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• Why after rendering with ffmpeg, file size did not decrease ?

  15 avril 2021, par ptrra

  PROBLEM : After rendering a certain video with ffmpeg file size increased from 4GB to 6GB.
  
ORIGINAL VIDEO : EE1.mkv
  
FFMPEG COMMAND : ffmpeg -i EE1.mkv -c:a copy -c:v libx264 -crf 23 -preset medium -profile:v high out.mp4
  
QUESTIONS : Why did the file size increase ? What am I doing wrong ?

  


   !DETAILS !
  
After a few years I made about 30 gaming videos (130GB) and with the current covid-19 situation I started recording my online classes (about 40 videos or 150GB). Now because I'm lacking space on my 1TB external HDD I started getting into ffmpeg. Before I was only using obs-studio and not good parameters for recording.

  


  I was using CBR mode for recording, either 5000KB or 15000KB bit rate with varying x264 presets and profiles because I was also experimenting with them. Usually superfast preset with high profile. So I wanted to convert all those videos with ffmpeg using CRF 23, medium preset and high profile. A note that when I'm recording with obs-studio it's set to record in matroska format (.mkv).

  


  When I was rendering my online classes videos with these settings I managed to achieve 10x better compression with the same quality. And when rendering my gaming videos I managed to achieve up to 3x better compression with the same quality. However there is this one video that when rendered with the same parameters the file size increases.

  


  The EE1.mkv should be recorded with CBR 15000KB bit rate, with superfast preset and high profile. Also the game that is recorded in this video is Empire Earth which needs around 8000KB for it to look good. Everything more than 8000KB is not needed.

  


  Thank you all for your help.

  


• avformat : add demuxer for argonaut games' ASF format

  26 janvier 2020, par Zane van Iperen

  avformat : add demuxer for argonaut games' ASF format
  Adds support for the custom ASF container used by some Argonaut Games'
  
  games, such as 'Croc ! Legend of the Gobbos', and 'Croc 2'.
  Can also handle the sample files in :
  
  https://samples.ffmpeg.org/game-formats/brender/part2.zip
  Signed-off-by : Zane van Iperen <zane@zanevaniperen.com>
  

  • [DH] Changelog
  • [DH] libavformat/Makefile
  • [DH] libavformat/allformats.c
  • [DH] libavformat/argo_asf.c
  • [DH] libavformat/version.h

• FFmpeg generic error in an external library

  13 octobre 2017, par Mher Didaryan

  I’m trying to encode the game play from Unreal Engine with h264_nvenc encoder on a windows with FFmpeg 3.3.3. FFmpeg was configured with —enable-cuda —enable-cuvid —enable-nvenc
  However avcodec_open2 can’t open the codec.

  Below is the function where call to avcodec_alloc_context3 is.

  void Encoder::AddStream(AVCodecID CodecID)
  
  {
  
  
  
  VideoCodec = avcodec_find_encoder(CodecID);
  
  if (!VideoCodec) {
  
      UE_LOG(LogTemp, Error, TEXT("Could not find encoder for '%s'"), ANSI_TO_TCHAR(avcodec_get_name(CodecID)));
  
  }
  
  
  
  VideoSt.Stream = avformat_new_stream(FmtCtx, nullptr);
  
  if (!VideoSt.Stream) {
  
      UE_LOG(LogTemp, Error, TEXT("Could not allocate stream"));
  
  }
  
  
  
  VideoSt.Stream->id = FmtCtx->nb_streams - 1;
  
  VideoSt.Ctx = avcodec_alloc_context3(VideoCodec);
  
  if (!VideoSt.Ctx) {
  
      UE_LOG(LogTemp, Error, TEXT("Could not alloc an encoding context"));
  
  }
  
  
  
  VideoSt.Ctx->codec_id = CodecID;
  
  VideoSt.Ctx->flags = 0;
  
  VideoSt.Ctx->me_range = 16;
  
  VideoSt.Ctx->max_qdiff = 4;
  
  VideoSt.Ctx->refs = 0;
  
  VideoSt.Ctx->qmin = 2;
  
  VideoSt.Ctx->qmax = 31;
  
  VideoSt.Ctx->qcompress = 0.6;
  
  VideoSt.Ctx->width = ViewportSize.X;
  
  VideoSt.Ctx->height = ViewportSize.Y;
  
  VideoSt.Ctx->bit_rate = 4000000;
  
  VideoSt.Stream->time_base = VideoSt.Ctx->time_base = { 1, 30 };
  
  VideoSt.Ctx->gop_size = 25;
  
  VideoSt.Ctx->max_b_frames = 0;
  
  VideoSt.Ctx->thread_count = 1;
  
  VideoSt.Ctx->pix_fmt = AV_PIX_FMT_YUV420P;
  
  VideoSt.Ctx->codec_type = AVMEDIA_TYPE_VIDEO;
  
  
  
  if (FmtCtx->oformat->flags & AVFMT_GLOBALHEADER)
  
      VideoSt.Ctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
  
  
  
  }

  As answer to this question suggests same issue I use avcodec_alloc_context3. Am I doing something wrong or error caused buy another reason ?

  Below is the part where call to avcodec_open2 is. It’s called after Encoder::AddStream so everything is set up I guess.

  auto c = VideoSt.Ctx;
  
  AVDictionary* opt = nullptr;
  
  av_dict_copy(&opt, Opt, 0);
  
  auto ret = avcodec_open2(c, VideoCodec, &opt);

  What can cause Generic error in an external library ?