VLC script for playing a video file in a series of defined segments

ros_randomise_i.lua

description="ROS Randomiser"
local common = require("common")
local json = require ("dkjson")

math.randomseed(os.time())
math.random(); math.random(); math.random()

running = true

json_string = [[
    {"vals": [{"start": 0.0320553790627291, "endval": 0.04635129800552663}, {"start": 0.8976023084008496, "endval": 0.9159915032802601}, {"start": 0.16587401545199917, "endval": 0.1928163242288099}, {"start": 0.6886102599770664, "endval": 0.7007772994717747}, {"start": 0.9159915032802601, "endval": 0.9798719852623268}, {"start": 0.7562503524634848, "endval": 0.7877370904374307}, {"start": 0.07777224279564637, "endval": 0.08883959621783183}, {"start": 0.44600729364437847, "endval": 0.4694813617309247}, {"start": 0.32810120871477716, "endval": 0.3479566516908848}, {"start": 0.8016100531984887, "endval": 0.8255211760061658}, {"start": 0.4933125928153843, "endval": 0.5150337425042766}, {"start": 0.7173712803353572, "endval": 0.7336785908979829}, {"start": 0.38998439761640696, "endval": 0.41833656033234956}, {"start": 0.06607985412711243, "endval": 0.07777224279564637}, {"start": 0.6091743895332443, "endval": 0.6317367520724853}, {"start": 0.13709889655431698, "endval": 0.1519540575596368}, {"start": 0.8429610692332274, "endval": 0.8680517698366449}, {"start": 0.10723349061037277, "endval": 0.11465402184333703}, {"start": 0.08883959621783183, "endval": 0.10723349061037277}, {"start": 0.5864522435475684, "endval": 0.6091743895332443}, {"start": 0.3479566516908848, "endval": 0.38998439761640696}, {"start": 0.04635129800552663, "endval": 0.06607985412711243}, {"start": 0.8680517698366449, "endval": 0.8976023084008496}, {"start": 0.9798719852623268, "endval": 1.0}, {"start": 0.7007772994717747, "endval": 0.7173712803353572}, {"start": 0.6317367520724853, "endval": 0.6630261104949527}, {"start": 0.41833656033234956, "endval": 0.44600729364437847}, {"start": 0.11465402184333703, "endval": 0.1240530481042164}, {"start": 0.5150337425042766, "endval": 0.5506654510592702}, {"start": 0.7877370904374307, "endval": 0.8016100531984887}, {"start": 0.5506654510592702, "endval": 0.5864522435475684}, {"start": 0.6630261104949527, "endval": 0.6886102599770664}, {"start": 0.3021176006165761, "endval": 0.31310506231554414}, {"start": 0.0010385924018271708, "endval": 0.0320553790627291}, {"start": 0.0, "endval": 0.0010385924018271708}, {"start": 0.8255211760061658, "endval": 0.8429610692332274}, {"start": 0.1240530481042164, "endval": 0.13709889655431698}, {"start": 0.7336785908979829, "endval": 0.7562503524634848}, {"start": 0.26282967084610037, "endval": 0.3021176006165761}, {"start": 0.1928163242288099, "endval": 0.2048940729740399}, {"start": 0.2048940729740399, "endval": 0.22818016053536855}, {"start": 0.31310506231554414, "endval": 0.32810120871477716}, {"start": 0.4694813617309247, "endval": 0.4933125928153843}, {"start": 0.22818016053536855, "endval": 0.26282967084610037}, {"start": 0.1519540575596368, "endval": 0.16587401545199917}]}
]]

json_obj, pos, err = json.decode(json_string)

if err then 
    vlc.msg.err("[ROS-R] json loaded: " .. err)
end
vlc.msg.dbg("[ROS-R] starting")

current_index = 1
next_milestone = 0.0

while running do
    local input = vlc.object.input()
    if input then
        local pos = vlc.var.get(input, "position")

        if pos > next_milestone and current_index <= #json_obj.vals then

            vlc.msg.dbg("[ROS-R] moving, reached: " .. tostring(next_milestone))

            pair = json_obj.vals[current_index]

            common.seek(tostring(pair.start*100.0) .. "%")
            next_milestone = pair.endval
            local pos2 = vlc.var.get(input, "position")

            vlc.msg.dbg("[ROS-R] new milestone: " .. tostring(next_milestone) .. " advancing to index " .. tostring(current_index))
            vlc.msg.dbg("[ROS-R] pos: " .. tostring(pos2))

            current_index = current_index + 1;
        end
    else
        current_index = 1
        next_milestone = 0.0
    end



end

vlc.msg.dbg("[ROS-R] ending")