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• How to set H264 NVENC encoding parameters to output high-quality video stream ?

  8 février 2021, par fredirty2017
  

  • I use NVENC (nvEncodeAPI) interface hardware encoding H264, and then RTMP to stream out, when using ffplay to pull the stream to watch, I found that the picture is obviously distorted : the green lines become sharper ? the text color becomes lighter and blurred, it is not improved even if I increase the video bitrate to 3Mbps(720P). I also know that H264 encoding is lossy, and some information will be discarded.

  


  • Then I try to adjust the NV_ENC_CONFIG_H264_VUI_PARAMETERS parameter : when set color-space to "pc, bt709", there are some minor improvements. Maybe the color-space setting has more potential for improvement ? For NVENC encoding, is there a higher video clarity setting scheme ? I don't know how much space for technical improvement is here ?

based on the code : https://github.com/obsproject/obs-studio/blob/master/plugins/obs-ffmpeg/obs-ffmpeg-nvenc.c

  


  


• doc/filters/crop : drop unmatched quote in example

  11 mai 2023, par Andriy Utkin

  doc/filters/crop : drop unmatched quote in example
  Commit 55b81528a991 ("doc/filters : itemize crop examples") dropped the
  
  quotation marks from these examples, but this one remained. Quotes are
  
  actually needed to put the example into a command line or a program, but
  
  removing it here makes the example consistent with the document.
  

  • [DH] doc/filters.texi

• Replace Special Characters In Batch-File Variable Feeding ffmpeg program

  14 janvier 2019, par whereswaller

  I am attempting to write a batch-file that leverages ffmpeg.exe to convert all files in a folder structure to mp3 format (specifically 128 KBps).

  My batch-file is presently unable to process filenames (constructed by concatenating the %_SOURCE% and %%~F variables) containing certain special characters generating the following errors :

  No such file or directory

  • … ellipsis sign
  • – en dash
  • — em dash
  • − minus sign

  Invalid argument

  • ‘ and ’ curved single quotation marks
  • “ and ” curved double quotation marks

  Invalid argument (yet sometimes passes depending on where symbol is in the filename, for example, seems to work if placed between the n and t of Dont in C:\Users\Test\Documents\Input\Peter Bjorn And John - I Know You Dont Love Me.mp3)

  • - hyphen
  • ! exclamation mark
  • ~ tilde
  • ' non-curved single quotation mark
  • = equals sign
  • + plus sign
  • % percentage sign
  • ( open bracket

  How can I modify my batch-file script so that the %%~F variable escapes these characters correctly ?

  Example current filename input : C:\Users\Test\Documents\Input\Peter Bjorn And John - I Know You Don't Love Me.mp3

  Example desired filename input : C:\Users\Test\Documents\Input\Peter Bjorn And John - I Know You Don"^'"t Love Me.mp3

  Script (see line beginning C:\ffmpeg\bin\ffmpeg.exe) :

  @echo off
  
  setlocal EnableExtensions DisableDelayedExpansion
  
  
  
  rem // Define constants here:
  
  set "_SOURCE=C:\Users\Test\Documents\Input" & rem // (absolute source path)
  
  set "_TARGET=C:\Users\Test\Documents\Output"  & rem // (absolute target path)
  
  set "_PATTERN=*.*" & rem // (pure file pattern for input files)
  
  set "_FILEEXT=.mp3"   & rem // (pure file extension of output files)
  
  
  
  pushd "%_TARGET%" || exit /B 1
  
  for /F "delims=" %%F in ('
  
      cd /D "%_SOURCE%" ^&^& ^(rem/ list but do not copy: ^
  
          ^& xcopy /L /S /Y /I ".\%_PATTERN%" "%_TARGET%" ^
  
          ^| find ".\" ^& rem/ remove summary line;
  
      ^)
  
  ') do (
  
      2> nul mkdir "%%~dpF."
  
  
  
      rem // Set up the correct `ffmpeg` command line here:
  
      set "FFREPORT=file=C\:\\Users\\Test\\Documents\\Output\\ffreport-%%~F.log:level=32"
  
      "C:\ffmpeg\bin\ffmpeg.exe" -report -n -i "%_SOURCE%\%%~F" -vn -c:a libmp3lame -b:a 128k "%%~dpnF%_FILEEXT%"
  
      if not errorlevel 1  if exist "%%~dpnF%_FILEEXT%" del /f /q "%_SOURCE%\%%~F"
  
  
  
  )
  
  popd
  
  
  
  endlocal
  
  pause