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Directshow RTP multimedia applications on the network adapter support

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Directshow RTP multimedia applications on the network adapter support


Intel architecture Labs


Interactive collaborative applications, or contains many procedures independent of the distributed multi-media games, the same pace run-time generation and \ or play multi-channel audio and video streaming. With the changes in a single flow and flow / application was activated, or the final termination of the demand for resources, the total available resources will also lead to dynamic change. Network multimedia applications (NetMM) must be prepared to adapt to these changes, using them can be acceptable to users at different levels of service to this fact. Add this article highlighted the adaptability of the network and host-based components of the Directshow RTP problems.

Directshow is a set of Microsoft's video data acquisition and display system architecture. Directshow RTP is a system architecture to expand the Directshow framework, add the RTP protocol for the use of multimedia applications through the network data transmission support. Directshow RTP framework has been designed to support high scalability of the broad mandate of the field of multimedia streaming. Directshow RTP as part of Windows NT5.0 operating system will accompany the issue. We have expanded this framework to add support for the application of the convection on the local host and computer network and receiving a result of the distribution of multimedia data caused by changes in available resources, to the dynamic compensation.

Including the expansion of our collection can be chosen to fit the relevant information to make decisions based on the information of the components, and architecture can make use of the foundation already has the capacity to carry out the strategy method. In this paper, for application development and for the development of these applications are designed to structure useful.

1. Introduction

NetMM is running on the client computer and the single-user workstations in the resource requirements for the implementation of procedures for the strongest category. These applications of the host processing power and network bandwidth consumption demands are very high. These applications also often need the underlying operating system and computer network in near real-time processing provides the necessary resources to implement. Visit any of the above resources will lead to significant delays noticeable to the user to show a decline in the quality. With a single procedures NetMM changes in demand for resources, and start and stop flow and procedures, the local host and network resources will be available for significant change. Because the available resources and demand for resources will be significant changes during operation, NetMM must be smooth adaptation to these changes.

In this paper, we mainly target two types of adapters and host adapters ------ Network Adapter. Network Adapter is the network available bandwidth, network jitter, data loss and other conditions, the flow process through a variety of methods can make full use of network resources. Host adapters can be defined as the local host-based applications, including CPU utilization, available memory, to change their behavior. The following examples of situations on the network and host adapters are useful:

Flow of resources and more competition. Assume that an application has a audio stream, a high-bit-rate video stream, and a sudden flow of the slides, in which the audio stream to the user in terms of the highest priority. If the quality of the audio stream be affected, in order to meet the user's priority, the program can fit slide show and video streams in order to reduce the system resources occupied. Applications must be able to detect the network resources, the corresponding adjustment of its transmit and receive behavior of the various streams.

Allow the experience of different network and processor resources, the user can afford. In a different bandwidth and processing power of the heterogeneity of the user's video conferencing or interactive session, all nodes will not be able to receive all of the flow. In such conditions, if we adopt the classification code personnel can participate in all meetings. This form of adaptation, compared with a classification code used to show the flow to allow the resource requirements have very little access to the heterogeneity of participants to great satisfaction.

Compensation for different applications an important role in the degree of change. In single-user environment, a program of the relative importance of other programs will change over time. For example, when a user to see news from the switch to the compiler or a design task, such as operating systems like Windows 95 will normally dispatch multimedia program to the background to run a lower priority. When users switch to the news, look at the events of interest (for example, the latest baseball news), the operating system would enhance the implementation of this program priority. NetMM should also be placed in the background or the future to respond. This, NetMM switching procedures should be reduced to the background after the network and the CPU occupancy rate, has returned to the forefront after running at full speed. Attached above and beyond the operating system in response to the implementation of the priority scheduling strategy is in urgent need of resources to those up to the task of resource allocation.

Researchers NetMM procedure has prepared several methods of adaptation. These methods include various forms of source flow control, the acceptance of the use of layered video driver, and host adapter resources. Although, like RSVP and ATM to provide QoS mechanisms for the protection of the agreements and procedures have been able to meet the NetMM, researchers have been studying the changes in resource constraints and resources under the conditions of the application adapter.

