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• Play video overlay over video not working in ffmpeg

  24 décembre 2017, par Sumit Marwha

  I am trying to play video over another video using ffmpeg. When i am trying to play video from starting then overlay video plays. But if i try to overlay video from n seconds it doesn’t work

  ffmpeg -i input.mp4 -i overlay.mp4
  
  -filter_complex [1:v]scale=920:920[out],[out][0]overlay=0:0:enable='between(t\,4\,8)'[out]
  
  -map [out] output.mp4

  If i change between(t\,4\,8) to between(t\,0\,4) then overlay video works normally. It is not working for between(t\,4\,8). Please help how to solve it

• Android MediaRecorder setCaptureRate() and video playback speed

  7 novembre 2013, par spitzanator

  I've got a MediaRecorder recording video, and I'm very confused by the effect of setCaptureRate().

  Specifically, I prepare my MediaRecorder as follows :

  mMediaRecorder = new MediaRecorder();
  
  mCamera.stopPreview();
  
  mCamera.unlock();
  
  mMediaRecorder.setCamera(mCamera);
  
  mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
  
  mMediaRecorder.setProfile(CamcorderProfile.QUALITY_TIME_LAPSE_480P);
  
  mMediaRecorder.setCaptureRate(30f);
  
  mMediaRecorder.setOrientationHint(270);
  
  mMediaRecorder.setOutputFile(...);
  
  mMediaRecorder.setPreviewDisplay(...);
  
  mMediaRecorder.prepare();

  I record for five seconds (with a CountDownTimer, but that's irrelevant), and this is the file that gets generated :

  $ ffmpeg -i ~/CaptureRate30fps.mp4 
  
  ...
  
  Seems stream 0 codec frame rate differs from container frame rate: 180000.00 (180000/1) -> 30.00 (30/1)
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/mspitz/CaptureRate30fps.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 0
  
      compatible_brands: isom3gp4
  
      creation_time   : 2013-06-04 00:52:00
  
    Duration: 00:00:02.59, start: 0.000000, bitrate: 5238 kb/s
  
      Stream #0.0(eng): Video: h264 (Baseline), yuv420p, 720x480, 5235 kb/s, PAR 65536:65536 DAR 3:2, 30 fps, 30 tbr, 90k tbn, 180k tbc
  
      Metadata:
  
        creation_time   : 2013-06-04 00:52:00

  Note that the Duration is just about 3 seconds. The video also plays much faster, as if it were 5 seconds of video crammed into 3.

  Now, if I record by preparing my mediaRecorder exactly as above, but subtracting the setCaptureRate(30f) line, I get a file like this :

  $ ffmpeg -i ~/NoSetCaptureRate.mp4 
  
  ...
  
  Seems stream 0 codec frame rate differs from container frame rate: 180000.00 (180000/1) -> 90000.00 (180000/2)
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/mspitz/NoSetCaptureRate.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 0
  
      compatible_brands: isom3gp4
  
      creation_time   : 2013-06-04 00:50:41
  
    Duration: 00:00:04.87, start: 0.000000, bitrate: 2803 kb/s
  
      Stream #0.0(eng): Video: h264 (Baseline), yuv420p, 720x480, 2801 kb/s, PAR 65536:65536 DAR 3:2, 16.01 fps, 90k tbr, 90k tbn, 180k tbc
  
      Metadata:
  
        creation_time   : 2013-06-04 00:50:41

  Note that the Duration is as expected, about 5 seconds. The video also plays at a normal speed.

  I'm using setCaptureRate(30f) because 30 frames per second is the value of my CamcorderProfile's videoFrameRate. On my Galaxy Nexus S2 (4.2.1), omitting setCaptureRate() is fine, but when I tested on a Galaxy Nexus S3 (4.1.1), omitting setCaptureRate() results in the ever-helpful "start failed -22" error when I called mMediaRecorder.start().

  So, what am I missing ? I thought that the capture rate and the video frame rate were independent, but it's clear that they're not. Is there a way to determine programmatically what I need to set the capture rate at in order to determine that my video plays back at 1x speed ?

• Split Video Files and Make them individually playable

  21 juillet 2013, par rash

  I am newbie to this python. I split webm video file into chunks, but i couldn't able to make them individually playable using python program.But it plays after I join the chunks to a single file. I know its due to the absence of header file. Please help me with the codes to attach the header file to the parts to make them indiviually playable. Please reply. Thanks alot in advance.

  Here is the code :

  Client side :

  import socket, os
  
  import time
  
  
  
  client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  
  client_socket.connect(("localhost", 5005))
  
  size = 1024
  
  
  
  while True:
  
      fname = "/home/xincoz/test/conn2.webm"
  
      fn = client_socket.recv(1024)
  
      print fn
  
  
  
      fp = open(fname,'wb')
  
      while True:
  
          strng = client_socket.recv(int(fn))
  
          print strng
  
          if not strng:
  
              break
  
          fp.write(strng)
  
      fp.close()
  
  
  
      print "Data Received successfully"
  
      exit()

  Server side :

  import os,kaa.metadata  
  
  import sys,time 
  
  import socket
  
  import Image
  
  
  
  server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  
  server_socket.bind(("localhost", 5005))
  
  server_socket.listen(5)
  
  
  
  client_socket, address = server_socket.accept()
  
  print "Conencted to - ",address,"\n"
  
  
  
  file = '/home/xincoz/Downloads/connect.webm'
  
  a = kaa.metadata.parse(file)
  
  
  
  print '\n Maybe, pending work'
  
  file_name = open(file,'rb')
  
  size=str(os.path.getsize(file))
  
  print size
  
  client_socket.send(str(os.path.getsize(file)))
  
  print file_name
  
  strng = file_name.read(os.path.getsize(file))
  
  client_socket.send(strng[0:2000000])
  
  file_name.close()
  
  
  
  print str(a)+"Meta Data"
  
  print "Data sent successfully"