-40ms delay on Kona up and downconversion

[Walter Biscardi]

[Christopher Tay] ” The audio is monitored through the Kona 3’s AES/EBU output, which is converted to analog through a audio DA converter. “

Are you measuring this audio delay before or after the analog conversion?

Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.

STOP STARING AND START GRADING WITH APPLE COLOR Apple Color Training DVD available now!
Read my Blog!

[Bob Zelin]

I have never used the ProBel Valid8. Are you just playing, or do you have clients complaining about audio sync errors with their down conversions ? I have never heard these complaints. HOWEVER, I have daily complaints about Plasma screen audio delay propogation, and this is being addressed by AJA with the audio SLEW adjustment which was announced at NAB (and is still not released).

I am not bitching at Chrispy, but just envision Discovery buying one of these units, and rejecting tapes because of it ! (where the hell is your Dolby LM100 meters !).

Bob Zelin

[Christopher Tay]

Forgot to add important info :

Mac Pro dual 3Ghz quadcore (latest batch) with 4GB RAM
OSX 10.5.4
Quicktime 7.5
FCP 6.0.04
Kona 3 driver 6.0

Thanks.

-chrispy

[Christopher Tay]

Hi Bob,

There is a Dolby LM100 on the rack by the way 😛

This is actually happening at my client’s place and is a TV station. I just did a quick test back in office with some of the clips that I took back from my client’s place and I’m not seeing the delay.

This machine that I just did a quick test on is running OSX 10.5.2, Quicktime 7.4.5, FCP 6.0.3 and Kona 5.1NDD so I’m gonna try with another boot drive which has the same OS,QT,FC and Kona driver as my client’s setup and see if the problem shows up.

Walter, the ProBel VALID8 measures the audio in the SDI embedded signal. So when I feed the SD downconverted output to the ProBel VALID8, it will measure the SDI video and embedded audio to see if there’s any delay. What I’m hearing through the speakers in the FCP suite is from the analog converted AES/EBU output of the Kona 3 card. I’m using a Behringer SRC2496 AD/DA converter. I could test by taking the RCA unbalanced output from the K3-BOX to see if it makes any difference.

Right now when we feed the SD downconverted output of the Kona 3 card to a DigiBeta VTR, we can see the video delay (audio is ahead) especially on close up scenes.

Also, when we playback the HD sequence in FCP, the playback in the Canvas and the TVLogic monitor (your favourite :P) is in sync when in HD mode but when in SD downconverted mode, we can see the video is delay on the TVLogic monitor as it is not in sync with the Canvas anymore.

-chrispy

[Walter Biscardi]

[Christopher Tay] “Mac Pro dual 3Ghz quadcore (latest batch) with 4GB RAM
OSX 10.5.4
Quicktime 7.5
FCP 6.0.04
Kona 3 driver 6.0 “

Again, are you running this test before or after the analog audio conversion?

Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.

STOP STARING AND START GRADING WITH APPLE COLOR Apple Color Training DVD available now!
Read my Blog!

[Bob Zelin]

If I am reading this right, he is using a Behringer SRC2496 as an AES to analog converter, but according to his post, the audio is ADVANCED (not delayed), so the delay is in the video. (If the Behringer was causing the problem, the audio would be delayed).

I don’t know what is going on here. I don’t have the ProBel audio delay measurement device, but I just did a job for Nickelodeon (My Family Has GUTS gameshow) with 2 Kona 3’s, 2 K3 boxes, and 2 Behringer SRC2496 AES/EBU to analog converters. Video monitoring was done with both Panasonic BT-LH2600W and Sony LMD-2030 monitors, and channel 1 and 2 audio was monitored with the K3 RCA analog outputs, while channel 3 and 4 was monitored via the Behringer SRC2496, and none of the 6 editors complained about any audio delay issues. The show was mastered on HDW-M2000, and no one has rejected the tapes from Nickelodeon.

Bob Zelin

[Jeremy Garchow]

[Bob Zelin] “and this is being addressed by AJA with the audio SLEW adjustment which was announced at NAB (and is still not released). “

It is released on the v6 drivers for ioHD just in case you have one.

[Christopher Tay]

Hi Bob,

May I know what OS,QT,FCP and Kona version are you running on those Macs that you used for the Nickelodeon job ?

AJA has replied that there is a 1 frame “video only” delay for the up/down/cross conversion since it is done on the hardware and the only way to compensate is to delay the audio in the sequence by 1 frame.

I’m not sure if there’s any difference and you’re in NTSC and I’m in PAL land.

-chrispy

[Bob Zelin]

Chrispy –
I have never seen these issues from any Kona 2 or Kona 3 product, including old and new OS and various MACs, including the latest ones (both MAC and OS).

As you can see, AJA has just released new drivers that affect delay issues, so you might as well download these right NOW, and see what happens.

BUT I ASK YOU AGAIN – are these “issues” you are seeing only with your ProBel test gear, or are you actually SEEING lip sync audio errors when doing a down conversion. I have NEVER heard of anyone saying “when I dump out to Digi Beta, the audio is out of sync”. I just never heard of anyone saying this. ( I am not defending the I/O HD audio delay issues that many have experienced, nor am I denying the propogation delay errors in every Plasma screen being manufactured today, which results in what appears to be lip sync audio delay issues).

bob Zelin

[Jeremy Garchow]

[Christopher Tay] “AJA has replied that there is a 1 frame “video only” delay for the up/down/cross conversion since it is done on the hardware and the only way to compensate is to delay the audio in the sequence by 1 frame. “

40ms is 1/25th of a second. Seems easy enough to shift the sequence audio until the slewing is released in the drivers.

Jeremy