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• Cutting and rejoining videos causes audio de-synchronization using ffmpeg [closed]

  10 décembre 2023, par Donotalo

  This is the original post. I'm not getting any answer there so I thought may be the programming community knows the answer.

  


  Main Post

  


  I'm trying to cut a video into pieces and rejoin them using ffmpeg on Windows 11 x64. Here's the details of ffmpeg :

  


  ffmpeg version 2023-11-22-git-0008e1c5d5-full_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers
  built with gcc 12.2.0 (Rev10, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --pkg-config=pkgconf --disable-w32threads
--disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp
--enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt
--enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2
--enable-libaribb24 --enable-libaribcaption --enable-libdav1d --enable-libdavs2 --enable-libuavs3d
--enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265
--enable-libxavs2 --enable-libxvid --enable-libaom --enable-libjxl --enable-libopenjpeg --enable-libvpx
--enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi
--enable-libharfbuzz --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg
--enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc
--enable-dxva2 --enable-d3d11va --enable-libvpl --enable-libshaderc --enable-vulkan --enable-libplacebo
--enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt
--enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame
--enable-libvo-amrwbenc --enable-libcodec2 --enable-libilbc --enable-libgsm --enable-libopencore-amrnb
--enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite
--enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
  libavutil      58. 32.100 / 58. 32.100
  libavcodec     60. 34.100 / 60. 34.100
  libavformat    60. 17.100 / 60. 17.100
  libavdevice    60.  4.100 / 60.  4.100
  libavfilter     9. 13.100 /  9. 13.100
  libswscale      7.  6.100 /  7.  6.100
  libswresample   4. 13.100 /  4. 13.100
  libpostproc    57.  4.100 / 57.  4.100


  


  I've a video file in MKV format. I've cut it into 3 pieces using the following command :

  


  ffmpeg.exe -ss 0:0:0 -i input.mkv -t 0:54:15 -c:v hevc_amf -b:v 3M -c:s mov_text seg-01.mp4
ffmpeg.exe -ss 0:54:29 -i input.mkv -t 0:35:35 -c:v hevc_amf -b:v 3M -c:s mov_text seg-02.mp4
ffmpeg.exe -ss 1:30:12 -i input.mkv -t 0:4:10 -c:v hevc_amf -b:v 3M -c:s mov_text seg-03.mp4


  


  The audio is copied in all 3 pieces like original. Now I'm joining them using the following command :

  


  ffmpeg.exe -y -f concat -safe 0 -i .\join.txt -c:v hevc_amf -c:a copy -c:s copy -fflags +genpts out.mp4


  


  where, join.txt is :

  


  file seg-01.mp4
file seg-02.mp4
file seg-03.mp4


  


  ffmpeg throws the following warning :

  


  [mp4 @ 000002a5cf9cc040] Non-monotonic DTS in output stream 0:1; previous: 156240896, current: 156240084; changing to 156240897.
This may result in incorrect timestamps in the output file.
[mp4 @ 000002a5cf9cc040] Non-monotonic DTS in output stream 0:1; previous: 258720980, current: 258720462; changing to 258720981.
This may result in incorrect timestamps in the output file.


  


  I've observed that audio is de-synchronized after the places where I cut.

  


  How to keep audio, video and subtitle synchronized after cutting and rejoining the video using ffmpeg ?

  


• 9 plugins you should definitely have heard of to prevent data leaks, security breaches and to get more flexibility in the way you log in to your Piwik.

  9 janvier 2017, par InnoCraft — Community

  At Piwik and at InnoCraft, we have always focussed on Security and take it very seriously. We were one of the first open source projects to offer a bug bounty for reporting security issues responsibly, Piwik has gone through several security audits and all changes in Piwik go through security reviews by our security experts.

  On the Piwik Marketplace you will find some plugins that give you just that extra bit of additional security to keep your data even more secure and to let you secure how your users log in to your Piwik.

  Security Info

  This plugin provides security information about the server(s) your Piwik is running on and offers suggestions on how to improve the security settings of your servers. We highly recommend to install the Security Info plugin. Checks performed include for example usage of the latest PHP version, usage of latest Piwik version, usage of PHP ini settings like magic_quotes_gpc and more. More details & download

  By Piwik

  Google Authenticator

  This plugins adds Two Factor Authentication, also known as 2FA, to Piwik. When logging in to Piwik, it forces you to confirm the identity by utilizing a combination of two different components. This means if someone knows your password, they will still need the other component in order to successfully log in, in this case a code that changes every minute on your phone. More details & download

  By Stefan Giehl

  Activity Log

  The plugin gives you a detailed audit log of all activities that happen in your Piwik for better security and problem diagnostic. It provides documentary evidence of over 80 different activities that happen in your Piwik and lets you for example see when someone successfully logged in, when someone tried to log in with your username, when someone deleted data, and much more. More details

  By InnoCraft, the makers of Piwik. Pricing starts from 39€ / $49 a year.

