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• Can ffmpeg extract multiple parts of a video file in a single command ?

  18 décembre 2020, par rcliao

  I have some huge MPEG files that is 24 hours long, and I need to extract a few parts (about 30 minutes each) of it into frame sequences (still images). I tried using commands like following :

  


  ffmpeg -i input.mpeg -ss 4:00:00 -to 4:30:00 outpath1\%05d.png
ffmpeg -i input.mpeg -ss 6:00:00 -to 6:30:00 outpath2\%05d.png
...


  


  But it seems that each time it is executed, ffmpeg scans the file from the beginning, causing the process to be very slow.

  


  For example, when I execute the above commands to extract the part of 4:00:00-4:30:00, ffmpeg will scan from 0:00:00 to 4:00:00, start extracting the image sequence, and stop at 4:30:00 ; and then I execute another command to extract the part of 6:00:00-6:30:00, and ffmpeg scans from 0:00:00 again to 6:00:00, and then start extracting.

  


  So I wanted to simplify this process to save time. Is there a way to extract multiple parts in a single command ? Like scans from 0:00:00 to 4:00:00, start extracting to 4:30:00, stop extracting and continue scanning to 6:00:00, and start extracting again...until the last part. Can ffmpeg do this ?

  


• Issues with FFmpeg Recording RTSP Stream with HEVC Codec : Blurred Bottom of Video

  31 août 2024, par user2877989

  I'm using FFmpeg to capture an RTSP stream from an IMOU camera, and I'm encountering an issue with the recorded video. The output video is encoded using the HEVC codec, but the bottom part of the video appears blurred while the top part displays correctly.

  


  Here is the command I'm using :

  


  ffmpeg -i "rtsp://admin:xxxxx@192.168.1.32:554/cam/realmonitor?channel=1&subtype=0&unicast=true&proto=Onvif" -c copy -f segment -segment_time 5 -reset_timestamps 1 -strftime 1 "./%Y_%m_%d_%H_%M_%S.mp4"


  


  Details :

  


  

  • FFmpeg Version : [Include your FFmpeg version here] Camera Model : IMOU
[Include model if known] Codec Used : HEVC (libx265) Issue : The output
video has a blurred bottom section, while the top part looks fine.

  


  


  Things I've Tried :

  


  

  • Re-encoding the video with -c:v hevc instead of -c copy.

  


  • Adding -bsf:v hevc_mp4toannexb to the command.

  


  


  None of these solutions have resolved the issue.

  


  Questions :

  


  What could be causing the bottom part of the video to appear blurred ?
Are there any additional FFmpeg options or settings that might help resolve this issue ?
Is there a better approach or command for handling RTSP streams with HEVC encoding to avoid this problem ?
Any advice or suggestions would be greatly appreciated !

  


  Thank you !

  


  

  


• OSError : MoviePy error : failed to read the first frame of video file

  1er août 2023, par Steve

  I am trying to extract and save a frame from an .mp4 using moviepy like so (simplified) :

  


  from moviepy.editor import *
clip = VideoFileClip('conditiontest1.mpg')
clip.save_frame('frame1.png', 20)


  


  When I run this I get :

  


  


  Traceback (most recent call last) :
  
File"C :\Users\boss\Documents\DVDFab\Video Enhancer AI\join.py", line 23, > in 
clip = VideoFileClip(d + f + '.mp4')
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  
File "C :\Python311\Lib\site-packages\moviepy\video\io\VideoFileClip.py", > line 88, in init_
self.reader = FFMPEG_VideoReader(filename, pix_fmt=pix_fmt,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  
File "C :\Python311\Lib\site-packages\moviepy\video\io\ffmpeg_reader.py", > line 73, in init_
self.lastread = self.read_frame()
^^^^^^^^^^^^^^^^^
  
File "C :\Python311\Lib\site-packages\moviepy\video\io\ffmpeg_reader.py", > line 133, in read_frame
raise IOError(("MoviePy error : failed to read the first frame of "
OSError : MoviePy error : failed to read the first frame of video file > conditiontest1.mp4. That might mean that the file is corrupted. That may also mean that you are using a deprecated version of FFMPEG. On Ubuntu/Debian for instance the version in the repos is deprecated. Please update to a recent version from the website.

  


  


  Quite a few people have reported this error. The file is not corrupted, at least it plays fine in VLC. I have the latest FFMPEG. I have tried the other recommended fix, i.e. giving the full path. No help.

  


  One interesting thing is that this only seems to happen to me when I'm processing clips I've produced with moviepy, as in :

  


  from moviepy.editor import *
clip = VideoFileClip('conditiontest.mpg4')
clip1 = clip.subclip(10,60)
clip1.write_videofile('conditiontest1.mpg4',codec='libx264')


  


  That runs fine. Anyone have ideas how I can fix this ?