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• ffmpeg Video Scan Progress during Frame Extarction

  5 avril 2013, par Isantipov

  I scan input video to extract certain frames using ffmpeg's select filter. The selection is based on a complex creteria and the number of extracted frames can't be predicted (I'm doing scene detection, but this can be something different - e.g. selecting all the I frames, etc).

  What I need is to display the percentage of scanned (decoded) video (e.g. 10% or 90%).

  ---

  I tried several ways to do this parsing console output as people usually do when dealing with encoding, but it doesn't help with the progress of scanning (e.g. Can ffmpeg show a progress bar ? or ffmpeg Progress Bar - Encoding Percentage in PHP)

  ffmpeg -progress sceneProgr.txt -i input.wmv -vsync passthrough -an -vf select='gt(scene\,0.2)',showinfo scene%%05d.png

  The output this produces is as follows :

  <..>    
  
  frame=    0 fps=0.0 q=0.0 size=N/A time=00:00:00.00 bitrate=N/A    
  
  n:0 pts:16550 pts_time:16.55 pos:4205325 fmt:rgb24 sar:0/1 s:640x480 i:P iskey:1 type:I checksum:95895BC9 plane_checksum:[95895BC9]
  
  frame=    1 fps=0.7 q=0.0 size=N/A time=00:00:00.00 bitrate=N/A    
  
  n:1 pts:24591 pts_time:24.591 pos:6685325 fmt:rgb24 sar:0/1 s:640x480 i:P iskey:0 type:P checksum:FF4CC015 plane_checksum:[FF4CC015]
  
  'frame=...' and 'n:...' lines are repeated for each of the extracted frames.

  Both frame=... and n:... lines refer to the numbers in the output and therefore can't be used to calculate progress the way people usually do this (as I can't predict how many frames will be found beforehead and besides, they are not uniformly spread across the input video).

  ---

  If I specify -progress progress.txt parameter, the progress.txt file is as follows :

  frame=5
  
  fps=1.2
  
  stream_0_0_q=0.0
  
  total_size=N/A
  
  out_time_ms=43209833
  
  out_time=00:00:43.209833
  
  dup_frames=0
  
  drop_frames=0
  
  progress=continue
  
  
  
  
  
  frame=6
  
  fps=1.3
  
  stream_0_0_q=0.0
  
  total_size=N/A
  
  out_time_ms=52252200
  
  out_time=00:00:52.252200
  
  dup_frames=0
  
  drop_frames=0
  
  progress=continue
  
  
  
  frame=6
  
  fps=1.2
  
  stream_0_0_q=0.0
  
  total_size=N/A
  
  out_time_ms=52252200
  
  out_time=00:00:52.252200
  
  dup_frames=0
  
  drop_frames=0
  
  progress=continue

  New portion is written approximately every second and refers to the last extracted frame.
  Which is somewhat helpful as out_time refers to the last extracted frames' position in the input video, so I can calculate the progress of the scan from it as

  progress = out_time_ms/total_input_time 

  But this is not ideal as it will be updated only when the new frame which matches the select criteria is extracted. So, If I have a large portion of video with no matching frames, the progress won't change for a lot of time.

  ---

  Wrapping-up :

  I am looking for a way to calculate the progress of video scanning when using select filter.

  Any ideas are strongly appreciated.

• ffmpeg : simple RTMP streaming

  2 avril 2013, par sajad

  I am trying to launch up a rtmp transcoder server using ffmpeg ; that receives udp MPEG-TS streams as input, transcodes it ; and generates an rtmp output to a URL, that can be accessed by users to receive and play the rtmp stream. All these are expected to be performed in a LAN and the output be accessed by all users.

  1) First I don't know where the URL should point to. Is it enought to specify the IP of the system and some optional port ? Is it neccessary that a program should be listening on that port ?

  2) How I can play the stream on the URL ?

  I use a linux ubuntu machine whith IP=10.1.1.229 and I want to transcode multicast stream on this URL : udp://@224.10.1.1:2001.

  here is the command used to transcode input stream and generate rtmp url "rtmp ://10.1.1.229:2020".

  ffmpeg -y -f mpegts -i "udp://@224.10.1.1:2001" -re -vcodec libx264 -maxrate 700k -r 25 -s 640x360 -deinterlace -acodec libfaac -ab 64k -ac 1 -ar 44100 -f flv "rtmp://10.1.1.229:2020"

  and here is the command by which I am trying to play rtmp stream :

  ffplay rtmp://10.1.1.229:2020

  Any guidance would be helpfull. Thank you.

• How to programatically generate video of a number or countdown

  27 novembre 2013, par xorsyst

  I've got some python that drives ffmpeg to convert some videos and do other processing. I'd like to prepend the videos with a couple of seconds of a number, and append a short countdown timer video.

  Each video could have different values for the numbers and length of countdown. Is there an easy programatic way to generate this sort of video ? I was thinking of perhaps coding some wxpython to generate the required stuff, but how to save that out as a video file or stream it to ffmpeg ?

  Ideas welcome - doesn't have to involve Python, external programs (Windows) are ok.