Specifications

DTC-325

Affordable Tools for Digital-TV Professionals March 2015

Appendix E: DtGrabber+ deployment in broadcast environment :

HE and STB Trouble-Shooting : Application Note.

This Application Note details and provides concrete example about how DtGrabber+ can be

deployed for troubleshooting of STB and Head-End system in real broadcast environment.

When broadcast engineer or operator faces a service disturbance with low occurrence, it is difficult

to identify the problem without a concrete capture of the broadcast signal at the time of the problem.

The reverse approach to this tricky situation is to set-up a continuous capture of the broadcast

stream for a long enough period of time.

A concrete example is given with a satellite operator who receives monthly claims of video

disturbance on his service. From the starting point of view, the operator has no idea if he’s facing a

STB problem or a service problem related with his Head-End system. Only with a concrete capture of

the problem at the time it occurs, would he be able to investigate, to discriminate whether the

problem is coming from broadcast signal or related to the receiver, and enforce the party

responsible for this problem to resolve this problem.

In this example, our satellite operator has 4 transports at 29,162 Mbps (TS rate) and wants to

capture the latest 12 hours. The transports are available out of the multiplexer as 204 bytes TS

packet‘s ASI signal. By a simple computation, he can evaluate that the minimum disk space of

(29162168/8)*(60*60*12)*(204/188) ~= 159GB will be required (*) per TS.

(*) Note that DtGrabber+ application provides also the correct estimation of total disk space per transport if the transport

signal is fed with proper rate to the input adapter linked to DtGrabber+. Multiple file recording and auto-erase rule need

to be set accordingly.

To have a maximum of cost-efficiency for his set-up, our operator decides to capture the four ASI

streams by using the DekTec DTA-124 and to execute four simultaneous instances of DtGrabber+,

one for each input. As for the host PC, he chose a P4@3Ghz PC with a 1GB RAM to have sufficient

and safe performances.

Knowing that common 7200RPM hard-disks can support safely two streams at 30Mbps, he decides

to split the four captures on two external 400GB hard-disks, setting two captures per hard-disk.

rmount

DTA-124

・・・・・

・・・・

MUX1

MUX2

MUX3

MUX4

Rack mount PC with DTA-124

External hard-disks

TS1

TS3

7200RP

/ 400GB