1.2.4 Video Images (MJPEG and MPEG-4) and Image Refresh Rate
Using the [Refresh Rate] selector in the operation bar, you can select whether video images ([MJPEG] or [MPEG-4]) are displayed, or still images that are refreshed periodically (3 seconds, 5 seconds, etc.) are displayed. You can change the default setting for [Refresh Rate] that is used each time the single camera page is accessed (see 7.1 Changing Image Display Settings).
MJPEG
MJPEG (Motion JPEG) is a video format that displays a continuous series of still images. Because each MJPEG frame is a still image, this format offers high-quality images, but uses more bandwidth, and frame rate may decrease as a result. To view images in MJPEG format, set the [Refresh Rate] selector to [MJPEG].
MPEG-4
MPEG-4 is a video format that updates images only when there is a variation in the image displayed, and as a result, requires less bandwidth. MPEG-4 is useful in situations when less bandwidth is available, such as when viewing camera images over the Internet. To view images in MPEG-4 format, set the [Refresh Rate] selector to [MPEG-4], then select the desired streaming format under [Streaming Method]. MPEG-4 images can be streamed using multicast, unicast, and HTTP (see 5.6 Changing Video Streaming Settings). When accessing the camera using HTTPS, multicast and unicast streaming is not possible; HTTP is the only available streaming method.
[Auto]: The first available MPEG-4 streaming method will be used, beginning with multicast, then unicast, then HTTP. The current streaming method is displayed below the camera image.
[Multicast] (Multicast RTP): Multicast allows you to stream the same data over the network to multiple parties, thus reducing the amount of data that is sent over the network.
Multicast streaming is not possible when viewing camera images over the Internet.
In order to use multicast streaming, the camera must be configured for multicasting (see 5.6 Changing Video Streaming Settings). Note that multicast streaming is not possible when viewing camera images on certain local networks. Consult your network administrator before configuring the camera for multicasting.
MPEG-4 images may break up when accessing the camera over a low bandwidth connection. This is normal. In this case, select [Unicast] or [HTTP] as the streaming method.
If MPEG-4 images cannot be displayed when [Multicast] is selected as the streaming method, select [Auto], [Unicast] or [HTTP].
[Unicast] (Unicast RTP): While no special settings are required to stream video using unicast, video is streamed to each individual user viewing MPEG-4 images, which creates more network traffic as more users access the camera. Unicast is generally more reliable than multicast, and is not as susceptible to image quality issues that may occur with when multicasting.
Unicast streaming is not possible when viewing camera images over the Internet.
Unicast streaming may not be possible when viewing camera images on certain local networks. Consult your network administrator for more information.
If a user with a low bandwidth connection or if many users are viewing images using unicast streaming, frame rate will decrease and image quality may be affected for all users viewing MPEG-4 images.
If MPEG-4 images cannot be displayed when [Unicast] is selected as the streaming method, select [Auto] or [HTTP].
[HTTP] (RTP over HTTP): When streaming video using HTTP, the camera confirms that the data is being received by the user. Video can be viewed in network environment that do not support multicast or unicast streaming, however, this streaming method requires more bandwidth than the other methods.
If a user with a low bandwidth connection or if many users are viewing images using HTTP streaming, frame rate will decrease and image quality may be affected for all users viewing MPEG-4 images.
If MPEG-4 images cannot be displayed when [HTTP] is selected as the streaming method, select [MJPEG] as the image refresh rate.
Note
If a user with a low bandwidth connection is viewing MPEG-4 images, frame rate will decrease and image quality may be affected for all users viewing MPEG-4 images.
When the camera is configured to buffer images in MPEG-4 format, frame rate will decrease when viewing MPEG-4 images on the single camera and multi camera pages.
To adjust video streaming settings in order to improve image quality or frame rate when viewing MPEG-4 images, see 5.6 Changing Video Streaming Settings.
Still Images
Still images that are refreshed periodically can be displayed instead of video images by selecting the desired refresh rate. For example, selecting [3 s] will refresh the camera image once every 3 seconds.