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Can you "re-digitize" from AVCHD to Prores and maintain timecode?

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Isaac Brillant
Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Dec 30, 2009 at 3:25:42 am

Hi,

I plan to buy the HMC tomorrow and have a question about transcoding and re-digitizing offline sequences. I've been getting mixed answers to this question, but maybe someone here has some firsthand experience with this issue:

I use FCP 7. If I transcode/transfer from AVCHD to Prores, and when I'm done with the project I delete the unused large ProRes files... If later I want to re-digitize a now offline sequence, can I re-transfer/re-capture from the smaller archived AVCHD and end up with Prores that maintains its original timecode and will sync up? AND can I do this without having to buy some expensive converter like a Kona card?

Also, does it make a difference if I use the FCP log&transfer to "capture" to Prores, or if I transcode the AVCHD files with some other software like CS4 Adobe Media Encoder, Compressor, Cineform etc?

Lastly, what is the difference between transcoding to Prores, vs AIC vs AVC-Intra 50 or 100 (if thats a possibility) and how do those other codecs deal with the timecode issue?

Thanks!
Isaac



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cow
Dave LaRonde
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Dec 30, 2009 at 6:39:40 pm

That's why thy make capture cards in the first place: so you can capture to a codec that's actually useful, AND maintains the timecode of the original footage.

So if you insist on cheaping out, you'll continue to have these kinds of problems.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Isaac Brillant
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Dec 30, 2009 at 6:58:08 pm

So then the answer is that it doesn't maintain timecode for any of those codecs?

If I'm going to have to pay another grand or more to buy a capture card for the HMC150, I may as well pay another grand to buy an HPX170 instead, right?


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John Christie
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Dec 31, 2009 at 7:08:20 pm

Isaac

Yes, you can do the workflow you've described. But once you've finished your edit, it's easier to media manage your project to an external drive and keep just the media you've used as a backup. Then you can just reopen the media managed project any time. You'll also want to keep copies of the original SDHC cards as well. Make sure you copy the whole file structure from the cards.

You can't use a capture card with an HMC150 as there is no external machine control. You can run HDMI out from the camera, but there's no timecode available.

Contrary to what Dave says, you are not cheaping out. These are the workflows we'll all be using as tape based recording systems start to become obsolete. A capture card is good to have for insuring proper outputs to monitors and video decks, but they're not used for capturing media from AVCHD, Sony SxS or P2 cards.

Cheers

John Christie


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Isaac Brillant
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Dec 31, 2009 at 8:14:03 pm

Hi,

Thanks John.
I'm not sure I understand though...

I'm not really so concerned with the footage that I did use in the final sequence, because I'll media manage that and just keep it in ProRes. (Although it would be nice to be able to have a duplicate backup on another drive in a smaller codec (I was hoping AVCHD), but one that could be redigitized if something happened to the 1st backup)

But I'm more concerned about the media that was used in earlier cuts and assemblies, but didn't make the final cut, and ends up offline. Sometimes down the line I want to look at an earlier cut, or make another version, or go back to an earlier version for another purpose, etc. This isn't so much an issue for strictly business projects, since once its done its done, but applies more to narrative films...

Thanks! Happy New Year!
Isaac

PS I'm leaning now towards just getting an HPX170. Any rumors of P2 cards going down in price again or is it just wishful thinking?




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Isaac Brillant
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Dec 31, 2009 at 8:15:52 pm

P.S.

I had another thought about transcoding to ProResLT 720p... I'd love your feedback on it. Here is the post:

http://forums.creativecow.net/readpost/122/859249




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John Christie
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Dec 31, 2009 at 11:16:09 pm

Hi Isaac

I'll do a test tomorrow and get back to you.

Nothing wrong with the HVX 170 route either (except for the pricey cards!)

Cheers

John C


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Isaac Brillant
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Jan 1, 2010 at 12:56:50 am

Thanks John, that's great! Happy new year!

Isaac


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John Christie
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Jan 1, 2010 at 9:40:49 pm

Hi Isaac

I did a quick test, loaded a few shots from AVCHD as Prores (regular) and cut them into a timeline. Then I media managed the sequence to create an offline sequence with handles as Prores HQ. I opened log and transfer and changed the preferences to transcode as Prores HQ , then I selected the offline sequence and asked it to batch capture. The clips all transferred and transcoded properly to HQ with handles.

So if FCP can do all that, I don't know why it would have any issues in recapturing offline clips from the original AVCHD files.

You also asked about converting files with some other software. I wouldn't do that as FCP wouldn't know how those files were made. IF FCP can do all this by itself, there's no reason to use other software.

Also, regarding codecs for FCP, your best off to stick with Prores. It's optimized to work well with FCP on just about any mac FCP can run on. AIC is what iMovie uses and isn't nearly as good as Prores. AVCintra is a great codec, superior to P2 which it's designed to replace, but I'd still stick with Prores for the ease of playback on FCP.

One caveat, I copy the cards to an external USB drive as backup. The folder name that the card files are copied into becomes the reel name. So the folder MYVIDEO with the PRIVATE folder from the SDHC card copied into it becomes reel MYVIDEO in FCP. I'm not sure if FCP needs this info to re-capture or not, but it's a good file management practice with AVCHD to copy all the files to a hard drive before importing to FCP.

Hope this answers all your questions. One of the things I love about My HMC 150 is that my capture VTR is a $10 card reader and my HD screening machine is a Playstation 3. I'm not sure about the new PS3 thin model, but the older one I have has an SD slot and plays back AVCHD cards beautifully. You can also convert h.264 files to play on PS3, so I can have all my finished projects on my PS3 as well, but i'm going a little off topic here.

