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Record losless RAW on BMPCC4K!

PostPosted: Thu Jan 10, 2019 10:01 am
by Cooper
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.

Re: Record losless RAW on BMPCC4K!

PostPosted: Thu Jan 10, 2019 10:43 am
by Robert Niessner
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.

Re: Record losless RAW on BMPCC4K!

PostPosted: Thu Jan 10, 2019 11:48 am
by Cooper
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.

Re: Record losless RAW on BMPCC4K!

PostPosted: Thu Jan 10, 2019 12:10 pm
by rick.lang
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.


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Re: Record losless RAW on BMPCC4K!

PostPosted: Thu Jan 10, 2019 2:35 pm
by Robert Niessner
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.

Re: Record losless RAW on BMPCC4K!

PostPosted: Thu Jan 10, 2019 5:16 pm
by rick.lang
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.


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Re: Record losless RAW on BMPCC4K!

PostPosted: Thu Jan 10, 2019 9:06 pm
by Australian Image
It'll record 4K DCI Lossless at 50fps onto a Samsung T5 SSD as well.