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1. Acquiring JPEG from VN-E4 via HTTP _
1.5. JPEG File Format Sent Out by VN-E4
JPEG files sent out by VN-E4 are compliant with JFIF and consist of the following.
The following information is stored in the comment segment. Each item has a fixed length.
Item names and values, excluding the version information that does not include =, are stored in the following format.
Example: When width=640, the 13-byte area will be written as follows.
1.5. JPEG File Format Sent Out by VN-E4
FFD8
Start Code
FFE0
Application Segment
FFFE
Comment Segment
FFC0
SOF Frame Information
FFDB
DQT Quantization Table
FFC4
DHT Huffman Table
FFDA
Data Start Segment
FFD9
End Code
Item
Size
Example
Description
Version Information
9
JVC V1.0
Indicates the version of information stored in the comment segment
File Size
18
size = 123456
The number of bytes of the JPEG file.
Width
13
width = 640
Width of JPEG.
Height
14
height = 480
Height of JPEG.
Model Name
18
type = VN-E4
Name of model that created the JPEG.
Invert Flag
12
Stores inversion
information set at VN-E4.
Specified as reverse=1 in the case of a vertical inversion.
Time Stamp
70
timestamp =
20050214130509123JST
Indicates the time at which JPEG is created. This is made up of the
year/month/day, hour/minute/second, millisecond and timezone code.
Alarm Information
13
alarm = 00000001
Indicates the alarm input status when the JPEG is created in a 4-byte
binary value. (Not ASCII code.) 4 alarm inputs are assigned to 4 bits
from the LSB. For example, value is alarm = 00000001when changes
occur with alarm input 1, alarm = 00000008 when changes occur with
alarm input 4, and alarm = 00000009 when changes occur with alarm
inputs 1 and 4.
Camera ID
50
camera = input01
Stores camera information set at VN-E4. Character code is Shift-JIS
when information is stored in Japanese.
Motion Detect Setting
11
motion = 1
Specified as 1 when the motion detect feature is ON.
Motion Detect Result
7
md = 1
Specified as 1 if motion is detected at the time when JPEG is created.
Reserved
17
Reserved
32
Synchronization Time Stamp
26
sync_timestamp =
1FDC5A34
Indicates the 8 kHz counter value in a 4-byte binary value. (Not
ASCII code.) This can be used when synchronizing with audio.
Video Signal Format
20
format = NTSCU
Indicates the input video signal. Stated as NTSCJ for NTSC in Japan,
and NTSCU for other NTSC formats. Stated as PAL for PAL format.
Input Channel
7
ch = 1
Indicates the signal source among the 4 inputs of VN-E4.
Picture Quality
9
intp = 0
Stated as 1 when this is set to field interpolation at VN-E4, and 0
when this is set to frame processing.
Rate Control
16
size_cntl = VFS
Describes the mode of rate control for JPEG. VFS (VariableFileSize),
AFS (AverageFileSize) or CFS (ConstantFileSize).
Target Size
19
size = 23456
Target size of rate control.
Quantization Scale
14
q_scale = 45
Indicates the quantization scale. Up to 3 digits.
Firmware Version Information 12
ver = 01.00
Indicates version of the firmware that is used to create JPEG.
Item names
Space
=
Space
values
0x00
w
i
d
t
h
=
6
4
0
0x00
0x00
Defined fixed length by each item.