CN101563886B - Redundant media packet streams - Google Patents

Abstract

The present invention relates to the transmission and reception of digital media packets such as audio and video channels and lighting instructions. In particular, the invention relates to the transmission and reception of redundant streams of media packets. Samples are extracted (556) from the first stream of media packets (904) and the second stream of media packets (906). The extracted samples are written into a buffer (910) based on the output time of each sample (556). The extracted samples with the same output time are written to the same location in the buffer. Both streams of media packets are always simply processed until written to the buffer, without specific knowledge that one of the packet streams is actually redundant. This simplifies the management of redundant packet flows, eg eliminating the need for "failback" switches and the concept of "active flows". The location is the memory space allocated for storing one sample. An extracted sample written to this location may overwrite another extracted sample from a different packet stream previously written to this location. These extracted samples written to the same location may be the same.

Description

Redundant Media Packet Stream

technical field

The present invention relates to the transmission and reception of digital media packets such as audio and video channels and lighting instructions. These media channels are sent as media packets from the sender device to the receiver device for playout. In particular, the invention relates to the transmission and reception of redundant streams of media packets. The invention relates to a sender device, a receiver device, a data network, a method of receiving a stream of media packets, and computer software for performing the method.

Background technique

Media channels such as audio and video channels have long been carried using application-specific cables. For example, use a dual-core speaker cable to route the left and right audio channels from the amplifier to the speakers.

More recently, media signals are transmitted over computer-based networks using protocols such as unicast or multicast. Unicast is a method of sending packets over a computer network to a single destination. The unicast packet must be retransmitted for each media device wishing to receive the packet.

Typically, multicast refers to IP multicast, which is a protocol for efficiently transmitting simultaneously to multiple receiver devices over a TCP/IP network using a multicast address. The computer network then operates to route the packet to each device on the network that wishes to receive the multicast packet.

A media network can allow redundant media packet streams to be sent and received. It is known that the sender processes the main media packet stream continuously and simply ignores the redundant copies of the media packet stream. In the event that a problem is detected in the main packet flow (ie, a transmission path in the network is broken), a "failback" switch occurs. Once the switch is activated, the receiver device ignores the primary media packet stream and processes redundant copies.

Contents of the invention

In one aspect, the invention provides a receiver device for receiving a stream of media packets from a data network, the receiver device comprising:

The first data interface is used to receive a first media packet flow, and the first media packet flow includes samples of media channels;

The second data interface is used to receive a second media packet stream, and the second media packet stream includes samples of media channels;

a processor configured to extract samples from the first media packet stream and the second media packet stream, and determine an output time of the extracted samples;

a buffer for temporarily storing the extracted samples for output; and

Wherein the processor is operative to write the extracted samples into the buffer based on the corresponding output time such that extracted samples having the same output time are written to the same location in the buffer.

In this way, the receiver device can simply process both streams of media packets all the way up to writing them in the buffer without specifically knowing that one of the packet streams is actually redundant. This simplifies the management of redundant packet flows, eg eliminating the need for a "failback" switch. Furthermore, the concept of "active flow" is no longer required.

The buffer may be designed to store a predetermined maximum number of extracted samples in order according to the output time of each extracted sample. A location is the memory space allocated to store a sample. A first extracted sample written to a location may overwrite a second extracted sample from a different packet stream previously written to that location. The first and second extracted samples written to the same location may be the same.

A buffer can be associated with one output channel, and each stream of media packets can be directed to the same output channel. Each media packet stream can contain two or more media channels.

The receiver device may further comprise a third data interface for receiving a third stream of media packets comprising samples of the media channel, wherein the processor is further operative to extract samples from the third stream of media packets and determine the extracted samples output time. Since no specific administrative controls are required for handling redundant packet flows, the number of redundant packet flows can easily be increased and all packet flows processed in the same manner.

The first and second media packet streams may be received from different data interfaces of the same sender device connected to the data network.

