This HD program landing and H.264 transcoding recommendation plan is designed based on the requirements for HD program landing and cable transmission in urban areas. The proposed plan provides a detailed explanation of the system structure, equipment configuration, and signal processing workflow.
In addition, based on our experience in previous related projects and the potential system cost investments that users may face, we have provided the most cost-effective solution.
The city needs to establish a high-definition broadcasting system to relay HD program signals within the cable digital television system, providing the residents with a clearer visual experience.
Therefore, the entire HD broadcasting system should include the signal source reception, multiplexing, scrambling, and modulation in the cable digital front-end system.
In addition, to save bandwidth and improve bandwidth utilization, the received high-definition program signals need to be appropriately transcoded to output H.264 high-definition signals.
The following is the requirements analysis, as follows:
- The high-definition program signal source is satellite signals, distributed across multiple satellites including Zhongxing 6B.
- The number of HD program signals to be processed is approximately 16 sets, including HD programs from China Central Television, some provincial satellite TV stations, and paid HD programs, among others.
- The perfect reuse function allows for the multiplexing of high-definition program signals according to a unified city plan;
- The system must be compatible with the local EPG system and support the insertion of EPG information;
- The system must be compatible with the local CA system and support HD program scrambling;
- The system's security and reliability must meet the safety broadcasting requirements, and core equipment is required to have redundant backups.
The solution's equipment utilizes high-performance, highly integrated hardware transcoding devices, all of which are equipped with redundant hot backup. The key feature is that all core devices have hot backups, ensuring high system security and stability.
The selected equipment includes the satellite receiver PVR-7000, the HD multiplexing scrambling transcoder/stream processing platform ProStream-1000, the edge QAM modulator bNSG-9000, and the core switch Cisco-3750. Additionally, an NMX network management system has been configured to provide unified management and primary/backup switching control for all devices.
Solution Introduction
Introduction to Signal Processing Workflow:As shown in the figure.
- The satellite receiver PVR7000, equipped with dual IP outputs and decryption capabilities, receives encrypted and unencrypted HD programs from satellites and decrypts the encrypted programs to produce unencrypted HD program signals. The clear HD program signals are then sent to the primary and backup core switches through its configured dual IP output ports.
- The core switch will send the incoming clear HD program signals through the connected network port to the ProStream-1000 for transcoding, multiplexing, scrambling, EPG reorganization, and various other functions;
- The ProStream-1000 multiplexer and scrambler (which can achieve HD H.264 transcoding by inserting an ACE transcoding card into the expansion slot) receives signals from the core switch and first sends them to the hardware processing chip on the ACE transcoding card for video encoding format conversion. (Although the processing is completed internally, the entire transcoding process is based on hardware decoding and re-encoding, which is fundamentally different from ordinary software transcoding.) It converts the MPEG-2 encoded HD signal into an H.264 encoded HD signal. Then, the ProStream-1000 multiplexes the generated H.264 format HD signal with the EPG information sent from the EPG system, inserting the EPG information into the HD program TS stream to form a complete TS stream. Finally, the completed multiplexed TS stream undergoes program scrambling. The final output is a complete multiplexed and scrambled stream, which is then sent back to the primary and backup core switches through its primary and backup IP interfaces.
- Prostream-1000It also features a clean stream output mirror, which can be applied to wired networks.H.264Bitrate (CBR、VBR) Optional simultaneous output toVODSystem, complete.VODTime-shifted program playback applications. This feature is exclusive to Harley devices. Available spaceASIThe port also supports input and output mirroring streams, making it convenient forASIMonitoring and surveillance of the stream analyzer.
- At this point, the core switch has received the H.264 encoded high-definition multiplexed scrambled stream processed by the multiplexer. Finally, the core switch sends the processed multiplexed scrambled stream to the edge QAM modulator bNSG-9000 for QAM modulation.
- The edge QAM modulator bNSG-9000 directly performs QAM modulation on the complete bitstream received from the core switch, outputting an RF signal to the RF mixer. After mixing with the original system's RF signal, it is sent into the urban HFC network. This completes the entire process of the system from receiving the final RF mix from the satellite, allowing users to watch H.264 encoded high-definition audio and video programs at home using a high-definition set-top box.
Description of Equipment Configuration(Reference system design diagram)：
- Please contact the Onebandxin Technical Service Department.
- Phone: 010-65302100
- Email:support@onebandsystem.com
Introduction to Redundant Backup:
All devices in the entire system are equipped with a redundant backup mechanism.
- The satellite receiver employs N+1 redundancy. When a primary receiver fails, it can be quickly replaced by a backup receiver to continue operation. Additionally, the receiver features 1+1 main and backup IP output ports, which provide a prerequisite guarantee for the redundant hot backup of the core switch.
- Core data switch redundancy and hot backup. The core data switch is the central device of this system, ensuring the secure operation of the entire system's secure broadcast. Therefore, the core switch employs a 1+1 redundancy hot backup configuration, connected by a heartbeat line. In the event of a failure of the primary core switch, the backup can completely take over the primary within 200ms, fulfilling all processing functions within the system.
- The ProStream-1000 Reusable Scrambling Transcoder employs an N+1 redundant hot backup method, with the primary and backup switching automatically managed under the control of the NMX network management system.Moreover, Harley's proprietary technology ensures control word latency during the switching of scrambling devices, guaranteeing that there are no delays caused by the switch.CAThe phenomenon of still frames and black fields caused by switching.
- The edge modulator bNSG-9000 adopts a 1+1 card redundancy hot backup. Due to its chassis being powered by dual power supplies in a master-slave configuration, the likelihood of chassis failure is very low, hence the use of 1+1 card redundancy hot backup. When the primary card fails, it will automatically switch to the backup card for output.
Introduction to the Unified Network Management System:
All devices in the entire solution are selected from products manufactured by Harris Corporation, allowing for unified network management across the system. As shown in the diagram, all devices are connected to the network management switch via the NMX network management port.
The network management server communicates with the connected devices using the SNMP protocol for control and management.
Operators can conveniently and flexibly make configuration changes, save configurations, and query operational status and alarm information for all devices within the system through the network management interface.
The network management system also features a comprehensive permission management mechanism, allowing different permissions to be assigned to operators of varying levels.
The primary and backup switching of devices is completed under the control of the network management system, with a smooth and rapid switching process that accurately transitions to the backup device.
Additionally, devices can operate normally without network management control, remaining unaffected. Therefore, there is no need to worry about network management failures impacting device operation.