for stream #%u\n", i);
  
                  return ret;
  
              }
  
              ret = avcodec_parameters_from_context(out_stream->codecpar, enc_ctx);
  
              if (ret &lt; 0) {
  
                  av_log(NULL, AV_LOG_ERROR, "Failed to copy encoder parameters to output stream #%u\n", i);
  
                  return ret;
  
              }
  
              if (ofmt_ctx->oformat->flags &amp; AVFMT_GLOBALHEADER)
  
                  enc_ctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
  
  
  
              out_stream->time_base = enc_ctx->time_base;
  
              stream_ctx[i].enc_ctx = enc_ctx;
  
          }
  
          else if (dec_ctx->codec_type == AVMEDIA_TYPE_UNKNOWN) {
  
              av_log(NULL, AV_LOG_FATAL, "Elementary stream #%d is of unknown type, cannot proceed\n", i);
  
              return AVERROR_INVALIDDATA;
  
          }
  
          else {
  
              /* if this stream must be remuxed */
  
              ret = avcodec_parameters_copy(out_stream->codecpar, in_stream->codecpar);
  
              if (ret &lt; 0) {
  
                  av_log(NULL, AV_LOG_ERROR, "Copying parameters for stream #%u failed\n", i);
  
                  return ret;
  
              }
  
              out_stream->time_base = in_stream->time_base;
  
          }
  
  
  
      }
  
      av_dump_format(ofmt_ctx, 0, filename, 1);
  
  
  
      if (!(ofmt_ctx->oformat->flags &amp; AVFMT_NOFILE)) {
  
          ret = avio_open(&amp;ofmt_ctx->pb, filename, AVIO_FLAG_WRITE);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Could not open output file '%s'", filename);
  
              return ret;
  
          }
  
      }
  
  
  
      /* init muxer, write output file header */
  
      ret = avformat_write_header(ofmt_ctx, NULL);
  
      if (ret &lt; 0) {
  
          av_log(NULL, AV_LOG_ERROR, "Error occurred when opening output file\n");
  
          return ret;
  
      }
  
  
  
      return 0;
  
  }
  
  
  
  int main(int argc, char **argv)
  
  {
  
      int ret;
  
      AVPacket packet = {0};
  
      packet.data = NULL;
  
      packet.size = 0 ;
  
      AVFrame *frame = NULL;
  
      enum AVMediaType type;
  
      unsigned int stream_index;
  
      unsigned int i;
  
      int got_frame;
  
      int(*dec_func)(AVCodecContext *, AVFrame *, int *, const AVPacket *);
  
  
  
      if (argc != 3) {
  
          av_log(NULL, AV_LOG_ERROR, "Usage: %s <input file="file" /> <output file="file">\n", argv[0]);
  
          return 1;
  
      }
  
  
  
      av_register_all();
  
      avfilter_register_all();
  
  
  
      if ((ret = open_input_file(argv[1])) &lt; 0)
  
          goto end;
  
      if ((ret = open_output_file(argv[2])) &lt; 0)
  
          goto end;
  
  
  
      /* read all packets */
  
      while (1) {
  
          if ((ret = av_read_frame(ifmt_ctx, &amp;packet)) &lt; 0)
  
              break;
  
          stream_index = packet.stream_index;
  
          type = ifmt_ctx->streams[packet.stream_index]->codecpar->codec_type;
  
          av_log(NULL, AV_LOG_DEBUG, "Demuxer gave frame of stream_index %u\n", stream_index);
  
  
  
          /* remux this frame without reencoding */
  
          av_packet_rescale_ts(&amp;packet,
  
              ifmt_ctx->streams[stream_index]->time_base,
  
              ofmt_ctx->streams[stream_index]->time_base);
  
  
  
          ret = av_interleaved_write_frame(ofmt_ctx, &amp;packet);
  
          if (ret &lt; 0)
  
              goto end;
  
  
  
          av_packet_unref(&amp;packet);
  