The processor is also operable to detect corrupted samples and prevent these corrupted samples from being written to the buffer.

All samples contained in one media packet of the first stream of media packets may not all be contained in any single media packet of the second stream of media packets. Even if the samples of the two media streams are not packetized in the same way, the processor is operable to extract and write the samples in the same way.

The samples of the media channel may have associated timestamps, and the processor may be operable to determine an output time of the extracted samples based on the respective timestamps. The timestamp may be an absolute timestamp and may represent a sampling time.

The present invention may also include a method for receiving a stream of media packets from a data network, the method comprising the steps of:

receiving a first stream of media packets, the first stream of media packets comprising samples of media channels;

receiving a second stream of media packets, the second stream of media packets comprising samples of media channels;

extracting samples from the first stream of media packets and the second stream of media packets;

determining an output time of the extracted samples;

Based on the corresponding output time, the extracted samples are written to the buffer for output, whereby the extracted samples with the same output time are written to the same location in the buffer.

In another aspect, the invention provides computer software to operate a receiver device to perform the method described above.

In yet another aspect, the present invention provides a sender device for sending a stream of media packets over a data network to a receiver device, the sender device comprising:

one or more data interfaces for sending a first media packet stream and a second media packet stream to a receiver device, the media stream comprising one or more media channels;

a processor that packetizes the media channel based on the request from the receiver device to create a stream of media packets for transmission over the data interface; and

A controller such that the processor creates two independent streams of media packets containing the same media channel to be sent to the receiver device.

The request may address a first stream of media packets comprising a media channel to a first interface of the receiver device and a second stream of media packets comprising the same media channel to a second interface of the receiver device. The request may be a single message received from the receiver device.

The sender device may comprise a first data interface for sending the first stream of media packets and a second data interface for sending the second stream of media packets.

The data network may include first and second data sub-networks. The controller may cause the first stream of media packets to be sent over the first data subnetwork and the second stream of media packets over the second subnetwork. In this way, if one data network fails to transmit one or more packets successfully, the same media channel is transmitted via another sub-network and no data loss occurs. Furthermore, the first data subnetwork may have a different configuration than the second data subnetwork, for example a different transmission protocol.

The invention also relates to a method and software for sending two streams of media packets comprising the same media channel to a receiver device.

In yet another aspect, the present invention provides a computer network comprising a receiver device and a transmitter device as described above.

Description of drawings

Examples of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of a network that may be used with the present invention;

Figure 2 is a schematic diagram of a single packet of a media packet stream sent over a network using the present invention;

3(a) to 3(d) are schematic diagrams of how to implement redundancy in a data network;

Figure 4 is a schematic diagram of a network using redundant interfaces according to an embodiment of the present invention;

Figure 5 is another schematic diagram of a network using redundant interfaces according to another embodiment of the present invention; and

Fig. 6 is a schematic diagram of a buffer of an output channel of a receiver device.

specific implementation plan

Overview of Network Components

Referring to Figure 1, a data network is depicted. The data network 100 includes a transmitter device 110 and a receiver device 112 . There may be multiple transmitter devices 110 and multiple receiver devices 112 in the network 100, but only one of them is discussed here for clarity. Furthermore, devices 110 and 112 may be able to perform both sending and receiving functions, but here for greater clarity, devices 110 and 112 are depicted as each performing only one function.

The sender device 110 and the receiver device 112 are connected to each other by a network 114 so that they are able to send and receive digital media packets as part of a stream of media packets. The sender device 110 includes an audio processing engine (APE) 120 and an audio processing engine controller (APEC) 122 . Receiver device 112 also includes APE 124 and APEC 126. Media packets are sent in a media packet stream that may contain one or more media channels. For simplicity, the embodiments describe all media channels in a media packet stream as being in the same format, however the present invention can be applied to multiple media channel formats within one media packet stream.

