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• How to combine a .MP4 video with a .WAV audio to create a new .MP4 video using ffmpeg from command line arguments ?

  18 mai 2017, par Ashish

  I want to merge a .WAV audio file with a .MP4 video file to create a new .MP4 video file.

  And i am currently using the following codes to do that :

  ffmpeg -i input_vid.mp4 -i input_audio.wav -vcodec copy -acodec copy output.mp4

  But it is only creating output.mp4 file but no videos embedded with that means if i am playing that output.mp4 file then nothing is playing.
  And i don’t know where i am doing wrong so that it is creating like this.

  I know this type of questions already asked by may persons but that didn’t help me much so if anybody can find where i am doing wrong or how to solve this problem please help me to solve my problem.

• How can I allow my users to combine audio and video tracks for downloading a youtube video ? [closed]

  1er décembre 2023, par Faizan Ahanger

  I have a website which, along a bunch a text, has a embedded youtube videos to play. I want to allow my users to also a be able to download those videos. There are too many videos there to store on my own server and I know that there are already website like y2mate.com and savefrom.net which do this.

  


  I used yt-dlp and using the --print-json parameter I can get the urls for downloading the files but the audio and video tracks are not combined for higher videos. Using ffmpeg seems to be the obvious solution but I don't understand where the videos should be combined. Should I download both needed tracks on my server and combine them before serving it to users ? This seems very inefficient as it take a lot of bandwidth for handling all download requests. There is also this library ffmpeg.wasm which according to them is "a pure WebAssembly / JavaScript port of FFmpeg enabling video & audio record, convert and stream right inside browsers !"

  


  This should work but it will require the users to download a 30MB webapp before they can download any video. This is also not very efficient, especially if they are downloading a video which is only a few MBs in size.

  


  Are these the only two options that I have or is there a better way to do this ?

  


• Convert mp4 video to avi video using imageio package

  3 février 2018, par Li.Chenyang

  I use the python imageio package to convert a .mp4 video to a .avi video, keeping the fps and size same. The following is my code :

  import imageio
  
  
  
  src_dir = "my/source/video.mp4"
  
  dst_dir = "my/dst/video.avi"
  
  
  
  reader = imageio.get_reader(src_dir)
  
  fps = reader.get_meta_data()['fps']
  
  writer = imageio.get_writer(dst_dir, fps=fps)
  
  
  
  for im in reader:
  
      writer.append_data(im[:, :, :])
  
  writer.close()

  I successfully make it.
  However, I find that the video.mp4 is 27.1 MB, while the video.avi is only 3.70 MB.
  Then I use cv2 to do the same thing :

  import cv2
  
  
  
  src_dir = "my/source/video.mp4"
  
  dst_dir = "my/dst/video_1.avi"
  
  
  
  video_cap = cv2.VideoCapture(src_dir)
  
  fps = video_cap.get(cv2.cv.CV_CAP_PROP_FPS)
  
  size = (int(video_cap.get(cv2.cv.CV_CAP_PROP_FRAME_WIDTH)),   
  
          int(video_cap.get(cv2.cv.CV_CAP_PROP_FRAME_HEIGHT)))  
  
  video_writer = cv2.VideoWriter(dst_dir, cv2.cv.CV_FOURCC('M', 'J', 'P', 'G'), fps, size) 
  
  
  
  success, frame = video_cap.read()
  
  while success:
  
      video_writer.write(frame)
  
      success, frame = video_cap.read()

  This time I get a video_1.avi, which is 65.6 MB.
  My questions :

  1. What is the different between these two method, why the video.avi (using imageio method) is so small ;
  2. Is there any problem to use the video.avi (using imageio method) to train a 3D-CNN instead of using video_1.avi (using cv2 method) ?

  ---

  supplement
  Here is the information of my video file :

  lichenyang@lichenyang-All-Series:~/chalearn2014/script$ file video.mp4
  
  video.mp4: ISO Media, MPEG v4 system, version 2
  
  lichenyang@lichenyang-All-Series:~/chalearn2014/script$ file video.avi
  
  video.avi: RIFF (little-endian) data, AVI, 640 x 480, 20.00 fps, video: H.264 X.264 or H.264
  
  lichenyang@lichenyang-All-Series:~/chalearn2014/script$ file video_1.avi
  
  video_1.avi: RIFF (little-endian) data, AVI, 640 x 480, 20.00 fps, video: Motion JPEG