system: Linux mars.sprixweb.com 3.10.0-1160.119.1.el7.x86_64 #1 SMP Tue Jun 4 14:43:51 UTC 2024 x86_64
# Copyright 2021 Joe Drago. All rights reserved.
# SPDX-License-Identifier: BSD-2-Clause
# READ THIS WHOLE COMMENT FIRST, BEFORE RUNNING THIS SCRIPT:
# The goal of this script is to detect AVIFs containing multiple adjacent iref boxes and merge them,
# filling leftover space with a free box (to avoid ruining file offsets elsewhere in the file). The
# syntax is simple:
# coffee irefmerge.coffee filename.avif
# This will look over the file's contents and if it detects multiple irefs, it will fix it in
# memory, make a adjacent backup of the file (filename.avif.irefmergeBackup), and then overwrite the
# original file with the fixed contents. Using -v on the commandline will enable Verbose mode, and
# using -n will disable the creation of backups (.irefmergeBackup files).
# This should be well-behaved on files created by old versions of avifenc, but **PLEASE** make
# backups of your images before running this script on them, **especially** if you plan to run with
# "-n". I do not advise running this script on AVIFs generated by anything other than avifenc.
# Possible responses for a file:
# * [NotAvif] This file isn't an AVIF.
# * [BadAvif] This file thinks it is an AVIF, but is missing important things.
# * [Skipped] This file is an AVIF, but didn't need any fixes.
# * [Success] This file is an AVIF, had to be fixed, and was fixed.
# * (the script crashes) I probably have a bug; let me know.
# Note on CoffeeScript:
# If you don't want to invoke coffeescript every time, you can compile it once with:
# coffee -c -b irefmerge.coffee
# ... and run the adjacent irefmerge.js with node instead. "It's just JavaScript."
# -------------------------------------------------------------------------------------------------
# Syntax
syntax = ->
console.log "Syntax: irefmerge [-v] [-n] file1 [file2 ...]"
console.log " -v : Verbose mode"
console.log " -n : No Backups (Don't generate adjacent .irefmergeBackup files when overwriting in-place)"
# -------------------------------------------------------------------------------------------------
# Constants and helpers
fs = require 'fs'
INDENT = " "
VERBOSE = false
verboseLog = ->
if VERBOSE
console.log.apply(null, arguments)
fatalError = (reason) ->
console.error "ERROR: #{reason}"
process.exit(1)
# -------------------------------------------------------------------------------------------------
# Box
class Box
constructor: (@filename, @type, @buffer, @start, @size) ->
@offset = @start
@bytesLeft = @size
@version = 0
@flags = 0
@boxes = {} # child boxes
nextBox: ->
if @bytesLeft < 8
return null
boxSize = @buffer.readUInt32BE(@offset)
boxType = @buffer.toString('utf8', @offset + 4, @offset + 8)
if boxSize > @bytesLeft
verboseLog("#{INDENT} * Truncated box of type #{boxType} (#{boxSize} bytes with only #{@bytesLeft} bytes left)")
return null
if boxSize < 8
verboseLog("#{INDENT} * Bad box size of type #{boxType} (#{boxSize} bytes")
return null
newBox = new Box(@filename, boxType, @buffer, @offset + 8, boxSize - 8)
@offset += boxSize
@bytesLeft -= boxSize
verboseLog "#{INDENT} * Discovered box type: #{newBox.type} offset: #{newBox.offset - 8} size: #{newBox.size + 8}"
return newBox
walkBoxes: ->
while box = @nextBox()
@boxes[box.type] = box
return
readFullBoxHeader: ->
if @bytesLeft < 4
fatalError("#{INDENT} * Truncated FullBox of type #{boxType} (only #{@bytesLeft} bytes left)")
versionAndFlags = @buffer.readUInt32BE(@offset)
@version = (versionAndFlags >> 24) & 0xFF
@flags = versionAndFlags & 0xFFFFFF
@offset += 4
@bytesLeft -= 4
return
ftypHasBrand: (brand) ->
if @type != 'ftyp'
fatalError("#{INDENT} * Calling Box.ftypHasBrand() on a non-ftyp box")
majorBrand = @buffer.toString('utf8', @offset, @offset + 4)
compatibleBrands = []
compatibleBrandCount = Math.floor((@size - 8) / 4)
for i in [0...compatibleBrandCount]
o = @offset + 8 + (i * 4)
compatibleBrand = @buffer.toString('utf8', o, o + 4)
compatibleBrands.push compatibleBrand
verboseLog "#{INDENT} * ftyp majorBrand: #{majorBrand} compatibleBrands: [#{compatibleBrands.join(', ')}]"
if majorBrand == brand
return true
for compatibleBrand in compatibleBrands
if compatibleBrand == brand
return true
return false
# -------------------------------------------------------------------------------------------------
# Main
irefMerge = (filename, makeBackups) ->
if not fs.existsSync(filename)
fatalError("File doesn't exist: #{filename}")
try
fileBuffer = fs.readFileSync(filename)
catch e
fatalError "Failed to read \"#{filename}\": #{e}"
fileBox = new Box(filename, "<file>", fileBuffer, 0, fileBuffer.length)
fileBox.walkBoxes()
ftypBox = fileBox.boxes.ftyp
if not ftypBox?
return "NotAvif"
if ftypBox.type != 'ftyp'
return "NotAvif"
if !ftypBox.ftypHasBrand('avif')
return "NotAvif"
metaBox = fileBox.boxes.meta
if not metaBox?
return "BadAvif"
metaBox.readFullBoxHeader()
merged = false
irefs = []
while box = metaBox.nextBox()
if box.type == 'iref'
irefs.push box
# console.log irefs
if irefs.length > 1
verboseLog "#{INDENT} * Discovered multiple (#{irefs.length}) iref boxes, merging..."
# merge irefs, and leave a free block in the dead space
newTotalSize = 8 + 4 # the new single iref header's size + fullbox
for iref in irefs
newTotalSize += iref.size - 4
fileBuffer.writeUInt32BE(newTotalSize, irefs[0].start - 8)
writeOffset = irefs[0].start + 4 # skip past the fullbox's version[1]+flags[3]
for iref in irefs
fileBuffer.copy(fileBuffer, writeOffset, iref.start + 4, iref.start + iref.size)
writeOffset += iref.size - 4
freeBoxSize = (irefs.length - 1) * 12
freeBox = Buffer.alloc(freeBoxSize)
freeBox.fill(0)
freeBox.writeUInt32BE(freeBoxSize)
freeBox.write("free", 4)
freeBox.copy(fileBuffer, writeOffset, 0, freeBoxSize)
verboseLog "#{INDENT} * Wrote a free chunk of size #{freeBoxSize} at offset #{writeOffset}"
merged = true
if merged
if makeBackups
backupFilename = filename + ".irefmergeBackup"
fs.writeFileSync(backupFilename, fs.readFileSync(filename))
fs.writeFileSync(filename, fileBuffer)
return "Success"
return "Skipped"
main = ->
showSyntax = false
makeBackups = true
files = []
for arg in process.argv.slice(2)
switch arg
when '-h', '--help'
showSyntax = true
break
when '-n', '--no-backups'
makeBackups = false
break
when '-v', '--verbose'
VERBOSE = true
break
else
files.push arg
if showSyntax or files.length == 0
return syntax()
for filename in files
verboseLog("[Reading] #{filename}")
result = irefMerge(filename, makeBackups)
console.log("[#{result}] #{filename}") # Always print this
return 0
main()