A transrate manager on a host computer determines if there is a limitation in network bandwidth and controls the bit-rate of streaming media content accordingly. The bit-rate is controlled by excluding types of video frames from the streaming media content and then reintroducing excluded types of video frames back into the streaming video content once the network has recovered.

Media transrating over a bandwidth-limited network

An audio mixer on a first device receives one or more incoming audio streams. Each of the one or more incoming audio streams has an associated timestamp. The audio mixer generates a mixed audio stream from the one or more incoming audio streams. The audio mixer determines differences in the time base of each of the one or more incoming audio streams and the time base for the mixed audio stream. The audio mixer generates mapping parameters associated with the determined differences and transforms the timestamp of each of the one or more incoming audio streams to a corresponding output timestamp associated with the mixed audio stream according to the mapping parameters. the mapping parameters are provided to a video mixer for similar processing and transformation such that the mixed audio stream is in synchronization with a mixed video stream.

System and method for providing video conferencing synchronization

In a network system, clock signals of a server device and a client device are synchronized with each other without having any influence of a change and a delay of the transmission time of data. Therefore, in the network system in which the client device receives and reproduces information transmitted from the server device, the server device counts the number of clock pulses of a server clock signal used to compress and encode information on the basis of a power source synchronous pulse signal synchronized with a power source frequency. The server device outputs information showing the counted clock pulse number and the compressed and encoded information to the client device. The client device counts the number of clock pulses of a client clock signal used to decode and decompress the compressed and encoded information on the basis of the power source synchronous pulse signal synchronized with the power source frequency. The client device conforms the frequency of the client clock signal to the frequency of the server clock signal on the basis of the clock difference between the clock pulse number received from the server device and the counted clock pulse number.

Synchronizing clock signals of server and client devices in a network system based on power source synchronous pulse signal

A client device (104) receives streaming content from a host device (102). The streaming content is placed in one or more buffers (128) prior to processing. Monitoring as to the capacity and fullness of the buffers prior to processing (132). Monitoring as to the capacity and fullness of the buffers is performed at the client device and information is sent to the host device. The host device adjusts the rate or flow of the streaming content based on the information provided by the client device.

Flow control for media streaming

An electronic message may be reconfigured to effect an enhanced notification using an input interface to receive at least one electronic message created by or on behalf of a message source for delivery to an intended recipient. A matching engine determines whether the electronic message corresponds to a predetermined definition of an enhanced notification. An enhancement engine reconfigures the electronic message to the enhanced notification if stored information related to the intended recipient indicates that the intended recipient is subscribed to receive the enhanced notification. Reconfiguring the electronic message may include reconfiguring the message to provide special handling, routing or presentation.

Reconfiguring an electronic message to effect an enhanced notification

In a real-time audio/visual system in which A/V data is conveyed over a jitter-introducing
network, dejittering and clock recovery processes can be achieved without requiring a Phase
Locked Loop (PLL). At the server, audio/video streams are encoded into transport packets
before being sent out. At the client, the dejittering process is achieved by a dejittering buffer
using the embedded timestamps in the transport packets and a client decoding clock. The
delay variations of data arriving are removed after the client buffering process. At the
scheduled time, each data packet is shifted to a synchronizing buffer and then fed to the A/V
decoder according to the speed of A/V stream. The clock synchronization between client and
server is achieved by a synchronizing buffer whose half-size position is taken as the
reference. By monitoring the movement of the buffer fill position over a given period, the
drift rate of clock unsynchronization between client and server can be derived and, therefore,
the client's clock can be adjusted to synchronize with the server's clock based on the derived
drift.

A dejittering and clock recovery technique for real-time audio/visual network applications

PROBLEM TO BE SOLVED: To enable jitter removal and clock recovery processing without using a phase-locked loop(PLL) circuit. SOLUTION: For a server 10, an A/V stream 11 is encoded and transmitted via a network 20, which contains jitter, to a client 30 as a transmission packet. For the client 30, jitter removal is performed by a jitter removing buffer 33, while using the time stamp of the transmission packet and a decoding clock 35 of the client himself. Then, respective data packets are outputted to a synchronizing buffer 36 for scheduled time and supplied to an A/V decoder 37, according to the velocity of the A/V stream. At this time, by monitoring the position of the synchronizing buffer 36 while defining the half position of the synchronizing buffer 36 as a reference position, clock synchronization between the client 30 and the server 10 can be performed. COPYRIGHT: (C)2000,JPO

Jinghong Xu

Papers

A dejittering and clock recovery technique for real-time audio/visual network applications

Clock fluctuation compensating method and real-time audio/visual system