Happy New Year.

John C


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Alf Hanna
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Jan 2, 2010 at 6:01:39 am

John, just for FAQ on this, what Mac model and setup are you doing this all on? I'm curious because I assume I have to go buy a MacPro (which I'm considering doing) to make the huge file sizes render in something under a year. I'm currently running a Mac Book Pro Intel 2.4 GHz core 2 duo. I'm under the impression I have to have a Mac Pro to handle AVCHD with any decent speed. Thoughts?

Thanks again for your doing this, I've just finished evaluating Vegas Video Pro 9.0c and had some real problems, more with Windows & graphics cards than Vegas, and assume I'll end up on the Mac Pro with FCP after all this.



Alf
Panasonic HMC-150 & Vegas Video 9.0c on Win7/64bit


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John Christie
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Jan 2, 2010 at 6:06:11 pm

Hi Alf

I edit at home on a 3.06Ghz Imac with 6GB RAM. It's about a year and a half old. I keep all my media on a striped FW 800 drive, and back up my cards to a USB hard drive as well. The majority of my work is 720P and the computer handles it beautifully. I don't do a lot of effects, other than smooth cam and some titles, so rendering never seems to bog me down.

The beauty of the FCP/AVCHD workflow is that once you've transcoded to ProRes, there's not a lot of heavy lifting for the computer to do. You can batch all the transcoding as well, so you don't have to be sitting in front of the computer while it's going on. Transcoding a 1 min clip takes roughly 25 seconds.

The only thing I don't like with the iMac is the lack of expansion. My day job is managing a department of 12 edit suites, all Mac Pros with fibre channel cards running off of XSAN, and I love how easy it is to get inside them and swap hard drives, video IO etc. I do a lot of H.264 work at home, and I've just ordered a Matrox MXO2 with Max compression to help with that. But I'll have to put that on my 17" Macbook Pro as it has a 34 card slot.

Cheers

John C


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Isaac Brillant
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Jan 2, 2010 at 11:22:07 pm

Hi John,

Thanks for running that test. So, when you opened log & transfer, and changed the preferences to transcode as Prores HQ , and selected the offline sequence and asked it to batch capture, were you batch capturing from the ProRes regular clips to ProRes HQ, or from the AVCHD clips? It makes sense that it would keep the timecode from Prores regular to Prores HQ, but I'm trying to avoid having to archive all this Prores material.

Also, similar question regarding your post on our other thread, where you wrote:

"Don't use Prores LT as a final codec, it's designed for offline editing. You can import everything as LT for space reasons, and then media manage and recapture your final timeline as Prores......
You don't want to be transcoding and changing frame sizes and frame rates, things will get ugly real fast."

So, when you say media manage and recapture as ProRes, do you mean recapture form the original AVCHD or from the ProRes LT?

About the frame size, maybe it's cheating, but the reason I was thinking about capturing and editing in 1080, and later downconverting the sequence it to 720, was so that in a talking head interview, I could - in a pinch, blow up the Medium CU by 30% and cheat it as a new CU shot, so that I can cut from one shot to the same shot, without it being obvious.

So I figured if I was working in 1080, but ultimately ending up in 720, once in 720 you wouldn't be able to tell the difference unless you're really sensitive to the optics of lenses.

In what way do you think it would get ugly? Aliasing or artifacting?

Thanks for all your input.

Yitz

BTW, where do you work in Vancouver? I was just there in August for a few days, and my short film played at the Jewish Film Festival there earlier last year.


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Isaac Brillant
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Jan 2, 2010 at 11:26:42 pm

Oh, also...

Do you do any sort of backup archival on DVDs or Bluerays? I'm wondering if thats a common workflow, when completing a project, to burn all the AVCHD files to DVD. It ought to be something like 2 or 3 DVDs per hour of footage? I guess it wouldn't be as easy with ProresLT or DVCPro (if using an HPX) though.

Thanks


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John Christie
Re: Can you "re-digitize" from AVCHD to Prores and maintain timecode?
on Jan 3, 2010 at 1:42:17 am

[Isaac Brillant] "So, when you opened log & transfer, and changed the preferences to transcode as Prores HQ , and selected the offline sequence and asked it to batch capture, were you batch capturing from the ProRes regular clips to ProRes HQ, or from the AVCHD clips? It makes sense that it would keep the timecode from Prores regular to Prores HQ, but I'm trying to avoid having to archive all this Prores material"

When redigitizing, FCP goes back to the original AVCHD files, I'm not transcoding from Prores LT to regular or HQ. So the bottom line is you can safely delete your Prores files after editing, knowing that you can always transcode the original files again and preserve all the timecode.

[Isaac Brillant] "About the frame size, maybe it's cheating, but the reason I was thinking about capturing and editing in 1080, and later downconverting the sequence it to 720, was so that in a talking head interview, I could - in a pinch, blow up the Medium CU by 30% and cheat it as a new CU shot, so that I can cut from one shot to the same shot, without it being obvious. "

Yeah, I've done that cheat as well. It works reasonably well, but not something I would rely on. I haven't noticed any aliasing issues when down-converting 1080 to 720, but I haven't looked closely at it.

I also backup files to data DVDs, one 16GB card spans across 3 DVDs using Toast. It's time consuming, but nothing wrong with being anal when it comes to your data. USB rives are pretty cheap though, buy two and keep one offsite for maximum data protection.

I'm head of post-production for Paperny Films in Vancouver, we don't work the HMC150 at work. I use the HMC150 on my own pet projects.

Cheers

John C



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