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• FFMPEG loop breaks all the time asking pessing Q

  18 juillet 2021, par Dentricky73

  I have a sh script using FFMPEG to take one picture from RTSP streams.
There is a timeout -stimeout to kill the connection if the connection takes too long.
(-timout is not possible). most IP list the -stimeout works without any problems.
But sometimes the script stops asking the user pressing -Q and the loop is broken until keypress Q.
I already tried adding -q in the code.
but this doesn't work at all.
any suggestions ?

  


  for IP in $IPS;          
do  

FFM="$(ffmpeg -y  -stimeout 8000000 -rtsp_transport tcp -ss 0.5  -i "rtsp://$IP:554/12" -vframes 1 -s 640x480 -f image2 images/$IP.jpg) >/dev/null"

done



  


  Error

  


  [rtsp @ 0000000000457c40] Could not find codec parameters for stream 0 (Video: h264, none, 640x352): unspecified pixel format
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
Guessed Channel Layout for Input Stream #0.1 : mono
Input #0, rtsp, from 'rtsp://123.456.789.101:554/12':
  Metadata:
    title           : 11
  Duration: N/A, start: 0.000000, bitrate: 64 kb/s
  Stream #0:0: Video: h264, none, 640x352, 90k tbr, 90k tbn, 180k tbc
  Stream #0:1: Audio: pcm_alaw, 8000 Hz, mono, s16, 64 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> mjpeg (native))
Press [q] to stop, [?] for help



  


  ignore the dev/null I got it wrong on purpose to see the output.

  


• ffmpeg timestamps on extracted frames wrong / extract frames a equal timestamps

  21 juillet 2021, par Sam

  I have a set of videos with different length, sizes, fps etc. and extract from each video exactly 60 frames as images, with timestamps put on each frame.

  


  For this purpose I divide each videos length by 60 and use fps=1/x to extract the frames at even seconds from the video.

  


  This works fine but the printed timestamps are slightly off.

  


  This is the code I use (part of a bash script).

  


  

  1. Compute intervals :

  


  


  output_frame_count=60
video_duration=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 -i file.mp4)
capture_distance=$(bc <<< "scale=0; ($video_duration / $output_frame_count)")


  


  

  2. Then run ffmpeg with the arguments

  


  


  ffmpeg -i file.mp4 -vf "fps=1/$capture_distance,scale=-1:$height,drawtext=fontfile=/usr/...: text='%{pts\:gmtime\:0\:%H\\\\\:%M\\\\\:%S}: x=(w-tw)/2: y=h-(2*lh): fontcolor=white: box=1: boxcolor=0x00000000@1" frames%04d.png


  


  I checked the images and all timestamps are wrong, compared to the original image from which they were extracted.

  


  Does anyone has a more reliable way to extract exactly 60 frames from a video with correct timestamps printed on them ?

  


• FFMPEG - concatenation of a dynamic number of files with different codecs

  15 septembre 2020, par timrodenbroeker

  I am trying to write a bash-script for FFMPEG that concatenates a dynamic number of video-files with different codecs.

  


  This is what i have right now : The script basically does the job and concatenates 3 videos.

  


  ffmpeg -i 1.mp4 -i 2.mp4 -i 3.mp4 \
    -filter_complex "[0:v] [0:a] [1:v] [1:a] [2:v] [2:a] concat=n=3:v=1:a=1 [v] [a]" \
    -map "[v]" -map "[a]" out.mp4


  


  But as mentioned i would like to write a script which can process a dynamic number of video-files.

  


  For this purpose i have created a text file that contains all the source-material.

  


  file './lib/intro.mp4'
file './temp/1.mp4'
file './temp/2.mp4'
file './temp/3.mp4'
file './lib/outro.mp4'


  


  I know that i can easily pass a text-file to the -i parameter. The problem is that it the -filter_complex-parameter is not dynamic. The number of files is fixed here.

  


  ffmpeg -i files.txt \
    -filter_complex "[0:v] [0:a] [1:v] [1:a] [2:v] [2:a] concat=n=3:v=1:a=1 [v] [a]" \ 
    -map "[v]" -map "[a]" out.mp4


  


  Is it possible to modify the script to concatenate a dynamic amount of video-files ?

  


  Thanks in advance !