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View Full Version : 855 HD>SD Downconvert terrible



liquidvishn
11-05-2012, 11:44 AM
Have a location that programs in HD but outputs in SD. HD looks great. Direct SD looks great. HD to SD downconvert looks like :cursin:

Having spent a few hours at a long-time reseller- they were unaware of how bad the HD>SD downconvert was. Anyone else experienced this?

Tricaster is 855 model.

SBowie
11-05-2012, 11:50 AM
Let's clarify a few details. Are you running an HD session and outputting SD on Aux? Or are you inputting HD into an SD session? What sort of output connection type and display? Or are you recording down-scaled SD and that's where it appears sub-par?

liquidvishn
11-05-2012, 12:14 PM
Let's clarify a few details. Are you running an HD session and outputting SD on Aux?
Yes.

Or are you inputting HD into an SD session?
No.

What sort of output connection type and display?
BNC Composite to SD monitor

Or are you recording down-scaled SD and that's where it appears sub-par?
No recording of downconvert is done. Downconvert is done live- recorded HD looks great. When the output is SD downconverted (out the AUX port) that is where the final output looks :cursin:

Minor addition- when with the reseller (at their location), they were unaware of it until they actually performed a test on their system and were able to see how bad it looks.

SBowie
11-05-2012, 12:37 PM
Minor addition- when with the reseller (at their location), they were unaware of it until they actually performed a test on their system and were able to see how bad it looks.Thanks for the added detail. I've done similar things plenty of times, and the SD output from Aux looked quite acceptable, so I'm not really sure how to proceed. It goes without saying that composite transmission will do a little degrading, but it really shouldn't be "bad". If you record Aux, does the result look equally unsatisfactory? Can you elaborate in any more detail on the nature of the degradation?

liquidvishn
11-05-2012, 01:50 PM
Thanks for the added detail. I've done similar things plenty of times, and the SD output from Aux looked quite acceptable, so I'm not really sure how to proceed. It goes without saying that composite transmission will do a little degrading, but it really shouldn't be "bad". If you record Aux, does the result look equally unsatisfactory? Can you elaborate in any more detail on the nature of the degradation?

The SD downconvert brings the old addage of "crap in, crap out" regardless of live or recorded.

What you have deemed acceptable could be pure :cursin: for others in comparison to an SD source through to TX.

My post was more of a query of others experiencing it (or even taking full HD and downconverting to SD)- It really does not bother me as I have placed a BMD UDXConverter on the program output and the quality is far better now than what the Tricaster can offer. My thought is that the machine is great for HD > HD or SD > SD. The HD > SD was more of a throw-away feature, than a value add. Almost an afterthought.

SBowie
11-05-2012, 02:26 PM
What you have deemed acceptable could be pure :cursin: for others in comparison to an SD source through to TX.Or not .... :2guns:


My post was more of a query of others experiencing it (or even taking full HD and downconverting to SD)Whereas my post was trying to get at specifics, so that if something needs improvement we would know about it. Sorry, I thought you actually wanted to try to get to the bottom of the matter. Just trying to help, carry on ....

ZachSchuster
11-05-2012, 03:20 PM
What type of HD session are you using?

At the beginning of sports season I accidentally set up a 720p/60 HD session and had a lot of trouble with the 480i Aux output. I changed to a 1080i session and the 480i Aux output is considerably improved.

SBowie
11-05-2012, 03:34 PM
Zach, please do bug this sort of thing when you encounter them - thanks.

ZachSchuster
11-05-2012, 09:07 PM
Zach, please do bug this sort of thing when you encounter them - thanks.

I did, and provided a number of test files for QA.

SBowie
11-06-2012, 05:39 AM
Awesome, thanks. Would you mind sending me the case number by PM, if you have it, and I'll follow up.

vanderwielen
11-06-2012, 06:37 AM
As a supporter of Netwek, I advocate it's pluses...and clarify it's minuses.

We'd done extensive comparisons between HD to SD down conversions using the AUX out of the tricaster and the use of a hardware solution using BMD down converters. The Hardware conversion is vastly superior. For 10 years, we ran an SD TV station that aired down converted HD productions. We couldn't afford to have less than pristine images.

That said, we do use the down conversion feature of the Tricaster to feed jumbotrons and other displays whose native resolution is less than SD and it works fine.

SBowie
11-06-2012, 07:02 AM
I certainly wouldn't be surprised if a dedicated hardware solution provided a better result. I am surprised, though, that anyone would describe TriCaster's downconversion as 'garbage'. I spoke to engineering about this yesterday, and - based on standard tests - they think it's actually pretty good. That said, this is not an issue of ego. Whenever an issue is raised, engineering is ready to listen. If specific complaints can be validated, it will not be hard to arrange for followup.

I was asked for specific cases accompanied by the sample HD source imagery and a frame grab or short clip recorded by feeding the Aux output back in as an SD source (or similar means). If any are not familiar with Fogbugz, I can provide direction. (If anyone does post a case, please copy me on the number by PM, and I'll be sure to track it.)

SBowie
11-06-2012, 11:32 AM
Update - this use case, i.e., SD Aux video out from HD sessions - is going to be reviewed (the report Zach referred to appears to be a different item relating to recording Aux>SD in a 720p60 session).

SBowie
11-06-2012, 12:53 PM
We've got a test build available that endeavors to improve on the shipping build in this respect. If anyone would like to put it through its paces, please feel free to PM or email me with contact details.

rally1
11-07-2012, 06:07 PM
We use a similar setup, and agree with Steve, not garbage. So it may not be a common issue.

I can think of a recent example of a 720p60 session, with primarily 1080i60 inputs and then a SD 480i AUX out to a DA then a jumbotron and 6 LCD TV's and it was quite acceptable (especially considering all the up/down/cross going on).
Now of course I will suddenly notice it's not that great ;)

Let us know if the new build helps.