      }
  
  
  
      av_write_trailer(ofmt_ctx);
  
  end:
  
      av_packet_unref(&amp;packet);
  
      av_frame_free(&amp;frame);
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          avcodec_free_context(&amp;stream_ctx[i].dec_ctx);
  
          if (ofmt_ctx &amp;&amp; ofmt_ctx->nb_streams > i &amp;&amp; ofmt_ctx->streams[i] &amp;&amp; stream_ctx[i].enc_ctx)
  
              avcodec_free_context(&amp;stream_ctx[i].enc_ctx);
  
      }
  
      av_free(stream_ctx);
  
      avformat_close_input(&amp;ifmt_ctx);
  
      if (ofmt_ctx &amp;&amp; !(ofmt_ctx->oformat->flags &amp; AVFMT_NOFILE))
  
          avio_closep(&amp;ofmt_ctx->pb);
  
      avformat_free_context(ofmt_ctx);
  
  
  
      return ret ? 1 : 0;
  
  }
  
  </output>

  This is a little bit changed code from official example of using ffmpeg called transcoding.c

  I only read packets from one stream and write them to another stream. It works fine.

  Proof below.
  

  then I add to main a condition. If it is a packet with video frame, I will decode it, then encode and write to another stream. No other actions with frame.

  My addition code below :

  static int encode_write_frame(AVFrame *filt_frame, unsigned int stream_index, int *got_frame) {
  
      int ret;
  
      int got_frame_local;
  
      AVPacket enc_pkt;
  
      int(*enc_func)(AVCodecContext *, AVPacket *, const AVFrame *, int *) = avcodec_encode_video2 ;
  
  
  
      if (!got_frame)
  
          got_frame = &got_frame_local;
  
  
  
      av_log(NULL, AV_LOG_INFO, "Encoding frame\n");
  
      /* encode filtered frame */
  
      enc_pkt.data = NULL;
  
      enc_pkt.size = 0;
  
      av_init_packet(&enc_pkt);
  
      ret = enc_func(stream_ctx[stream_index].enc_ctx, &enc_pkt,
  
          filt_frame, got_frame);
  
      if (ret < 0)
  
          return ret;
  
      if (!(*got_frame))
  
          return 0;
  
  
  
      /* prepare packet for muxing */
  
      enc_pkt.stream_index = stream_index;
  
      av_packet_rescale_ts(&enc_pkt,
  
          stream_ctx[stream_index].enc_ctx->time_base,
  
          ofmt_ctx->streams[stream_index]->time_base);
  
  
  
      av_log(NULL, AV_LOG_DEBUG, "Muxing frame\n");
  
      /* mux encoded frame */
  
      ret = av_interleaved_write_frame(ofmt_ctx, &enc_pkt);
  
      return ret;
  
  }
  
  
  
  static int filter_encode_write_frame(AVFrame *frame, unsigned int stream_index)
  
  {
  
      int ret;
  
      av_log(NULL, AV_LOG_INFO, "Pushing decoded frame to filters\n");
  
  
  
      while (1) {
  
          av_log(NULL, AV_LOG_INFO, "Pulling filtered frame from filters\n");
  
  
  
          ret = encode_write_frame(frame, stream_index, NULL);
  
          if (ret < 0)
  
              break;
  
          break;
  
      }
  
  
  
      return ret;
  
  }
  
  
  
  
  
  int main(int argc, char **argv)
  
  {
  
      int ret;
  
      AVPacket packet = {0};
  
      packet.data = NULL;
  
      packet.size = 0 ;
  
      AVFrame *frame = NULL;
  
      enum AVMediaType type;
  
      unsigned int stream_index;
  
      unsigned int i;
  
      int got_frame;
  
      int(*dec_func)(AVCodecContext *, AVFrame *, int *, const AVPacket *);
  
  
  
      if (argc != 3) {
  
          av_log(NULL, AV_LOG_ERROR, "Usage: %s <input file="file" /> <output file="file">\n", argv[0]);
  
          return 1;
  
