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• could be recording video & OS timestamp with ffmpeg ?

  2 septembre 2020, par sooyongchoi

  I'm newbie of Video, Image processing.

  


  I want to recording High resolution & frame video with FFmpeg. (1920 * 1080 * 60FPS)
and, I need to Timestamp data of OS(Windows or ubuntu) for each frames.
I hope to Timestamp data is formatted with text data.

  


  I searched any of using FFmpeg, but I couldn't find recording video with timestamp data.

  


  Is there any idea of recording video & timestamp data with ffmpeg ?

  


  Or, could you notice me with simple tip of making solution with ffmpeg ?

  


  Thanks ! :)

  


• Video players questions

  31 mai 2015, par yayuj

  Given that FFmpeg is the leading multimedia framework and most of the video/audio players uses it, I’m wondering somethings about audio/video players using FFmpeg as intermediate.

  I’m studying and I want to know how audio/video players works and I have some questions.

  I was reading the ffplay source code and I saw that ffplay handles the subtitle stream. I tried to use a mkv file with a subtitle on it and doesn’t work. I tried using arguments such as -sst but nothing happened. - I was reading about subtitles and how video files uses it (or may I say containers ?). I saw that there’s two ways putting a subtitle : hardsubs and softsubs - roughly speaking hardsubs mode is burned and becomes part of the video, and softsubs turns a stream of subtitles (I might be wrong - please, correct me).

  • The question is : How does they handle this ? I mean, when the subtitle is part of the video there’s nothing to do, the video stream itself shows the subtitle, but what about the softsubs ? how are they handled ? (I heard something about text subs as well). - How does the subtitle appears on the screen and can be configured changing fonts, size, colors, without encoding everything again ?

  • I was studying some video players source codes and some or most of them uses OpenGL as renderer of the frame and others uses (such as Qt’s QWidget) (kind of or for sure) canvas. - What is the most used and which one is fastest and better ? OpenGL with shaders and stuffs ? Handling YUV or RGB and so on ? How does that work ?

  • It might be a dump question but what is the format that AVFrame returns ? For example, when we want to save frames as images first we need the frame and then we convert, from which format we are converting from ? Does it change according with the video codec or it’s always the same ?

  • Most of the videos I’ve been trying to handle is using YUV720P, I tried to save the frames as png and I need to convert to RGB first. I did a test with the players and I put at the same frame and I took also screenshots and compared. The video players shows the frames more colorful. I tried the same with ffplay that uses SDL (OpenGL) and the colors (quality) of the frames seems to be really low. What might be ? What they do ? Is it shaders (or a kind of magic ? haha).

  Well, I think that is it for now. I hope you help me with that.

  If this isn’t the correct place, please let me know where. I haven’t found another place in Stack Exchange communities.

• Announcement : Piwik to focus on Reliability, Performance and Security

  7 octobre 2014, par Matthieu Aubry — About, Community

  To our valued team and community,

  Well, we have moved fast and achieved so much during the past few months. Relentlessly releasing major version after major version… We got a lot done including several major new features !

  The speed of adding new features was a great showcase of how agile our small teams and the larger community are. And I’m so proud to see automated testing becoming common practice among everyone hacking on Piwik !

  For the next few months until the new year we will focus on making what we have better. We will fix those rare but longstanding critical bugs, and aim to solve all Major issues and other must-have performance and general improvements. The core team and Piwik PRO will have the vision of making the existing Piwik and all plugins very stable and risk free. This includes edge cases, general bugs but also specific performance issues for high traffic or issues with edge case data payloads.

  We’ll be more pro-active and take Piwik platform to the next level of Performance, Security, Privacy & Reliability ! We will prove to the world that Free/Libre Web software can be of the highest standard of quality. By focusing on quality we will make Piwik even easier to maintain and improve in the future. We are building the best open platform that will let every user liberate their data and keep full control of it.

  If you have any feedback or questions get in touch or let’s continue the discussion in the forum.

  Thank you for your trust and for liberating your data with Piwik,

  Matthieu Aubry
  Piwik founder

  More information

  • How long is each release of Piwik maintained for ? (FAQ)
  • When is the next release of Piwik ? What is the release schedule ? (FAQ)
  • Pulse of Piwik : our monthly pulse report shows 27 different people contributed to Piwik core in the last month !

  

  This is an amazing testament of the power of free/libre software and yet we think this is just the beginning. We hope more developers will join and contribute to the Piwik project !