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• More precision from ffmpeg silencedetect

  13 novembre 2022, par nerfherder616

  I am trying to split a very large (70 hours) mp3 file into smaller files. My first step is the get the timestamps using the silencedetect command in ffmpeg. It works fine for the first few timestamps, but unfortunately, the results are rounded to six significant digits.

  


  The code I am executing is :

  


  ffmpeg -i input.mp3 -af silencedetect=d=3 -hide_banner -nostats -f null -


  


  My results are :

  


  Input #0, mp3, from 'input.mp3':
  Duration: 70:46:05.32, start: 0.050113, bitrate: 64 kb/s
    Stream #0:0: Audio: mp3, 22050 Hz, stereo, fltp, 64 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (mp3 (mp3float) -> pcm_s16le (native))
Press [q] to stop, [?] for help
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf58.29.100
    Stream #0:0: Audio: pcm_s16le, 22050 Hz, stereo, s16, 705 kb/s
    Metadata:
      encoder         : Lavc58.54.100 pcm_s16le
[silencedetect @ 0x5590d08bd700] silence_start: 10.6895
[silencedetect @ 0x5590d08bd700] silence_end: 15.0054 | silence_duration: 4.31587
[silencedetect @ 0x5590d08bd700] silence_start: 446.958
[silencedetect @ 0x5590d08bd700] silence_end: 450.959 | silence_duration: 4.00168
[silencedetect @ 0x5590d08bd700] silence_start: 1168.17
[silencedetect @ 0x5590d08bd700] silence_end: 1172.17 | silence_duration: 4.00694
[silencedetect @ 0x5590d08bd700] silence_start: 1880.8
[silencedetect @ 0x5590d08bd700] silence_end: 1884.8 | silence_duration: 3.99265

...

[silencedetect @ 0x5590d08bd700] silence_start: 123108
[silencedetect @ 0x5590d08bd700] silence_end: 123111 | silence_duration: 3.61946
[silencedetect @ 0x5590d08bd700] silence_start: 123286
[silencedetect @ 0x5590d08bd700] silence_end: 123290 | silence_duration: 4.01646
[silencedetect @ 0x5590d08bd700] silence_start: 124229
[silencedetect @ 0x5590d08bd700] silence_end: 124233 | silence_duration: 4.01846
[silencedetect @ 0x5590d08bd700] silence_start: 124442
[silencedetect @ 0x5590d08bd700] silence_end: 124446 | silence_duration: 4.0298

...


  


  Rounding to the nearest second is not sufficient for my purposes. Ideally, I would like each timestamp to be accurate to the hundredth of a second or something similar. Does anybody know a way to achieve this ?

  


• FFMpeg overlay moving in steps instead of continous motion

  8 septembre 2017, par techr

  I had to repost this question, since I couldn’t add the console output in comment. The original post can be found here
  and the video can be found here.

  ffmpeg -y -stream_loop -1 -i b.mpg -i bg.jpg -filter_complex "
  
  [0:v]scale=320:240[vid];[1][vid]overlay=x='(180+(30-180)*(t-
  
  0)/60)*between(t,0,60)+(30+(290-30)*(t-60)/60)*between(t,60,120)':y='(120+
  
  (120-120)*(t-0)/60)*between(t,0,60)+(120+(30-120)*(t-
  
  60)/60)*between(t,60,120)'[out]" -map "[out]" -r 29.97 -aspect 4:3 -b:v 
  
  4000k -minrate 4000k -maxrate 4000k -bufsize 2000k -t 64 t.mpg
  
   Input #0, mpegvideo, from 'b.mpg':
  
  Duration: 00:00:32.34, bitrate: 4000 kb/s
  
  Stream #0:0: Video: mpeg2video (Main), yuv420p(tv, progressive), 720x480 
  
  [SAR 32:27 DAR 16:9], 4000 kb/s, 29.97 fps, 29.97 tbr, 1200k tbn, 59.94 tbc
  
  Input #1, image2, from 'bg.jpg':
  
  Duration: 00:00:00.04, start: 0.000000, bitrate: 19637 kb/s
  
  Stream #1:0: Video: mjpeg, yuvj444p(pc, bt470bg/unknown/unknown), 640x480, 
  
  25 tbr, 25 tbn, 25 tbc
  
  Stream mapping:
  
  Stream #0:0 (mpeg2video) -> scale
  
  Stream #1:0 (mjpeg) -> overlay:main
  
  overlay -> Stream #0:0 (mpeg1video)
  
  Press [q] to stop, [?] for help
  
  [swscaler @ 0000000002adc740] deprecated pixel format used, make sure you 
  
  did set range correctly
  
  Output #0, mpeg, to 't.mpg':
  
  Metadata:
  
  encoder         : Lavf57.73.100
  
  Stream #0:0: Video: mpeg1video, yuv420p, 640x480 [SAR 1:1 DAR 4:3], q=2-31, 
  
  4000 kb/s, 29.97 fps, 90k tbn, 29.97 tbc (default)
  
  Metadata:
  
    encoder         : Lavc57.99.100 mpeg1video
  
  Side data:
  
    cpb: bitrate max/min/avg: 4000000/4000000/4000000 buffer size: 2000000 
  
  vbv_delay: -1
  
  warning, clipping 1 dct coefficients to -255..255repeated 2 timesnter

• Pipe ffmpeg output to named pipe

  9 novembre 2016, par user3657114

  I’m trying to get ffmpegs output to a named pipe, where I could read from another shell. I do not need the video stream piped, just the informations below to get a state of the conversion process back. I am not able to achieve the piping behavior in any way, but I can write the data to a file with the following command :

  ffmpeg -i vid.mov -vcodec h264 -acodec aac -strict -2 -y vid.mp4 > fflog.txt 2>&1

  This leads to the following output in fflog.txt

  Stream mapping:
  
  Stream #0:1 -> #0:0 (h264 (native) -> h264 (libx264))
  
  Stream #0:0 -> #0:1 (aac (native) -> aac (native))
  
  Press [q] to stop, [?] for help
  
  frame=   50 fps=0.0 q=0.0 size=       0kB time=00:00:03.20 bitrate=   0.1kbits/s
  
  frame=   73 fps= 70 q=28.0 size=     230kB time=00:00:04.05 bitrate= 465.4kbits/s
  
  frame=  100 fps= 65 q=28.0 size=     462kB time=00:00:05.44 bitrate= 695.3kbits/s

  Afterwards I can get lines via

  tail -f -1 fflog.txt

  out of the file. But the lines are not escaped correctly, I think. Vi shows me the following :

  frame=   50 fps=0.0 q=0.0 size=       0kB time=00:00:03.20 bitrate=   0.1kbits/s
  
  ^Mframe=   73 fps= 70 q=28.0 size=     230kB time=00:00:04.05 bitrate= 465.4kbits/s
  
  ^Mframe=  100 fps= 65 q=28.0 size=     462kB time=00:00:05.44 bitrate= 695.3kbits/s
  
  ^Mframe=  125 fps= 61 q=28.0 size=     608kB time=00:00:06.48 bitrate= 767.5kbits/s

  So the questions are :

  1. How to convert the CRLF to UNIX like LF to return data correctly via tail -n ?
  2. Or even better : How to pipe the ffmpeg results correctly to a mkfifo named pipe ?
  3. Or the most general : Is there a different way to achieve my goal in a more clever manner ?