A media device 140 such as a guitar is connected to the APE 120, and the APE 120 receives media signals generated by the media device 140. A pre-processor (not shown) may be added to convert a media channel from analog to digital or from one digital format to another (eg, sample rate or bit depth conversion). APE 120 then packetizes the digital media channels. The resulting packet stream is sent to the APE 124 of the receiver device 112 using the network 114. APE 124 then depackets the digital media signal, converts it (if appropriate) to an analog signal, and sends the analog media signal to media device 142, such as a speaker for playout. When the media signal is a non-analog source such as a MIDI source, no conversion is necessary. The rate and skew of packetization and transmission are tightly controlled in time to ensure that the playout of the media signal by the media device 142 is compatible with another media device (not shown) connected to the network 114 that also receives the media signal from the APE 120 Synchronization between broadcasting of media signals. The packetization operation of APEs 120 and 124 is described in detail in co-pending PCT application PCT/AU2006/000538 (WO2006/110960). In addition, reference is also made to co-pending PCT applications claiming priority from AU2006906015 and AU2006902741 filed on the same date.

APEC 122/126 is a component implemented in software or hardware. In this network 100, the APEC 122/126 is on the same physical device as the APE 120/124, but may optionally be remote from the APE 120/124, such as on another device or a central computer connected to the network 114. APEC122/126 provides the user with an overview of the APE 120/124 and any audio equipment 140 and 142 connected to it. The sender device 110 has a number of transmittable channels that can be named and offered to receiver devices 112 on the network 114; this is called an advertisement. The receiving device 112 has a plurality of receiving channels. Named send channels can be assigned to receive channels; this is called a subscription. APEC 122 and 126 will configure APE 120/124 to route media signals from transmit channels to receive channels.

Receive and transmit APEC 126 and 122 exchange configuration information and control messages over network 114. Configuration information is exchanged via a service discovery database 118 such as DNS-SD. The database may be implemented in a distributed manner such that each device 110 and 112 stores and provides configuration information associated with its APEC 122/126. Additional control messages are sometimes required to complete the subscription process and cause media signals to be routed. These additional control messages are sent between receiving APEC 126 and sending APEC 122.

Each APEC 122/126 configures its own APE 120/124 and interacts with other APEC 122/126 to ensure that configurations match between communicating APEs 120/124.

Inside each device 110 and 112, input channels such as those from audio device 140 are referred to as "TX channels" because they will be sent over the network, while channels such as those sent to audio device 142 Output channels are called "RX channels" because they will receive data from the network.

First, devices must connect to create the network 104 . Referring to FIG. 4 , four media devices (keyboard 144 , guitar 140 , left channel 146 for CD, and right channel 148 for CD) are connected to four input channels of transmitter device 110 . In this example, the keyboard and guitar use the same sample rate and sample format (eg 48kHz, 24bit, PCM encoding). CD channels have different sampling rates and sampling formats (eg 44.1kHz, 16 bit, PCM encoding).

media packet flow

Referring now to FIG. 2, a single media packet 550 is schematically shown. A plurality of media packets sent sequentially constitutes a stream of media packets. Each media packet 550 in the same media stream includes the same media channel. Each media packet 550 includes frames 554 . In each frame 554 of a media packet 550, each media channel must be allocated a sample space 556. This sample space is also called a time slot. Each packet 550 has one time slot per channel and thus one sample space 556 per frame 554 .

Each frame 554 is associated with an absolute timestamp, which is also recorded within the packet. The notion of time is synchronized between all devices 110 and 112 on the network 100 so they share a common clock. All devices 112 that control the playout of the media channels contained within frame 554 must simultaneously play out the channels in each frame. This is done based on timestamps in each frame 554. For example, each playout device may play out samples 556 in each frame 554 with a predetermined delay beyond the absolute timestamp, with reference to a common clock.

Redundant Media Packet Stream

Redundancy will now be described with reference to FIG. 4 . Redundancy is achieved by duplicating packet streams on different interfaces of the network device. Redundancy is mainly controlled at the APEC layer. APEC can program a given packet flow on an APE to be sent or received over a specific data interface. If a particular media packet stream is to be sent redundantly, APEC will program two or more copies of the packet stream. One copy is sent from the first interface 130 of the APE 120, and a second copy of the packet flow is sent from the second interface 136 of the APE 120.

