JVC 4ch Network Encoder VN-E4 - Manual (Page 9)

9
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.