      }
  
  
  
      av_register_all();
  
      avfilter_register_all();
  
  
  
      if ((ret = open_input_file(argv[1])) &lt; 0)
  
          goto end;
  
      if ((ret = open_output_file(argv[2])) &lt; 0)
  
          goto end;
  
  
  
      /* read all packets */
  
      while (1) {
  
          if ((ret = av_read_frame(ifmt_ctx, &amp;packet)) &lt; 0)
  
              break;
  
          stream_index = packet.stream_index;
  
          type = ifmt_ctx->streams[packet.stream_index]->codecpar->codec_type;
  
          av_log(NULL, AV_LOG_DEBUG, "Demuxer gave frame of stream_index %u\n",
  
              stream_index);
  
  
  
           if (type == AVMEDIA_TYPE_VIDEO)
  
           {
  
               av_log(NULL, AV_LOG_DEBUG, "Going to reencode&amp;filter the frame\n");
  
               frame = av_frame_alloc();
  
               if (!frame) {
  
                   ret = AVERROR(ENOMEM);
  
                   break;
  
               }
  
               av_packet_rescale_ts(&amp;packet,
  
                   ifmt_ctx->streams[stream_index]->time_base,
  
                   stream_ctx[stream_index].dec_ctx->time_base);
  
               dec_func = avcodec_decode_video2;
  
               ret = dec_func(stream_ctx[stream_index].dec_ctx, frame,
  
                   &amp;got_frame, &amp;packet);
  
               if (ret &lt; 0) {
  
                   av_frame_free(&amp;frame);
  
                   av_log(NULL, AV_LOG_ERROR, "Decoding failed\n");
  
                   break;
  
               }
  
  
  
               if (got_frame) {
  
                   frame->pts = frame->best_effort_timestamp;
  
                   ret = filter_encode_write_frame(frame, stream_index);
  
                   av_frame_free(&amp;frame);
  
                   if (ret &lt; 0)
  
                       goto end;
  
               }
  
               else {
  
                   av_frame_free(&amp;frame);
  
               }
  
           }
  
           else 
  
          {
  
              /* remux this frame without reencoding */
  
              av_packet_rescale_ts(&amp;packet,
  
                  ifmt_ctx->streams[stream_index]->time_base,
  
                  ofmt_ctx->streams[stream_index]->time_base);
  
  
  
              ret = av_interleaved_write_frame(ofmt_ctx, &amp;packet);
  
              if (ret &lt; 0)
  
                  goto end;
  
          }
  
          av_packet_unref(&amp;packet);
  
      }
  
  
  
      av_write_trailer(ofmt_ctx);
  
  end:
  
      av_packet_unref(&amp;packet);
  
      av_frame_free(&amp;frame);
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          avcodec_free_context(&amp;stream_ctx[i].dec_ctx);
  
          if (ofmt_ctx &amp;&amp; ofmt_ctx->nb_streams > i &amp;&amp; ofmt_ctx->streams[i] &amp;&amp; stream_ctx[i].enc_ctx)
  
              avcodec_free_context(&amp;stream_ctx[i].enc_ctx);
  
      }
  
      av_free(stream_ctx);
  
      avformat_close_input(&amp;ifmt_ctx);
  
      if (ofmt_ctx &amp;&amp; !(ofmt_ctx->oformat->flags &amp; AVFMT_NOFILE))
  
          avio_closep(&amp;ofmt_ctx->pb);
  
      avformat_free_context(ofmt_ctx);
  
  
  
      return ret ? 1 : 0;
  
  }
  
  </output>

  And the result is different.

  For a test I took a SampleVideo_1280x720_1mb.flv.
  It has

  File size : 1.00 MiB
  Overall bit rate : 1 630 kb/s

  After my decode/encode actions the result became :

  File size : 1.23 MiB
  Overall bit rate : 2 005 kb/s

  Other parameters (video bit rate, audio bit rate, etc) are the same.
  

