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• too long video trace file volume ?

  12 juin 2021, par david

  I have produced an XML trace file of a 20-sec video and the volume of this trace file is 8.57 Gigabyte !! the videos is encoded using this command :

  


  ffmpeg  -i  input_1080p60.mp4  -c:v  libx264 -pix_fmt yuv420p  -b:v 8000K -bufsize 8000K -minrate 8000K -maxrate 8000K -x264opts keyint=120:min-keyint=120 -preset veryfast -profile:v high out_1080p.mp4


  


  then I used the following command I changed the format in .264 because the input of JM software for producing an XML trace file is .264 :

  


  ffmpeg  -i  out_1080p.mp4  -c:v  libx264 -pix_fmt yuv420p  -b:v 8000K -bufsize 8000K -minrate 8000K -maxrate 8000K -x264opts keyint=120:min-keyint=120 -preset veryfast -profile:v high out_1080p.264


  


  after using JM using the following code :

  


  ldecod.exe -i E:\software\out_1080p.264 -o E:\software\out.yuv -xmltrace out_1080p_xml.xml


  


  it is really weird for me. because I have more than 1000 videos that I need to produce their trace files and I do not know what should I do with this size of the trace file. furthermore, I can not open a file with this volume and no software can open the file !! :((. could you please tell me what is the problem ? and how can I solve it ? do you know another way to produce this trace file ?
THanks

  


• record long videos from multiple webcams with FFmpeg

  4 août 2020, par Nagamoto

  I am using

  


  ffmpeg -f dshow -vcodec mjpeg -t 6000 -rtbufsize 2.14748e+09  -video_size 1920x1080 -framerate 60 -i video=camID-0 -f dshow -vcodec mjpeg -t 6000 -rtbufsize 2.14748e+09  -video_size 1920x1080 -framerate 60 -i video=camID-1 -map 0  -c:v libx264 -preset ultrafast -y -r 30 fileName_0.mp4 -map 1  -c:v libx264 -preset ultrafast -y -r 30 fileName_1.mp4

  


  to record video from two webcams. Since the output will be compressed further down the line I am mostly concerned with quality and not losing frames. But after about 2min the real-time buffer is full :

  


  [dshow @ 00000221716edf80] real-time buffer [@device_pnp_\\?\usb#vid_15aa&pid_1555&mi_00#6&b8e4142&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global] [video input] too full or near too full (75% of size: 2147480000 [rtbufsize parameter])! frame dropped!


  


  On the other hand capturing uncompressed video results in huge filesizes (1.3 TB for an hour) but encoding with the settings above the computer can't keep up.
Currently the webcams capture 60fps- which is not a must but I can't set them to anything lower.

  


  How can I record long video (max 1.5h) with good quality while keeping file-sizes manageable ?

  


  ffmpeg -f dshow -list_options true -i video="3.0 USB Camera"



ffmpeg version 4.3 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 9.3.1 (GCC) 20200621
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libsrt --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libgsm --disable-w32threads --enable-libmfx --enable-ffnvcodec --enable-cuda-llvm --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
[dshow @ 000001f32953c380] DirectShow video device options (from video devices)
[dshow @ 000001f32953c380]  Pin "Capture" (alternative pin name "0")
[dshow @ 000001f32953c380]   vcodec=mjpeg  min s=1920x1080 fps=60.0002 max s=1920x1080 fps=60.0002
[dshow @ 000001f32953c380]   vcodec=mjpeg  min s=1920x1080 fps=60.0002 max s=1920x1080 fps=60.0002
[dshow @ 000001f32953c380]   vcodec=mjpeg  min s=1280x720 fps=60.0002 max s=1280x720 fps=60.0002
[dshow @ 000001f32953c380]   vcodec=mjpeg  min s=1280x720 fps=60.0002 max s=1280x720 fps=60.0002
[dshow @ 000001f32953c380]   vcodec=mjpeg  min s=640x480 fps=60.0002 max s=640x480 fps=60.0002
[dshow @ 000001f32953c380]   vcodec=mjpeg  min s=640x480 fps=60.0002 max s=640x480 fps=60.0002
[dshow @ 000001f32953c380]   pixel_format=yuyv422  min s=1920x1080 fps=60.0002 max s=1920x1080 fps=60.0002
[dshow @ 000001f32953c380]   pixel_format=yuyv422  min s=1920x1080 fps=60.0002 max s=1920x1080 fps=60.0002
[dshow @ 000001f32953c380]   pixel_format=yuyv422  min s=1280x720 fps=60.0002 max s=1280x720 fps=60.0002
[dshow @ 000001f32953c380]   pixel_format=yuyv422  min s=1280x720 fps=60.0002 max s=1280x720 fps=60.0002
[dshow @ 000001f32953c380]   pixel_format=yuyv422  min s=640x480 fps=60.0002 max s=640x480 fps=60.0002
[dshow @ 000001f32953c380]   pixel_format=yuyv422  min s=640x480 fps=60.0002 max s=640x480 fps=60.0002
video=3.0 USB Camera: Immediate exit requested


  


• ffmpeg as subprocess takes too long

  12 décembre 2019, par almosthero

  One part of my program requires FFMPEG to transcode files using GPU.

  When I execute the FFMPEG command alone in terminal, without Python, it takes aproximetly 0.7 second. Running 50 simultaneous commands doesn’t affect the results. The time is always around 0.7 sec (thanks to a powerful GPU that can handle that amount of requests).

  Putting this command to subprocess increases the time to 1.7 second and raises up to 20 seconds when I run multiple instance even though this command should work asynchronously.

  def run_ffmpeg(filename, gop, representation, output_filename=None):
  
      process_result = subprocess.run(
  
          args=[
  
              'sudo', FFMPEG_PATH,
  
              '-vsync', '0',
  
              '-hwaccel', 'cuvid', # transport decoded file through GPU without touching CPU
  
              '-hwaccel_device', '0',
  
              '-c:v', 'h264_cuvid', # Decoding using GPU
  
              '-i', filename,
  
              # ...
  
              '-c:v', 'hevc_nvenc', # Encoding using GPU
  
              # ...more filters...
  
              output_filename
  
          ]
  
      )
  
      log_process_result(process_result)
  
      return output_filename

  The sequence is way more complex :

  def transcode_file(media_id, target_repr, target_nr):
  
      # ... variables definitions
  
      run_ffmpeg(target_segment_path, gop='120', representation=target_repr, output_filename=result)
  
  
  
  def prepare_file(media_id, representation_id, file_name):
  
      # ... variables definitions
  
          path = transcode_file(media_id, target_repr, target_nr)
  
  
  
  async def download_media_handler(request):
  
      # ... variables definitions
  
      file_info = await loop.run_in_executor(
  
          executor, prepare_file, media_dir_name, representation_id, file_name)

  Neither GPU or CPU is fully used so this is not the case.

  Do you know why ? Does subprocess really takes so much time to run ?

  How can I rewrite this to minimize the time ? Are there any quicker alternatives ?