Streaming Video Basics
algorithms to appropriately meet the exact constraints without quality loss due A. Frame types. The MPEG-2 standard defines three types of frames, Б, И .. B B P. B7 B8 P1. P B B. I reference. B input. I. B1 B2 P2 B3 B4 P3 B5 B6. I. B7 B8 P1. BNC-to-RCA adapters are readily available if RCA type cables are used. In compressed video, each frame is compressed using a "lossy" compression BBIBBP. 7. IPP PP. IBPBP. IBBPBBP. 8. IPP PP. BIBPBP. ††. 9. IPP. . We encourage you to override specific template settings in order to meet the unique. Select channel, click ”search” button, all the names of files which meet the time and file type conditions Frame type: BBP and P can be selected. I Frame: can.
For streaming video e. One-Way Broadcast and Desktop Streaming VBrick 4xxx and 62xx models provide a powerful streaming broadcast and desktop streaming solution. Each VBrick is capable of multicasting live video IP streams to an unlimited number of desktop clients in a given network.
Video compression picture types
With StreamPlayer, the user selects a stream for viewing by selecting the transmitted SAP from the VBrick, which identifies the video in the program guide. On a television monitor, a user can select the appropriate VBrick SAP program name through the use of the provided remote control device. This illustration shows a VBrick in a network multicasting live video traffic to other VBrick appliances as well as to the desktop clients using StreamPlayer or StreamPlayer Plus.
The program stream is displayed on the desktop client and the user can view the stream in real time. This application can be expanded to include previously recorded material such as training tapes and pre-recorded VHS tapes. Since the Session Advertisement Protocol, or SAP, containing the name of each program are small and are only sent periodically, they have practically little or no impact on the network bandwidth.
Two-Way Interactive Conferencing For two-way interactive conferencing applications, appropriate audio conference equipment such as amplifiers, microphones, and echo control equipment is required. Contact VBrick for accessories. VBrick 's enable automatic two-way television via IP unicast. Each VBrick in the network automatically announces its "name" to other VBricks in the network and displays a conference guide on a TV screen.
The conference guide indicates who is available for a conference. It is only necessary to select from the list of names to establish a two-way video communications. These illustrations show how the conference system works. Each VBrick also receives a list of available names from the network. To place a call, select the party and when the call is answered, a two-way, private, unicast video conference is established.
Because the name advertisements are small and only sent periodically, they have practically no impact on the network. These advertisements are typically sent to a default multicast address, but may be configured to be broadcast or configured to be sent to any valid IP Address. Once the call is established, the calling party may "ring" the other end to get their attention, if desired.
Several configuration options are available: Auto answer — the party receiving the call does not have to answer. The VBrick automatically receives the call and two-way video is instantly available. Manual Answer — the party receiving the call must answer it before the call is established. How often to advertise the Call Name. The address on which to advertise the Call Name.
Two-way interactive conferencing may be initiated from the IR remote handheld device. VBrick Accessories VBrick units have a number of optional hardware accessories, including the AudioMate microphone, remote control devices and cameras.
These work directly with VBrick appliances or through the use of ActiveX control software, also available from VBrick. For information about microphones, cameras and other VBrick hardware accessories, please contact VBrick directly. ActiveX controls for cameras and other software accessories are also available from VBrick.
Serial Port Passthrough When configured properly, VBricks provide full duplex, end-to-end transparent passthrough of user data from one VBrick to another, or to other IP devices. Two serial ports are provided, each independently supporting this feature. COM1 is dedicated to Passthrough. COM2 is normally used for management control, but may be configured to support Passthrough, depending on the VBrick hardware revision.
Each serial port operates at its configured baud rate e. Some common applications include: Remote control of a camera, pan-tilt-zoom. Remote control of a security door lock. Low speed data transport. Frames that use prediction from a single preceding reference frame or a single frame for prediction of each region are called P-frames.
- Inter frame
B-frames use prediction from a possibly weighted average of two reference frames, one preceding and one succeeding.
Slices[ edit ] In the H. Macroblocks[ edit ] Typically, pictures frames are segmented into macroblocksand individual prediction types can be selected on a macroblock basis rather than being the same for the entire picture, as follows: I-frames can contain only intra macroblocks P-frames can contain either intra macroblocks or predicted macroblocks B-frames can contain intra, predicted, or bi-predicted macroblocks Furthermore, in the H.
Facilitates switching between coded streams; contains SI-macroblocks a special type of intra coded macroblock. When such frames are used along with a smart decoder, it is possible to recover the broadcast streams of damaged DVDs. Key frame animation and Intra-frame I-frames contain an entire image. They are coded without reference to any other frame except parts of themselves. May be generated by an encoder to create a random access point to allow a decoder to start decoding properly from scratch at that picture location.
May also be generated when differentiating image details prohibit generation of effective P or B-frames.
Typically require more bits to encode than other frame types. B-frame[ edit ] B-frame is the term for bidirectionally predicted pictures. Similar to P-frames, B-frames are expressed as motion vectors and transform coefficients. In order to avoid a growing propagation error, B-frames are not used as a reference to make further predictions in most encoding standards. However, in newer encoding methods such as AVCB-frames may be used as reference.
Time goes from left to right. The I-frame is used to predict the first P-frame and these two frames are also used to predict the first and the second B-frames.
Video compression picture types - Wikipedia
The second P-frame is predicted also using the first I-frame. Both P-frames join together to predict the third and fourth B-frames. The scheme is shown in the next picture: This structure suggests a problem because the fourth frame a P-frame is needed in order to predict the second and the third B-frames.
So we need to transmit the P-frame before the B-frames and it will delay the transmission it will be necessary to keep the P-frame. This structure has strong points: It minimizes the problem of possible uncovered areas.