View Full Version : HDMI vs. Firewire output
08-01-2007, 02:02 PM
Ok, a couple basic observations and questions about the HV20 capture and export processes. Corrections or answers are welcome:
1. I can bypass the HDV compression process by capturing uncompressed HD "live" to my Mac through the HDMI output. I don't have the need, hardware or space for this, but it's possible with the right card and Mac specs.
2. If I don't capture uncompressed HD "live" per the above process, I have to capture it to my mini-DV tape using HDV compression, correct? (There are miniSD card capture possibilities, but they aren't worth discussing, are they?)
3. I can export the HDV-compressed footage to a computer using a firewire. Can I also export the HDV-compressed footage to a computer using an HDMI wire? Do I need a special capture card for that (e.g. Intensity)? Is transfer of HDV-compressed footage using HDMI different or superior than transfer via firewire? What can I do using HDMI as the transfer wire that I can't do using Firewire?
08-01-2007, 02:11 PM
2) yep. (but there's no mini-SD card capture possible on an HDV camcorder; you'd have to go with an AVC-HD cam to be able to capture to a memory card).
3) Yes you can do both, but no, it would not be superior to send HDV through HDMI.
08-01-2007, 04:31 PM
Thanks Barry. Here is an explanation from the Apple forums. It is confusing me a little. Once you record to HDV, how can you convert it to "uncompressed HD" and "eliminate HDV from post-production? Does this make sense to you:
"OK, you have an HDV camera and you record HDV to tape. This is the acquisition process and if shot properly a decent one. Now here is the transcode or conversion process, by playing the HDV tape on the camera and sending the signal out of the HDMI port it is now converted to uncompressed HD and the Intensity capture card then feeds it to allows Final Cut to transcode into any codec of your choice, and eliminates HDV from post production. You only shoot with it. You can toss the tape on a shelf and that becomes your backup. The better resolution and color space comes from the hardware processor on board the camera/deck before it is sent out to the HDMI port, Final Cut allows this signal to be converted to whatever you want."
Here's the full back-and-forth link: http://discussions.apple.com/thread.jspa?threadID=1065092&tstart=15
08-01-2007, 05:07 PM
You can't have uncompressed from off the tape. You have to shoot "live' to get uncompressed over HDMI. You can capture your "tape recorded" footage over the HDMI but you get no added benefits there other than in camera it upconverts the footage to1920x1080.....but you can do that in post. It is still compressed through the HDV codec off the tape, at 1440x1080, no matter how you capture it.
08-01-2007, 06:38 PM
What they're trying to do is get rid of the slow editing that HDV involves; transcoding away from HDV and into an "editing codec" gives much more responsive performance. You can do that during capture via HDMI, or after capture using a program like CineForm, etc.
08-02-2007, 07:22 AM
So, let's say I wanted to upgrade to FCP2, but because of my slightly older computer, I couldn't "capture HD resolution video using the ProRes 422 format."
Can I still do the workflow described in this thread (http://www.dvxuser.com/V6/showthread.php?t=98411)?
08-03-2007, 01:59 PM
What would be the best (well, reasonably good considering costs involved) to convert from HV20 to intermedate format:
- upload as HDV, then recompress (or recompress on the fly if computer is powerful enough)
- upload via HDMI and compress
I understand that HDMI transfer does not add to information in the original compressed HDV, I am just wondering would this be less processor-intensive then on-the-fly HDV recompress, because there is no need for decoding of HDV. Are there decent free/cheap converters/codecs for intermediate format? Which intermediate format to choose? If I have 24psf, should it be converted to 24p before or after converting to intermediate format? Found this on DVInfo:
You can: 1. Buy the CineForm capture tool for 200.00 to use with VMS 2. Use the free version that comes with Vegas Movie Studio 3. Edit native HDV I did not see anyting for $200 on Cineform site, also what does this guy mean by capture tool? If VMS has free version (of something, what? capture tool?) then why using option 1 as he recommends, not option 2? I would ask there, but I am not authorized on DVInfo.
Found this on AVSForum:
You can edit HDV on the PC listed in you initial post (I know because I have a P4 3.0 GHz, 2 GB of RAM); just use the built-in Cineform intermediate codec to convert your HDV .m2t clips to the visually lossless and easily-editable .avi format. Check out Cineform's website for more details. I know Sony's Vegas Home Studio Video+DVD imports HDV, but I'm not sure if includes the Cineform intermediate codec. This is a bit clearer, but this guy is not sure whether Cineform intermediate codec is included into VMS. Is it? Or do I have to upgrade to full Vegas (currently I am using VMS 6.0, no HDV support). What if I will be editing native HDV strictly at I-frame boundaries, will I lose quality? Is Vegas intelligent enough to not recompress if I cut on I-frames?