Originally featured on BroadcastEngineering.com
New look at IP over ENG illustrates potential
The dawn of file-based ENG acquisition formats offers new opportunities for reporters and producers working in an electronic newsgathering environment.
Transmitting files rather than video removes an ingest step. It also lets journalists in the field draw on the digital news assets of the station while working from an ENG truck as if it were just another desk in a digital newsroom. The key is marrying the best of the traditional broadcast infrastructure with Internet file transfer technology.
A new technical paper on the Microwave Radio Communications Web site explains all of the ins and outs. The excerpt below from “IP over ENG: Broadcast Applications and Solutions for Remote IP Connectivity” examines the possibility of using a private communications channel between a DTV station and a news crew in the field.
The paper, in part, says: Currently, in the 2GHz licensed spectrum band, there are no requirements or provisions to support an upstream network path from the studio to the D-ENG van. Within the broadcast industry, a separate ATSC specialist group has been formed, which will focus on digital electronic newsgathering (D-ENG). Its charter is to develop a standard or recommended practice for private communications services between a DTV station facility and their D-ENG crews, using the ATSC transport stream.
Some of the potential applications suggested for using an ATSC compliant return path include the following:
- LAN or network access for newsroom management systems
- Return acknowledgements for a FTP file transfers from laptop editors as described above in support of the TCP/IP protocol requirements
- Metadata to/from the station to newsroom production systems
- Low-resolution proxy video returns to the van from the studio
- Remote monitoring and control of van equipment
- Internet connectivity
- Remote Vehicle Location Data (GPS) to station and return acknowledgement
- Interruptible fold back (IFB) communications for program sound and cueing instructions back to talent and crew.
The way this application could potentially work is that an ASI stream would be used to support the digitally encoded video and audio information from an MPEG encoder. At the same time, the modulator would be able to multiplex IP data from a network or Ethernet hub. The ASI and IP data would be simultaneously transmitted over the 2GHz microwave link from the van.
At the central receive site, the ASI and IP data is extracted from the COFDM demodulator and associated circuitry, and then distributed back to the studio over the transmitter to studio (TSL) link in its existing digital format. At the studio, the ASI data is decoded for its video and audio content and passed on to newsroom production. Subsequently, the network IP data is supplied to the station's LAN or communications hub. The station's LAN could then supply the network IP data for the return upstream data path back to the van via the ATSC transport stream. At the van, the ATSC off-air signal would be demodulated to complete the return communications path for remote ENG communications.
This technique would allow for a high IP down stream bandwidth from the van to the studio and a significantly lower upstream bandwidth to the van from the studio.
To read the paper in its entirety, visit www.mrcbroadcast.com/tech_services/IPEng.html.
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