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• FFMPEG with node , using child_process , suppressing un-necessary stderr

  16 mai 2018, par drexdelta

  I am trying to resize the video using (FFMPEG + node + child_process). and my code looks something like this , You can read comments and understand it. it’s self-explanatory for people who are familiar with node and ffmpeg. when I run this code, I keep getting error in
  newThread.stderr.on() function . which is not expected behaviour. After running this process I am getting expected video translation, which is expected behaviour.

  const spawn = require('child_process').spawn;
  
  
  
  // resize and compress video promise  = prom2
  
  const resizeVideoWith_FFMPEG_Promise = (sourceFile , sinkFile)=>{
  
      return new Promise ( (resolve , reject)=>{
  
  
  
          // actual command for ffmpeg is something like this , "ffmpeg -i oldVideo -vf scale=-2:480 newVideo"
  
          // New thread
  
          const newThread = spawn('ffmpeg' , ['-i','vid1.mp4','-vf','scale=-2:480','vid2.mp4']);
  
  
  
          // on close signal
  
          newThread.on('close',(data)=>{
  
              console.log(' thread closed for video ' , sourceFile);
  
              return resolve();
  
          });
  
          // on stderr signals
  
          newThread.stderr.on('data',(data)=>{
  
              console.log(' got error in the thread of video ' , sourceFile);
  
              fullError = data.toString();
  
              console.log(fullError);
  
              // return resolve();
  
              // return reject();
  
          });
  
          newThread.stdout.on('data',(data)=>{
  
              // just ignore all stadanrd outputs
  
          });
  
      });
  
  }
  
  
  
  resizeVideoWith_FFMPEG_Promise('vid1.mp4' , 'vid2.mp4' ).then((res)=>{
  
      console.log(res);
  
  });

  For the sake of simplicity I am resolving the promise everytime, even if I get stderr. And at end of running this code I get output something like this ,

   got error in the thread of video  vid1.mp4
  
  frame= 3277 fps=116 q=28.0 size=   12288kB time=00:02:16.64 bitrate= 736.7kbits/s speed=4.82x    
  
   got error in the thread of video  vid1.mp4
  
  frame= 3313 fps=115 q=28.0 size=   12544kB time=00:02:18.15 bitrate= 743.8kbits/s speed=4.79x    
  
   got error in the thread of video  vid1.mp4
  
  frame= 3362 fps=115 q=28.0 size=   12800kB time=00:02:20.17 bitrate= 748.0kbits/s speed=4.78x    
  
   got error in the thread of video  vid1.mp4
  
  frame= 3408 fps=114 q=28.0 size=   12800kB time=00:02:22.12 bitrate= 737.8kbits/s speed=4.77x    
  
   got error in the thread of video  vid1.mp4
  
  frame= 3465 fps=114 q=28.0 size=   13056kB time=00:02:24.49 bitrate= 740.2kbits/s speed=4.76x    
  
   got error in the thread of video  vid1.mp4
  
  frame= 3522 fps=114 q=28.0 size=   13312kB time=00:02:26.86 bitrate= 742.5kbits/s speed=4.76x    
  
   got error in the thread of video  vid1.mp4
  
  frame= 3580 fps=114 q=28.0 size=   13568kB time=00:02:29.28 bitrate= 744.6kbits/s speed=4.76x

  Now, my problem is if I always keep resolving errors, then I will never be able to catch when the video ACTUALLY FAILED TO RESCALE. so, how can I ignore these type of un-necessary stderr and catch only useful errors ?

  Pls someone help.

  I have been through lot of related links like this, but none of these actually solve my problem(even if they did, I couldn’t figure out)

  Error while using h264_cuvid decoder with ffmpeg

  Using module "child_process" without Webpack

  Suppressing STDOUT with node child_process

  Small hint will be very helpful. Thank you .

  BTW , SO moderators , My actual title was like

  stderr problem while using FFMPEG with node via child_process module

  But it didn’t allow me to use such title. so, I am using some dummy title.

• ffmpeg : PNGs to mp4 video is strange scaled quicktime

  15 mai 2024, par v_b

  I am trying to create a video from multiple PNG files.
  
The files contain an animation of a line.
  
However, the output MP4 video looks really strange, as if the content is stretched or scaled.

  


  Below, you can see screenshots of one of the PNG files and the resulting video file.

  


  Some additional information :
  
I am on a MacPro M3 w. latest MacOs updates.
  
The images have transparent backgrounds.

