WFT-E5 grip, USB hard drive and RAW video ?

Started by vyskocil, February 08, 2014, 06:27:55 PM

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vyskocil

Hi !

I own a 7D and a WFT-E5 grip that can be used to plug USB device like USB key and hard drive (and Bluetooth adapter for GPS).
I tried to record RAW video with mlv_rec but alas it insists to record on the compact flash and not to the hard drive when this one is connected and configured to be used as the default target (it works with pictures, they are well recorded on the USB drive).
I think the USB drive may have a dedicated drive letter or mount point that mlv_rec should use to redirect the writing there, but how to discover this ? Does somebody have some experience with WFT and Magic Lantern ?

Midphase

I don't think this set up will work.

Further, I highly doubt the USB is nearly as fast enough as the CF card.

vyskocil

Why not ? As USB 2.0 should give around 30MB/s write speed, perhaps I could record 720p continuously.
It should also be possible to do write spanning on CF and HD like it is possible on 5DMkIII with CF and SD !

Midphase

I don't make the hardware nor the code, so I can't tell you why. Maybe one of the code guys will pop in here and elaborate as to why that can't happen (hint....I suspect it has to do with the CPU).

What I can tell you is that near-1080p requires over 60Mb/sec write speed. I doubt that 720p would necessarily cut that in half, and even if it did, you're skating awfully close to the limit of USB.

So the answer remains no.

1%

The best we can hope is something like 5DIII with both CF and USB going at the same time... if USB makes another drive like C: or something it can be coded into MLV rec but I don't have one to test. Maybe when the WFT comes down in price.

vyskocil

I have checked that the USB hard drive is seen as "C:" when connected !
I'll try to substitute the 'A:' used in mlv_rec filename with 'C:' and do some bench... I'll also try the 5DMkIII disk spanning substituting the 'B:' drive with 'C:'.
Even if the USB connexion is too slow for realtime recording I can imagine this could be used to move RAW files from CF to HD, making room on the CF card for more recording.

vyskocil

The first benches with the usb hard drive as target aren't glorious, I could only achieve 864x486 at 23.976fps continuous recording (about 16MB/s) but it works ! I'll check this again with a "real" USB hard drive because actually I only used a USB to SATA adapter, maybe this is not optimal speed wise...

1%

Try it with the spanning... I bet you could crank some decent 2k or full 1080P with 80+16MB

Midphase

But that would require shooting crop mode which is another can of worms (IMHO).

Also, regarding transferring the data from a CF card to the USB drive...it can take well over 30 minutes on a USB 2 connection to transfer a 64Gb CF card...and I suspect the throughput of this thing isn't as fast as what one would find on a laptop.

I still say that if you're looking for faster storage, more overall stability and options, and a no compromise solution...Blackmagic is waiting for you with open arms.

1%

lol, so are red and arri... but we have these canons

Midphase

Sure, I've always said that if you already own a CF equipped Canon camera, ML raw gives you effectively a brand new camera at no additional cost (or at the cost of fast CF cards).

I was ready to sell off my 5D3 until ML raw appeared, and now I am extremely happy to have bought it.

Having said that, I accept that there are limits and compromises to what this clever code can accomplish and that at some point the limits will be reached regardless. For instance, I think it's pretty safe to say that we will never have 4K raw recording available to us using the full sensor. It's also pretty safe to say that we're probably not getting FS700 or GH4 slow motion on this camera, nor an option to encode in ProRes, or record to CDNG natively.

I'm fine with that, I accept it, and I am very happy and lucky to own the very best camera for ML raw which offers the least amount of compromises of the bunch. Having said that, if I needed functions like reliable 2K or greater recording, reliable outboard monitoring and playback, more reliable (and larger) recording media, more direct post-production workflow, etc, I'd need to come to the realization that ML is probably not the right choice for that. We just shot a fairly high-end short film on your code 1% with two 7D's. It was a cool thing, but what I wasn't particularly thrilled with was spending an entire week converting hundreds of files into CDNG and ProRes for editorial.

ARRI and Red are not "ownership" type of cameras, they are rentals. However Blackmagic Cinema Camera is, and so is the pocket camera (and one could argue that they are more affordable than DSLR's).

I would hope that at this stage, more emphasis is being put on solidifying the code and strengthening the post production tools rather than chasing after possible functions which are simply too clunky or costly to implement (anyone remember the CF to SATA project?).

Midphase

P.S.

Since I have your attention 1%....could you explain why it is that the cameras can't write CDNG sequences directly on the CF cards? Is this a CPU issue or a 14bit vs 16bit? If at least something like the 5D3 could write directly into CDNG format instead of .mlv that would be a huge improvement for post workflow.

1%

It can, look at how it does silent pics... just the throughput isn't there. It takes more CPU/resources to write each frame out than it does to just put the buffer into 1 file and convert on the PC.

QuoteIt was a cool thing, but what I wasn't particularly thrilled with was spending an entire week converting hundreds of files into CDNG and ProRes for editorial.

Even worse are bad takes and with MLV_REC you have to go into play and remember the file name to delete. I shot like 100gb for 1 min of keeps. When the screw up was at the end after like 20-30sec I was basically stuck converting the files anyway and then listening to the pro-res + audio and going back to delete mlv+mov

Midphase

Quote from: 1% on February 09, 2014, 11:23:41 PM
It can, look at how it does silent pics... just the throughput isn't there. It takes more CPU/resources to write each frame out than it does to just put the buffer into 1 file and convert on the PC.

Is the throughput that far off even on the 5D3? I understand that ML is trying to be consistent across all of the supported cameras, but is the inability to create CDNG quickly enough extend to the top range of the CPU's as well?

Also, has anyone ever tried to port ML on a C100? Is it just a question of none of the developers owning one?

1%

C series are completely different and I don't know any devs that have one... but yea, the overhead of creating files and all of that is too much to get a decent res. Remember it started off as dng sequences if you used the earliest raw stuff.

Jackeatley

An old thread I know.

I wondered the same thing last night, but i assumed it would be too slow to write too, but could we use a fast CF card as a buffer, and automatically or manually move the files to a hard disk so the user didn't have to keep changing cards.

Can you move .MLVs or .RAWs from the CF card to the USB hard disk for example?  You could then format the card and start shooting again.

I know you can move raw files around the CF using File Manager, but can file manager access the USB drive c:/ aswell as a:/ the CF?