LCD delay connected to ioHD

[Jeremy Garchow]

Let me get this straight.

You are sending HD material downconverted to an LCD (what kind of lcd and what connection) along with analog audio, then having the LCD reupconvert to HD and you are getting some lip slip?

Or your LCD is not matching FCP?

Jeremy

[Carsten Orlt]

Thanks for your response Jeremy.

Sorry for not being clearer 🙂

I send 1080i25 from the HDMI ioHDconnector to the LCD (using a HDMI to DVI-D adapter and connected to the DVI-D input on the monitor)

SD via RGB into my SD CRT

Audio via analogue into my mixer

Looking at the LCD HD and the SD CRT side by side the LCD has the delay.
Because the audio is in sync with the SD CRT it is not with the LCD HD.

[Jeremy Garchow]

Got ya. Not real sure without seeing it, but your suggestions seem feasible.

What kind of LCD?

[Carsten Orlt]

BenQ FP241W

I know I know, not the super duper thingy, but if you want to save yourself a lot of money to be able to see your HD 1080 (or whatever) at 1:1 this monitor is pretty amazing and surprisingly accurate in the colour reproduction.

After a long search and not having the money for the big guns I settled for this one.

And to be honest I’m glad I didn’t spend 10x as much for the others. Grading is done in SD anyway.

But don’t take my word. Always do your own testing 🙂

[Jeremy Garchow]

I understand. It’s all good.

Does it have analog audio on it? Tyr sending analog audio to it straight from the ioHD and see if it’s in sync then.

Jeremy

[Carsten Orlt]

Nope, no speakers on the monitor.

I have the feeling I need a audio delay processor, which I have seen for home theater setups. They have the same problem 🙂

Still I can’t find any reliable information that my explanation is correct?

Cheers

Carsten

[Gary Adcock]

[Jeremy Garchow] “Tyr sending analog audio to it straight from the ioHD and see if it’s in sync then.”

try sending analog Video TOO!!!!

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Inside look at the IoHD

[Gary Adcock]

[Carsten Orlt] “Still I can’t find any reliable information that my explanation is correct? “

Carsten.

You are correct, the 2 frame delay is inherent within the conversions process, it is especially evident on plasma displays. options for this issue are to try the analog video in as the HDMI process ( most likely 1.1) has to convert all signals to be progressive so the delay tends to be more apparent with P material than with Interlaced originals. (even in the 25/50i would you live in)

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Inside look at the IoHD

[Carsten Orlt]

Thanks for your response Gary.

Yes maybe using analogue to the monitor would be the solution, but it would defeat the purpose of buying the monitor in the first place.
I got it so I can see the 1080i signal fully digital and 1:1 to be able to really access the sharpness and possible defects. I already noticed that just looking at the down converted SD picture doesn’t give you all information and some shots looking ok in SD are not ok in HD.

Lets see what Aja might develop in the future as it happens with all LCD’s be it $500 or $20,000.

Cheers

Carsten

[Gary Adcock]

[Carsten Orlt] “Yes maybe using analogue to the monitor would be the solution, but it would defeat the purpose of buying the monitor in the first place.”

it would also solve another potential issue- most displays do not support 24/25p over HDMI since they were built with the HDMI 1.1 spec ( that means interlace only in your world- NO true P)

” I already noticed that just looking at the down converted SD picture doesn’t give you all information and some shots looking ok in SD are not ok in HD.
“

I am not talking about a downconverted signal I am talking about CMPT analog HD to your display to solve the audio sync issue- and you get progressive output back.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Inside look at the IoHD