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• libx264 encoder video plays too fast

  23 avril 2014, par Nick

  I’m trying to write a program that uses libx264 to encode the video frames. I’ve wrapped this code into a small class (see below). I have frames that are in YUV420 format. libx264 encodes the frames and I save them to a file. I can play the file back in VLC, all of the frames are there, but it plays back at several hundred times the actual frame rate. Currently I am capturing frames at 2.5 FPS, but they play back as if it was recorded at 250 or more FPS. I’ve tried to change the frame rate with no luck.

  I’ve also tried to set

  _param.b_vfr_input = 1

  and then set the time bases appropriately, but that causes my program to crash. Any ideas ? My encode code is shown below. I’ve also included the output of ffprobe -show_frames

  Wrapper Class :

  x264wrapper::x264wrapper(int width, int height, int fps, int timeBaseNum, int timeBaseDen, int vfr)
  
  {
  
      x264_param_default_preset(&_param, "veryfast", "zerolatency");
  
      _param.i_threads = 1;
  
      _param.i_width = width;
  
      _param.i_height = height;
  
      _param.i_fps_num = fps;
  
      _param.i_fps_den = 1;
  
      // Intra refres:
  
      _param.i_keyint_max = fps;
  
      _param.b_intra_refresh = 1;
  
      //Rate control:
  
      _param.rc.i_rc_method = X264_RC_CRF;
  
      //_param.rc.i_rc_method = X264_RC_CQP;
  
      _param.rc.f_rf_constant = 25;
  
      _param.rc.f_rf_constant_max = 35;
  
      //For streaming:
  
      _param.b_repeat_headers = 1;
  
      _param.b_annexb = 1;    
  
      // misc
  
      _param.b_vfr_input = vfr;
  
      _param.i_timebase_num = timeBaseNum; 
  
      _param.i_timebase_den = timeBaseDen;
  
  
  
      _param.i_log_level = X264_LOG_DEBUG;
  
  
  
      _encoder = x264_encoder_open(&_param);
  
  
  
      cout << "Timebase " << _param.i_timebase_num << "/" << _param.i_timebase_den << endl;
  
      cout << "fps " << _param.i_fps_num << "/" << _param.i_fps_den << endl;
  
      _ticks_per_frame = (int64_t)_param.i_timebase_den * _param.i_fps_den / _param.i_timebase_num / _param.i_fps_num;
  
      cout << "ticks_per_frame " << _ticks_per_frame << endl;
  
      int result = x264_picture_alloc(&_pic_in, X264_CSP_I420, width, height);
  
      if (result != 0)
  
      {
  
          cout << "Failed to allocate picture" << endl;
  
          throw(1);
  
      }
  
  
  
      _ofs = new ofstream("output.h264", ofstream::out | ofstream::binary);
  
      _pts = 0;
  
  }
  
  
  
  
  
  x264wrapper::~x264wrapper(void)
  
  {
  
      _ofs->close();
  
  }
  
  
  
  
  
  
  
  void x264wrapper::encode(uint8_t * buf)
  
  {
  
      x264_nal_t* nals;
  
      int i_nals;
  
      convertFromBalserToX264(buf);
  
      _pts += _ticks_per_frame;
  
      _pic_in.i_pts = _pts;
  
      x264_picture_t pic_out;
  
      int frame_size = x264_encoder_encode(_encoder, &nals, &i_nals, &_pic_in, &pic_out);
  
      if (frame_size >= 0)
  
      {
  
          _ofs->write((char*)nals[0].p_payload, frame_size);
  
      }
  
      else
  
      {
  
          cout << "error: x264_encoder_encode failed" << endl;
  
      }
  
  }

  Output of ffprobe -show_frames :

  [FRAME]
  
  media_type=video
  
  key_frame=1
  
  pkt_pts=N/A
  
  pkt_pts_time=N/A
  
  pkt_dts=N/A
  
  pkt_dts_time=N/A
  
  pkt_duration=48000
  
  pkt_duration_time=0.040000
  
  pkt_pos=0
  
  width=1920
  
  height=1080
  
  pix_fmt=yuv420p
  
  sample_aspect_ratio=N/A
  
  pict_type=I
  
  coded_picture_number=0
  
  display_picture_number=0
  
  interlaced_frame=0
  
  top_field_first=0
  
  repeat_pict=0
  
  reference=0
  
  [/FRAME]
  
  [FRAME]
  
  media_type=video
  
  key_frame=0
  
  pkt_pts=N/A
  
  pkt_pts_time=N/A
  
  pkt_dts=N/A
  
  pkt_dts_time=N/A
  
  pkt_duration=N/A
  
  pkt_duration_time=N/A
  
  pkt_pos=54947
  
  width=1920
  
  height=1080
  
  pix_fmt=yuv420p
  
  sample_aspect_ratio=N/A
  
  pict_type=P
  
  coded_picture_number=1
  
  display_picture_number=0
  
  interlaced_frame=0
  
  top_field_first=0
  
  repeat_pict=0
  
  reference=0
  
  [/FRAME]
  
  [FRAME]
  
  media_type=video
  
  key_frame=0
  
  pkt_pts=N/A
  
  pkt_pts_time=N/A
  
  pkt_dts=N/A
  
  pkt_dts_time=N/A
  
  pkt_duration=N/A
  
  pkt_duration_time=N/A
  
  pkt_pos=57899
  
  width=1920
  
  height=1080
  
  pix_fmt=yuv420p
  
  sample_aspect_ratio=N/A
  
  pict_type=P
  
  coded_picture_number=2
  
  display_picture_number=0
  
  interlaced_frame=0
  
  top_field_first=0
  
  repeat_pict=0
  
  reference=0
  
  [/FRAME]

