1 | #------------------------------------------------------------------------------
|
---|
2 | # File: BPG.pm
|
---|
3 | #
|
---|
4 | # Description: Read BPG meta information
|
---|
5 | #
|
---|
6 | # Revisions: 2016-07-05 - P. Harvey Created
|
---|
7 | #
|
---|
8 | # References: 1) http://bellard.org/bpg/
|
---|
9 | #------------------------------------------------------------------------------
|
---|
10 |
|
---|
11 | package Image::ExifTool::BPG;
|
---|
12 |
|
---|
13 | use strict;
|
---|
14 | use vars qw($VERSION);
|
---|
15 | use Image::ExifTool qw(:DataAccess :Utils);
|
---|
16 |
|
---|
17 | $VERSION = '1.01';
|
---|
18 |
|
---|
19 | # BPG information
|
---|
20 | %Image::ExifTool::BPG::Main = (
|
---|
21 | PROCESS_PROC => \&Image::ExifTool::ProcessBinaryData,
|
---|
22 | GROUPS => { 0 => 'File', 1 => 'File', 2 => 'Image' },
|
---|
23 | NOTES => q{
|
---|
24 | The information listed below is extracted from BPG (Better Portable
|
---|
25 | Graphics) images. See L<http://bellard.org/bpg/> for the specification.
|
---|
26 | },
|
---|
27 | 4 => {
|
---|
28 | Name => 'PixelFormat',
|
---|
29 | Format => 'int16u',
|
---|
30 | Mask => 0xe000,
|
---|
31 | PrintConv => {
|
---|
32 | 0 => 'Grayscale',
|
---|
33 | 1 => '4:2:0 (chroma at 0.5, 0.5)',
|
---|
34 | 2 => '4:2:2 (chroma at 0.5, 0)',
|
---|
35 | 3 => '4:4:4',
|
---|
36 | 4 => '4:2:0 (chroma at 0, 0.5)',
|
---|
37 | 5 => '4:2:2 (chroma at 0, 0)',
|
---|
38 | },
|
---|
39 | },
|
---|
40 | 4.1 => {
|
---|
41 | Name => 'Alpha',
|
---|
42 | Format => 'int16u',
|
---|
43 | Mask => 0x1004,
|
---|
44 | BitShift => 0,
|
---|
45 | PrintHex => 1,
|
---|
46 | PrintConv => {
|
---|
47 | 0x0000 => 'No Alpha Plane',
|
---|
48 | 0x1000 => 'Alpha Exists (color not premultiplied)',
|
---|
49 | 0x1004 => 'Alpha Exists (color premultiplied)',
|
---|
50 | 0x0004 => 'Alpha Exists (W color component)',
|
---|
51 | },
|
---|
52 | },
|
---|
53 | 4.2 => {
|
---|
54 | Name => 'BitDepth',
|
---|
55 | Format => 'int16u',
|
---|
56 | Mask => 0x0f00,
|
---|
57 | ValueConv => '$val + 8',
|
---|
58 | },
|
---|
59 | 4.3 => {
|
---|
60 | Name => 'ColorSpace',
|
---|
61 | Format => 'int16u',
|
---|
62 | Mask => 0x00f0,
|
---|
63 | PrintConv => {
|
---|
64 | 0 => 'YCbCr (BT 601)',
|
---|
65 | 1 => 'RGB',
|
---|
66 | 2 => 'YCgCo',
|
---|
67 | 3 => 'YCbCr (BT 709)',
|
---|
68 | 4 => 'YCbCr (BT 2020)',
|
---|
69 | 5 => 'BT 2020 Constant Luminance',
|
---|
70 | },
|
---|
71 | },
|
---|
72 | 4.4 => {
|
---|
73 | Name => 'Flags',
|
---|
74 | Format => 'int16u',
|
---|
75 | Mask => 0x000b,
|
---|
76 | PrintConv => { BITMASK => {
|
---|
77 | 0 => 'Animation',
|
---|
78 | 1 => 'Limited Range',
|
---|
79 | 3 => 'Extension Present',
|
---|
80 | }},
|
---|
81 | },
|
---|
82 | 6 => { Name => 'ImageWidth', Format => 'var_ue7' },
|
---|
83 | 7 => { Name => 'ImageHeight', Format => 'var_ue7' },
|
---|
84 | # length of image data or 0 to EOF
|
---|
85 | # (must be decoded so we know where the extension data starts)
|
---|
86 | 8 => { Name => 'ImageLength', Format => 'var_ue7' },
|
---|
87 | );
|
---|
88 |
|
---|
89 | %Image::ExifTool::BPG::Extensions = (
|
---|
90 | GROUPS => { 0 => 'File', 1 => 'File', 2 => 'Image' },
|
---|
91 | VARS => { ALPHA_FIRST => 1 },
