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-   -   AVC-Intra Question (https://www.dvinfo.net/forum/panasonic-p2hd-dvcpro-hd-camcorders/468533-avc-intra-question.html)

Clint Harmon November 29th, 2009 12:01 AM

AVC-Intra Question
 
Is AVC-Intra just as intensive on the NLE processor as AVCHD? I am about to upgrade workflow and want to leave the AVCHD headaches behind. Will I be reliving AVCHD if I upgrade to a camera (HPX300) using AVC-Intra?

Gary Nattrass November 29th, 2009 03:47 AM

No it isnt AVC intra is a superb codec and far better for editing than AVCHD, I am using AVC intra 100 a lot and it goes into final cut pro as re-wrapped native AVC to pro res files.

It is a dream to work with and the lower bit rate AVC intra 50 is even easier, the files also go into FCP at 3X real time for AVC intra 100 on my mac machines.

I also use AVCHD from a canon HF11 and find that it is better to transcode to pro res LT than re-wrap and try to use AVCHD for editing.

Hope this helps, I have the HPX301 and the picture quality of AVC intra is superb.

Denny Lajeunesse November 29th, 2009 04:26 AM

Sorry to go some what off topic here, but is there any way to convert from AVCHD (or nay format) to AVCIntra? I'm thinking the storage would be much smaller than say DNxHD codec.

Gary Nattrass November 29th, 2009 06:32 AM

I dont think there is a way to copy AVCHD to AVC intra and it would up the size and bit rates.

I transcode all my AVCHD to pro res LT now and that seems to be the best balance for bit rate and file sizes. It also gives the advantage of all my media from the 301 and HF11 being in the same format for edit.

Perrone Ford November 29th, 2009 07:09 AM

Quote:

Originally Posted by Denny Lajeunesse (Post 1453484)
Sorry to go some what off topic here, but is there any way to convert from AVCHD (or nay format) to AVCIntra? I'm thinking the storage would be much smaller than say DNxHD codec.

DNxHD is variable bit-rate, and you can use sizes down to 36Mbps which is even smaller than AVC-Intra 50. There are several DNxHD codec bitrates below 100 Mbps. Why not use one of those?

David Heath November 29th, 2009 12:31 PM

Quote:

Originally Posted by Gary Nattrass (Post 1453472)
AVC intra is a superb codec and far better for editing than AVCHD, I am using AVC intra 100 a lot and it goes into final cut pro as re-wrapped native AVC to pro res files.

AVC-Intra and ProRes are two totally different codecs surely? The first a native Panasonic codec, the second the "native" codec for FCP.

Hence, if you're originating AVC Intra 100, but using ProRes within FCP, the inputting process is not re-wrapping (where the codec remains the same) but transcoding. Hence the edit performance has nothing to do with AVC-Intra (which is the question asked), but everything to do with ProRes.

Perrone Ford November 29th, 2009 12:36 PM

Apparently, at least from what I've seen on the internets, ProRes can take in AVC-Intra without a transcode. And it's just a re-wrap. Not sure how they are doing it, but that's what Panasonic and Apple claim. So...

Denny Lajeunesse November 29th, 2009 02:13 PM

Quote:

Originally Posted by Gary Nattrass (Post 1453509)
I dont think there is a way to copy AVCHD to AVC intra and it would up the size and bit rates.

I transcode all my AVCHD to pro res LT now and that seems to be the best balance for bit rate and file sizes. It also gives the advantage of all my media from the 301 and HF11 being in the same format for edit.

Well, yes it's an up-res, which is what most do when doing effects etc.

Quote:

Originally Posted by Perrone Ford (Post 1453519)
DNxHD is variable bit-rate, and you can use sizes down to 36Mbps which is even smaller than AVC-Intra 50. There are several DNxHD codec bitrates below 100 Mbps. Why not use one of those?

I thought AVCIntra was a more efficient codec. I'm guessing that 10 bit avcintra100 vs 10bit dnxhd, avc-i should be smaller?

