ffprobe.rb

#!/usr/bin/env ruby
require 'json'
require 'pry'

url = "rtmp://fms.105.net/live/rmc1"
BITS_IN_BYTE = 8
BYTES_IN_KB = 1024


def compute_data type: 'video', frames: 1000, url: 
  out = JSON.parse(`ffprobe -loglevel error -show_frames -of json -read_intervals \"%+\##{frames}\" #{url}`)['frames']

  video = out.select{|e| e['media_type'] == 'video'}

  keyframe_index = video.select{|e| e['key_frame'] == 1}.map{ |e| video.index(e) }
  puts keyframe_index

  video_indexes = get_keyframe_interval(keyframe_index)

  res = [out.index(video[video_indexes.first]), out.index(video[video_indexes.last])]

  data = {}
  if (res.size == 2)
    data[:gop_size] = video_indexes.last - video_indexes.first
    data[:width] = out[res.last]['width']
    data[:height] = out[res.last]['height']
    data.merge!(get_bitrate(out, res.first, res.last))
  end
  data
end

def get_bitrate input, i1, i2
  time = (input[i2]['pkt_pts_time'].to_f - input[i1]['pkt_pts_time'].to_f).ceil(3)
  video_bytes = input[i1..i2].select{|e| e['media_type'] == 'video'}
    .map{ |e| e['pkt_size'].to_i }
    .reduce(:+)
  audio_bytes = input[i1..i2].select{|e| e['media_type'] == 'audio'}
    .map{ |e| e['pkt_size'].to_i }
    .reduce(:+)

  bytes = video_bytes + audio_bytes

  bitrate = ((bytes * BITS_IN_BYTE) / (time * BYTES_IN_KB)).ceil

  fps = (input[i1..i2].select{|e| e['media_type'] == 'video'}.size / time).ceil(3)

  { time_offset: time, bitrate: bitrate, fps: fps }
end

def get_keyframe_interval(keyframe_index)
  res = []

  keyframe_index.each_with_index do |e, i|
    if i == keyframe_index.size - 1
      res << e if res.size == 1
      break
    end

    next if (keyframe_index[i+1] == e + 1) && res.empty?
    res << e
    break if res.size == 2
  end
  res
end

puts(compute_data(url: url))
# puts keyframe_interval
# puts out['frames'].map{|e| e['key_frame']}
# puts out.keys