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• Best Web Video Encoding Practices for IOS (FFMpeg)

  21 juin 2012, par MagicMushroom

  I am working on an online video repository system for a client, written mostly in PHP. At the moment I am building a mobile version of our desktop website. Our desktop site allows users to watch videos in the browser, much like YouTube.

  My client uploads videos through the manager interface I have created, and my application uses FFmpeg on the server to transcode his videos into several resolutions and bitrates. I am no expert on FFmpeg, and while I do not know the ins and outs of each individual setting, I do understand how it works as a whole. Right now, we are using the mp4 container format with the h.264 codec to encode our videos. Our command looks like :

  ffmpeg -y -i "INPUT FILE.mov" -f mp4 -s 640x480 -vcodec libx264 -preset fast -maxrate 1500 -bitrate 1000 -bufsize 4096 -acodec libfaac -ab 192 -ac 2 "OUTPUT_FILE.mp4" >> "FILE.log" 2>&1 &

  I'm hoping to gain information about best practices with encoding video for web streaming on IOS and other mobile devices using FFmpeg. What resolutions and settings make for good mobile streaming video ? How can I ensure maximum compatibility across the sea of Android devices ?

• Revision 1e30547984 : Skip mode search based on reference frame consistency This commit enables the e

  12 août 2014, par Jingning Han

  Changed Paths :
   Modify /vp9/encoder/vp9_rdopt.c

  
  
  Skip mode search based on reference frame consistency

  This commit enables the encoder to skip NEARMV and ZEROMV if the
  above and left blocks have identical reference frame, and the
  current reference is different from that. It reduces the runtime
  of speed 3 for test sequences :
  bus cif at 1000 kbps 10064 ms -> 9823 ms
  pedestrian 1080p at 2000 kbps 193078 ms -> 189559 ms

  The compression performance is changed by
  derf -0.085%
  stdhd -0.103%

  Change-Id : If304f26d42e6412152a84c3dd7b02635c38444f4

• Cropping Square Video using FFmpeg

  27 juin 2014, par zoruc

  Updated

  So I am trying to decode a mp4 file, crop the video into a square, and then re encode it back out to another mp4 file. This is my current code but there are a few issues with it.

  One is that the video doesn’t keep its rotation after the video has been re encoded

  Second is that the frames get outputted in a very fast video file that is not the same length as the original

  Third is that there is no sound

  Lastly and most importantly is do I need AVFilter to do the frame cropping or can it just be done per frame as a resize of the frame and then encoded back out.

  const char *inputPath = "test.mp4";
  
  const char *outPath = "cropped.mp4";
  
  const char *outFileType = "mp4";
  
  
  
  static AVFrame *oframe = NULL; 
  
  static AVFilterGraph *filterGraph = NULL;  
  
  static AVFilterContext *crop_ctx = NULL;
  
  static AVFilterContext *buffersink_ctx = NULL;
  
  static AVFilterContext *buffer_ctx = NULL;
  
  
  
  int err;
  
  
  
  int crop_video(int width, int height) {
  
  
  
  av_register_all();
  
  avcodec_register_all();
  
  avfilter_register_all();
  
  
  
  AVFormatContext *inCtx = NULL;
  
  
  
  // open input file
  
  err = avformat_open_input(&inCtx, inputPath, NULL, NULL);
  
  if (err < 0) {
  
      printf("error at open input in\n");
  
      return err;
  
  }
  
  
  
  // get input file stream info
  
  err = avformat_find_stream_info(inCtx, NULL);
  
  if (err < 0) {
  
      printf("error at find stream info\n");
  
      return err;
  
  }
  
  
  
  // get info about video
  
  av_dump_format(inCtx, 0, inputPath, 0);
  
  
  
  // find video input stream
  
  int vs = -1;
  
  int s;
  
  for (s = 0; s < inCtx->nb_streams; ++s) {
  
      if (inCtx->streams[s] && inCtx->streams[s]->codec && inCtx->streams[s]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
  
          vs = s;
  
          break;
  
      }
  
  }
  
  
  
  // check if video stream is valid
  
  if (vs == -1) {
  
      printf("error at open video stream\n");
  
      return -1;
  
  }
  
  
  
  // set output format
  
  AVOutputFormat * outFmt = av_guess_format(outFileType, NULL, NULL);
  
  if (!outFmt) {
  
      printf("error at output format\n");
  
      return -1;
  
  }
  
  
  
