Record losless RAW on BMPCC4K!

The place for questions about shooting with Blackmagic Cameras.
  • Author
  • Message
Offline

Cooper

  • Posts: 121
  • Joined: Sat Sep 29, 2018 9:46 am
  • Real Name: Jari Keskisalo

Record losless RAW on BMPCC4K!

PostThu Jan 10, 2019 10:01 am

Suprise... it seems the cfast slot can sustain the datarate needed for 4096 losless CDNG raw at 60fps. Need to retest once the battery charges, but recorded 30+ minutes before I stopped the recording, 15 minutes left on the 2TB Samsung 860 EVO + Cfast to SATA data cable and USB to SATA power cable. The USB port on the camera fails miserably at the same task.
Last edited by Cooper on Tue Jan 15, 2019 10:34 am, edited 1 time in total.
Offline
User avatar

Robert Niessner

  • Posts: 2490
  • Joined: Thu Feb 21, 2013 9:51 am
  • Location: Graz, Austria

Re: Record losless RAW on BMPCC4K!

PostThu Jan 10, 2019 10:43 am

That is not surprising because the USB-C port of the camera is USB 3.1 Gen 1 (which is USB3.0 on USB-C) with a max. real theoretical data rate of 450 MB/s while CFast 2.0 is capable of a maximum of 600 MB/s.

And 4k DCI raw lossless 60fps needs around 544 MB/s of bandwidth.
Robert Niessner
LAUFBILDkommission
Graz / Austria
---------------------------------------------------------------------
Blackmagic Camera Blog (German):
http://laufbildkommission.wordpress.com

Read the blog in English via Google Translate:
http://tinyurl.com/pjf6a3m
Offline

Cooper

  • Posts: 121
  • Joined: Sat Sep 29, 2018 9:46 am
  • Real Name: Jari Keskisalo

Re: Record losless RAW on BMPCC4K!

PostThu Jan 10, 2019 11:48 am

Yes, but the surprise for me is having a single media (1 slot) to write at that speed. At least on the PC world the SATA 6G has hard time reaching such sustained write speeds by my experience. And I don’t know that many if any cfast 2.0 cards that write at that rate.
Online
User avatar

rick.lang

  • Posts: 11492
  • Joined: Wed Aug 22, 2012 5:41 pm
  • Location: Victoria BC Canada

Re: Record losless RAW on BMPCC4K!

PostThu Jan 10, 2019 12:10 pm

None of the approved CFast 2 cards will actually record DCI 4K at 60 fps for more than a couple of seconds I believe in any BMD camera. BMD recommends raw 3:1 for 60 fps on a single card or raw lossless on dual card recording. The port may be capable as you’ve found, but the cards don’t work quite fast enough.


Sent from my iPhone using Tapatalk
Rick Lang
Offline
User avatar

Robert Niessner

  • Posts: 2490
  • Joined: Thu Feb 21, 2013 9:51 am
  • Location: Graz, Austria

Re: Record losless RAW on BMPCC4K!

PostThu Jan 10, 2019 2:35 pm

Rick, just got my Angelbird 1TB Cfast cards today. I have tried them out in the PCC4k and they are capable of recording 4k DCI raw lossless up to 50fps without dropping frames, which is 453 MB/s.
60fps isn't possible of course.
Robert Niessner
LAUFBILDkommission
Graz / Austria
---------------------------------------------------------------------
Blackmagic Camera Blog (German):
http://laufbildkommission.wordpress.com

Read the blog in English via Google Translate:
http://tinyurl.com/pjf6a3m
Online
User avatar

rick.lang

  • Posts: 11492
  • Joined: Wed Aug 22, 2012 5:41 pm
  • Location: Victoria BC Canada

Re: Record losless RAW on BMPCC4K!

PostThu Jan 10, 2019 5:16 pm

That’s great news for PAL countries! Very impressive. I have only recorded off speed 60 fps dual card a few times, but I did get appreciative feedback when one of those times was a training exercise played back at 30 fps. Just running things in half time allows one to see their body motion so much better.


Sent from my iPhone using Tapatalk
Rick Lang

Return to Cinematography

Who is online

Users browsing this forum: Bing [Bot], Majestic-12 [Bot], Shaoyan and 23 guests