1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package jpeg
import (
"bytes"
"fmt"
"image"
"io/ioutil"
"os"
"testing"
)
// TestDecodeProgressive tests that decoding the baseline and progressive
// versions of the same image result in exactly the same pixel data, in YCbCr
// space for color images, and Y space for grayscale images.
func TestDecodeProgressive(t *testing.T) {
testCases := []string{
"../testdata/video-001",
"../testdata/video-001.q50.420",
"../testdata/video-001.q50.422",
"../testdata/video-001.q50.440",
"../testdata/video-001.q50.444",
"../testdata/video-005.gray.q50",
}
for _, tc := range testCases {
m0, err := decodeFile(tc + ".jpeg")
if err != nil {
t.Errorf("%s: %v", tc+".jpeg", err)
continue
}
m1, err := decodeFile(tc + ".progressive.jpeg")
if err != nil {
t.Errorf("%s: %v", tc+".progressive.jpeg", err)
continue
}
if m0.Bounds() != m1.Bounds() {
t.Errorf("%s: bounds differ: %v and %v", tc, m0.Bounds(), m1.Bounds())
continue
}
switch m0 := m0.(type) {
case *image.YCbCr:
m1 := m1.(*image.YCbCr)
if err := check(m0.Bounds(), m0.Y, m1.Y, m0.YStride, m1.YStride); err != nil {
t.Errorf("%s (Y): %v", tc, err)
continue
}
if err := check(m0.Bounds(), m0.Cb, m1.Cb, m0.CStride, m1.CStride); err != nil {
t.Errorf("%s (Cb): %v", tc, err)
continue
}
if err := check(m0.Bounds(), m0.Cr, m1.Cr, m0.CStride, m1.CStride); err != nil {
t.Errorf("%s (Cr): %v", tc, err)
continue
}
case *image.Gray:
m1 := m1.(*image.Gray)
if err := check(m0.Bounds(), m0.Pix, m1.Pix, m0.Stride, m1.Stride); err != nil {
t.Errorf("%s: %v", tc, err)
continue
}
default:
t.Errorf("%s: unexpected image type %T", tc, m0)
continue
}
}
}
func decodeFile(filename string) (image.Image, error) {
f, err := os.Open(filename)
if err != nil {
return nil, err
}
defer f.Close()
return Decode(f)
}
// check checks that the two pix data are equal, within the given bounds.
func check(bounds image.Rectangle, pix0, pix1 []byte, stride0, stride1 int) error {
if len(pix0) != len(pix1) {
return fmt.Errorf("len(pix) %d and %d differ", len(pix0), len(pix1))
}
if stride0 != stride1 {
return fmt.Errorf("strides %d and %d differ", stride0, stride1)
}
if stride0%8 != 0 {
return fmt.Errorf("stride %d is not a multiple of 8", stride0)
}
// Compare the two pix data, one 8x8 block at a time.
for y := 0; y < len(pix0)/stride0; y += 8 {
for x := 0; x < stride0; x += 8 {
if x >= bounds.Max.X || y >= bounds.Max.Y {
// We don't care if the two pix data differ if the 8x8 block is
// entirely outside of the image's bounds. For example, this can
// occur with a 4:2:0 chroma subsampling and a 1x1 image. Baseline
// decoding works on the one 16x16 MCU as a whole; progressive
// decoding's first pass works on that 16x16 MCU as a whole but
// refinement passes only process one 8x8 block within the MCU.
continue
}
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
index := (y+j)*stride0 + (x + i)
if pix0[index] != pix1[index] {
return fmt.Errorf("blocks at (%d, %d) differ:\n%sand\n%s", x, y,
pixString(pix0, stride0, x, y),
pixString(pix1, stride1, x, y),
)
}
}
}
}
}
return nil
}
func pixString(pix []byte, stride, x, y int) string {
s := bytes.NewBuffer(nil)
for j := 0; j < 8; j++ {
fmt.Fprintf(s, "\t")
for i := 0; i < 8; i++ {
fmt.Fprintf(s, "%02x ", pix[(y+j)*stride+(x+i)])
}
fmt.Fprintf(s, "\n")
}
return s.String()
}
func benchmarkDecode(b *testing.B, filename string) {
b.StopTimer()
data, err := ioutil.ReadFile(filename)
if err != nil {
b.Fatal(err)
}
cfg, err := DecodeConfig(bytes.NewReader(data))
if err != nil {
b.Fatal(err)
}
b.SetBytes(int64(cfg.Width * cfg.Height * 4))
b.StartTimer()
for i := 0; i < b.N; i++ {
Decode(bytes.NewReader(data))
}
}
func BenchmarkDecodeBaseline(b *testing.B) {
benchmarkDecode(b, "../testdata/video-001.jpeg")
}
func BenchmarkDecodeProgressive(b *testing.B) {
benchmarkDecode(b, "../testdata/video-001.progressive.jpeg")
}
|
