BMD Media Express software dropping Frames with 4k capture

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praful

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  • Joined: Sun Jun 10, 2018 1:12 am
  • Real Name: Praful Gupta

BMD Media Express software dropping Frames with 4k capture

PostSun Jun 10, 2018 5:38 pm

We’ve got the latest Decklink 4k extreme 12G card from Blackmagic design that is dropping frames with 4k capture.
I am trying to capture a 4k video from my MacBook Pro. There is absolutely no problem in displaying video on the media express software, thus no issues related to HDCP.
There is also no dropping frames issue in capturing a 1080p video in any projection format (compressed/ uncompressed). However, capturing 4k videos is dropping frames with all available formats.

- SSD Drives (these are fresh empty drives, so plenty of storage available)
First thing I tried after looking up for solutions addressing similar questions in BMD forums is the BMD Disk Speed Test. Here is the screenshot, which indicates that the disk (a Samsung SSD 970 drive; mentioned in the "preferences" section of Media Express) I am trying to write a 4k video on, is more than capable for 4k capture with massive read/write speeds (3500 MB/s):
https://drive.google.com/file/d/19z6R41 ... sp=sharing
This was very puzzling to me.

- PCIe SLOT
The Decklink card manual says it should be plugged in atleast x4 PCIe Slot. We are using a x16 PCIe Slot, so that should also not be a worry.

- HDMI cable length:
In one of the questions, I even saw that the length of the HDMI cable may also be a possible problem. We, however, are using a relatively short (3 feet) high speed HDMI cable which is specifically designed for transferring 4k content.

- Rolling back to previous Desktop Video versions (10.4 to 10.9) did not help either.


What I think (you don’t have to concur):
In addition to SSD drives, the machine has SCSI drives (non SSD) on which the operating system is running. The Disk speed test indicates the following read/write speeds of this drive.
https://drive.google.com/file/d/1uQs4ZI ... sp=sharing

This read/write speed is exactly what will allow 1080p writes but not the 4k ones (looking at the following capture data rate of 1080p and 4k videos [4k captured with unchecked “stop when dropping frames” in “preferences” of media express] ).
https://drive.google.com/file/d/13lHZLQ ... sp=sharing

And obviously, I am suspecting BMD is somehow using these drives to either read/ write the content.

Since installing BMD’s Desktop Video software does not provide us capabilities to change the installing directory of the software, and automatically installs it in C:\ drive. This just doubles my suspicion of what might be causing this issue.

Questions:

In our end application, we cannot tolerate any frames to drop. Thus capturing with dropped frames is not an option we can rely on.

Do you have any idea what might be causing this? Will appreciate any kind of help. :) :)

- Also, is there any way to change the installation directory of media express software to validate if this is what is causing problems?

- We can also get some cues from the logs of the dropped frames error. Do you know where can these log files be accessed?

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System specs:

Windows 10 Pro x64
Dell Precision 7920 Tower
2 processors:
- Intel Xeon Bronze 3106 CPU @ 1.7 GHz, 8 Core
- Intel Xeon Bronze 3106 CPU @ 1.7 GHz, 8 Core

32 GB RAM 512 GB SATA Class 20 Solid State - this is the drive that the OS is running on
4, 2 TB SSD Drive: Samsung SSD 970 - set up as an 8TB array
• These are capable of reading at 3700 MB/s, writing at 2700 MB/s
2, 4 TB 7200 rpm Nearline SAS - these drives are for set up as an array for long term storage on the PC
******************************************************************************
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praful

  • Posts: 2
  • Joined: Sun Jun 10, 2018 1:12 am
  • Real Name: Praful Gupta

Re: BMD Media Express software dropping Frames with 4k captu

PostMon Jun 11, 2018 4:31 pm

Got this fixed...

PCIe Slot x16 (1,4) in which the Decklink card is plugged in, is actually a wired x1 slot (got it confirmed from the Dell Support).

Plugging it in a full power x16 slot fixed everything.

It might be of help to many. Enjoy playing with the super powerful card! Cheers :)

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