  What am I doing wrong ? How to control overall bit rate ? I suppose, something wrong with encoder/decoder, but what ?

  UPD :
  I get that when in function open_input_file I write

  if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO)
  
  {
  
       codec_ctx->framerate = av_guess_frame_rate(ifmt_ctx, stream, NULL);
  
  }

  I get what I get (bigger size and bit rate).

  And when in this function I write

  if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO)
  
  {
  
      codec_ctx = ifmt_ctx->streams[i]->codec;
  
  }

  I get smaller size and bit rate.

  File size : 900 KiB
  Overall bit rate : 1 429 kb/s

  But how to get the exactly size and frame rate as in the original file ?

• ffmpeg encode video with incorrect output mediainfo encoding settings

  24 août 2021, par Foong

  I've been trying to do batch encode videos to H265 format. I am using media-autobuild_suite to build ffmpeg and have already updating ffmpeg to the latest version.

  


  ffmpeg version N-103367-g5ddb4b6a1b-g88b3e31562+1 Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 10.3.0 (Rev5, Built by MSYS2 project)
configuration:  --pkg-config=pkgconf --cc='ccache gcc' --cxx='ccache g++' --ld='ccache g++' --disable-autodetect --enable-amf --enable-bzlib --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-iconv --enable-lzma --enable-nvenc --enable-schannel --enable-zlib --enable-sdl2 --enable-ffnvcodec --enable-nvdec --enable-cuda-llvm --enable-gmp --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libdav1d --enable-libaom --disable-debug --enable-libfdk-aac --extra-libs=-liconv --enable-gpl --enable-version3 --enable-nonfree
libavutil      57.  4.101 / 57.  4.101
libavcodec     59.  5.101 / 59.  5.101
libavformat    59.  4.102 / 59.  4.102
libavdevice    59.  0.101 / 59.  0.101
libavfilter     8.  3.100 /  8.  3.100
libswscale      6.  0.100 /  6.  0.100
libswresample   4.  0.100 /  4.  0.100
libpostproc    56.  0.100 / 56.  0.100


  


  However, the Writing library and Encoding settings output is incorrect. Before update ffmpeg doesn't have this issue. I wonder what have been missing that causing this issue.

  


  encoding CLI :

  


  ffmpeg -y -hide_banner -loglevel error -stats -hwaccel dxva2 -i "input.mkv" -c:v libx265 -vsync cfr -pix_fmt yuv420p10le -preset fast -tune animation -x265-params ctu=32:min-cu-size=8:max-tu-size=16:tu-intra-depth=2:tu-inter-depth=2:me=1:subme=3:merange=44:max-merge=2:keyint=250:min-keyint=23:rc-lookahead=60:lookahead-slices=6:bframes=6:bframe-bias=0:b-adapt=2:ref=6:limit-refs=3:limit-tu=1:aq-mode=3:aq-strength=0.6:rd=3:psy-rd=1.00:psy-rdoq=1.50:rdoq-level=1:deblock=-1,-1:crf=21.0:qblur=0.50:qcomp=0.60:qpmin=0:qpmax=51:frame-threads=1:strong-intra-smoothing=1:no-lossless=1:no-cu-lossless=1:constrained-intra=1:no-fast-intra=1:no-open-gop=1:no-temporal-layers=1:no-limit-modes=1:weightp=1:no-weightb=1:no-analyze-src-pics=1:no-rd-refine=1:signhide=1:sao=1:no-sao-non-deblock=1:b-pyramid=1:no-cutree=1:no-intra-refresh=1:no-amp=1:temporal-mvp=1:no-early-skip=1:no-tskip=1:no-tskip-fast=1:no-deblock=1:no-b-intra=1:no-splitrd-skip=1:no-strict-cbr=1:no-rc-grain=1:no-const-vbv=1:no-opt-qp-pps=1:no-opt-ref-list-length-pps=1:no-multi-pass-opt-rps=1:no-opt-cu-delta-qp=1:no-hdr=1:no-hdr-opt=1:no-dhdr10-opt=1:no-idr-recovery-sei=1:no-limit-sao=1:no-lowpass-dct=1:no-dynamic-refine=1:no-single-sei=1 -c:a libfdk_aac -vf "fps=fps=29.970,setdar=16/9,scale=960:540:flags=lanczos" -map 0:v:? -map 0:a:? -map_metadata:g -1 -map_chapters 0 "output.mkv"