Similarly, the receiving APEC 126 has its APE 124 programmed to receive copies through the respective data interfaces 132 and 134. Each replicated packet stream is programmed to provide samples to the same output channel. This means that the packet streams are written into the same buffer. Since the samples and the determined output times are the same in both packet streams, the same samples are processed and used to overwrite the buffer for the output channel. Usually, this will lead to errors and race conditions. However, since all redundant media packet streams contain identical samples with synchronized output times, it does not matter which sample data of which media packet stream is written to the buffer first, since all duplicate copies are simply overwritten. Write, so only one copy of each sample is actually sent to the output channel.

The output time indicates where in the buffer the samples are to be written. The output time of the samples is determined based on timestamps associated with the samples in the stream of media packets. This may include compensating for delay and skew of each media packet stream. Note that timestamping each sample of a media channel does not require physically timestamping each sample. If 20 samples of periodic audio data from a single media signal are sent in one packet, simply timestamping the first sample implies timestamping the rest as well. Therefore, the rest of the samples are also time-stamped by association.

Figure 3 shows some ways in which redundancy can be implemented on a data network. The interfaces may be connected to separate networks 114(a) and 114(b) or to a single network 114 via multiple paths. The interfaces 138 and 139 in FIG. 8(c) are the second redundant interfaces of the transmitter 110 and the receiver 112, respectively. FIG. 8( d ) shows that one interface on the transmitter 110 can transmit to multiple separate interfaces on the receiver 112 .

APEs 120 and 124 with multiple channel data interfaces each designate one interface as the primary interface. The primary interface is interface #0. Any other (redundant) channel data interfaces are numbered starting from 1. For example, APE 124 in FIG. 4 with one primary interface 132 and one redundant interface 134 has interfaces #0 and #1.

For simplicity, APEs 120 and 124 are configured to only transmit or receive with the equivalent interface when transmitting or receiving. Primary interface 130 on one APE 120 communicates with primary interface 132 on the other APE 124. Interface 136#1 on one APE 120 communicates only with interface 134#1 on the other APE 124. and so on. This enables the marking of individual APE interfaces from the outside. For example, on the hardware itself, the primary interface could be colored black, the first redundant interface red, the second redundant interface blue, and so on. This allows the user to easily distinguish the different interfaces and ensure they are wired correctly during assembly.

Redundancy in Unicast Protocols

The media channel is advertised on the network 114 to indicate that receivers can subscribe to the media channel using a unicast protocol. The receiver can request to receive the TXT record of the media channel, the TXT record includes the information of the media channel, including sampling rate (rate), bit depth (bits) and encoding (enc) (1=PCM). The "txtvers" field is the version number of the TXT record. The "nchan" field is the maximum number of channels per dynamic bundle. Each dynamic bundle of stage-box 110 has a maximum of four lanes, which is sufficient to route all inputs 144, 140, 146 and 148 through a single packet. The id field is an arbitrary physical channel identifier used by APEC 120 to briefly identify its channel. The channel named "keyboard" has exactly ID 16. Except for sending APEC 120, this ID is only helpful for receiver APEC 124 to configure dynamic bundles on APEC 122.

The advertisement's TXT record includes a field labeled "nred". The value of "nred" indicates the number of redundant interfaces. If this field is omitted, the value is treated as zero. A value of zero indicates no redundant interface, which means that the APE 120 of the sender 110 only supports the primary data stream. A value of 1 indicates that there is a single redundant interface. Values greater than 1 indicate multiple redundant interfaces (numbered 1..n).

In addition to sending a single Dynamic Bundle Request, a receiving APEC 126 may also send a request for each redundant interface available on the sender, each with a different interface field. Optionally, the request for the redundant flow sent to the redundant interface may be merged into the initial request message for the packet flow sent to the non-redundant interface.

