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• setting a correct ffmpeg GOP (group of pictures) [closed]

  9 mai 2013, par Robert Cantarutti

  I'm using ffmpeg to ser the GOP (Group of pictures) with mpeg4.
  I had success to set a GOP of :
   12,2 (12 frames between two I frames, and 2 frames between each P frames)
   15,2
   18,2
   30,2
  And I had not success in this cases :
   8,2
   4,2

  1- Example to set a GOP of 12,2 :
  ffmpeg -s cif -r 30 -i video.yuv -vcodec mpeg4 -g 12 -bf 2 -sameq video.m4v

  2-Example to set a GOP of 8,2 :
  ffmpeg -s cif -r 30 -i video.yuv -vcodec mpeg4 -g 8 -bf 2 -sameq video.m4v

  1. The result of (1) - ok :

  $ head trace
  ...
  11 H 20313 14 0.43
  12 B 10752 8 0.43
  13 B 10718 8 0.43
  14 P 12643 9 0.529
  15 B 11338 8 0.529
  16 B 11136 8 0.529
  17 P 12999 9 0.634
  18 B 10666 8 0.634
  19 B 11000 8 0.634
  20 P 12530 9 0.727
  21 B 10345 8 0.727
  22 B 10887 8 0.727
  23 H 20300 14 0.825
  24 B 11258 8 0.825
  25 B 10759 8 0.826
  26 P 12482 9 0.925
  27 B 10871 8 0.925
  28 B 11249 8 0.925
  29 P 13229 10 1.024
  30 B 11003 8 1.024
  31 B 10904 8 1.024
  32 P 12788 9 1.123
  33 B 11063 8 1.123
  34 B 11365 8 1.123
  35 H 20253 14 1.234

  1. The result of (2) - nok :

  ...
  8 H 19824 14 0.33
  9 B 11238 8 0.331
  10 B 11566 8 0.331
  11 P 13314 10 0.929
  12 B 11117 8 0.929
  13 B 11152 8 0.929
  14 H 19683 14 0.929
  15 B 11002 8 0.93
  16 B 10827 8 0.93
  17 P 13240 10 0.93
  18 B 11060 8 0.93
  19 B 11220 8 0.93
  20 H 19942 14 0.93
  21 B 10353 8 2.283
  22 B 10897 8 2.283
  23 P 13386 10 2.283
  24 B 11433 8 2.283
  25 B 10945 8 2.283
  26 H 19623 14 2.284
  27 B 10630 8 2.284
  28 B 11247 8 2.284
  29 P 13430 10 2.284
  30 B 11294 8 2.284
  31 B 10954 8 2.284
  32 H 19654 14 2.351
  33 B 10989 8 2.352
  34 B 11127 8 2.352
  35 P 13630 10 2.352
  36 B 11121 8 2.352
  37 B 11640 8 2.352
  38 H 19691 14 2.352
  39 B 11426 8 2.353
  40 B 11294 8 2.353
  41 P 12675 9 2.353
  42 B 11705 9 2.353
  43 B 11333 8 2.399
  44 H 19659 14 2.399

  Note : "I" frames is same as "H" above.

  First :
  1-Itś possible to have a GOP 8,2 and 4,2 ?
  2-How they are ? Ex. : I,B,B,P,B,B,P,B,I ? I,B,B,P,B,I ?

• ffmpeg batch convert and automator on mac - automator won't complete script

  24 février 2021, par Penarth Sounds

  Please forgive me for my lack of knowledge, i've written a short shell script for the mac in order to convert files in a folder using ffmpeg. it outputs them after conversion to a different folder, and puts the original in another folder. it all works fine in Terminal :

  


  This is the code :
&#xA;1 #! /bin/bash&#xA;2 srcExt=$1&#xA;3 destExt=$2&#xA;4&#xA;5 srcDir=$3&#xA;6 destDir=$4&#xA;7&#xA;8 opts=$5&#xA;9&#xA;10&#xA;11 for filename in "$srcDir"/<em>.$srcExt; do&#xA;12&#xA;13        basePath=${filename%.</em>}&#xA;14        baseName=${basePath##*/}&#xA;15&#xA;16        ffmpeg -i "$filename" -af loudnorm=I=-16:TP=-1.5:LRA=11 -ar 48000 -c:a libmp3lame -b:a 192k "$destDir"/"$baseName"."$destExt";&#xA;17 mv "$filename" /Users/Documents/ps_source/&#xA;18 done

  


  And this is how i run it :
./ffmpeg-ps.sh wav mp3 /Users/Documents/ps_toconvert/ /Users/Documents/ps_toconvert/ps_converted/

  


  I'm trying to use Automator to automatically run this script when a file drops into a folder. It does that ok, and sends the original to the ps_source folder, but it doesn't do the conversion or output a file to the ps_converted folder.

  


  Can anyone tell me what i'm doing wrong ? Banging my head against a wall here.

  


  Thanks heaps.

  


• How do you set up carrierwave-video with ffmpeg ?

  24 septembre 2013, par Maleckai

  This has been doing my head in for the past 2 days, and I just cannot seem to get it working.

  I am building a simple Rails app with the sole purpose of uploading & processing images and videos. I'm working on Ubuntu Linux.

  Here's the relevant gems in my Gemfile :

  gem 'delayed_job_active_record'
  
  gem 'carrierwave'
  
  gem 'carrierwave-video'
  
  gem 'carrierwave_backgrounder'
  
  gem 'mini_magick'
  
  gem 'streamio-ffmpeg'

  At first I was having problems with ffmpeg complaining about certain arguments (I determined this by taking the command the rails app attempted to run when it was to convert a video, and running it manually outside rails), which I discovered was because the version of ffmpeg I was using was 'too new'. So I downgraded to 1.2.1, which is what streamio-ffmpeg says is the only version of ffmpeg they're tested against.

  After that, I could run the command manually, fine. But whenever I tried to convert through the app, I'd get the error :

  Failed to transcode with FFmpeg. Check ffmpeg install and verify video is not corrupt or cut short. Original error: nil is not a symbol

  I did a bit of Googling on the error, and only came up with one relevant result, but nothing in there has helped my situation.

  I'm at a total loss at this point, and am not sure where I can go from here. I assume many of people have tried this before, so I'm hoping someone can guide me on the exact steps they took to get carrierwave-video & ffmpeg working together.