Broadcom supports video-on-demand and video streaming direct to VideoCore® enabled phones. We support a wide variety of different specifications and all of the specifications commonly used in cellular phones.
Standard data transfer protocols based on mechanisms, such as TCP, enforce reliability without regard to timelines. In video, a late packet is worse than no packet, because it clogs up the network before arriving too late to be used.
In addition, these protocols often throttle the client-server connection based on the availability of bandwidth, and not on the needs of the media involved. They often have only rudimentary mechanisms for random access to files, and are therefore not suited to time-based seeking. Finally, these protocls are not often suited to multicast.
Streaming protocols get over these issues by providing resilient mechanisms for the transmission of data.
Video format and streaming format
Whereas video standard such as MPEG4 typically specify a media API, set of datatypes, and a file format for multimedia presentations; additional protocols are required to specify the necessary client-server interaction and session control to stream multimedia over the Internet.
RTP and RTSP
The Realtime Transport Protocol (RTP) is both an IETF Proposed Standard (RFC 1889) and an International Telecommuncations Union (ITU) Standard (H.225.0). It is a packet format for multimedia data streams. RTP is used by many standard protocols, such as RTSP for streaming applications, H.323 and SIP for IP telephony applications, and by SAP/SDP for pure multicast applications. It provides the data delivery format for all of these protocols.
RTP is a transport protocol for the delivery of real-time data, such as streaming audio and video. RTCP is a part of RTP which deals issues like lip-synchronization and quality of service (QOS). RTSP is a control protocol for initiating and directing delivery of streaming multimedia from media servers. RTP and RTSP can be used together in many systems, but either protocol can be used without the other.
RTSP is designed to work with time-based media, such as streaming audio and video, or any other application where application-controlled, time-based delivery is essential. It has mechanisms for time-based seek into media clips, compatibility with many timestamp formats such as SMPTE timecodes. In addition, RTSP is designed to control multicast delivery of streams, and is ideally suited to full multicast solutions.
Broadcom fully supports these methods of streaming
MPEG2 Transport Stream
In some types of Mobile TV, transmission is achieved using a transport stream. Broadcom fully supports this method of streaming.