As shown in FIG. 4 , in addition to the main interface 130 (#0), the interface box 110 also has a redundant interface 136 (#1). Now format the TXT record of the channel advertisement as follows:

Record: keyboardstage-box._netaudio_chan._udp.local TXT

txtvers=2

rate=48000

bits=24

enc=1

nchan=4

id=16

nred=1

Mixer 112 also supports redundant channels. The address of its main data interface 132 is 169.254.28.12. The address of its second data interface 134 is 169.254.132.15.

Locally, the Mixer 112 sends the following 'Create RX Bundle' message from its APEC 126 to its APE 124:

field value Remark Destination address 169.254.28.12 The main data interface address of the mixer destination port 26528 interface 0 The main data interface is #0 number of channels 2 Mapping for slot 1 [8] Array with one element: RX channel 1 Mapping for slot 2 [11] Array with one element: RX channel 4

field value Remark Destination address 169.254.132.15 The address of the second data interface of the mixer destination port 28452 interface 1 The second data interface is #1 number of channels 2 Mapping for slot 1 [8] Array with one element: RX channel 1 Mapping for slot 2 [11] Array with one element: RX channel 4

Each message configures a received packet flow to interface 132 or 134 . The second interface 134 (#1) may use the same or a different port number as the primary interface 132, depending on the design of the APE 124. This example assumes a different port is selected.

Just as the mixer 112 must create two separate beams on its APE 124, it needs to create two separate dynamic beams on the interface box 110. Send the following message from APEC 126 to APEC 122:

field value Remark Destination address 169.254.28.12 The main data interface address of the mixer destination port 26528 interface 0 The main data interface is #0 Number of slots 2 Time slot 1 16 I D of keyboardstage-box time slot 2 17 ID of guitarstage-box

field value Remark Destination address 169.254.132.15 The address of the second data interface of the mixer destination port 28452 interface 1 The second data interface is #1 Number of slots 2 Time slot 1 16 I D of keyboardstage-box time slot 2 17 I D for guitarstage-box

Ultimately, pod 110 creates two bundles on local APE 120 to satisfy these requests. The following information is sent from APEC 122 to APE 120:

field value Remark Destination address 169.254.28.12 The main data interface address of the mixer destination port 26528 interface 0 The main data interface (on the interface box) is #0 number of channels 2 TX channel of time slot 1 16 TX channel 1 TX channel of time slot 2 17 TX channel 1

field value Remark Destination address 169.254.132.15 The address of the second data interface of the mixer destination port 26452 interface 1 (On the interface box) the second data interface is #1 number of channels 2 TX channel of time slot 1 16 TX channel 1 TX channel of time slot 2 17 TX channel 2

multicast redundancy

To support redundant multicasting, the sender 110 creates several distinct packet streams and advertises them as separate static bundles associated with a single bundle name.

For example, to advertise two copies of bundles bl and b2, primary bundle 130 and secondary bundle 136, pod 110 will first declare the multicast address for each bundle. Use 239.254.46.46 for the main beam. For the second beam use 239.254.98.147. For this example, assume that both bundles use the same interface (29061).

Create two service records (SRVs), one for each packet flow. Since each packet stream is formatted identically, only a single TXT record is required.

Record: b1stage-box._netaudio_bund._udp.local SRV

0 1 2906146.46.254.239.mcast.local

Record: b1stage-box._netaudio_bund._udp.local SRV

1 1 29061 147.98.254.239.mcast.local

Record: b1stage-box._netaudio_bund._udp.local TXT

txtvers=1

rate=48000

bits=24

enc=1

nchan=4

If only a single (primary) interface is used, set the "Priority" field (represented as the first number) in the SRV to 0. A non-zero priority indicates that the bundle is to be applied to the redundant interface, interface 1 in this example.

