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• How is time_base different then framerate in ffmpeg ? [duplicate]

  29 juin 2019, par Gilgamesh22

  This question already has an answer here :

  • What is video timescale, timebase, or timestamp in ffmpeg ? [closed]
    
    1 answer
    

  I have a project in which I receive frames sequentially to encode a mp4-h264 video. I also receive the timestamp in milliseconds along side the frame to indicate where in the video to place the frame. Because of this I decided to have a time_base of 10000 to simplify the placement of the frame since the frame rate is variable with an average fps of 30. I later learned that this causes problems in some video players. I was wondering if there is a proper way to accomplish this. at the moment my current solution is to set the time_base to 30 and simply set the frame->pts to timestamp of the frame divide by (10000/30).

  Original Setup

      AVCodecContext *cctx;
  
      AVStream* stream;
  
  
  
      stream->time_base.num = 1;
  
      stream->time_base.den = 10000;
  
  
  
      stream->r_frame_rate.num = 30;
  
      stream->r_frame_rate.den = 1;
  
  
  
      cctx->time_base.num = 1;
  
      cctx->time_base.den = 10000;
  
  
  
      cctx->framerate.num = 30;
  
      cctx->framerate.den = 1;

  My Question

  what exactly is time_base because I always though time_base was simply used to extract location of the frame and was abstracted away during the encoding process. this is why i though you have to declare both a framerate and time_base. If it is simply a ffmpg abstraction why is a time_base with large gaps of missing frames cause this problem in only some players. does the time base and frame rate need to match

• m3u8 but for mp4 (instead of ts)

  13 octobre 2022, par Rostyslav Bornitskyi

  I know that .m3u8 contains list of .ts videos. This is pretty cool, because you can take 2+ .m3u8 files and merge it on text level. Pretty easy.
I’m curious can we use .mp4 in .m3u8 manifest or maybe there are some formats like .m3u8 but for .mp4

  


  I need html player that can play 2+ videos as single one. So, I would be able to skip ffmpeg merging

  


• Returning a success or failure from ffmpeg

  2 novembre 2017, par user3331834

  I have some code executed in PHP after meeting some criteria through if/then statements which looks something like this :

  if(in_array($ext,$video)&&($ext!=="mp4")){
  
      exec("ffmpeg -i ".$fileName.".".$ext." -s 640x360 ".$fileName.".mp4");
  
      /*
  
      if(successful){
  
          unlink($fileName.$ext);
  
          $status="Video entry approved. File converted.";
  
      }
  
      */
  
  }

  As you can see, the issue I’m having is trying to figure out what should go in place of if(successful). The point of this section of the code is to check the files extension against an array of known extensions that are in video format, and that aren’t already in the mp4 format. If it passes this check, ffmpeg should run and convert to mp4.

  So a few questions here. Firstly, how can I return a status to tell me if it is converting, succeeded, or failed ? Secondly, how can this be run asynchronously ? That is, if I wanted to convert multiple files, would I be able to do so ? Would I be able to limit ffmpeg to ensure it does not take up all of my server’s processing power and inadvertently bring the site to a grinding halt ?

  Or is there a better way to go about converting files than this ? I’m pretty sure my method must be crude.

  EDIT : In addition to this, how does one run ffmpeg in the background, so that the page can be closed, and/or another instance from the same page can be started up by the user for multiple simultaneous conversions ? Is it possible to include a real-time progress status of each conversion ?