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• A 'clean' way to cut an MP4 movie into two sections using FFMPEG ?

  30 août 2020, par Peter in Japan

  I am attempting to use FFMPEG to make a script that can easily split a short MP4 movie with sound into two pieces at a certain point. I've searched through what feels like hundreds of posts to try to find "the" answer, but most of my attempts end up with poor results, broken video files that cause my video play to freeze, and so on. I am attempting to make a script that allows me to easily cut a short anime movie (something grabbed from Twitter or some other short source) and cut it into two sections, so it can be under the 2:20 Twitter time limit, or to cut out some scene I don't want to show my followers.

  


  The issue is that FFMPEG is good at cutting videos into segments, but bad at know where keyframes are, so most videos have two seconds of blank video at the front before some keyframe appears, which looks terrible.

  


  One example I found that works well is below, which cuts any mp4 into a bunch of chunks of n second size (six seconds in the example below). Source and documentation for this is https://moe.vg/3b8eNTs

  


  ffmpeg -i seitokai.mp4 -c:v libx264 -crf 22 -map 0 -segment_time 6 -reset_timestamps 1 -g 30 -sc_threshold 0 -force_key_frames "expr:gte(t,n_forced*1)" -f segment output%03d.mp4

  


  This code works great, at least allowing me to access the "left" side of a video that I want, in this case a six-second segment I want. Can anyone tell me how to accomplish the above, but starting at the 13-second period in said video, so I could get right "right" (not starting from 00:00:00) video cut cleanly ?

  


  Alternately, a single, unified and elegant way to split (re-encode) an MP4 into two segments that forces keyframes from the very beginning of the cut pieces would be wonderful. I can't believe how hard this seems to be.

  


  Thanks in advance for any help you can give ! Greetings from rural Japan !

  


• We are hiring engineers to build an awesome product and platform used by millions of people

  16 février 2016, par Piwik Core Team — Jobs

  Are you ready for a new challenge ? Or maybe you know someone who is looking for a change ? We have some exciting problems to solve and are looking for senior developers to work with us and our community on our open source Piwik Analytics platform. Piwik is used by more than one million websites all over the world. It is deployed on more than 300.000 servers and some users track more than 1 billion actions per month.

  What is it like to work on Piwik ?

  We develop this software using modern PHP, MySQL, Redis, AngularJS and more. We provide several kind of APIs and a plugin architecture to allow developers to extend and change Piwik to their needs. However, we would not be Piwik if we stopped at this point ! We want to turn Piwik into an even more awesome product and platform.
  You can imagine there is a lot to do and many challenges to face !

  While one part is to always make Piwik scale better and to improve UI and UX, we also want to provide simple APIs to make the life of developers as pleasant as possible. We aim to solve things the right way and our thousands of unit, integration, system, JavaScript and screenshot tests help us to innovate and to not be afraid of change. We like clean code and constant improvements.

  The Piwik team lives in New Zealand, Europe (Poland, Germany) and in the U.S. We do the vast majority of our collaboration online. Our values include being open, transparent and sharing knowledge. For this we use tools like GitHub and Slack to communicate and Quake servers to take our minds off complex challenges. We are a small, flexible team, so when you come aboard, you will play an integral part in engineering and have a big impact on the product loved by so many people. You’ll help to create a welcoming environment for new contributors and set an example with your development practices and communications skills.

  Apply now, or spread the word !

  If you have strong skills in PHP send us an email with your CV and tell us a little about yourself and your experience in engineering complex applications.

  Apply for a job here http://piwik.org/jobs/ and if you’re maybe not the right candidate, contribute to the project by sharing this blog post and by sending it to your friends !

• Is it still possible to compile modern x264 with the nal long start code used prior to release r1510 ?

  25 avril 2024, par Bryan Knowles

  I'm currently nerding out on old technology with HD-DVDs. The only freely available muxer is hddvdmux, I'm using MultiAVCHD for this.
Beginning with r1510, x264 switched to short start packets for NAL HRD (from what I understand). This makes the stream incompatible with hddvdmux.
deank on doom9 patched hddvdmux to accept short start codes, but in doing so, the video file plays too quickly and the audio goes out of sync.
The results I'm getting from the 2009 release of x264 leave much to be desired in comparison to modern releases, and I'd like to get those benefits while still maintaining compatibility with the original hddvdmux.
Is it possible ? If so... Any chance someone could compile a Windows binary for me with that change ? (I think it needs to be 32 bit, but not sure)

  


  I've tried multiple options with MultiAVCHD 4.1, fell back to 4.0 but am seeing weird rainbowing effects in the color from the extremely old version if x264. I admit I haven't dived in to programming, but seemed like a single change might be a reasonable request from someone already knowledgeable.