Api format, Structure, Parameter description – JVC 4ch Network Encoder VN-E4 User Manual

Page 6: Structure parameter description, Api format structure

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1. Acquiring JPEG from VN-E4 via HTTP _

1.2. API Format

Structure

Unlike parameter acquisition/setting, Accept line is not required. Basic authentication is also not necessary.

Example

GET

/api/video?input=1&framesize=vga&framerate=30&header=0&assured=0&send

buffer=128 HTTP/1.1<CRLF>

Host: 10.0.0.1<CRLF><CRLF>

Parameter values are indicated using =. Do not insert space before and after =.
Example input=1
Parameters are segmented using &. Do not insert space before and after &.
Example input=1&framesize=vga
There is no need to specify all parameters. Default values will be used for parameters that are not specified.

Parameter Description

input

For specifying the input video channel. For example, specify as input=4 when acquiring CH4. Specify as either
1, 2, 3 or 4.

framesize

For specifying the frame size. Specify as framesize=vga when acquiring VGA and framesize=qvga when
acquiring QVGA.

framerate

For specifying the frame rate. For example, specify as framerate=5 when acquiring at 5 fps. Specify as
framerate=-5 to acquire at 1/5 fps, or in other words, 1 frame in 5 seconds. Selection range is as follows.

● VN-E4 and VN-E4U (NTSC)

30, 15, 10, 7.5, 6, 5, 3, 2, 1, 0, -2, -3, -5, -10, -15, -20, -30, -60

● VN-E4E (PAL)

25, 12.5, 8.3, 6.25, 5, 4.1, 3, 2, 1, 0, -2, -3, -5, -10, -15, -20, -30, -60

Only 1 frame of the JPEG data will be sent when the parameter is specified as framerate=0. In this case, VN-
E4 will disconnect TCP after 5 seconds if this is not disconnected by the client.

header

For specifying whether to add a 12-byte header to the JPEG data. Default value is 0.
Header format is as follows. The first 4 bytes (0x00000001) indicate that the payload is a JPEG data.

assured

VN-E4 temporarily saves up to 2.5 seconds of the compressed data. Specify as assured=0 to request for the
latest data that is temporarily saved and assured=1 to request for the oldest data. Specify as assured=0 to
shorten the delay time. To acquire as many frames as possible in a network where delay fluctuates, it is
recommended that this be specified as assured=1. Default value is 0.

sendbuffer

Use this to increase the send buffer size. Default value is 16. Window scale will be enlarged upon increasing
the send buffer size, hence enhancing the transmission volume on networks with considerable delay. The send
buffer size may be increased up to 1024. When the send buffer size has already been increased to 1024 by other
clients, sendbuffer will remain as the default value even if a larger value is specified Refer to "10. Advanced
Topics" on countermeasures against network delays.

1.2. API Format

GET

Space

API Character String

Space

HTTP/1.1

0x0D 0x0A

Host:

Space

IP Address of VN-E4

0x0D 0x0A 0x0D 0x0A

0x00000001

JPEG size in bytes

Time stamp (Unit: 8 kHz)

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