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• NodeJS - Looking for faster ways to create FFMPEG thumbnails

  18 mars 2016, par RunningFromShia

  I am using fluent-ffmpeg and ffmpeg in node :

  var ffmpeg = require('fluent-ffmpeg');
  
  var src = "http://upload.wikimedia.org/wikipedia/commons/7/79/Big_Buck_Bunny_small.ogv";
  
  ffmpeg(src)
  
  .on('filenames', function(filenames) {
  
      console.log('Will generate ' + filenames.join(', ') + ' into tempfiles.')
  
  })
  
  .on('end', function() {
  
      console.log('1 Screenshot successfully taken');
  
  
  
  })
  
  .on('error', function(err, stdout, stderr) {
  
  console.log("ffmpeg stdout:\n" + stdout);
  
  console.log("ffmpeg stderr:\n" + stderr);
  
  })
  
  .screenshots({
  
      filename: randomResult,
  
      timemarks: [520.929831],
  
      folder: '/'
  
  });

  Usually, it takes 2-3 seconds to take one thumbnail.
  I need it to be 0.5-1 seconds for real-time development. I mean, what is the problem here - downloading a single png file on my computer takes way below 2-3 seconds to complete, why is ffmpeg lagging so much ? something just doesn’t seem right.

• FFmpeg error : ratecontrol_init : can't open stats file

  18 décembre 2015, par oldo.nicho

  I’ve setup an AWS EC2 instance running Ubuntu 14.04 and have installed FFmpeg so that I can compress and transcode video.

  I’m trying to do a two pass conversion with the following code :

  ffmpeg -i input-file.avi -codec:v libx264 -profile:v high -preset slow -b:v 500k -maxrate 500k -bufsize 1000k -vf scale=702:-1 -threads 0 -pass 1 -an -f mp4 ~/encoded/null

  and second pass :

  ffmpeg -i input-file.avi -codec:v libx264 -profile:v high -preset slow -b:v 500k -maxrate 500k -bufsize 1000k -vf scale=702:-1 -threads 0 -pass 2 -codec:a libfdk_aac -b:a 128k -f mp4 output-file.mp4

  However I get the following error :

  ffmpeg version N-77283-g91c2a33 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04)
  
    configuration: --prefix=/home/ubuntu/ffmpeg_build --pkg-config-flags=--static --extra-cflags=-I/home/ubuntu/ffmpeg_build/include --extra-ldflags=-L/home/ubuntu/ffmpeg_build/lib --bindir=/home/ubuntu/bin --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libx264 --enable-nonfree
  
    libavutil      55. 11.100 / 55. 11.100
  
    libavcodec     57. 17.100 / 57. 17.100
  
    libavformat    57. 20.100 / 57. 20.100
  
    libavdevice    57.  0.100 / 57.  0.100
  
    libavfilter     6. 21.100 /  6. 21.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.101 /  2.  0.101
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Input #0, avi, from 'input-file.avi':
  
    Duration: 01:18:05.29, start: 0.000000, bitrate: 2025 kb/s
  
      Stream #0:0: Video: mpeg4 (Simple Profile) (XVID / 0x44495658), yuv420p, 720x480 [SAR 1:1 DAR 3:2], 1789 kb/s, 29.97 fps, 29.97 tbr, 29.97 tbn, 29.97 tbc
  
      Stream #0:1: Audio: ac3 ([0] [0][0] / 0x2000), 48000 Hz, stereo, fltp, 224 kb/s
  
  [libx264 @ 0x1e04240] using SAR=1/1
  
  [libx264 @ 0x1e04240] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX AVX2 FMA3 LZCNT BMI2
  
  [libx264 @ 0x1e04240] ratecontrol_init: can't open stats file
  
  Output #0, mp4, to '/home/ubuntu/encoded/null':
  
      Stream #0:0: Video: h264, none, q=2-31, 128 kb/s, SAR 1:1 DAR 0:0, 29.97 fps
  
      Metadata:
  
        encoder         : Lavc57.17.100 libx264
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (mpeg4 (native) -> h264 (libx264))
  
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

  The command as written above works fine on my local computer (running OSX). Would anyone have any suggestions as to how to fix this problem ?

• For modifying MPEG-2 Part 4 video, which is the easiest library/approach can I use ?

  17 décembre 2015, par liamzebedee

  I’m trying to implement a video watermarking system which modifies a subset of individual pixels (i.e. the RGB values at sets of x,y). The base use case would be modifying an MP4, which consists of modifying the contained MPEG-2 Part 4 Video stream.

  I’ve done some research, and have found that it isn’t as simple as just modifying the raw frames, as the ubiquitous P-frames and B-frames rely on compressing the output by only storing the differences between frames.

  I’m relatively technology-agnostic, I just want to find a solution. Which library/framework should I use (seems like ffmpeg for now) and which approach do I take ?