|
---|
92 | 1 => {
|
---|
93 | Name => 'EXIF',
|
---|
94 | SubDirectory => {
|
---|
95 | TagTable => 'Image::ExifTool::Exif::Main',
|
---|
96 | ProcessProc => \&Image::ExifTool::ProcessTIFF,
|
---|
97 | },
|
---|
98 | },
|
---|
99 | 2 => {
|
---|
100 | Name => 'ICC_Profile',
|
---|
101 | SubDirectory => { TagTable => 'Image::ExifTool::ICC_Profile::Main' },
|
---|
102 | },
|
---|
103 | 3 => {
|
---|
104 | Name => 'XMP',
|
---|
105 | SubDirectory => { TagTable => 'Image::ExifTool::XMP::Main' },
|
---|
106 | },
|
---|
107 | 4 => {
|
---|
108 | Name => 'ThumbnailBPG',
|
---|
109 | Binary => 1,
|
---|
110 | },
|
---|
111 | 5 => {
|
---|
112 | Name => 'AnimationControl',
|
---|
113 | Binary => 1,
|
---|
114 | Unknown => 1,
|
---|
115 | },
|
---|
116 | );
|
---|
117 |
|
---|
118 | #------------------------------------------------------------------------------
|
---|
119 | # Get ue7 integer from binary data (max 32 bits)
|
---|
120 | # Inputs: 0) data ref, 1) location in data (undef for 0)
|
---|
121 | # Returns: 0) ue7 as integer or undef on error, 1) length of ue7 in bytes
|
---|
122 | sub Get_ue7($;$)
|
---|
123 | {
|
---|
124 | my $dataPt = shift;
|
---|
125 | my $pos = shift || 0;
|
---|
126 | my $size = length $$dataPt;
|
---|
127 | my $val = 0;
|
---|
128 | my $i;
|
---|
129 | for ($i=0; ; ) {
|
---|
130 | return() if $pos+$i >= $size or $i >= 5;
|
---|
131 | my $byte = Get8u($dataPt, $pos + $i);
|
---|
132 | $val = ($val << 7) | ($byte & 0x7f);
|
---|
133 | unless ($byte & 0x80) {
|
---|
134 | return() if $i == 4 and $byte & 0x70; # error if bits 32-34 are set
|
---|
135 | last; # this was the last byte
|
---|
136 | }
|
---|
137 | return() if $i == 0 and $byte == 0x80; # error if first byte is 0x80
|
---|
138 | ++$i; # step to the next byte
|
---|
139 | }
|
---|
140 | return($val, $i+1);
|
---|
141 | }
|
---|
142 |
|
---|
143 | #------------------------------------------------------------------------------
|
---|
144 | # Extract EXIF information from a BPG image
|
---|
145 | # Inputs: 0) ExifTool object reference, 1) dirInfo reference
|
---|
146 | # Returns: 1 on success, 0 if this wasn't a valid BPG file
|
---|
147 | sub ProcessBPG($$)
|
---|
148 | {
|
---|
149 | local $_;
|
---|
150 | my ($et, $dirInfo) = @_;
|
---|
151 | my $raf = $$dirInfo{RAF};
|
---|
152 | my ($buff, $size, $n, $len, $pos);
|
---|
153 |
|
---|
154 | # verify this is a valid BPG file
|
---|
155 | return 0 unless $raf->Read($buff, 21) == 21; # (21 bytes is maximum header length)
|
---|
156 | return 0 unless $buff =~ /^BPG\xfb/;
|
---|
157 | $et->SetFileType(); # set the FileType tag
|
---|
158 |
|
---|
159 | SetByteOrder('MM');
|
---|
160 | my %dirInfo = (
|
---|
161 | DataPt => \$buff,
|
---|
162 | DirStart => 0,
|
---|
163 | DirLen => length($buff),
|
---|
164 | VarFormatData => [ ],
|
---|
165 | );
|
---|
166 | $et->ProcessDirectory(\%dirInfo, GetTagTable('Image::ExifTool::BPG::Main'));
|
---|
167 |
|
---|
168 | return 1 unless $$et{VALUE}{Flags} & 0x0008; # all done unless extension flag is set
|
---|
169 |
|
---|
170 | # add varSize from last entry in VarFormatData to determine
|
---|
171 | # the current read position in the file
|
---|