Decoding these bundle advertisements enables the receiver to configure the appropriate bundle on each interface. APEC 126 configures APE 124 to receive the primary bundle on first primary interface 132 and the second bundle on second interface 134.

buffer management

Whether a unicast or multicast protocol is used, the manner in which the receiver device 112 manages the replicated packet stream is the same.

Referring to data network 902 in Figure 5, it is shown that sender device 110 sends two identical packet streams. One packet flow 904 is sent from the primary data interface 130 and a second packet flow 906 is sent from the first redundant interface 136 . Both packet streams contain samples generated by the media channel to which keyboard 144 is connected.

The first primary packet stream 904 is received at the primary data interface 132 by a receiver device (ie amplifier 908). The second redundant packet stream 906 is received at the first redundant data interface 134 by the amplifier 908 . APE 124 processes each of packet streams 904 and 906 according to instructions received from APEC 126.

Here, APE 124 will process received packet streams 904 and 906 for playout through speaker 142, which is connected to output channel 2 of amplifier 908. Optionally, the device connected to output channel 2 may not be a playout device, but may be, for example, a mixer or an amplifier.

APE 124 extracts samples from received data streams 904 and 906 and determines an output time for each sample based on the corresponding timestamp. APE 124 then writes the samples to buffer 910 based on the determined output time before sending the samples to output channel 2 for playout through speaker 142.

The method of writing samples to the buffer will now be described with reference to FIG. 6 . Packet streams 904 and 906 are processed independently, and APE 124 need not specifically recognize that they are substantially identical.

APE 124 extracts samples of the keyboard media channel from the packet stream and writes 912 them into buffer 910 such that the samples are in output order in the buffer. The buffer is conceptually divided into intervals t ₀ , t ₂ , t ₃ . . . t _n as the length of each sample, and each of which corresponds to an output time. Writes one sample into each interval based on the respective output time. Once a sample has been written to the last interval t _n in the buffer 910, continue writing samples to the first interval t ₀ to overwrite the sample that was written there but was sent to output channel 2 and played out by speaker 142 previous sampling.

Since each sample received has an associated time stamp with an absolute time reference, the output time corresponding to the absolute time reference can be easily determined. In this example, the same samples must be delivered synchronously to the output channels, so the output time of each sample must also be the same. Therefore, if a sample is received out of sequence, it can also be written to the correct interval, since the correct interval can be selected based on the output time of that sample. If a sample belongs to a time interval that has already been played out, the sample will simply be dropped.

Both the first packet flow 904 and the second packet flow 906 are processed in this manner. Since the sample and its determined output time are the same, the same sample is written twice to the same interval. It does not matter whether the samples from the first packet stream 904 or the second packet stream 906 are written to the buffer 910 first, the net result of the samples temporarily stored in the buffer will be the same.

In this way, if a packet from the first packet stream 904 is lost during transmission by the sender device 110 , samples from the same packet in the second packet stream 906 are written into the buffer 910 . In this case, the samples are written to the buffer only once. Of course, the reverse could also happen when a packet from the second packet stream 906 is lost, and only samples from the same packet in the first packet stream 906 are written into the buffer 910 .

Since APEC 126 knows that packet streams 904 and 906 (more specifically, specific time slots in each packet stream 904 and 906) contain the same data, and in the above message sent from APEC 126 to APE 124, APEC 126 sends APE 124 Programmed to unconditionally copy both into the same buffer, the APE 124 does not need to determine which packet stream is "current" or "active". The APE 124 processes and copies both at the same interval (position) in the buffer, regardless of which of the packet streams 904 and 906 is processed and written to the buffer first, both streams in normal The method is simple to handle. This reduces the complexity of managing a system capable of sending and receiving redundant packet streams. For example, it is no longer necessary to determine whether to activate a failover switch. Once a path is established, no additional decision logic is required for APE 124 or APEC 126 unless both paths fail.

