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• lavc/hevc : Don't parse NAL unit for a dummy buffer

  30 mars 2018, par Haihao Xiang

  lavc/hevc : Don't parse NAL unit for a dummy buffer
  hevc parser mistakenly reports the following message if a dummy buffer
  
  is padded for EOF
     [hevc @ 0x559b63848610] missing picture in access unit
  Signed-off-by : Haihao Xiang <haihao.xiang@intel.com>
  
  Reviewed-by : Steven Liu <lq@chinaffmpeg.org>
  
  Reviewed-by : "Li, Zhong" <zhong.li@intel.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/hevc_parser.c

• Problems using Cuda for video transcoding [closed]

  19 août 2022, par Jay Adlard

  I just bought a new pc as my faithful old windows 7 i7 laptop died. Now the laptop had both intel and nvidea gtx660m chips. When I transcoded video with handbrake the intel graphics managed 8fps when I changed over to the nvidia it managed 80fps and the graphics card got nice and hot so was obviously working.

  


  The new machine i bought is a i9 with an nvidea gtx780 running windows 10. When I tried to transcode some video hoping for it to use the cpu and Gpu but no joy,the card stays cool power usage is only a handful of watts higher than it running something simple.I had been using handbrake but I read it doesn’t support Cuda so why the laptop speeded up I don’t know. A friend of mine that is into ffmpeg came round found that ffmpeg reports no Cuda yet the card works fine in every other respect. Unlike the rest of the machine the graphics card wasn’t new but it looked like new…

  


  One thing to note I am not talking about nvenc as the quality is rather poor, no point in capturing uncompressed files cleaning them up and not using an encoder that will do 2 pass and an exhaustive search.
Can anyone recommend a reasonably priced encoder that will use the Cuda cores ?

  


  Has anyone got any idea what the problem is ?

  


• AVCodecContext settings for H264 (1080i)

  23 septembre 2013, par moose

  I'm trying to configure x264 for 1080i capturing. Most of these settings below are found in different examples. However, compiled together they don't work. ffmpeg API reports no error, but avcodec_encode_video() always returns zero.

  Some of the numbers are strange to me... for example, gop_size. Isn't 250 too high ?

  Event you can't offer the final answer, I'm still interested in any kind of comment on this subject.

  pCodecContext->codec_type              = AVMEDIA_TYPE_VIDEO;
  
  pCodecContext->codec_id                = CODEC_ID_H264;
  
  
  
  pCodecContext->coder_type              = FF_CODER_TYPE_AC;
  
  pCodecContext->flags                  |= CODEC_FLAG_LOOP_FILTER | CODEC_FLAG_INTERLACED_ME | CODEC_FLAG_INTERLACED_DCT;
  
  pCodecContext->me_cmp                 |= 1;
  
  pCodecContext->partitions             |= X264_PART_I8X8 | X264_PART_I4X4 | X264_PART_P8X8 | X264_PART_B8X8;
  
  pCodecContext->me_method               = ME_UMH;
  
  pCodecContext->me_subpel_quality       = 8;
  
  pCodecContext->me_range                = 16;
  
  
  
  pCodecContext->bit_rate                = 10 * 1024 * 1024; // 10 Mbps??
  
  pCodecContext->width                   = 1920;
  
  pCodecContext->height                  = 1080;
  
  
  
  pCodecContext->time_base.num           = 1;    // 25 fps
  
  pCodecContext->time_base.den           = 25;   // 25 fps
  
  
  
  pCodecContext->gop_size                = 250; // 250
  
  pCodecContext->keyint_min              = 25;
  
  pCodecContext->scenechange_threshold   = 40;
  
  pCodecContext->i_quant_factor          = 0.71f;
  
  pCodecContext->b_frame_strategy        = 1;
  
  pCodecContext->qcompress               = 0.6f;
  
  pCodecContext->qmin                    = 10;
  
  pCodecContext->qmax                    = 51;
  
  pCodecContext->max_qdiff               = 4;
  
  pCodecContext->max_b_frames            = 3;
  
  pCodecContext->refs                    = 4;
  
  pCodecContext->directpred              = 3;
  
  pCodecContext->trellis                 = 1;
  
  pCodecContext->flags2                 |= CODEC_FLAG2_WPRED | CODEC_FLAG2_MIXED_REFS | CODEC_FLAG2_8X8DCT | CODEC_FLAG2_FASTPSKIP;  // wpred+mixed_refs+dct8x8+fastpskip
  
  pCodecContext->weighted_p_pred         = 2; // not implemented with interlaced ??
  
  pCodecContext->crf                     = 22;
  
  
  
  pCodecContext->pix_fmt                 = PIX_FMT_YUV420P;
  
  
  
  pCodecContext->thread_count            = 0;