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-40ms delay on Kona up and downconversion

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Christopher Tay
-40ms delay on Kona up and downconversion
on Aug 20, 2008 at 12:05:14 pm

Hi,

Has anyone encounter a video delay on Kona's up and downconversion ?

I did some testings today on a Kona 3 with a ProBel VALID8 Lipsync Measurement gear (http://www.pro-bel.com/products/C132/) and both the Kona 3's up and downconversion has a delay of -40ms on the embedded audio as indicated by the VALID8 gear on-screen display, which means the audio is ahead of the video.

Visually if you see the Kona 3's HD output on a HD monitor and the downconverted SD on a SD monitor, you can tell that the downconverted SD output is slightly delayed. The audio is monitored through the Kona 3's AES/EBU output, which is converted to analog through a audio DA converter.

We then tested the downconversion through the HDCAM VTR itself and there is no delay on the downconverted output and the VALID8 gear indicated +0001ms on the embedded audio which is well within the acceptable range.

The Kona 3 driver was 5.1NDD when the problem was reported and updating to the latest 6.0 did not solve the problem. The Kona 3 card was initially installed in slot 3 in the Mac Pro (latest batch) and moving to slot 2, which is what AJA says it should be in, did not solve the problem as well.

I'm testing this in PAL mode using PAL 625i25 and HD 1080l25 materials.


-chrispy





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walter biscardi
Re: -40ms delay on Kona up and downconversion
on Aug 20, 2008 at 12:21:27 pm

[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.

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Bob Zelin
Re: -40ms delay on Kona up and downconversion
on Aug 20, 2008 at 12:32:53 pm

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




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Christopher Tay
Re: -40ms delay on Kona up and downconversion
on Aug 20, 2008 at 1:31:52 pm

Hi Bob,

There is a Dolby LM100 on the rack by the way :P

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




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Jeremy Garchow
Re: -40ms delay on Kona up and downconversion
on Aug 20, 2008 at 2:36:57 pm

[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.


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Christopher Tay
Re: -40ms delay on Kona up and downconversion
on Aug 20, 2008 at 1:20:58 pm

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



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walter biscardi
Re: -40ms delay on Kona up and downconversion
on Aug 20, 2008 at 1:32:10 pm

[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!
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Bob Zelin
Re: -40ms delay on Kona up and downconversion
on Aug 20, 2008 at 2:22:24 pm

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




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Christopher Tay
Re: -40ms delay on Kona up and downconversion
on Aug 20, 2008 at 3:44:29 pm

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



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Bob Zelin
Re: -40ms delay on Kona up and downconversion
on Aug 20, 2008 at 3:56:03 pm

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




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Jeremy Garchow
Re: -40ms delay on Kona up and downconversion
on Aug 20, 2008 at 4:23:18 pm

[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


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Ben Scott
Re: -40ms delay on Kona up and downconversion
on Aug 21, 2008 at 3:29:54 pm

got the same reply about 1 frame delay on audio in downconversion using PAL from AJA



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Christopher Tay
Re: -40ms delay on Kona up and downconversion
on Aug 21, 2008 at 4:13:36 pm

Hi Ben,

The delay is on the video actually as it goes through the hardware conversion and this causes the audio to be ahead.

However I did some tests with the same clip that I saw the delay on another system and it wasn't so apparent. I'm beginning to support it has to do with the OS,QT and FCP combo. Will do more testings.

-chrispy



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gary adcock
Re: -40ms delay on Kona up and downconversion
on Aug 22, 2008 at 3:04:11 pm

[Ben Scott] "got the same reply about 1 frame delay on audio in downconversion using PAL from AJA "

Guys
the one frame delay is correct for the conversion, even Teranex has frame delay in the processing by 2-6 frames depending on what you are doing - the image processing needs to actually be converted and the audio is normally slewed to match it sounds as if that is not happening here.

That actual delay "timing" will vary slightly between 23.98, 24, 25, and 29.97 since the delay is always 1 frame and not a specific millisecond value.







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




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Ramona Howard
Re: -40ms delay on Kona up and downconversion
on Aug 22, 2008 at 5:28:24 pm

Gary is absolutely correct!

We added settings in Rave to handle to frame delays so that HD and SD could be in sync. This was internal coding, not a standard setting within the AJA hardware.

Cheers,
Ramona



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