172 | my $dataPos = 9 + $dirInfo{VarFormatData}[-1][1];
|
---|
173 | # read extension length
|
---|
174 | unless ($raf->Seek($dataPos, 0) and $raf->Read($buff, 5) == 5) {
|
---|
175 | $et->Warn('Missing BPG extension data');
|
---|
176 | return 1;
|
---|
177 | }
|
---|
178 | ($size, $n) = Get_ue7(\$buff);
|
---|
179 | defined $size or $et->Warn('Corrupted BPG extension length'), return 1;
|
---|
180 | $dataPos += $n;
|
---|
181 | $size > 10000000 and $et->Warn('BPG extension is too large'), return 1;
|
---|
182 | unless ($raf->Seek($dataPos, 0) and $raf->Read($buff, $size) == $size) {
|
---|
183 | $et->Warn('Truncated BPG extension');
|
---|
184 | return 1;
|
---|
185 | }
|
---|
186 | my $tagTablePtr = GetTagTable('Image::ExifTool::BPG::Extensions');
|
---|
187 | # loop through the individual extensions
|
---|
188 | for ($pos=0; $pos<$size; $pos+=$len) {
|
---|
189 | my $type = Get8u(\$buff, $pos);
|
---|
190 | # get length of this extension
|
---|
191 | ($len, $n) = Get_ue7(\$buff, ++$pos);
|
---|
192 | defined $len or $et->Warn('Corrupted BPG extension'), last;
|
---|
193 | $pos += $n; # point to start of data for this extension
|
---|
194 | $pos + $len > $size and $et->Warn('Invalid BPG extension size'), last;
|
---|
195 | $$tagTablePtr{$type} or $et->Warn("Unrecognized BPG extension $type ($len bytes)", 1), next;
|
---|
196 | # libbpg (in my opinion) incorrectly copies the padding byte after the
|
---|
197 | # "EXIF\0" APP1 header to the start of the BPG EXIF extension, so issue a
|
---|
198 | # minor warning and ignore the padding if we find it before the TIFF header
|
---|
199 | if ($type == 1 and $len > 3 and substr($buff,$pos,3)=~/^.(II|MM)/s) {
|
---|
200 | $et->Warn("Ignored extra byte at start of EXIF extension", 1);
|
---|
201 | ++$pos;
|
---|
202 | --$len;
|
---|
203 | }
|
---|
204 | $et->HandleTag($tagTablePtr, $type, undef,
|
---|
205 | DataPt => \$buff,
|
---|
206 | DataPos => $dataPos,
|
---|
207 | Start => $pos,
|
---|
208 | Size => $len,
|
---|
209 | Parent => 'BPG',
|
---|
210 | );
|
---|
211 | }
|
---|
212 | return 1;
|
---|
213 | }
|
---|
214 |
|
---|
215 | 1; # end
|
---|
216 |
|
---|
217 | __END__
|
---|
218 |
|
---|
219 | =head1 NAME
|
---|
220 |
|
---|
221 | Image::ExifTool::BPG - Read BPG meta information
|
---|
222 |
|
---|
223 | =head1 SYNOPSIS
|
---|
224 |
|
---|
225 | This module is used by Image::ExifTool
|
---|
226 |
|
---|
227 | =head1 DESCRIPTION
|
---|
228 |
|
---|
229 | This module contains definitions required by Image::ExifTool to read BPG
|
---|
230 | (Better Portable Graphics) images.
|
---|
231 |
|
---|
232 | =head1 AUTHOR
|
---|
233 |
|
---|
234 | Copyright 2003-2021, Phil Harvey (philharvey66 at gmail.com)
|
---|
235 |
|
---|
236 | This library is free software; you can redistribute it and/or modify it
|
---|
237 | under the same terms as Perl itself.
|
---|
238 |
|
---|
239 | =head1 REFERENCES
|
---|
240 |
|
---|
241 | =over 4
|
---|
242 |
|
---|
243 | =item L<http://bellard.org/bpg/>
|
---|
244 |
|
---|
245 | =back
|
---|
246 |
|
---|
247 | =head1 SEE ALSO
|
---|
248 |
|
---|
249 | L<Image::ExifTool::TagNames/BPG Tags>,
|
---|
250 | L<Image::ExifTool(3pm)|Image::ExifTool>
|
---|
251 |
|
---|
252 | =cut
|
---|
253 |
|
---|