The assumption that the quality of adaptation on the application of a positive impact, we decided to study how application developers can not worry about the complexity of adaptation, the adapter is added to the application. In this paper, a detailed study of how the NetMM component-based framework for adaptive multimedia streaming network and host conditions change. Paper we discussed the results in this area, including resource constraints for the adaptation of new research, create support networks for the host adapter NetMM of middleware, and some of the use of adapters or the application development framework for designers useful lessons.

Microsoft's DirectShow we as the basis of our framework. Directshow provides a modular, scalable system to achieve multimedia applications. In the DirectShow architecture, we add a set of framework agreements to achieve RTP, we called DirectShow RTP, used to create NetMM applications,

The remainder of this paper as follows. Part 2 on the DirectShow architecture and DirectShow RTP. Part 3 of this were discussed, analyzed a number of adaptive features added to these DirectShow RTP as the framework for component-based methods. Part 4 gives the data sources based on the realization of the adaptation, Part 5, introduced the use of layer multicast receiver-driven adaptation to achieve. Part 6 provides an overall flow for component-based framework for network, host adapters to achieve the empirical analysis. Part 7 to discuss the possibility of further improving the application of adaptation in the next step NetMM areas of work. Finally, in the framework of the realization of component-based adaptation of the Department should be the end of the discussion in this article.

2. DirectShow Architecture

2.1 Microsoft's DirectShow

DirectShow architecture for many applications are used to provide the basic multimedia stream processing functions. It is for a full range of multimedia processing, including the collection, coding and decoding, playback, audio and video data storage. DirectShow used mainly four kinds of multimedia data abstraction to operate. These abstract terms for the filter (filter), pin (pin), media samples (media sample) and the media type (media types).

MPEG File MPEG Decoder Video Render

Data Flow

DirectShow filters are used to package one or more streaming and multimedia-related tasks. Examples of DirectShow filters are included video capture filter, is used to control the video camera equipment, output of the original RGB video frame; H.261 codec filter, is used to compress the original RGB video data to H.261 frame and decompression. Similar for the audio stream of Filters, collecting filter and G.711 audio codec filter. Filter has also been used in the local audio and video playback equipment. Procedures to allow a combination of functions to deal with audio or video, DirectShow using filter graphs. Filter graph is connected to a number of serial order to deal with multimedia data buffer filters. Figure 1 gives an example of filter graph, read a file containing filter, an MPEG decoder filter, and a video rendering filter, for video playback.

Filters through the pins connecting the composition of filter graph. Pins in the DirectShow There are two main effects. The first is consensus in the filters when the Internet media type, and Filter the Internet at the time of the distribution of memory. Media type consultations media type is determined by the management of the two way data exchange filters. Consultations memory allocation is being used to designate a buffer to preserve multi-media (also known as media sample) where the memory allocation, the allocation of how much memory (byte alignment, the use of memory-mapped devices from a specific region of memory, etc.).

DirectShow in Pins second task is to hide the filters exchange data. Once a link has been successfully established, filters simply receiving and distribution of media samples to its pins, pins of the implementation of the actual operation, that is, samples were distributed to a filter graph in the filter.

Media samples in DirectShow is stored in the buffer zone of the abstract multi-media data. In addition to their ease with the multimedia data, media samples also include samples used to determine the lifetime of the start and termination of time-stamp. These values can be used to determine the renderer when the issue of player performance and testing.

DirectShow media types designate the exchange between the filters of the media sample data that contains format. Media types include several parts; the most important of which is the major and minor types. A main type generally used in accordance with the guidance of the highest level of semantic distinction format. MAJORTYPE_VIDEO and MAJORTYPE_AUDIO two main types. Sub-genre in general used to determine the different formats, such as MINORTYPE_AUDIO_G711A and MINORTYPE_AUDIO_G723. If two filters can be found between the pins of the same media type, so they can establish a connection on. DirectShow allows the definition of the new filters, pins, and media types. DirectShow take full advantage of the inherent scalability, we define two new media types and a few filters, the realization of the DirectShow framework agreement through the use of RTP network transmission of multimedia data streams. NetMM this new framework, known as DirectShow RTP.

2.2 DirectShow RTP

DirectShow RTP defines a set of RTP protocol supports the use of network transmission of multimedia streaming fitlers and media types.