• ffmpeg used vda from os x

  13 mai 2014, par user2618420

  I try to enable hardware decoding project earlier decoded using ffmpeg

  ffmpeg has support in hard-copy decoding
  Here documentation kotoroya I did https://github.com/dilaroga/ffmpeg-vda/wiki/FFmpeg-vda-usage
  my code

  enum AVPixelFormat myGetFormatCallback(struct AVCodecContext *ctx, const enum AVPixelFormat * fmt)
  
  {
  
      struct vda_context *vda_ctx;
  
      vda_ctx = (struct vda_context *)malloc(sizeof(vda_context));
  
      vda_ctx->decoder = NULL;
  
      vda_ctx->width = ctx->width;
  
      vda_ctx->height = ctx->height;
  
      vda_ctx->format = 'avc1';
  
      vda_ctx->use_ref_buffer = 1;
  
      switch (ctx->pix_fmt) {
  
          case PIX_FMT_UYVY422:{
  
              vda_ctx->cv_pix_fmt_type = '2vuy';
  
              break;
  
          }
  
          case PIX_FMT_YUYV422:{
  
              vda_ctx->cv_pix_fmt_type = 'yuvs';
  
              break;
  
          }
  
          case PIX_FMT_NV12:{
  
              vda_ctx->cv_pix_fmt_type = '420v';
  
              break;
  
          }
  
          case PIX_FMT_YUV420P:{
  
              vda_ctx->cv_pix_fmt_type = 'y420';
  
              break;
  
          }
  
          default:{
  
              av_log(ctx, AV_LOG_ERROR, "Unsupported pixel format: %d\n", ctx->pix_fmt);
  
              Logger::debug(LOG_LEVEL_ERROR, "Unsupported pixel format: %d", ctx->pix_fmt);
  
              throw AbstractException("Unsupported pixel format");
  
          }
  
       }
  
      int status = ff_vda_create_decoder(vda_ctx, (unsigned char*)ctx->extradata,ctx->extradata_size);
  
      if (status){
  
          Logger::debug(LOG_LEVEL_ERROR, "Error create VDA decoder");
  
          throw AbstractException("Error create VDA decoder");
  
      }else{
  
          ctx->hwaccel_context = vda_ctx;
  
      }
  
  
  
      return ctx->pix_fmt;
  
  }
  
  
  
  static void release_vda_context(void *opaque, uint8_t *data)
  
  {
  
      vda_buffer_context *vda_context = (vda_buffer_context *)opaque;
  
      av_free(vda_context);
  
  }
  
  
  
  int myGetBufferCallback(struct AVCodecContext *s, AVFrame *av_frame, int flags)
  
  {
  
      vda_buffer_context *vda_context = (vda_buffer_context *)av_mallocz(sizeof(*vda_context));
  
      AVBufferRef *buffer = av_buffer_create(NULL, 0, release_vda_context, vda_context, 0);
  
  
  
      if( !vda_context || !buffer )
  
      {
  
          av_free(vda_context);
  
          return -1;
  
      }
  
  
  
      av_frame->buf[0] = buffer;
  
      av_frame->data[0] = (uint8_t*)1;
  
      return 0;
  
  }
  
  
  
  
  
  static void release_buffer(struct AVCodecContext *opaque, AVFrame *pic)
  
  {
  
      vda_buffer_context *context = (vda_buffer_context*)opaque;
  
      CVPixelBufferUnlockBaseAddress(context->cv_buffer, 0);
  
      CVPixelBufferRelease(context->cv_buffer);
  
      av_free(context);
  
  }
  
  
  
  main(){
  
      //init ff context
  
      if (avcodec_open2(mCodecContext, mCodec, NULL) < 0) throw AbstractException("Unable to open codec");
  
  
  
      mCodecContext->get_format = myGetFormatCallback;
  
      mCodecContext->get_buffer2 = myGetBufferCallback;
  
      mCodecContext->release_buffer = release_buffer;
  
  }

  but I did not myGetFormatCallback the method is called, and called myGetBufferCallback falls
  why not called myGetFormatCallback ? what’s wrong ? may not work well at all

• Extract audio from video in mp3 format using android-ffmpeg-library

  28 mai 2014, par user2870161

  I want extrat audio from any type of video file and save it in mp3 format using android-ffmpeg-library.

  My most of work is done here i am create wav file using this code but problame is when i create mp3 file it make only 0kb file in sdcard.

  I hope I’ve made myself clear, and thanks for taking the time to read this.

      if (inputPath == null || outputPath == null) {
  
          throw new IllegalStateException("Need an input and output filepath!");
  
      }   
  
  
  
      final List<string> cmd = new LinkedList<string>();
  
  
  
  
  
      String baseDir = Environment.getExternalStorageDirectory().getAbsolutePath();
  
      String fileName = "3.mp4";
  
      String fileName1 = "2.mp3";
  
  
  
      String path  = baseDir + "/" + fileName;
  
      String path1  = baseDir + "/" + fileName1;
  
  
  
        File f = new File(path);
  
  
  
        if(f.exists()){
  
            System.out.println("File existed");
  
        }else{
  
            System.out.println("File not found!");
  
        }
  
  
  
        cmd.add(mFfmpegPath);
  
        cmd.add("-i");
  
        cmd.add(path);
  
  
  
        cmd.add("-vn");
  
        cmd.add("-acodec");
  
        cmd.add("copy");
  
  
  
        cmd.add(path1);
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
      final ProcessBuilder pb = new ProcessBuilder(cmd);
  
      return new ProcessRunnable(pb);
  
  </string></string>