  


  Command :

  


  ffmpeg -framerate 30 -pattern_type glob -i "*.png" -s:v 1600x800 -pix_fmt yuv420p -c:v libx264 result.mp4


  


  Example PNG file :


  


  PNG Information :


  


  Resulting Video :


  


  Video Info :

  


  ffprobe ./result.mp4                                                                
ffprobe version 7.0 Copyright (c) 2007-2024 the FFmpeg developers
  built with Apple clang version 15.0.0 (clang-1500.3.9.4)
  configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/7.0_1 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags='-Wl,-ld_classic' --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libaribb24 --enable-libbluray --enable-libdav1d --enable-libharfbuzz --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopenvino --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox --enable-audiotoolbox --enable-neon
  libavutil      59.  8.100 / 59.  8.100
  libavcodec     61.  3.100 / 61.  3.100
  libavformat    61.  1.100 / 61.  1.100
  libavdevice    61.  1.100 / 61.  1.100
  libavfilter    10.  1.100 / 10.  1.100
  libswscale      8.  1.100 /  8.  1.100
  libswresample   5.  1.100 /  5.  1.100
  libpostproc    58.  1.100 / 58.  1.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from './result.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf61.1.100
  Duration: 00:00:03.03, start: 0.000000, bitrate: 103 kb/s
  Stream #0:0[0x1](und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, unknown/bt709/iec61966-2-1, progressive), 1600x800, 98 kb/s, 30 fps, 30 tbr, 15360 tbn (default)
      Metadata:
        handler_name    : VideoHandler
        vendor_id       : [0][0][0][0]
        encoder         : Lavc61.3.100 libx264


  


  ffmpeg version

  


  ffmpeg version 7.0 Copyright (c) 2000-2024 the FFmpeg developers
  built with Apple clang version 15.0.0 (clang-1500.3.9.4)
  configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/7.0_1 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags='-Wl,-ld_classic' --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libaribb24 --enable-libbluray --enable-libdav1d --enable-libharfbuzz --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopenvino --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox --enable-audiotoolbox --enable-neon
  libavutil      59.  8.100 / 59.  8.100
  libavcodec     61.  3.100 / 61.  3.100
  libavformat    61.  1.100 / 61.  1.100
  libavdevice    61.  1.100 / 61.  1.100
  libavfilter    10.  1.100 / 10.  1.100
  libswscale      8.  1.100 /  8.  1.100
  libswresample   5.  1.100 /  5.  1.100
  libpostproc    58.  1.100 / 58.  1.100
Universal media converter
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...


  


• Why does every encoded frame's size increase after I had use to set one frame to be key in intel qsv of ffmpeg

  22 avril 2021, par TONY

  I used intel's qsv to encode h264 video in ffmpeg. My av codec context settings is like as below :

  


   m_ctx->width = m_width;
    m_ctx->height = m_height;
    m_ctx->time_base = { 1, (int)fps };
    m_ctx->qmin = 10;
    m_ctx->qmax = 35;
    m_ctx->gop_size = 3000;
    m_ctx->max_b_frames = 0;
    m_ctx->has_b_frames = false;
    m_ctx->refs = 2;
    m_ctx->slices = 0;
    m_ctx->codec_id = m_encoder->id;
    m_ctx->codec_type = AVMEDIA_TYPE_VIDEO;
    m_ctx->pix_fmt = m_h264InputFormat;
    m_ctx->compression_level = 4;
    m_ctx->flags &= ~AV_CODEC_FLAG_CLOSED_GOP;
    AVDictionary *param = nullptr;
    av_dict_set(&param, "idr_interval", "0", 0);
    av_dict_set(&param, "async_depth", "1", 0);
    av_dict_set(&param, "forced_idr", "1", 0);


  


  and in the encoding, I set the AVFrame to be AV_PICTURE_TYPE_I when key frame is needed :

  


    if(key_frame){
        encodeFrame->pict_type = AV_PICTURE_TYPE_I;
    }else{
        encodeFrame->pict_type = AV_PICTURE_TYPE_NONE;
    }
    avcodec_send_frame(m_ctx, encodeFrame);
    avcodec_receive_packet(m_ctx, m_packet);
   std::cerr<<"packet size is "<size<<",is key frame "<code>

  


  The strange phenomenon is that if I had set one frame to AV_PICTURE_TYPE_I, then every encoded frame's size after the key frame would increase. If I change the h264 encoder to x264, then it's ok.

  


  The packet size is as below before I call "encodeFrame->pict_type = AV_PICTURE_TYPE_I" :

  


  packet size is 26839
packet size is 2766
packet size is 2794
packet size is 2193
packet size is 1820
packet size is 2542
packet size is 2024
packet size is 1692
packet size is 2095
packet size is 2550
packet size is 1685
packet size is 1800
packet size is 2276
packet size is 1813
packet size is 2206
packet size is 2745
packet size is 2334
packet size is 2623
packet size is 2055


  


  If I call "encodeFrame->pict_type = AV_PICTURE_TYPE_I", then the packet size is as below :

  


  packet size is 23720,is key frame 1
packet size is 23771,is key frame 0
packet size is 23738,is key frame 0
packet size is 23752,is key frame 0
packet size is 23771,is key frame 0
packet size is 23763,is key frame 0
packet size is 23715,is key frame 0
packet size is 23686,is key frame 0
packet size is 23829,is key frame 0
packet size is 23774,is key frame 0
packet size is 23850,is key frame 0