  // get an output context to write to
  
  AVFormatContext *outCtx = NULL;
  
  err = avformat_alloc_output_context2(&outCtx, outFmt, NULL, NULL);
  
  if (err < 0 || !outCtx) {
  
      printf("error at output context\n");
  
      return err;
  
  }
  
  
  
  // input and output stream
  
  AVStream *outStrm = avformat_new_stream(outCtx, NULL);
  
  AVStream *inStrm = inCtx->streams[vs];
  
  
  
  // add a new codec for the output stream
  
  AVCodec *codec = NULL;
  
  avcodec_get_context_defaults3(outStrm->codec, codec);
  
  
  
  outStrm->codec->thread_count = 1;
  
  
  
  outStrm->codec->coder_type = AVMEDIA_TYPE_VIDEO;
  
  
  
  if(outCtx->oformat->flags & AVFMT_GLOBALHEADER) {
  
      outStrm->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  }
  
  
  
  outStrm->codec->sample_aspect_ratio = outStrm->sample_aspect_ratio = inStrm->sample_aspect_ratio;
  
  
  
  err = avio_open(&outCtx->pb, outPath, AVIO_FLAG_WRITE);
  
  if (err < 0) {
  
      printf("error at opening outpath\n");
  
      return err;
  
  }
  
  
  
  outStrm->disposition = inStrm->disposition;
  
  outStrm->codec->bits_per_raw_sample = inStrm->codec->bits_per_raw_sample;
  
  outStrm->codec->chroma_sample_location = inStrm->codec->chroma_sample_location;
  
  outStrm->codec->codec_id = inStrm->codec->codec_id;
  
  outStrm->codec->codec_type = inStrm->codec->codec_type;
  
  
  
  if (!outStrm->codec->codec_tag) {
  
      if (! outCtx->oformat->codec_tag
  
          || av_codec_get_id (outCtx->oformat->codec_tag, inStrm->codec->codec_tag) == outStrm->codec->codec_id
  
          || av_codec_get_tag(outCtx->oformat->codec_tag, inStrm->codec->codec_id) <= 0) {
  
          outStrm->codec->codec_tag = inStrm->codec->codec_tag;
  
      }
  
  }
  
  
  
  outStrm->codec->bit_rate = inStrm->codec->bit_rate;
  
  outStrm->codec->rc_max_rate = inStrm->codec->rc_max_rate;
  
  outStrm->codec->rc_buffer_size = inStrm->codec->rc_buffer_size;
  
  
  
  const size_t extra_size_alloc = (inStrm->codec->extradata_size > 0) ?
  
  (inStrm->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE) :
  
  0;
  
  
  
  if (extra_size_alloc) {
  
      outStrm->codec->extradata = (uint8_t*)av_mallocz(extra_size_alloc);
  
      memcpy( outStrm->codec->extradata, inStrm->codec->extradata, inStrm->codec->extradata_size);
  
  }
  
  
  
  outStrm->codec->extradata_size = inStrm->codec->extradata_size;
  
  
  
  AVRational input_time_base = inStrm->time_base;
  
  AVRational frameRate = {25, 1};
  
  if (inStrm->r_frame_rate.num && inStrm->r_frame_rate.den
  
      && (1.0 * inStrm->r_frame_rate.num / inStrm->r_frame_rate.den < 1000.0)) {
  
      frameRate.num = inStrm->r_frame_rate.num;
  
      frameRate.den = inStrm->r_frame_rate.den;
  
  }
  
  
  
  outStrm->r_frame_rate = frameRate;
  
  outStrm->codec->time_base = inStrm->codec->time_base;
  
  
  
  outStrm->codec->pix_fmt = inStrm->codec->pix_fmt;
  
  outStrm->codec->width = width;
  
  outStrm->codec->height =  height;
  
  outStrm->codec->has_b_frames =  inStrm->codec->has_b_frames;
  
  
  
  if (!outStrm->codec->sample_aspect_ratio.num) {
  
      AVRational r0 = {0, 1};
  
      outStrm->codec->sample_aspect_ratio =
  
      outStrm->sample_aspect_ratio =
  
      inStrm->sample_aspect_ratio.num ? inStrm->sample_aspect_ratio :
  
      inStrm->codec->sample_aspect_ratio.num ?
  
      inStrm->codec->sample_aspect_ratio : r0;
  
  }
  
  
  
  avformat_write_header(outCtx, NULL);
  
  
  
  filterGraph = avfilter_graph_alloc();
  
  if (!filterGraph) {
  
      printf("could not open filter graph");
  
      return -1;
  
  }
  
  
  
  AVFilter *crop = avfilter_get_by_name("crop");
  