  


  Input video info :

  


  Video
ID                          : 1
Format                      : AVC
Format/Info                 : Advanced Video Codec
Format profile              : High@L3
Format settings             : CABAC / 5 Ref Frames
Format settings, CABAC      : Yes
Format settings, Reference  : 5 frames
Codec ID                    : V_MPEG4/ISO/AVC
Bit rate                    : 1 595 kb/s
Nominal bit rate            : 2 030 kb/s
Width                       : 720 pixels
Height                      : 480 pixels
Display aspect ratio        : 16:9
Original display aspect rat : 3:2
Frame rate mode             : Variable
Original frame rate         : 29.970 FPS
Color space                 : YUV
Chroma subsampling          : 4:2:0
Bit depth                   : 8 bits
Scan type                   : Progressive
Bits/(Pixel*Frame)          : 0.196
Writing library             : x264 core 66 r1115M 11863ac
Encoding settings           : cabac=1 / ref=5 / deblock=1:1:1 / analyse=0x3:0x133 / me=esa / subme=7 / psy_rd=1.0:0.0 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=2 / deadzone=21,11 / chroma_qp_offset=-2 / threads=1 / nr=0 / decimate=0 / mbaff=0 / bframes=1 / b_pyramid=0 / b_adapt=1 / b_bias=0 / direct=3 / wpredb=1 / keyint=250 / keyint_min=25 / scenecut=40 / rc=2pass / bitrate=2030 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / pb_ratio=1.30 / aq=1:1.00
Default                     : Yes
Forced                      : No


  


  Output video info :

  


  Video
ID                          : 1
Format                      : HEVC
Format/Info                 : High Efficiency Video Coding
Format profile              : Main 10@L3.1@Main
Codec ID                    : V_MPEGH/ISO/HEVC
Duration                    : 23 min 29 s
Width                       : 960 pixels
Height                      : 540 pixels
Display aspect ratio        : 16:9
Frame rate mode             : Constant
Frame rate                  : 29.970 (29970/1000) FPS
Color space                 : YUV
Chroma subsampling          : 4:2:0
Bit depth                   : 10 bits
Writing library             : Lavc59.5.100 libx265
Encoding settings           : cabac=1 / ref=5 / deblock=1:1:1 / analyse=0x3:0x133 / me=esa / subme=7 / psy_rd=1.0:0.0 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / cqm=2 / deadzone=21,11 / chroma_qp_offset=-2 / threads=1 / nr=0 / decimate=0 / mbaff=0 / bframes=1 / b_pyramid=0 / b_adapt=1 / b_bias=0 / direct=3 / wpredb=1 / keyint=250 / keyint_min=25 / scenecut=40 / rc=2pass / bitrate=2030 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / pb_ratio=1.30 / aq=1:1.00
Default                     : Yes
Forced                      : No
Color range                 : Limited


  


  Expecting (from previous encoded videos) :

  