If samples are corrupted during network transmission, those samples should be discarded once identified. Duplicated media packet streams will ensure that the output buffer receives at least one copy of the samples without switching between media packet streams. Any transmit-level error checking or error recovery is performed before the sampled data is written to the shared buffer.

The actual sample content of each packet in media packet streams 904 and 906 need not be the same. For example, the media channel may be packetized differently into packet streams 904 and 906 such that packets from each stream do not contain the same samples. The method of writing samples into the buffer is always the same, since each identical sample will share output time regardless of the position of the associated frame in the packet. When writing samples into the buffer, the APE 124 will refer to the output time of each sample to determine which interval (position) the sample should be written to.

The invention also allows for other redundant streams each containing the same media channel. Each stream of media packets may be sent to a different data interface. Likewise, the APE 124 will process all packet streams independently and write the extracted samples into the same buffer for the output channels.

Of course, sample 556 may be a mix of one or more media sources, such as keyboard 144 and guitar 140 . Optionally, a mixer can be provided for mixing the samples before writing them into the buffer.

It will be appreciated by those skilled in the art that various variations and/or modifications may be made to the invention shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described.

■ When using static bundles, channels can be assigned to bundles in any convenient way. Redundancy can also be achieved by creating specific bundles on specific interfaces.

■ Dynamic bundles are usually unicast. Static bundles are usually multicast. Dynamic bundles can also be configured as multicast, or static bundles as unicast, if desired.

■Physical channel input/output can also be implemented in software, for example of a mixer, instead of actual physical plugs.

■ Although the above examples assume sampled channel data, the exact same protocol mechanism will work on arbitrary fixed-size periodic data streams. Aperiodic or variable-sized data can also be supported using variants of the transport (packet and bundle) mechanism.

■ Assigning homogeneous channels to time slots is for convenience. Non-homogeneous channel media data with a common sampling rate can be identified in a frame using a start byte and a length.

■ MIDI is an example of aperiodic data. The same interface that enables users to abstractly route audio to audio and video to video can route MIDI to MIDI. Like periodic packets, MIDI packets will have time stamps, but receivers should not expect that MIDI data units will arrive periodically. Aperiodic data may require periodic "keepalive" messages to distinguish silent from non-functional streams. Aperiodic data can be automatically aggregated just as easily as periodic data, as long as there is a flag stating "this data is not in this packet".

Accordingly, the present embodiments should be considered in all respects as illustrative and not restrictive.

Claims (27)

1. be used to receive the receiver device from the media packet streams of data network, said receiver device comprises:

First data-interface is used to receive first media packet streams, and said first media packet streams comprises the sampling of media channel;

Second data-interface is used to receive second media packet streams, and said second media packet streams comprises the said sampling of said media channel;

Processor is used for extracting sampling from said first media packet streams and said second media packet streams, and confirms the output time of the sampling of this extraction;

Buffer is used for temporarily storing the sampling of said extraction, to be used for output; And

Wherein, the sampling with said extraction writes in the said buffer thereby said processor operations is based on said output time, and the sampling that has the extraction of identical output time thus is written into the same position in this buffer.

2. receiver device according to claim 1, wherein, the sampling of the extraction that said buffer can temporary transient storing predetermined maximum number.

3. receiver device according to claim 1 and 2, wherein, said buffer can temporarily be stored the sampling of this extraction in order according to the corresponding output time of the sampling of said extraction.

4. receiver device according to claim 1 and 2, wherein, said output time is the broadcast time that media device broadcasts said sampling.

5. receiver device according to claim 1, wherein, said position is the memory space that branch is used in a sampling of storage.

6. receiver device according to claim 1 wherein, is written into the sampling of extracting from second of different packets stream that the sampling of extracting first of said position writes this position before rewriting.

7. receiver device according to claim 6, wherein, the sampling that the sampling of said first extraction and said second is extracted is identical.

8. receiver device according to claim 1, wherein, said buffer is associated with an output channel, and each media packet streams is directed to identical output channel.