  AVFilter *buffer = avfilter_get_by_name("buffer");
  
  AVFilter *buffersink = avfilter_get_by_name("buffersink");
  
  
  
  char args[512];
  
  
  
  snprintf(args, sizeof(args), "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
  
           width, height, inStrm->codec->pix_fmt,
  
           inStrm->codec->time_base.num, inStrm->codec->time_base.den,
  
           inStrm->codec->sample_aspect_ratio.num, inStrm->codec->sample_aspect_ratio.den);
  
  
  
  err = avfilter_graph_create_filter(&buffer_ctx, buffer, NULL, args, NULL, filterGraph);
  
  if (err < 0) {
  
      printf("error initializing buffer filter\n");
  
      return err;
  
  }
  
  
  
  err = avfilter_graph_create_filter(&buffersink_ctx, buffersink, NULL, NULL, NULL, filterGraph);
  
  if (err < 0) {
  
      printf("unable to create buffersink filter\n");
  
      return err;
  
  }
  
  snprintf(args, sizeof(args), "%d:%d", width, height);
  
  err = avfilter_graph_create_filter(&crop_ctx, crop, NULL, args, NULL, filterGraph);
  
  if (err < 0) {
  
      printf("error initializing crop filter\n");
  
      return err;
  
  }
  
  
  
  err = avfilter_link(buffer_ctx, 0, crop_ctx, 0);
  
  if (err < 0) {
  
      printf("error linking filters\n");
  
      return err;
  
  }
  
  
  
  err = avfilter_link(crop_ctx, 0, buffersink_ctx, 0);
  
  if (err < 0) {
  
      printf("error linking filters\n");
  
      return err;
  
  }
  
  
  
  err = avfilter_graph_config(filterGraph, NULL);
  
  if (err < 0) {
  
      printf("error configuring the filter graph\n");
  
      return err;
  
  }
  
  
  
  printf("filtergraph configured\n");
  
  
  
  for (;;) {
  
  
  
      AVPacket packet = {0};
  
      av_init_packet(&packet);
  
  
  
      err = AVERROR(EAGAIN);
  
      while (AVERROR(EAGAIN) == err)
  
          err = av_read_frame(inCtx, &packet);
  
  
  
      if (err < 0) {
  
          if (AVERROR_EOF != err && AVERROR(EIO) != err) {
  
              printf("eof error\n");
  
              return 1;
  
          } else {
  
              break;
  
          }
  
      }
  
  
  
      if (packet.stream_index == vs) {
  
  
  
          //
  
          //            AVPacket pkt_temp_;
  
          //            memset(&pkt_temp_, 0, sizeof(pkt_temp_));
  
          //            AVPacket *pkt_temp = &pkt_temp_;
  
          //
  
          //            *pkt_temp = packet;
  
          //
  
          //            int error, got_frame;
  
          //            int new_packet = 1;
  
          //
  
          //            error = avcodec_decode_video2(inStrm->codec, frame, &got_frame, pkt_temp);
  
          //            if(error < 0) {
  
          //                LOGE("error %d", error);
  
          //            }
  
          //
  
          //            // if (error >= 0) {
  
          //
  
          //            // push the video data from decoded frame into the filtergraph
  
          //            int err = av_buffersrc_write_frame(buffer_ctx, frame);
  
          //            if (err < 0) {
  
          //                LOGE("error writing frame to buffersrc");
  
          //                return -1;
  
          //            }
  
          //            // pull filtered video from the filtergraph
  
          //            for (;;) {
  
          //                int err = av_buffersink_get_frame(buffersink_ctx, oframe);
  
          //                if (err == AVERROR_EOF || err == AVERROR(EAGAIN))
  
          //                    break;
  
          //                if (err < 0) {
  
          //                    LOGE("error reading buffer from buffersink");
  
          //                    return -1;
  
          //                }
  
          //            }
  
          //
  
          //            LOGI("output frame");
  
  
  
          err = av_interleaved_write_frame(outCtx, &packet);
  
          if (err < 0) {
  
              printf("error at write frame");
  
              return -1;
  
          }
  
  
  
          //}
  
      }
  
  
  
      av_free_packet(&packet);
  
  }
  
  
  
  av_write_trailer(outCtx);
  
  if (!(outCtx->oformat->flags & AVFMT_NOFILE) && outCtx->pb)
  
      avio_close(outCtx->pb);
  
  
  
  avformat_free_context(outCtx);
  
  avformat_close_input(&inCtx);
  
  
  
  return 0;

  }