Recherche avancée

Sur d’autres sites (3370)

• FFMpeg - how to encode a F4M manifest file to mp4

  20 novembre 2015, par Roee

  I’m working on a project, where we want to encode flash videos to mp4 (for example, we want to encode a f4v file), and live-stream them (which means we can’t just download all the f4f files, then encode them to a single mp4 and just then stream it. The encoding and streaming has to be done while downloading the files).

  If the format of the flash video is flv for example, FFMpeg can do what I’ve described without any problem. I just give the address of the flv file to FFMpeg, and it encodes and streams it as mp4.

  But, if the format of the flash video is something more complicated as f4v (which gets downloaded as many f4f files), I don’t have a single url to give to FFMpeg as input - I have many addresses of f4f files. I don’t even know how many f4f files the video has before playing it - it looks like the flash player just fetches the next f4f file when needed.

  I read online that there is a manifest file (its extension is f4m), that "describes" to the flash player which f4f files it should download and play, and what’s their playing-order and everything.

  My question is - if I have the url of this f4m file, what should I do in order to encode all its f4f files to mp4 ?
  I’ve tried to give to FFMpeg just the f4m file as input, but it doesn’t know what to do with it...

  I’ll really appreciate any response that might help, as I’ve been working on this issue for few days now and I still haven’t found any answer...

  Thanks,
  Roee.

• Detect scene change on part of the frame

  16 juin 2021, par user18130814200115

  I have a video file of an online lecture cosisting of a slideshow with audio in the background.
  
I want to save images of each slide as well as the timestamp of that slide.
I do this using the scene and metadata filters :

  


  ffmpeg -i week-01.mp4 -filter_complex "select='gt(scene,0.011)',metadata=print:file=frames/time.txt" -vsync vfr frames/img%03d.jpg


  


  This works fine exept for one thing, there is a timer onscreen on the right in the video file.
If i set the thershold small enough to pick up all the slide changes, it also picks up the timer changes.

  


  So here is my question, Can I ask ffmpeg to :

  


  

  1. analize part of the frame (only the right side till roughly 75% to the left).

  


  2. Then, on detecting a scene change in this area, save the entire frame and the timestamp.

  


  


  I though of making a script that

  


  

  1. crops the video and saves it alongside the origional

  


  2. analize the cropped video for scene changes and save the timestamps

  


  3. extract the frames from the origional video using the timestamps

  


  


  Is there a better/faster/shorter way to do this ?
Thanks in advance !

  


• Importing PIL images into FFMPY/FFMPEG to save as GIF/video

  24 mai 2023, par Tricky Devil

  I would like to know how I can transfer PIL images to FFMPY to save it as video, or gif, since the PIL library's quantization method has strong quality losses in certain cases. I first do some modifications with PIL, and then want to export and save the result.

  


  I did not find any information on the topic online, beside one post with PIL to FFMPEG :
Pipe PIL images to ffmpeg stdin - Python
How could I implement something similar in FFMPY ?

  


  If I have for example this setup to begin with :

  


  import ffmpy
import PIL
from PIL import Image as Img

images = [Img.open('frame 1.png'),Img.open('frame 2.png')]#How do I convert them to FFMPEG?

#Here I modify the images using PIL

#Save with FFMPEG:
ff = ffmpy.FFmpeg(
    inputs={images ?: None},#How do I insert PIL images here?
    outputs={'output.gif': None},
    executable='ffmpeg\\bin\\ffmpeg.exe')
ff.run()


  


  How would I proceed to convert and save the images as a video using FFMPY ?
Is it possible by adding some steps inbetween ? I wouldn't want to have to save all PIL images first as images, and then import them and save them with FFMPY a second time, since that would be very time consuming with larger files.