Recherche avancée

Sur d’autres sites (11824)

• ffmpeg questions

  23 avril 2015, par QuestionGuy

  I have a problem with ffmpeg and I don’t know how to continue. I have 2 computers :

  Client :

  • Run Ubuntu 14.04
  • FFmpeg installed
  • Use c++ language
  • Features : use ffmpeg to encode h264 video data from webcam of client laptop, then real time streaming to server

  Server :

  • Running Windows 7
  • FFmpeg installed
  • Use c++ language (MFC)
  • Features : Get real time data from client and show it on screen.

  I’ve just connected client to server and they can chat text data together, and I don’t have any idea to make real time video work.

  And my questions are :

  1. [Client] How to get video from webcam on laptop (using ffmpeg code), save it to buffer (raw data), encode it and send to server ?

     I use ffmpeg to get video from wc but it save to file. I really don’t want it. Code is :

     ffmpeg -f v4l2 -framerate 25 -video_size 640x480 -i /dev/video0 output.mkv

  2. [Client] How to get raw data from client, decode it and play it ?

     I have an idea to play it by using directshow in MFC.

• Glitchy mp4 File saved with Matplotlib Animation via ffmpeg

  9 janvier 2024, par Jacob Ivanov

  I am attempting to save an .mp4 file using matplotlib.animation to output some simulation results. The relevent section is as follows :

  


  ANI = FuncAnimation(fig, update, init_func = lambda : None, frames = range(0, 21300, 50))
ANI.save("[removed]/anim/v6 256 unforced 0.02.mp4", dpi = 600, fps = 30, writer = 'ffmpeg')


  


  However, it appears that there is some issue in the produced .mp4 file, as when I use macOS Quicktime to view the file, it pauses on certain frames, and restarts later on. It appears to consistently pause on the same frame a few seconds in. In order to check if Quicktime was the problem, I opened some random .mp4 files I found in a family group chat, and did not have this issue.

  


  I also tried viewing this .mp4 file with VLC, which had no issue, and played without any glitches. The Slack media viewer built into the app pauses similar to Quicktime.

  


  The following are all relevant versions :

  


  

  • macOS : 14.2.1 (23C71)

  


  • Python : 3.10.9 via Homebrew

  


  • Matplotlib : 3.6.2

  


  • ffmpeg : 6.1.1

  


  


  If it would help, I can also provide the .mp4 file itself, but I'm not quite sure how to upload it. I will be happy to provide any additional information as well.

  


  Unfortunately, I'm not very familiar with video rendering, but I would appreciate any help anyone could provide. Thank you in advance !

  


• FFMEPG：Why does the video sound become smaller when I use pictures and wavs to compose a video, and there is less audio at the beginning of the video ?

  13 novembre 2022, par Naldo hwang

  ffmpeg.exe -r 10 -loop 1 -i 5197.jpg -i audio5197.wav -c:v libx264 -x264-params keyint=1:scenecut=0 -c:a aac -b:a 32k -pix_fmt yuvj420p -shortest out.mp4

  


  I'm trying to make a video with a picture and 7 hours of wav,There is always a few seconds less audio at the beginning of the video, and the sound becomes smaller.

  


  Thanks for reading and help.