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• Concatenate chunk containg headers to another chunk in h264

  18 novembre 2014, par Ortixx

  I’m trying to extract thumbnails from a torrent stream by downloading the first couple of chunks to get the headers, another set of chunks from the middle and then concat them to have a single video file.

  For this I’m using nodejs but I’m having trouble with the concatenation part. Obviously the headers include the length of the video so if I simply concat another chunk to the end of the headers chunk, it won’t work.

  In other words, I have 2 chunks of a video file : The first one contains the headers and some material and the other one is fully composed of a video stream. I want to combine the two to form a single video file
  So my question is how can I make this work properly if at all ?

• Add an image behind a video file (.mp4) in python

  12 avril 2020, par George Lua

  I am attempting to add an image behind a video using moviepy and cannot come up with any way to do it. My image dimension is (1080 x 720) and my video dimension is (200 x 200). I am trying to put the video file on top of the image file, place it in the midlle and export the final video with the dimensions of the image. This is a visual representation of what I am trying to achieve :

  



  View image

  



  I tried doing this with the following code, but could not manage to get it to work. Any help is seriously appreciated :)

  



  import moviepy
import moviepy.editor as mp

video = mp.VideoFileClip("/media/pi/vid.mp4")

logo = (mp.ImageClip("/media/pi/pic.png"))

# Preferably I would want the image to be the same duration as the video file. 
# The following was just for testing.
final = mp.CompositeVideoClip([video, logo.set_duration(3)])
final.write_videofile("test.mp4")


  


• Got two working ffmpeg commands, help me transform them

  7 mars 2019, par lukistar

  here are two different commands.

  ffmpeg -i input.mp3 -i second.mp3 -filter_complex "[0:a]atrim=end=10,asetpts=N/SR/TB[begin];[0:a]atrim=start=10,asetpts=N/SR/TB[end];[begin][1:a][end]concat=n=3:v=0:a=1[a]" -map "[a]" output

  This command inserts second.mp3 into input.mp3. It seems to always keep the parameters of input.mp3. It inserts it in exact 10 seconds of input.mp3.

  Here is the second command :

  ffmpeg -i input.mp3 -i second.mp3 -filter_complex "[1:a]adelay=10000|10000[1a];[0:a][1a]amix=duration:first" output

  This command is closer to my final goal. It plays input.mp3 and in exact 10 seconds it plays along second.mp3 without stopping input.mp3’s sound.

  My final goal is to create final.mp3.

  Its duration must always equal input.mp3 duration. It must keep the samplerate, the count of channels, etc of input.mp3

  When playing final.mp3, it must play the whole input.mp3.
  But each 10-15 seconds, it must play second.mp3 without stopping input.mp3.
  It could be said that I must use "Second command" but in a loop.
  It would be great if there is one-line command for that in ffmpeg.
  I am working with flac, mp3 and wav and both of the commands, I got, work great for what they are doing.

  For example :

  input.mp3 could be 40 seconds long.

  second.mp3 could be 2 seconds long.

  When I play final.mp3 it will be 40 seconds long, but each 10-15 seconds(on random) it will play second.mp3 at the same time as input.mp3.

  Sadly I have no experience with ffmpeg, both of the commands I got are answers to questions here in stackoverflow. Hope somebody can help me. Thank you !