9. receiver device according to claim 1; Wherein, said receiver device also comprises the 3rd data-interface, is used to receive the 3rd media packet streams of the said sampling that comprises said media channel; Wherein, Said processor is also operated from the 3rd media packet streams, extracting sampling, and confirms that output time and the sampling that will extract based on this corresponding output time of the sampling of this extraction write in the said buffer.

10. receiver device according to claim 1, wherein, said processor is also operated detecting ruined sampling, and prevents that these ruined samplings are written in the said buffer.

11. receiver device according to claim 1, wherein, all samplings that comprised in the media packet of said first media packet streams are not all to be comprised in any single medium grouping of said second media packet streams.

12. receiver device according to claim 1, wherein, said first media packet streams and said second media packet streams are that the different pieces of information interface from the transmitter apparatus that is connected with said data network receives.

13. receiver device according to claim 1, wherein, the said sampling of said media channel has related timestamp separately, and said processor operations is to confirm the output time of the sampling of this extraction based on the timestamp of said association.

14. be used to receive the method from the media packet streams of data network, said method comprises step:

Receive first media packet streams, said first media packet streams comprises the sampling of media channel;

Receive second media packet streams, said second media packet streams comprises the said sampling of said media channel;

From said first media packet streams and said second media packet streams, extract sampling;

Confirm the output time of the sampling of said extraction;

Based on the corresponding output time of the sampling of said extraction, the sampling of each said extraction is write in the said buffer to be used for output, the sampling that has the said extraction of identical output time thus is written into the same position in this buffer.

15. method according to claim 14, wherein, the step that said sampling with each said extraction writes in the said buffer comprises: write the sampling of said extraction in order according to the corresponding output time of the sampling of each said extraction.

16. method according to claim 14, wherein, said output time is the broadcast time that media device broadcasts said sampling.

17. method according to claim 14, wherein, said position is the memory space that branch is used in a sampling of storage.

18. method according to claim 14; Wherein, The step that said sampling with each said extraction writes in the said buffer comprises: the sampling of first extraction is write a position, use the sampling of extracting from second of different grouping stream to rewrite the sampling of this first extraction of said position then.

19. method according to claim 18, wherein, the sampling that the sampling of said first extraction and said second is extracted is identical.

20. method according to claim 14, wherein, said buffer is associated with an output channel, and each media packet streams is directed to identical output channel.

21. method according to claim 14, wherein, said method is further comprising the steps of: receive the 3rd media packet streams of the said sampling that comprises said media channel, and from said the 3rd media packet streams, extract sampling.

22. method according to claim 14, wherein, said method is further comprising the steps of: detect ruined sampling, and make these ruined samplings not be written in the said buffer.

23. method according to claim 14, wherein, all samplings that comprised in the media packet of said first media packet streams are not all to be comprised in any single medium grouping of said second media packet streams.

24. method according to claim 14, wherein, the sampling in the said media channel has related timestamp separately, and the step of the output time of the sampling of said definite said extraction is based on the timestamp of said association.

25. method according to claim 14; Wherein, Said first media packet streams is from first data-interface of the transmitter apparatus that is connected with said data network, and said second media packet streams is from said first data-interface or another data-interface of the transmitter apparatus that is connected with said data network.

26. method according to claim 14, wherein, said method comprises that also sending a message asks to receive said first media packet streams and said second media packet streams.

27. data network comprises:

Be used for through the transmitter apparatus of data network to receiver device transmission media packet streams, said transmitter apparatus comprises:

One or more data-interfaces are used for sending first media packet streams and second media packet streams to said receiver device, and said media packet streams comprises one or more media channels;

Processor carries out packetizing based on the request from said receiver device to said media channel, is used for the media packet streams that sends through said data-interface with establishment; And

Controller makes said processor create two independently media packet streams, said two independently media packet streams comprise the identical media passage that will be sent to said receiver device;

According to each described receiver device in the claim 1 to 13; And

Communicator is used to make media packet streams to be sent to said receiver device from said transmitter apparatus.

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