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• How to stop ffmpeg from manipulating mp3 metadata ?

  13 septembre 2024, par he rambled

  I'm using ffmpeg to change bitrate of my mp3 files. It works well, but one thing is very frustrating.

  



  ffmpeg automatically changes some of metadata fields. Specifically it converts ID3v2.3 to ID3v2.4, and it does it incorrectly. For example, it writes TYER field that actually does not exist in ID3v2.4. But the most frustrating thing is, it converts USLT field to lyrics-LANGCODE(like lyrics-eng). Most of music players does not recognise this tag !

  



  I don't want ffmpeg to mess up with metadata fields. I just want it to change bitrate. Is there anyway to tell ffmpeg that it should not touch any metadata fields ?

  



  I'm running ffmpeg 4.0.2 in windows 64bit. Options are :

  



  ffmpeg -i input.mp3 -codec:a libmp3lame -b:a 128k output.mp3


  



  And no, -id3v2_version 3 did not help. It corrected TYER problem, but not lyrics problem.

  


• Looping over images in a batch script [on hold]

  31 juillet 2018, par Santosh Kr

  I’m trying to convert .jpg images in a directory to .yuv images with the ffmpeg command :

  ffmpeg -i 1.jpg -s 6720x3360 -pix_fmt nv12 1.yuv

  I’m trying to loop over them using a batch script as follows :

  set "sourcedir=C:\Users\santvenk\Desktop\Repo\Testing"
  
  PUSHD "%sourcedir%"
  
  for %%f in (*.jpg) DO ffmpeg -i "%%f" -s 6720x3360 -pix_fmt nv12 "%sourcedir%\%%~nf.yuv"

  But this is how it’s printing in the command prompt :

  ffmpeg -i "2.JPG" -s 6720x3360 -pix_fmt nv12 "C:\Users\santvenk\Desktop\Repo\Testing\2.JPG.yuv"

  How do I fix this ?

  EDIT : I had made few syntactical errors and now I have corrected it. The correct syntax for anyone looking for a solution to a similar problem is :

  FOR %%f in (*.jpg) DO ffmpeg -i %%f -s 6720x3360 -pix_fmt nv12 %%~nf.yuv

• Add lensfun filter

  13 juillet 2018, par Stephen Seo

  Add lensfun filter
  Lensfun is a library that applies lens correction to an image using a
  
  database of cameras/lenses (you provide the camera and lens models, and
  
  it uses the corresponding database entry's parameters to apply lens
  
  correction). It is licensed under LGPL3.
  The lensfun filter utilizes the lensfun library to apply lens
  
  correction to videos as well as images.
  This filter was created out of necessity since I wanted to apply lens
  
  correction to a video and the lenscorrection filter did not work for me.
  While this filter requires little info from the user to apply lens
  
  correction, the flaw is that lensfun is intended to be used on indvidual
  
  images. When used on a video, the parameters such as focal length is
  
  constant, so lens correction may fail on videos where the camera's focal
  
  length changes (zooming in or out via zoom lens). To use this filter
  
  correctly on videos where such parameters change, timeline editing may
  
  be used since this filter supports it.
  Note that valgrind shows a small memory leak which is not from this
  
  filter but from the lensfun library (memory is allocated when loading
  
  the lensfun database but it somehow isn't deallocated even during
  
  cleanup ; it is briefly created in the init function of the filter, and
  
  destroyed before the init function returns). This may have been fixed by
  
  the latest commit in the lensfun repository ; the current latest release
  
  of lensfun is almost 3 years ago.
  Bi-Linear interpolation is used by default as lanczos interpolation
  
  shows more artifacts in the corrected image in my tests.
  The lanczos interpolation is derived from lenstool's implementation of
  
  lanczos interpolation. Lenstool is an app within the lensfun repository
  
  which is licensed under GPL3.
  v2 of this patch fixes license notice in libavfilter/vf_lensfun.c
  v3 of this patch fixes code style and dependency to gplv3 (thanks to
  
  Paul B Mahol for pointing out the mentioned issues).
  v4 of this patch fixes more code style issues that were missed in
  
  v3.
  v5 of this patch adds line breaks to some of the documentation in
  
  doc/filters.texi (thanks to Gyan Doshi for pointing out the issue).
  v6 of this patch fixes more problems (thanks to Moritz Barsnick for
  
  pointing them out).
  v7 of this patch fixes use of sqrt() (changed to sqrtf() ; thanks to
  
  Moritz Barsnick for pointing this out). Also should be rebased off of
  
  latest master branch commits at this point.
  Signed-off-by : Stephen Seo <seo.disparate@gmail.com>
  

  • [DH] configure
  • [DH] doc/filters.texi
  • [DH] libavfilter/Makefile
  • [DH] libavfilter/allfilters.c
  • [DH] libavfilter/vf_lensfun.c