Increment by 5.005, sometimes 207, sometimes 196? - loops

Question

This problem deals with HLS playlists, and it may help to understand how HLS works before diving in.
HLS (HTTP Live Streaming) is a playlist, similar to that of an iTunes .m3u playlist. HLS takes a video file (such as an .mpg), and splits it into multiple, equal-length segment files (.ts — stands for Transport Stream). For simplicity, you can think of these segment files as chunks of the original .mpg file, which are to be played consecutively.
There are many ways to name these segment files. Sometimes you have…
file_segment_0.ts
file_segment_1.ts
file_segment_2.ts
But sometimes you have something like,
22/51/04.ts
22/51/09.ts
22/51/14.ts
(H/M/S)
The client (such as VLC) knows how to handle these files. It’s up to the producer to decide how they want to name their files.
An HLS playlist can also be “VOD” (Video On-Demand) or “Live”. If the playlist is “Live”, the client will jump to the current live time. Inside the playlist, a header will define the program’s (in terms of the streamed event) start datetime, like so:
#EXT-X-PROGRAM-DATE-TIME:2016-09-16T21:59:09+00:00
The playlist will also tell the client how far apart the segmented files are, in terms of seconds.
My issue falls with H/M/S format. You can find an example playlist here: http://pastebin.com/raw/rS84YJwN
The segments are 5.005s apart, as defined by #EXTINF:5.005.
At first glance, it doesn’t look so bad. Start at the EXT-X-PROGRAM-DATE-TIME, increment by 5.005, round accordingly, and format the date as H/M/S.ts
But there’s a bigger question: Why are there sometimes 207 segments between EXT-X-PROGRAM-DATE-TIME + 5.005, and why are there sometimes 196 segments between EXT-X-PROGRAM-DATE-TIME + 5.005?
My math tells me that I will increment by 6 (instead of 5) every 200 segments, which I can calculate as true with some quick and dirty ruby code[0], which produces this output:
139 22/14/40.ts
339 22/31/21.ts
539 22/48/02.ts
746 23/05/18.ts
946 23/21/59.ts
1146 23/38/40.ts
1346 23/55/21.ts
1402 00/00/01.ts
1542 00/11/42.ts
1742 00/28/23.ts
1942 00/45/04.ts
2142 01/01/45.ts
2342 01/18/26.ts
2542 01/35/07.ts
2742 01/51/48.ts
2942 02/08/29.ts
3142 02/25/10.ts
3342 02/41/51.ts
3542 02/58/32.ts
3749 03/15/48.ts
3949 03/32/29.ts
4149 03/49/10.ts
Where 139 is a line number, and 22/14/40.ts is the segment file.
My question is this: What’s going on here, and how can I reproduce it accurately? I obviously don’t/won’t have access to the actual input video file, and I need to rebuild these playlist files.
[0]
require 'date'
file = `curl 'http://pastebin.com/raw/rS84YJwN'`
start_date = DateTime.parse(file.scan(%r{#EXT-X-PROGRAM-DATE-TIME:(.*)$}).to_a.first.first)
lines = file.split("\n").select { |line| !line.index('.ts').nil? }
date_lines = []
lines.each_with_index do |line, i|
str = line.gsub("/", ':').split(".ts")[0]
date = "#{start_date.to_date} #{str}"
date_obj = DateTime.parse(date)
date_lines << date_obj
next unless i > 0
diff = date_obj.to_time - date_lines[i - 1].to_time
if diff != 5.0
puts "#{i} #{line}"
end
end