  Login Revokable

  This feature allows a user to log in from multiple locations (different browsers, computers, …) as usual and makes sure to log you out of all sessions as soon as you log out from any of these locations. More details & download

  By Bryan Torosian

  Force SSL

  For security and privacy reasons you should always use Piwik over HTTPS (SSL). By activating this plugin, you make sure to redirect all “http://” requests to “https://” in the Piwik UI and API. More details & download

  By InnoCraft, the makers of Piwik.

  Performance Info

  This plugin checks your Piwik configuration and compares it with some best practice settings. For example whether debug modes are disabled in a production environment, whether the example plugins that are shipped with Piwik are disabled, and more. Please note that this plugin works only with Piwik 2. More details & download

  By Martin Keckeis

  Login Ldap

  Some companies might already manage their users in an LDAP server. This plugin allows you to log in to your Piwik via a central LDAP and supports web server authentication (eg. for Kerberos SSO). It authenticates with an LDAP server and uses LDAP information to personalize Piwik. More details & download

  By Piwik

  Login Shibboleth

  Shibboleth is an open-source project that provides a Single Sign-On and allows websites to make informed authorization decisions in a privacy-preserving manner. Using this plugin allows you to connect to an existing Shibboleth environment so you need to manage users only once. More details & download

  By Universität Würzburg Rechenzentrum

  Login Http Auth

  This plugin allows you to sign in to your Piwik using the HTTP Auth protocol instead of the standard login mechanism. It extends the standard Piwik authentication to use Basic HTTP Authentication. This may be useful if you use Basic HTTP Authentication already anyway and don’t want to manage your users additionally in Piwik itself. We recommend to use this only over SSL, for example with the Force SSL plugin. More details & download

  By Piwik

  Custom Development

  Piwik is an analytics platform that you can extend and customize to your needs. Besides many configuration options you can change existing functionality and also build new functionality on top of Piwik, for example to log in to your Piwik via any Single-Sign-On. Read more about extending Piwik on the Piwik Developer Zone or get in touch with us and we take care of it for you.

• libavformat : add RCWT closed caption muxex

  14 janvier 2024, par Marth64

  libavformat : add RCWT closed caption muxex
  Signed-off-by : Marth64 <marth64@proxyid.net>
  Raw Captions With Time (RCWT) is a format native to ccextractor, a commonly
  
  used open source tool for processing 608/708 closed caption (CC) sources.
  
  It can be used to archive the original, raw CC bitstream and to produce
  
  a source file file for later CC processing or conversion. As a result,
  
  it also allows for interopability with ccextractor for processing CC data
  
  extracted via ffmpeg. The format is simple to parse and can be used
  
  to retain all lines and variants of CC.
  A free specification of RCWT can be found here :
  
  https://github.com/CCExtractor/ccextractor/blob/master/docs/BINARY_FILE_FORMAT.TXT
  
  This muxer implements the specification as of 01/05/2024, which has
  
  been stable and unchanged for 10 years as of this writing.
  This muxer will have some nuances from the way that ccextractor muxes RCWT.
  
  No compatibility issues when processing the output with ccextractor
  
  have been observed as a result of this so far, but mileage may vary
  
  and outputs will not be a bit-exact match.
  Specifically, the differences are :
  
  (1)  This muxer will identify as "FF" as the writing program identifier, so
  
  as to be honest about the output's origin.
  (2)  ffmpeg's MPEG-1/2, H264, HEVC, etc. decoders extract closed captioning
  
  data differently than ccextractor from embedded SEI/user data.
  
  For example, DVD captioning bytes will be translated to ATSC A53 format.
  
  This allows ffmpeg to handle 608/708 in a consistant way downstream.
  
  This is a lossless conversion and the meaningful data is retained.
  (3)  This muxer will not alter the extracted data except to remove invalid
  
  packets in between valid CC blocks. On the other hand, ccextractor
  
  will by default remove mid-stream padding, and add padding at the end
  
  of the stream (in order to convey the end time of the source video).
  

  • [DH] Changelog
  • [DH] doc/muxers.texi
  • [DH] libavformat/Makefile
  • [DH] libavformat/allformats.c
  • [DH] libavformat/rcwtenc.c
  • [DH] tests/fate/subtitles.mak