The choice in front of every producer
Almost every outside broadcast we plan reaches the same question sooner or later: what happens to the picture if the main route out of the venue fails? Live signal management answers it with a second path, and there are two ways to build that. The first is a mirrored path, where an identical feed travels a separate route all the time. The second is a standby path, which sits ready and is switched in only when the main one falters.
Both are sound engineering and both are used across the trade. They differ in cost, in how quickly they recover, and in how much attention they demand from the crew on the day. I am writing this from the distribution side of renyzo, where I see what the broadcaster receives and how it feels when a feed hiccups.
In this piece I compare the two on equal terms and finish with a recommendation. It is a view formed from our own jobs, not a rule for every production.
How a mirrored path works
With a mirrored path, the same video and audio are encoded twice and sent over two independent routes, for example a fibre circuit and a bonded cellular link, or two circuits from different exchanges. At the receiving end, equipment watches both arrivals and chooses the healthier one, frame by frame if it is set up well. If one route drops, the viewer sees nothing, because the other was already carrying the programme.
The strength of this approach is that there is no switchover moment to get wrong. Nobody needs to notice a fault, make a decision and press a button. The second path has been proving itself throughout the broadcast, so we already know it works.
The cost is plain. You pay for two circuits, two sets of encoding equipment and more monitoring for the whole booking, even when the first path never misses a beat.
- Recovery is instant because both paths are live
- Higher hire and circuit cost for the full duration
- Needs two genuinely separate routes to be worthwhile
How a standby path works
A standby path is built and tested before transmission but carries nothing while the main route is healthy. Callum Reid, our senior video engineer, usually has it patched through to the same destination, with the encoder warm and the link established, so that it can take over quickly. When the monitoring shows the main path failing, the crew switches the programme across.
The attraction is economy. Equipment and capacity are reserved rather than fully used, and the day is quieter on the wire. For a bulletin, a rehearsal or a feed that can tolerate a short interruption, that saving is sensible.
The weakness is the gap. Someone has to spot the fault, judge that it is real and act, and even a slick change takes seconds. Viewers see a freeze or a blank in that window, and a link that has sat idle can surprise you when it is first asked to carry the full load.
Comparing them on cost, speed and effort
Set side by side, the trade is between money and certainty. Mirrored paths cost more up front and remove the human step. Standby paths cost less and accept a brief interruption in exchange. Neither is free of effort: a mirrored setup needs careful comparison of the two arrivals, while a standby needs a disciplined switching procedure and a crew member watching throughout.
There is also a question of what a failure costs. A dropped second of a studio chat is forgivable. A dropped second of a goal, a speech or the headline moment of a festival headline set is not, and it tends to be the clip everyone remembers afterwards.
I find it useful to ask producers one question: if this feed cut out for ten seconds at the worst possible moment, what would you lose? Their answer usually settles the choice before we reach any price.
- Mirrored: higher cost, no gap, less reliance on reaction time
- Standby: lower cost, a short gap, more reliance on the crew
- The consequence of one lost moment should decide the weighting
What I recommend for most productions
For live events with a fixed, unrepeatable moment, I recommend a mirrored path. The extra spend buys the removal of the single most fragile point in the chain, which is the decision and the switch. For scheduled news and studio output, where a short interruption can be covered by the presenter or a holding slate, a well-rehearsed standby path is a reasonable and honest choice.
A middle course also works and we use it often. We mirror the final, riskiest stretch from venue to first connection point, and keep a standby further along the chain where faults are rarer and easier to isolate.
Whichever you choose, the route diversity matters more than the label. Two paths that share one cable run or one power supply are really one path, and no recommendation survives that.
Preparing the decision with your crew
Before booking, tell us the transmission time, the venue and what the broadcaster will accept in the event of a fault. Priya Sharma and the camera crew will want to know too, because a mirrored arrangement can change where equipment sits at the venue and how cabling is laid out.
We also like a short rehearsal of the failover itself. Pulling a cable on purpose, in daylight and with nothing on air, teaches the crew more than any diagram. In these darker autumn weeks, with outdoor events often running into the evening, we allow extra time for that test because conditions on site change as the light goes.
- Share transmission time, venue and tolerable interruption
- Confirm the two routes do not share cable or power
- Rehearse a deliberate failover before going on air
Neither option is wrong, but they answer different risks. If one lost moment would be costly, mirror the path and accept the higher bill. If a brief interruption can be covered, a tested standby does the job for less. Talk to us about the event, the audience and what you cannot afford to lose, and we will set out both routes in writing so you can compare them before deciding.