Filters is a new definition of RTP Source filter, RTP Render Filter, RTP Demux filter, RTP Receive Payload Handler (RPH) filter, and RTP Send Payload (SPH) filter. The use of these five filters (at the same time using the standard CODEC and collection / rendering filters), can construct a network transmission protocol RTP streaming audio and video data platform is possible.

RTP Source filter is used to from a separate RTP session to receive RTP and RTCP packets. These packages are packaged in a media sample of hair to the filter graph. This filter is being used to connect the radio to go out, including the main types of media type

RTP_MAJORTYPE_MULTIPLE_STREAM and sub-types RTP_MINORTYPE_PAYLOAD_ANY, they both are part of the DirectShow RTP framework. This combination of media types that the filter can be generated that contains one or more of RTP streams flow, put together may be a single or multi-load type of load types. The filter to provide a specified host to send to other RTCP receiver reports and designated network address and port to receive RTP session interface of the interface.

RTP Source filter and is closely related to the RTP Render filter. Media type of the receiver filter for the main types of RTP_MAJORTYPE_SINGLE_STREAM, any sub-genre of external connections. In order to comply with the AVP to the sender in the RTP stream SSRC on the load type and the provisions of the main types of more rigorous selection is necessary. This filter provides the RTP Source filter with similar control interface.

RTP Demux filter is used to multiplex RTP Source filter separated from the RTP packets. Separation of multi-channel package to comply with the SSRC, and each type of load. This type of filter to receive RTP_MAJORTYPE_MULTIPLE_STREAM main and sub-type of the pin connection RTP_MINORTYPE_PAYLOAD_ANY. Registration of this filter to one or more output pin,

The main type of RTP_MAJORTYPE_SINGLE_STREAM, and are discussing a single pin on the distribution of flow of the sub-genre of the load. This filter provides control over how the multi-stream separation and how to allocate to a specific interface output pin.

RTP RPH filter is used to change the type of load from a single fixed source of RTP packets to their corresponding non-packaged form. Therefore, a version of this filter is used to obtain the packet and RTP H.261 video frame generation H.261 compression. This version of the filter has been designed to support H.261, H.263, Indeo, G.711, G.723 and G.729, and a variety of common types of audio and video loads. These commonly used audio and video are RPH filter to comply with the provisions of RTP AVP packaged media sample. It provides a specified number of buffers in the interface to resolve the data loss (or forward) before the wait time, especially when the reconstruction of dropped frames, the need for re-allocation of the buffer. RTP SPH fitler and RTP RPH filter similar to the task it is to filter the output audio and video compression of media samples for the RTP packet decomposition. It provides the interface are designated to generate the largest packet size (in order to apply different network MTU (Maximum Transmission Unit)) and the PT value (allowing the use of Dynamic RTP PT value).

Video Capture codec SPH RTP Render

Data Flow

Figure 2 using the DirectShow RTP Send network data

RTP Source RTP Demux RPH Decoder Video Render

Data Flow

Figure 3 used to receive network data DiectShow RTP

Figures 2 and 3 show the DirectShow RTP defined how to use filters. Figure 2 is a collection of local data and multimedia network using RTP protocol to send the filter graph. It contains the original video frame output of the video capture filter, keep up with a compression encoding frame filter. Once compressed, these frames will be sent to the RTP SPH filter, sub-chip package to generate RTP packets sent to the corresponding RTP Render filter, these packets are transmitted over the network. Figure 3 shows a filter graph, used to receive RTP packets include video streaming, video. This graph is used to receive a packet from the RTP Source filter, a source and load in accordance with the classification of types of RTP Demux filter, the RTP packets into a compressed video frame composed of RTP RPH filter. These filter is then used to extract the frame decoder filter, a display frame rendering uncompressed filter.

DirectShow RTP framework of the most important thing is to display the RTP streams and for receiving, processing, sending RTP packet filters of the five media type definition. Media type definition provides a useful system to describe the structure of DirectShow streaming RTP method, allowing the future to add new methods to deal with RTP streams of the definition of filters. The realization of these filter providedpieces, based on the application of this NetMM can easily be created and provides a framework for the future can be used for further study NetMM the field of architecture.

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