  Video
ID                          : 1
Format                      : HEVC
Format/Info                 : High Efficiency Video Coding
Format profile              : Main 10@L3.1@Main
Codec ID                    : V_MPEGH/ISO/HEVC
Duration                    : 24 min 37 s
Bit rate                    : 833 kb/s
Width                       : 960 pixels
Height                      : 720 pixels
Display aspect ratio        : 4:3
Frame rate mode             : Constant
Frame rate                  : 23.976 (23976/1000) FPS
Color space                 : YUV
Chroma subsampling          : 4:2:0
Bit depth                   : 10 bits
Bits/(Pixel*Frame)          : 0.050
Stream size                 : 147 MiB
Title                       : HEVC
Writing library             : x265 3.4+28-419182243:[Windows][GCC 10.2.0][64 bit] 10bit
Encoding settings           : cpuid=1111039 / frame-threads=3 / numa-pools=12 / wpp / no-pmode / no-pme / no-psnr / no-ssim / log-level=2 / input-csp=1 / input-res=960x720 / interlace=0 / total-frames=0 / level-idc=0 / high-tier=1 / uhd-bd=0 / ref=5 / no-allow-non-conformance / no-repeat-headers / annexb / no-aud / no-hrd / info / hash=0 / no-temporal-layers / no-open-gop / min-keyint=1 / keyint=360 / gop-lookahead=0 / bframes=4 / b-adapt=2 / b-pyramid / bframe-bias=0 / rc-lookahead=20 / lookahead-slices=4 / scenecut=40 / hist-scenecut=0 / radl=0 / no-splice / no-intra-refresh / ctu=64 / min-cu-size=8 / no-rect / no-amp / max-tu-size=32 / tu-inter-depth=1 / tu-intra-depth=1 / limit-tu=0 / rdoq-level=0 / dynamic-rd=0.00 / no-ssim-rd / signhide / no-tskip / nr-intra=0 / nr-inter=0 / no-constrained-intra / strong-intra-smoothing / max-merge=2 / limit-refs=3 / no-limit-modes / me=1 / subme=3 / merange=16 / temporal-mvp / no-frame-dup / no-hme / weightp / no-weightb / no-analyze-src-pics / no-deblock / sao / no-sao-non-deblock / rd=3 / selective-sao=4 / no-early-skip / rskip / no-fast-intra / no-tskip-fast / no-cu-lossless / no-b-intra / no-splitrd-skip / rdpenalty=0 / psy-rd=0.20 / psy-rdoq=0.00 / no-rd-refine / no-lossless / cbqpoffs=0 / crqpoffs=0 / rc=crf / crf=26.0 / qcomp=0.60 / qpstep=4 / stats-write=0 / stats-read=0 / ipratio=1.40 / pbratio=1.00 / aq-mode=0 / aq-strength=0.00 / no-cutree / zone-count=0 / no-strict-cbr / qg-size=64 / no-rc-grain / qpmax=51 / qpmin=0 / no-const-vbv / sar=1 / overscan=0 / videoformat=5 / range=0 / colorprim=2 / transfer=2 / colormatrix=2 / chromaloc=0 / display-window=0 / cll=0,0 / min-luma=0 / max-luma=1023 / log2-max-poc-lsb=8 / vui-timing-info / vui-hrd-info / slices=1 / no-opt-qp-pps / no-opt-ref-list-length-pps / no-multi-pass-opt-rps / scenecut-bias=0.05 / hist-threshold=0.03 / no-opt-cu-delta-qp / no-aq-motion / no-hdr10 / no-hdr10-opt / no-dhdr10-opt / no-idr-recovery-sei / analysis-reuse-level=0 / analysis-save-reuse-level=0 / analysis-load-reuse-level=0 / scale-factor=0 / refine-intra=0 / refine-inter=0 / refine-mv=1 / refine-ctu-distortion=0 / no-limit-sao / ctu-info=0 / no-lowpass-dct / refine-analysis-type=0 / copy-pic=1 / max-ausize-factor=1.0 / no-dynamic-refine / no-single-sei / no-hevc-aq / no-svt / no-field / qp-adaptation-range=1.00 / no-scenecut-aware-qpconformance-window-offsets / right=0 / bottom=0 / decoder-max-rate=0 / no-vbv-live-multi-pass
Language                    : English
Default                     : Yes
Forced                      : No
Color range                 : Limited


  


  I have tried with simplest ffmpeg from official wedsite and encoding cli but the output still same.

  


  ffmpeg -i "input.mkv" -c:v libx265 "output.mkv"