Recherche avancée

Sur d’autres sites (5046)

• Transcode video with php ffmpeg library

  27 juin 2019, par dev

  I need to upload video in 3 formate/resolution as 360p, 480p, 720p.

  After some research i got to know that some paid service are there like Amazone Elastic Transcoder . But i want to do with open source so i found FFMPEG.

  Also i want to upload video on Amazon s3 after transcode and video are in big size like video may contain 1GB size.

  I got php library for FFMPEG Library Link

  I have installed ffmpeg and it successfully generate new video. But i cannot figure out that how can i generate different formate/resolution as 360p, 480p, 720p.

  My sample Code is

          error_reporting(E_ALL);
  
          ini_set('display_errors', 1);
  
  
  
          require 'vendor/autoload.php';
  
  
  
          //$ffmpeg = FFMpeg\FFMpeg::create();
  
          $video = $ffmpeg->open('assets/small.mp4');
  
          $video
  
              ->filters()
  
              ->resize(new FFMpeg\Coordinate\Dimension(320, 240))
  
              ->synchronize();
  
          $video
  
              ->frame(FFMpeg\Coordinate\TimeCode::fromSeconds(2))
  
              ->save('assets/frame.jpg');
  
  
  
          $format = new FFMpeg\Format\Video\X264();
  
          $format->setAudioCodec("libmp3lame");
  
  
  
          $video->save($format, 'assets/new.mp4');

  Can anyone suggest me any way that how can i achieve this ??

• Can you think of a reason why windows might not enable audio if noone is logged in ?

  3 juillet 2017, par Caius Jard

  I’m having a bizarre problem with some virtual servers created to record podcasts. They run on amazon AWS as windows server 2012 instances and a small c# app tells FFMPEG to do the heavy lifting of capturing from the virtual screen and reading from the virtual sound card (Virtual Audio Cable : https://en.wikipedia.org/wiki/Virtual_Audio_Cable) via DirectShow filters

  The problem I have is if I leave the machine to do its stuff unattended, the recordings are sometimes silent. If I log in via VNC and watch it doing its stuff the audio is recorded just fine. All other aspects of the test op are the same, and the virtual machine is shut down between successive recordings so each one should theoretically be a clean slate. The app runs under a logged in session (hence the use of VNC rather than RDP)

  I’m now wondering if there is some optimisation of the windows sound engine whereby it doesn’t bother playing audio if it thinks noone is listening. The confusing thing to me is that not every virtual machine suffers these problems ; some of them record fine (and they’re all created from the same seed virtual hard disk image) in unattended mode

  I’m asking this question with the aim of getting together a list of things I can check/look into/debug.. I don’t have much knowledge of how MME/DirectSound/WASAPI work internally...

• vsync flag usage in ffmpeg while filtering

  13 octobre 2022, par antortjim

  I am trying to apply a threshold to an input video with ffmpeg, but I observe the following warning emitted for every processed frame

  


  [mp4 @ 0x56360181a200] Non-monotonous DTS in output stream 0:0; previous: 182272, current: 182272; changing to 182273. This may result in incorrect timestamps in the output file.


  


  where the previous and current are always 1 less than the value to which the DTS (Decoding Time Stamp) is changed

  


  I have noticed this warning is emitted only if I set -vsync passthrough (which I changed from the original -vsync 0 which is seen in many online examples).

  


  # input.mp4 has resolution 790x790
ffmpeg -vsync passthrough  -i input.mp4  -f lavfi -i color=808080:s=790x790 -f lavfi -i color=black:s=790x790 -f lavfi -i color=white:s=790x790 -filter_complex '[0:v][1:v][2:v][3:v]threshold' -an -c:v h264_nvenc threshold.mp4


  


  Shall I leave the vsync flag set to the default (auto or -1), or is -vsync passthrough essential to guarantee the frames are displayed in the right order ? In that case, how do I handle this warning ? Some other online examples I found of users experiencing this warning are different from mine, because in their case they are concatenating videos (see 1, 2

  


  From the documentation on the -vsync flag, at the end, I see :

  


  


  With -map you can select from which stream the timestamps should be taken. You can leave either video or audio unchanged and sync the remaining stream(s) to the unchanged one

  


  


  Maybe this warning should be handled with -map ? But I don't know how.

  


  Sidenote, I keep getting the deprecation warning asserting me to change -vsync for -fps_mode, however doing so breaks the command.

  


  FFPEG Version :

  


  commit 28ac2279adb860ea8b90d3073603912bf3eb6a83 from ffmpeg master branch

  


  ffmpeg version N-108625-g28ac2279ad Copyright (c) 2000-2022 the FFmpeg developers
built with gcc 9 (Ubuntu 9.4.0-1ubuntu1~20.04.1)
configuration: --enable-nonfree --enable-cuda-nvcc --enable-libnpp --enable-gpl --extra-cflags=-I/usr/local/cuda/include --extra-ldflags=-L/usr/local/cuda/lib64 --disable-static --enable-shared
libavutil      57. 39.101 / 57. 39.101
libavcodec     59. 50.100 / 59. 50.100
libavformat    59. 34.101 / 59. 34.101
libavdevice    59.  8.101 / 59.  8.101
libavfilter     8. 49.101 /  8. 49.101
libswscale      6.  8.112 /  6.  8.112
libswresample   4.  9.100 /  4.  9.100
libpostproc    56.  7.100 / 56.  7.100


  


  OS

  


  Ubuntu 20.04.4 LTS