Urgent Direct Capture problem with HVX, FCP6, and 720/24p

G

gabrielw

New member
Hi All,

We're currently shooting a bunch of direct to drive stuff on the HVX in 720/24p and capturing into FCP6 using log and capture. Were capturing as non-controllable device with the DVCPRO HD 720/24p capture preset, but the files are coming in as 60P, so were overloading our drives.
Our cameras have 4.06 firmware, and we've tried the cams with different laptops and different versions of FCP.

Any thoughts???

Thanks guys,
Gabriel
 
That's normal. You cannot record PN modes, and the 24P and 24PA modes are embedded in a 60 field interlaced stream with frame duplication.
 
Interesting... I've certainly done this a lot in FCP 5 without a problem. Not to be disagreeable, THoff, but HVX progressive footage is never sent out in an interlaced stream, and FCP (at least 5!) is able to remove pulldown from the "over 60p" stream.

Unfortunately, I haven't tried this in FCP 6 yet... do you have a copy of FCP 5 around you can trry with, to rule out any potential issues on the camera side?
 
You cannot record 24pn mode over firewire as firewire is disabled in any of the pn modes. You can remove pulldwown after the fact in Final Cut Pro for the other modes.
 
Also, just to cover bases, Gabriel - are you very familiar with the HVX? That is, is there any chance you're doing something like shooting 720p60 at 24fps (that is, undercranking) rather than shooting 720p24?

What does the 60p footage look like? Do you see repeated frames (i.e., pulldown) or are they all different?
 
THoff said:
and the 24P and 24PA modes are embedded in a 60 field interlaced stream with frame duplication.
Click to expand...

ullanta said:
Not to be disagreeable, THoff, but HVX progressive footage is never sent out in an interlaced stream, and FCP (at least 5!) is able to remove pulldown from the "over 60p" stream.
Click to expand...

I think you are both right and both wrong.
If I remember correctly, 720 footage is always progressive and sent out the firewire port in a 60p stream. There will be frame duplication in 24p so the pulldown will need to be removed on import.
1080/24PA footage is progressive but sent out in a 60 interlaced stream but again the advanced pulldown will need to be removed on import to get it back to 24p.
 
The solution

The solution

I had this same problem...

So you wnat to record 720/24p to harddrive on a laptop/computer?

Final cut works with standard formats, thats why you cant record 720/24p native as a capture preset as its not a normal formatt ( For instance when you imposrt your 24PN footage, Final cut will wrap it and duplicate the needed frames to fit on a 720p standard timeline.

standard 720p(the kind you watch on HDTV) is always 60p, when you record 24p, it just duplicates frames to fit them into the 720/60p standard. And DVCPRO HD 720/60p is 100mb/s

Thats about 12.5 Megabytes per second
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The Problem is your Harddrives, Make sure you have a 16Mega BYTE buffer and a 7200rpm drive at least. Most built-in laptop hardrives only have an 8MB buffer or less.
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The solution:

Get a firewire 800 or USB2 External hardrive with a 16Megabyte buffer!

You wont drop any frames after that. (but you might drop your laptop!)
 
When you say "overloading" the hard drives, it's hard to interpret the problem and cause. Is it too much data to fit on the hard drive or too much data to I/O? The answer to the "too much to fit" is obvious, so here is some potential for the other issue:

There are 3 potential bottlenecks when you suck on that big of a firehose:

1. hard drive (and buffer)
2. cpu
3. ram

Most likely it's the read/write and hardrive like Hunter recommends. However, the guys at Apple told me that cpu is a often underestimated as a factor, considering that some processing must take place...it's not simply an I/O issue. Also, RAM is a help for buffering the stream.

I chose to use DV Rack HD on a PC laptop for capture and monitor. The laptop is dedicated to the task and has had no throughput issues. It can gulp down anything the HVX sends. My Macbook Pro is set up for FCP only and not capture.

It would be cool if Panasonic sent native-sized files through the firewire.
 
Last edited:
From the FCP (5) manual, in the section on the Capture preset editor:

"Remove Advanced Pulldown and/or Duplicate Frames During Capture From FireWire
Sources: Some camcorders, such as the Panasonic DVX100 or Varicam, can record
alternate frame rates within a standard frame rate. For example, the DVX100 can
record 23.98 fps video within 29.97 fps by adding an advanced 2:3:3:2 pulldown. The
Varicam can record multiple frame rates, such as 23.98 fps (720p24) by adding
redundant frames within a 59.94 fps (720p60) video signal. When this option is
selected, Final Cut Pro removes the redundant fields or frames during capture. If this
option is not selected, all the redundant frames are captured. You can remove
redundant frames later by choosing Tools > Remove Advanced Pulldown.
For more information about working with multiple frame rate video formats in
Final Cut Pro, see Working With High Definition and Broadcast Formats (choose HD
and Broadcast Formats from the Help menu.) "

Like I said, I have no trouble capturing 24p/30p without the redundant frames over firewire with FCP 5....

(And, yes, Ozduc, I should've said "720p footage", not "progressive footage"!)
 
hunter richards said:
For instance when you imposrt your 24PN footage, Final cut will wrap it and duplicate the needed frames to fit on a 720p standard timeline.
Click to expand...

Ah, I dont think that is correct.

hunter richards said:
The solution:

Get a firewire 800 or USB2 External hardrive with a 16Megabyte buffer!

You wont drop any frames after that. (but you might drop your laptop!)
Click to expand...

FW 800, yes. But I dont think the USB drive will work very well.
 
On the PC, I have captured hours of HVX video to an external 7200RPM drive using USB with DV Rack HD. No problem.
 
one of the cameras i just recently shot a concert with was done exclusively to Final Cut Pro 6 through FireWire and it worked without a problem

in fact, i shot the 'master' camera to the laptop at 720/24p over 60 and the other two 'roaming' cameras in 720/24pN and i experienced not a single problem. the entire process was quick and easy. i was even able to sync the timecode with the other two cameras so multiclip was SUPER easy.
 
THoff said:
On the PC, I have captured hours of HVX video to an external 7200RPM drive using USB with DV Rack HD. No problem.
Click to expand...


Same here with only 4,200rpm and 5,400rpm drives using PC w DV Rack HD.

(haven't tried hours, but over 20 minutes at a time)
 
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