bpgview.lua

-- Simple hook that converts .bpg files as you open them with mpv
-- libbpg needs to be installed on your system

-- You can specify the output format (.ppm or .png) but conversion
-- to .png is slower. You can also increase the bit depth for .png
-- by passing "-b 16" and it supports transparency.
-- It seems animated files are not yet supported by bpgdec.

local msg = require 'mp.msg'

function convert_bpg()
    local file_in = mp.get_property_osd("stream-open-filename")
    local file_in = string.gsub(file_in, "'", "'\\''")

    if file_in:sub(file_in:len()-3,file_in:len()) == ".bpg" then
      local file_out = os.tmpname() .. ".ppm"

      if os.execute("bpgdec " .. file_in .. " -o " .. file_out) then
        mp.set_property("stream-open-filename", file_out)
      else
        msg.info("Failed to convert " .. file_in)
      end
    end
end

mp.add_hook("on_load",   50, convert_bpg)