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• Compression rate (final size) ffmpeg with h263 as codec, can be improved ?

  29 août 2013, par voskyc

  With the following data :

  Sample 1 :
  vcodec : H263
  Duration : 4seconds
  Resolution:1288/720
  FR : 30fps/s
  datarate : 195.135 kB/s
  MP3 : 44HZ, 16bits

  ---

  Size file : 5.84MB.

  Sample 2 :
  vcodec : H263
  Duration : 4seconds
  Resolution:640/480
  FR : 30fps/s
  datarate : 195.135 kB/s
  MP3 : 44HZ, 16bits

  ---

  Size file = 3.34MB.

  Both in flv container.

  Aren't those sizes a little bit high for 4 second video ?

  I believe we are doing some kind of error or missing an optimization.
  Should we decrease the datarate ?
  Maybe we are missing some option for h263 encoding with FFMPEG ?.

  Thanks a lot in advance for your suggestions.

  Note : no, we "can not" use h264. :-)

• MoviePy : Concatenating video clips causes weird glitches in final video

  16 mai 2022, par JohnSmithy1266

  Is there a way to successfully always patch up any clips together in such a way that prevents weird glitches ? I put together a .mp4 from smaller .mp4 files and I got a final video with weird glitches. I am running Python 3.6.1 on Windows 10 through Sublime Text 3. I used MoviePy to do the concatenation.

  



  The code :

  



  from moviepy.editor import VideoFileClip, concatenate_videoclips
import os.path

path = "C:/Users/blah/videos/out/"

cliparray = []

for filename in os.listdir(path):
    cliparray.append(VideoFileClip(path + filename))

final_clip = concatenate_videoclips(cliparray)

final_clip.write_videofile(path + "concatenatedvideo.mp4", codec = "libx264")


  



  The weird glitches :

  



  

  1. One of the clips turns into a 3x3 grid of smaller clips.

  


  2. Another has the audio not lined up with the video

  


  3. Another is sped up faster than what was normal.

  


  


• FFMPEG command works on terminal but not with Java/Kotlin

  11 septembre 2019, par Antony

  I’m trying to use an FFMPEG command for concatenating different videos. The command is

  ffmpeg -i video.mp4 -i video-2.mp4 -filter_complex "[0:v:0] [0:a:0] [1:v:0] [1:a:0] concat=n=2:v=1:a=1 [v] [a]" -map "[v]" -map "[a]" output.mp4

  This command works good when I run on Windows PowerShell. But when I try to run with Kotlin code it doesn’t work.

  val firstVideo = "D:\\Videos\\ffmpeg\\video.mp4"
  
  val secondVideo = "D:\\Videos\\ffmpeg\\video-2.mp4"
  
  val resultPath = "D:\\Videos\\ffmpeg\\result-2.mp4"
  
  
  
  val cmd = "ffmpeg -i $firstVideo -i $secondVideo -filter_complex \"[0:v:0] [0:a:0] [1:v:0] [1:a:0] concat=n=2:v=1:a=1 [v] [a]\" -map \"[v]\" -map \"[a]\" $resultPath"
  
  .split(" ").toTypedArray()
  
  
  
  Runtime.getRuntime().exec(cmd)

  I’m not taking any error messages since I’m using FFMPEG cli.

  Also, this piece of Kotlin works perfect when I’m trying to run other FFMPEG operations.