FPA and PSE UKDPP Delivery
I have had a bit of back and forward with the DPP crew this week. I’m about to invest in some new kit and I just wanted some clarification on the Harding FPA/PSE section of the latest spec.
2.9.1 Testing for flashes and patterning
Programmes delivered on tape must be tested using the Harding Flash Pattern Analyser Algorithm v2.5 on an SD (down-converted) SDI feed from playback of the TX tape itself. A test certificate must be printed and inserted into the tape box.
Programmes for file delivery must be tested using any file based PSE device that meets the guidance given by Ofcom. The DPP maintains a list of approved devices, available at: pse-approved-devices
So the part that had me stumped was the reason for sticking with the SD down-convert for doing the report for tape but then not doing a SD file for the PSE report for file based delivery. I assumed the reason for the SD down-convert was because of something like it was more likely to have fail points on an SD signal then HD so that’s why this needed to be done, but if that was the case surely you would need to take the same approach for HD file based delivery.
So then I got the below response from one of the guys from the DPP team
There has been no change to the tape delivery PSE testing process, it must be done via the SD output of an HDCamSR deck set to 702 pixels (not 720) with a Cambridge Research FPA v2.54 algorithm. This has been the case since HD started and we asked Dr Harding for confirmation that resolution was not a factor in PSE testing.
This meant no one had to buy any HD equipment for PSE testing and we could continue with the known algorithm v2.54. We have had no breaches of the Ofcom guidelines using this method from HD or SD programmes so we do not approve any other testing method. All the broadcasters test tape programmes after delivery and use the 2.54 linear algorithm.
As part of the move to file we intended allow programme makers to supply a test certificate instead of the dual testing that often happens. During our discussions about file QC we discovered there was no way to compare the two processes (linear tape testing and file testing) when the Cambridge Research FPA was used for both tests and at the same time we also learned that Ofcom did not consider the use of PSE testing devices as a guarantee of compliance. This left us free to use any device that met the three Ofcom test criteria but this only applies to file delivered programmes. The DPP published the new guidelines with a list of approved file devices.
If you have a Cambridge Research FPA that can run v3 it can also run v2.54 so you can switch between modes. All other approved devices are file based only.
Hope this helps.
So this was a big help. In simple terms they just never forced anyone to move to an HD harding because it made no difference to the test results. So that clarifies the reasons for the difference. But what about people buying new test equipment. Do you need to have an older harding FPA system for any tape delivery and one of the new PSE systems for file based delivery? Well kind of. The issue is that it needs to analyse the pictures directly off the tape and none of the other options offer this. I’m hoping if resolution is not an issue then maybe we could look at playing out to tape and taking to SD or HD signal into a hard drive recorder and test that file within the more modern PSE test systems. Then we would get all the other handy automated QC stuff at the same time. Hopefully a solution like that will become an option but who knows. I’ll keep this post updated with any new information as it unfolds.