Sandisk Extreme 60MB/s really too slow?

[Dieter Piesch]

Hi,

My nanoFlash ist in a good state (Firmware 1.6.248, no pins damaged) and my Cards are Sandisk 32GB Extreme 60 MB/s.

I never encountered a message "Card in slot x too slow" before, until I did this:

- Feed the nanoFlash by HDMI via Matrox MXo2 (10 Bit Video processing). Source ist Adobe Premiere Pro CS 5.5.2 with "very detailed HD footage at 720p50.
- at the nanoflash side, I tried 50, 100, 140, 180 mbps, Long GOP or I-frame only. Container is MXF.

The "not-so-high-detailed" parts of the footage store as I am accustomed to: no problem. (JVC HM700 footage screencasts of PowerPoint)
The "very high detailed" parts (HD blu-ray trailers of the most detailed Quality I found, animation stuff) always result in a message "card in slot x too slow" and a degradation of date rate.

I tried 4 different cards in every slot.

I guess, it's a "codec overflow". The fifo meter display is, as I had expected it to be, always almost not visible: a small box of approx 5%, far away from the middle or even 100%.

Any ideas please?

Thank you for your kind help! (Hope this has not been discussed somewhere else. I tried to search before posting ...)

Regards
Dieter

[Dan Keaton]

Dear Dieter,

Does this only occur when recording from your Premiere Pro, through the Maxtrox interface?

For example, does all recording from your camera work fine?

I will be consulting with our support team shortly.

Is there an possiblity that "Illegal Values" are being sent out the HDMI?

Could you run a test, after applying a "Legal Values" filter?

I am thinking that the "Card Too Slow" error message may be in error.

[Andy Mangrum]

Hello Dieter,

I will try to replicate this in our Lab this week, could you try the same scenario using the SDI out instead of the HDMI out, to see if you receive the same result,

Best Regards,

[Jack Zhang]

Agreed on the legal values thing, fading to black or even 16/255 will cause the nano to drop the signal and go NO SRC. Put a black color down beneath all your video and set it to 17/255 whenever you're fading to black on the timeline, then limit the black on any clip that shows on your waveform to dip below 17/255.

Unfortunately, the nano chooses not to record anything below and including 16/255. Simply put, at the moment, it is designed as an acquisition device and not a VTR. All bitrates will show a "Card too slow" warning if the source dips below 17/255.

[Dieter Piesch]

Hi,
thank you for your kind replies!
I did some further testing:
- Yes, I did not encounter such a problem so far. No problems with my cameras, scan converter, ...
- It depends on the footage: I broke it down to 25 frames. It happens every time, I try to record.
Starting with black, there is a fade to "rango" in the bright sun within 4 frames. (bright blue sky, some clouds, close up to the head, magnificent details)
- It happens if I use the original footage (1920@23,974, H.264) and let Premiere do the scaling.
- It happens with a rendered version at 720p25, MPEG-2, 30mbpsVBR
- It happens with my Matrox Mxo2MinMax (10 bit Video, YUV, HDMI out. Sorry, no SDI out at this box.
- It happens with my BlackmagicDesign UltraStudio Pro using HDMI out.
- It does NOT happen using the UltraStudio Pro using SDI out.

When it happens, ...
.. while recording: realtime out to SDI turns to black, it stops recording and tells me the "card too slow message"
.. while not recording: there is a short message "no timecode" on the display of the nanoflash.

Do you have any advice on the legal values thing please? Can I test for that with Premiere Pro (for the whole sequence)? Or do I have observe a vectorscope as Jack did ...

[Dieter Piesch]

Hello Jack,
Thank you, probably you are right: Frame grabbing of the black frame results in a value of "0" for black pixels and the vectorscopes of Premiere show zero lines.
On the other side:
- The Matrox control panel offers a "allow super black" option, which is not checked.
- BMD does not offer such a super black option.
Do you have any advice on how to prevent Premiere from outputting values below 16 without having to adjust every clip as you did describe?
Regards
Dieter

[Jack Zhang]

Very interesting. It seems if what you are saying is correct, the illegal values cutoff are not applied with SDI.

Try this, feed pure black (0/255) through SDI and see if it suffers from NO SRC. If it doesn't, stick to SDI. If it does, still apply the fix to the applicable clips (apply a "Levels" effect filter and limit your output black to 17)

In Sony Vegas, you can apply a track effect to use the "Levels" filter on an entire video track, but I'm not 100% sure that's available in Premiere.

[Trevor Asquerthian]

I would imagine you can apply a 'safe colour' effect of some description to limit values to between 16-235. (I don't use PPro but maybe search for 'broadcast safe' or 'broadcast legal' or 'rgb legal').

I suspect that PPro will have some form of software waveform monitoring to check levels.

I'd be surprised if the nano didn't capture outside these limits as many cameras produce 'illegal' RGB levels.

My first stab at testing it would be to use just use simple colour bars - check the legal ones record (i.e. values are 16-235 only) then adjust the brightness / contrast so they are 0-255 and see if you get the same errors. This removes detail from the equation and checks levels.

[Jack Zhang]

It still records it if the luminance level is 16 or lower, but only if there is also an object in the image that is above that level. In the case of color bars, it will record it since there are portions of the image other than 16 or lower.

However, when fading to black, your master levels MUST be limited to 17-255 on HDMI. A black solid with a luminance of 16 will not record. SDI is apparently not affected by this, so you can possibly go 0-255 on SDI.

A problem encountered would be if a POV camera was covered and was sending black, the nano would stop recording and would not gracefully recover.