Quote:

Originally Posted by Perrone Ford (Post 1453624)
Apparently, at least from what I've seen on the internets, ProRes can take in AVC-Intra without a transcode. And it's just a re-wrap. Not sure how they are doing it, but that's what Panasonic and Apple claim. So...

I can;t see hpow it can be a re-wrap. Prores is colser to DNxHD. It is definately not the same as AVC-I. I could see it transcoding quite quickly though as it is an easier codec to handle than AVCHD.

Perrone Ford November 29th, 2009 02:20 PM

I didn't say AVC-Intra wasn't more efficient than DNxHD. I just said that DNxHD offered variable bit rates, since you seem to be worried about space. The efficiency of the codec is immaterial to how much space it consumes on the drive. That is a function of frame size and bit rate.

Gary Nattrass November 29th, 2009 03:18 PM

Quote:

Originally Posted by David Heath (Post 1453621)
AVC-Intra and ProRes are two totally different codecs surely? The first a native Panasonic codec, the second the "native" codec for FCP.

Hence, if you're originating AVC Intra 100, but using ProRes within FCP, the inputting process is not re-wrapping (where the codec remains the same) but transcoding. Hence the edit performance has nothing to do with AVC-Intra (which is the question asked), but everything to do with ProRes.

Yes as said FCP re-wraps AVC intra to pro res so it is a lot quicker than transcoding.

Denny Lajeunesse November 29th, 2009 10:02 PM

I thought prores was a codec, not a wrapper?

Not a mac guy but this is what I had been led to believe.

Barry Green November 29th, 2009 11:27 PM

Quote:

Originally Posted by Denny Lajeunesse (Post 1453484)
Sorry to go some what off topic here, but is there any way to convert from AVCHD (or nay format) to AVCIntra?

Well, you could import the AVCHD into EDIUS and export as AVC-Intra, but ... not a whole lot of reasons to do that.

Quote:

I'm thinking the storage would be much smaller than say DNxHD codec.
Intra would be smaller file sizes than normal full-rate DNxHD, which is I think 145mbps? But Intra won't edit as quickly as DNxHD.

Intra's way faster to use than AVC-HD, but it's still quite processor intensive.

Barry Green November 29th, 2009 11:30 PM

Quote:

Originally Posted by David Heath (Post 1453621)
AVC-Intra and ProRes are two totally different codecs surely? The first a native Panasonic codec, the second the "native" codec for FCP.

Correct.

Quote:

Hence, if you're originating AVC Intra 100, but using ProRes within FCP, the inputting process is not re-wrapping (where the codec remains the same) but transcoding. Hence the edit performance has nothing to do with AVC-Intra (which is the question asked), but everything to do with ProRes.
Yep.

FCP 7 can execute a simple rewrap, where it keeps the files in native AVC-Intra mode. Or it can do a transcode to ProRes. FCP 7 has native AVC-Intra support; prior versions didn't offer this and so could only do a transcode to prores.

Barry Green November 29th, 2009 11:31 PM

Quote:

Originally Posted by Perrone Ford (Post 1453624)
Apparently, at least from what I've seen on the internets, ProRes can take in AVC-Intra without a transcode. And it's just a re-wrap. Not sure how they are doing it, but that's what Panasonic and Apple claim. So...

FCP can take in AVC-Intra, but not to ProRes. It just does a file re-wrap to Quicktime.

Barry Green November 29th, 2009 11:35 PM

Quote:

Originally Posted by Perrone Ford (Post 1453682)
The efficiency of the codec is immaterial to how much space it consumes on the drive. That is a function of frame size and bit rate.

Well, no, the efficiency of the codec is actually the primary determinant of how much space it will consume on the drive, for any given quality standard.

Uncompressed HD = 1920 x 1080 x 59.94i = 62 megabytes per second. AVC-Intra = 1920x1080x59.94i, same frame size and frame rate, but 12 megabytes per second, and delivering what people could arguably call "visually uncompressed" quality.

So if you hold to a specific standard of quality, the more efficient codec will take up less space on the drive. I think what was being asked was if DNxHD at 145mbps looks the same as AVC-Intra at 100mbps, because if so, the more-efficient codec is storing the same quality footage in less drive space.


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