wrong component output colour on multibridge extreme

[Michael D]

Thank you for your interest. I don

[Gene Colburn — email address bounces notices]

Other possible considerations when dealing with Component Analog, would be how all cables in the path are terminated. All coax in this loop needs to be terminated with .1% tolerance terminations. These can drift or even be manufactured out of tolerance. A very slight (half an ohm difference out of 75 ohm)can add subtle color variations in this path. This implies also that all cables are perfect (no tolerance for poor crimp connectors). Monitors with built in terminations are notorious culprits for screwing up this path.
PS I have to agree with Bob Z… Even Sony BVM $10,000 so called production monitors exhibited an ever so slight green tint using their $2000 calibration probe, and the best of Tektronix test equipment.

Gene Colburn

I love digital, but the universe still seems to be analog.

[Michael D]

Thank you for your reasoned response. I don

[Gene Colburn — email address bounces notices]

Michael
I would be interested in knowing how the footage looks if you export back to Digibeta using SDI and then looking again at the digibeta component out on the JVC. You may have already tried it and I did not gleen that. It is possible that MBe is the culprit. But it could also be something as simple as a leaky cap in the input circuit of the JVC that is throwing off DC offset bias of the decklink. The Digibeta may be a little more forgiving of this by the nature of its output circuitry design. I am trying to keep this as simple as possible, but all component analog paths are calibrated with no measurable DC on the path. There are usually trim pots on some gear to set this. In the MBe it could also be that some production component is slightly off in value that has the same effect.

The bottom line is that a very slight DC offset on any channel is observable in the blacks, and can throw the calibration of many monitors off. I know that it’s annoying, but you can look at any two CRT monitors, fed by the same signal, and they will never absolutely look identical for the same reasons. It just may be one of those situations where you need to bring a service tech with adequate test equipment to sort this out.

[Michael D]

Gene

Thank you for your continued interest. As I described in my last post (again with respect to my black and white files), the gain of the blue channel was less than the gain of the red and green channels when the DeckLink Pro card and drivers were installed but the gain of the blue channel was equal to the gain of the red and green channels when the card and drivers were removed. I had removed the JVC monitor from the system. What I didn

[Gene Colburn — email address bounces notices]

Hi Michael.
My continued interest, is in part because we are beginning to build systems with BM prodcuts(although not yet as an authorized dealer), so I am really interested in related posts on this forum. That aside, your problem does appear to suspect BM, which could be some component that is just enough out of tolerance to exhibit the shift. For both of your monitors (LCD and CRT) to exhibit it the same does leave a question. I do question why the necessity to completely remove drivers, and codecs etc. They should be totaly transparent to a native digital import, transfer, or export, and would have little to do with the component output which this thread was originally based on. There are however codec footprints that are not totally transparent. Is that a possibility you are concluding, (BM in particular) or is it still only the component output of the BM? I would truly like to know what you find in your effort to fix.

[michael d] “By the way, I find your comments and Bob Zelin

[Samuel Hearn]

Hello, I have added a new post about colour loss is anyone able to give me some feedback? It worked fine for 4 months and then suddenly reds have a green tint. This same problem happened after 3 months of originally buying the card and I had it replaced. The replacment card worked fine but they have said that nothing was wrong with the one I sent back? I am very confused? Is anyone able to help?

Sam

[Michael D]

Hello Gene,

I am impressed. In just a few posts you hit the nail on the head and figured out that my concern goes beyond the green tint on the component out of the DeckLink Pro card. If only Blackmagic support had such insight. Let me expand on my previous comments by summarizing some results from my analysis of one of the color files I captured using the DeckLink Pro card.

I captured eight hours of digibeta files which were telecine transfers of 16mm color films. I will limit my observations to the third hour of capture, a file I have labeled nhour03.mov, and I will limit my observations to the mean values of luma, red, green, and blue using the software waveform monitor of the Color Finesse plugin within After Effects (and eliminate any influence of the JVC monitor).

I created a clip approximately 40 s long from the original capture nhour03.mov. I exported the clip to movie with the card and drivers in the system and labeled the clip card.mov. I also exported the clip to movie with the drivers removed, the card physically removed, and the standalone codecs installed and I labeled the clip code.mov.

Now for some numbers with the card and drivers installed. The mean values of luma, red, green, and blue for a frame from the original capture nhour03.mov were 116, 104, 120, and 127, respectively. The mean values for the same frame in the clip card.mov were 115, 104, 119, and 126, respectively (close enough for government work). The mean values for the same frame in the clip code.mov were also 115, 104, 119, and 126, respectively.

Now for some numbers with the drivers removed, the card physically removed, and the standalone codecs installed. I neglected to obtain the values for the original capture nhour03.mov. The mean values for luma, red, green, and blue for the frame from the clip card.mov were 107, 94, 110, and 126, respectively. The mean values for the frame from the clip code.mov were also 107, 94, 110, and 126, respectively.

The mean values of luma, red, and green for the clips card.mov and code.mov with the card and drivers installed are different than the mean values with the card and drivers removed and the standalone codecs installed. However, the mean value of the blue channel in both clips with the card and drivers installed is the same as the mean value in both clips with the card and drivers removed and the standalone codecs installed.

There

[Michael D]

Hello Gene,

The last sentence of the fourth paragraph from the end of my last post should read

[Gene Colburn — email address bounces notices]

Hi Michael
Just breifly reading your thread here, as I am getting ready to go out of town for a few and my brain is fuzzy. Your analysis however points to some codec rounding taking place. If its any reassurance though, I know there lots of users using BM with Digibeta to Beta work taking place on a regular basis. If there were inherent problems with the cards, we would be seeing large number of similiar posts. I can’t help but wonder though. I have seen SDI devices with some gear pass setup values, that are totally stripped when encoded by the codecs. Looking at the numbers, I see some offsets that appear to be that. If that is in fact what is happening the channel paths can be truncated by the codec. Almost like cliping, which can account for varying path differences.