avc_refcalc.py

某所にて

(boiled_sugar) level計算機とかないのかなー
(Chikuzen) どんな計算したいの？
(boiled_sugar) 解像度とlevelで最大ref計算
(Chikuzen) この前D_Sがそんなの書いてx264に組み込んでなかったっけ？
(boiled_sugar) 独立したプログラムが欲しい

というわけで、書いてみた。

#!/bin/env python
# coding: utf-8

#****************************************************************************
#  avc_refcalc.py 0.20
#                                   written by Chikezun
#  Reference literature:
#    インプレス標準教科書シリーズ改訂版 H.264/AVC教科書
#           著者：（監修）大久保 榮／（編者）角野 眞也、菊池 義浩、鈴木 輝彦
#    http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC
#    猫科研究所(http://www.up-cat.net/FrontPage.html)
#        　x264(vbv-maxrate,vbv-bufsize,profile,level),H.264(Profile/Level)
#
#****************************************************************************

import sys
import math

def usage():
    print "Usage: avc_refcalc.py [options]\n"
    print "  -r, --resolution <string> :set 'width x height' ('1280x720')"
    print "  -l, --level <string>      :set 'level' ('4.1')"
    print "  -p, --profile <string>    :set 'profile' ('high')"
    print "  -i, --interlaced          :specify interlaced mode (not specified)"
    print "  -h, --help                :display this help and exit\n"

def check_prof(pr, ip):
    for i in ['baseline', 'main', 'high']:
        if i == pr:
            if i != 'baseline' or ip != 'interlaced':
                return i
            else:
                print "ERROR : baseline cannot accept interlaced."
    print "ERROR : invalid profile setting.\n"
    usage()
    sys.exit()

def check_level(lv, ip, dic):
    lvl = lv.replace('0','').replace('.','')
    if dic.has_key(lvl):
        if ip[0] != 'i' or dic.get(lvl)[0] == 'i':
            return lvl
        else:
            print "ERROR : specified level cannot accept interlaced."
    print "ERROR : invalid level value.\n"
    usage()
    sys.exit()

def calc_mbs(w, h, ip):
    mbh = int(math.ceil(float(w) / 16))
    mbv = int(math.ceil(float(h) / 16))
    if mbv % 2 == 1 and ip == 'interlaced':
        mbv += 1
    mbs = mbh * mbv
    if mbs > 0:
        return mbs
    else:
        print "ERROR : invalid resolution setting.\n"
        usage()
        sys.exit()

def calc_vbv(lv, pr, dic):
    vbvmax = dic.get(lv)[1]
    vbvbuf = dic.get(lv)[2]
    if pr == 'high':
        return [int(vbvmax * 1.25), int(vbvbuf * 1.25)]
    else:
        return [vbvmax, vbvbuf]

def calc_maxref(lv, mbs, dic):
    ref = int(dic.get(lv)[3] / mbs)
    if ref > 16:
        ref = 16
    if ref > 0:
        return ref
    else:
        print "ERROR : resolution is too large to level.\n"
        usage()
        sys.exit()

options = sys.argv
len_opt = len(options)

#set default values
width  = 1280
height = 720
level  = '4.1'
prof   = 'high'
mode   = 'progressive'
help   = 0

#H.264/AVC level dictionary {level: [interlaced flag, MaxBR, MaxCPB, MaxDbpMbs]}
avcdic = {'1' :['p',     64,    175,    396], '1b':['p',    128,    350,    396],
          '11':['p',    192,    500,    900], '12':['p',    384,   1000,   2376],
          '13':['p',    768,   2000,   2376], '2' :['p',   2000,   2000,   2376],
          '21':['i',   4000,   4000,   4752], '22':['i',   4000,   4000,   8100],
          '3' :['i',  10000,  10000,   8100], '31':['i',  14000,  14000,  18000],
          '32':['i',  20000,  20000,  20480], '4' :['i',  20000,  25000,  32768],
          '41':['i',  50000,  62500,  32768], '42':['p',  50000,  62500,  34816],
          '5' :['p', 135000, 135000, 110400], '51':['p', 240000, 240000, 184320]}

if len_opt > 1:
    for i in range(len_opt):
        try:
            if options[i] == '-r' or options[i] == '--resolution':
                res    = options[i + 1].split('x')
                width  = int(res[0])
                height = int(res[1])
            if options[i] == '-l' or options[i] == '--level':
                level = options[i + 1]
            if options[i] == '-p' or options[i] == '--profile':
                prof = options[i + 1]
            if options[i] == '-i' or options[i] == '--interlaced':
                mode = 'interlaced'
            if options[i] == '-h' or options[i] == '--help':
                help = 1

        except:
            print "ERROR : invalid arguments\n"
            help = 1

        else:
            pass

    if help == 1:
        usage()
        sys.exit()

else:
    usage()

profile = check_prof(prof, mode)
lv_tmp  = check_level(level, mode, avcdic)
mbs     = calc_mbs(width, height, mode)
vbv     = calc_vbv(lv_tmp, profile, avcdic)
maxref  = calc_maxref(lv_tmp, mbs, avcdic)

print " resolution       : %i x %i" % (width, height)
print " level            : %s" % level
print " profile          : %s" % profile
print " mode             : %s" % mode
print " vbv-maxrate(vlc) : %i" % vbv[0]
print " vbv-bufsize(vlc) : %i" % vbv[1]
print " max ref number   : %i" % maxref