Recherche avancée

Sur d’autres sites (9348)

• avformat/segafilm - revert keyframe detection

  21 avril 2018, par Gyan Doshi

  avformat/segafilm - revert keyframe detection
  Keyframe detection was inverted in cfe1a9d311 in order to fix keyframe
  
  flags set for the sample attached to trac #7091. However, that sample is
  
  errantly muxed.
  As noted at
  
  https://web.archive.org/web/20020803104640/http://www.pcisys.net:80/~melanson/codecs/film-format.txt,
  
  the original keyframe detection logic is correct, and this patch
  
  restores it.
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] libavformat/segafilm.c

• After ffmpeg encode, AVPacket pts and dts is AV_NOPTS_VALUE

  29 novembre 2017, par Li Zehan

  I would like to ask a question about ffmpeg when i use encoder (x264).

  this is my code :

  int
  
  FFVideoEncoder::init(AVCodecID codecId, int bitrate, int fps, int gopSize,
  
                       int width, int height, AVPixelFormat format) {
  
      release();
  
  
  
      const AVCodec *codec = avcodec_find_encoder(codecId);
  
      m_pCodecCtx = avcodec_alloc_context3(codec);
  
      m_pCodecCtx->width = width;
  
      m_pCodecCtx->height = height;
  
      m_pCodecCtx->pix_fmt = format;
  
      m_pCodecCtx->bit_rate = bitrate;
  
      m_pCodecCtx->thread_count = 5;
  
      m_pCodecCtx->max_b_frames = 0;
  
      m_pCodecCtx->gop_size = gopSize;
  
  
  
      m_pCodecCtx->time_base.num = 1;
  
      m_pCodecCtx->time_base.den = fps;
  
  
  
      //H.264
  
      if (m_pCodecCtx->codec_id == AV_CODEC_ID_H264) {
  
  //        av_dict_set(&opts, "preset", "slow", 0);
  
          av_dict_set(&m_pEncoderOpts, "preset", "superfast", 0);
  
          av_dict_set(&m_pEncoderOpts, "tune", "zerolatency", 0);
  
  
  
          m_pCodecCtx->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
          m_pCodecCtx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
  
      }
  
      int ret = avcodec_open2(m_pCodecCtx, m_pCodecCtx->codec, &m_pEncoderOpts);
  
      if (ret == 0) {
  
          LOGI("open avcodec success!");
  
      } else {
  
          LOGE("open avcodec error!");
  
          return -1;
  
      }
  
      return ret;
  
  }
  
  
  
  int FFVideoEncoder::encode(const Frame &inFrame, AVPacket *outPacket) {
  
      AVFrame *frame = av_frame_alloc();
  
  //    avpicture_fill((AVPicture *) frame, inFrame.getData(), AV_PIX_FMT_YUV420P, inFrame.getWidth(),
  
  //                   inFrame.getHeight());
  
      av_image_fill_arrays(frame->data, frame->linesize, inFrame.getData(), m_pCodecCtx->pix_fmt,
  
                           inFrame.getWidth(), inFrame.getHeight(), 1);
  
  
  
      int ret = 0;
  
      ret = avcodec_send_frame(m_pCodecCtx, frame);
  
      if (ret != 0) {
  
          LOGE("send frame error! %s", av_err2str(ret));
  
      } else {
  
          ret = avcodec_receive_packet(m_pCodecCtx, outPacket);
  
          LOGI("extract data size = %d", m_pCodecCtx->extradata_size);
  
          if (ret != 0) {
  
              LOGE("receive packet error! %s", av_err2str(ret));
  
          }
  
      };
  
      av_frame_free(&frame);
  
      return ret;
  
  }

  I expect that the AVPacket will carry the pts and dts about this frame.

  but in fact, i only can get encoded frame data and size.

  //====================================

  except this question, i have another quesiont :

  x264 docs say that "tune" opts can be set like film、animation and others. but i only can get a normal video when i set "zerolatency" params. When i set others opts, video’s bitrate is very low.

  Thanks your answer.

• FFMPEG disabled automatic compression file

  2 novembre 2017, par HenrykVIII

  How to disable FFMPEG in its own compressed file compression, which does not come from the program code. This is when the file is merged (as the first task) or file stabilization (as the first task). I lose on file quality by reducing itself from 16k to 7k birate files (in parts) input.

  So, without loss, I have to merge files or stabilize them so that they do not change ?

  I will add that the effect does not affect every film - only the majority. None of which come out of a duel completely and eg for 16.2k input birate have output 16k birate .. What is no visible loss.

  But the loss from 16k to 7k is already visible on the details and especially the movies shot at night and in the wrong light.

  I enclose the wrapper code c # :
   
  The same situation occurs when the first task is to combine files :

  Can anyone help ?? : (((