AIC vs DVCPRO HD at DVinfo.net

Steve Mullen · June 12th, 2007, 06:36 PM

I'm working with JVC's new HD7 that can record at 1920x1080 or 1440x1080 using MPEG-2 at about 27Mbps.

I have the choice of converting to: M2V with AIF, AIC, DVCPRO HD, or ProRes. ProRes is obviously best, but not on a laptop. DVCPRO HD works really well in RT, but there's the fact that the 1920 or 1440 must be scaled to 1280.

Opinions wanted:

The scale from 1920 to 1280 is 1.5. The scale from 1440 to 1280 is 1.125.

1) The 1.5 scale would SEEM likely to be smoother than the 1.125 scale.

2) But IF the scale factor is the amount by which the image's resolution is reduced -- then the smaller scale factor reduces the video resolution the least.

3) Alternately, perhaps the scale factor doesn't scale down video resolution. Perhaps the 1280 simply acts as a low-pass filter. If this is true -- then there's no real video resolution lost because the ACTUAL image resolution is under 600x600 just like with a P2 camcorder.

-------

I've avoided AIC with 1080i until now. I've gone back and looked at all the posts and the claims are that AIC mangles 1080i because it doesn't do interlace well. Yet I can find no proof of this claim. And, so far I haven't seen any issues. What's the real and current story on AIC?

PS: while AIC does allow a 1920x1080 timeline, "Unlimited RT" is not available! Is this true, or only true with my MBP 2?

Henrik Reach · July 15th, 2007, 12:20 PM

Quote:

Originally Posted by Steve Mullen

PS: while AIC does allow a 1920x1080 timeline, "Unlimited RT" is not available! Is this true, or only true with my MBP 2?

Same for me (2x2,5ghz G5)...
I'm just starting out with HD, and I thought I'd use AIC instead of HDV, but it seems I won't get Unlimited RT if so.

Mark OConnell · July 15th, 2007, 12:37 PM

The main complaint about AIC seems to be the loss of timecode. I've read complaints about loss of image quality as well but I haven't seen it, then again, I've been shooting everything 30p, so if the problem is with interlaced footage I obviously wouldn't see it. I don't need the timecode, and capturing to AIC and editing with it is so easy that I use it all the time. Not sure if unlimited RT is available or not. I honestly haven't noticed any difference between editing AIC and regular DV in Final Cut.

Chuck Spaulding · July 15th, 2007, 04:58 PM

There's considerable confusion about this, or at least I should say that I'm considerably confused... Like most things it depends on what you want to do.

If you want to master on HDV then editing HDV natively might be the way to go. One thing I've noticed in FCP6 is that outputting HDV takes considerably longer than it did in 5.1.4. Interestingly enough I believe it has to do with the mixed format timeline. In 5x many of the changes you made to HDV timelines required rendering so when it came to output much of the timeline was already conformed correctly [render-as-you-go] so it didn't seem to take as long. In FCP6 if its not too complicated and doesn't require rendering then the conform seems to take for ever. But I bet the aggregate render/conforming time is about the same in both versions.

Using Apple's intermediate codec will significantly reduce render times to output to any other format other than HDV. There are several things to keep in mind with this workflow:

1. The data rate and file sizes are considerably higher, the same 15s file:
a. HDV file is 54.3MB -- data rate of 3.3MB/s
b. AIC is 175.3MB -- data rate of 11.6MB/s
c. ProRes 216.4MB [That's the 14.4MB/s, not the 220Mb HQ]

2. At the moment there is no way to capture via firewire directly to DVCProHD or ProRes. I used media manager to batch convert from HDV to both formats which consumes more hard disk and takes a considerable amount of time. It would be nice of you could use the new log and transfer window to or the log and capture window to capture HDV with the AIC.

3. If you plan on mastering back to HDV tape then I don't see any reason to use ProRes or AIC, any times savings you might have gained will be lost converting it back to HDV.

I'm on a Mac Pro 2.66 and I have not had any issues with AIC and Unlimited RT.

Regarding the scaling issue, I have only gone the other way DVCProHD 1280x1080 to 1920x1080 output which required rendering. [Obviously it outputs real time to DVCProHD tape where the deck takes care of the up-convert]. But if I did it in the timeline it required rendering and I don't know if there would be much of a difference going from 1440 vs 1920...

It appears from the nature of your questions that you're concerned with quality, remember both the ProRes and DVCProHD codecs are lossy, if you want a lossless codec check out SheerVideo. Again a considerable jump in file size but much less demand on the processor. But this would only be useful if you are trying to mix uncompressed with compressed HD formats.

Its been my experience that the DVCProHD coedc does not hold up well to multi generational encoding and I have not used the ProRes codec enough to say for certain but I would us it before the DVCProHD codec.

June 12th, 2007, 06:36 PM	#1
Steve Mullen HDV Cinema Join Date: Feb 2003 Location: Las Vegas Posts: 4,007	AIC vs DVCPRO HD I'm working with JVC's new HD7 that can record at 1920x1080 or 1440x1080 using MPEG-2 at about 27Mbps. I have the choice of converting to: M2V with AIF, AIC, DVCPRO HD, or ProRes. ProRes is obviously best, but not on a laptop. DVCPRO HD works really well in RT, but there's the fact that the 1920 or 1440 must be scaled to 1280. Opinions wanted: The scale from 1920 to 1280 is 1.5. The scale from 1440 to 1280 is 1.125. 1) The 1.5 scale would SEEM likely to be smoother than the 1.125 scale. 2) But IF the scale factor is the amount by which the image's resolution is reduced -- then the smaller scale factor reduces the video resolution the least. 3) Alternately, perhaps the scale factor doesn't scale down video resolution. Perhaps the 1280 simply acts as a low-pass filter. If this is true -- then there's no real video resolution lost because the ACTUAL image resolution is under 600x600 just like with a P2 camcorder. ------- I've avoided AIC with 1080i until now. I've gone back and looked at all the posts and the claims are that AIC mangles 1080i because it doesn't do interlace well. Yet I can find no proof of this claim. And, so far I haven't seen any issues. What's the real and current story on AIC? PS: while AIC does allow a 1920x1080 timeline, "Unlimited RT" is not available! Is this true, or only true with my MBP 2? __________________ Switcher's Quick Guide to the Avid Media Composer >>> http://home.mindspring.com/~d-v-c

July 15th, 2007, 12:37 PM	#3
Mark OConnell Major Player Join Date: Feb 2007 Location: Seattle WA Posts: 420	The main complaint about AIC seems to be the loss of timecode. I've read complaints about loss of image quality as well but I haven't seen it, then again, I've been shooting everything 30p, so if the problem is with interlaced footage I obviously wouldn't see it. I don't need the timecode, and capturing to AIC and editing with it is so easy that I use it all the time. Not sure if unlimited RT is available or not. I honestly haven't noticed any difference between editing AIC and regular DV in Final Cut.

July 15th, 2007, 04:58 PM	#4
Chuck Spaulding Trustee Join Date: Nov 2004 Location: Thousand Oaks Posts: 1,104	There's considerable confusion about this, or at least I should say that I'm considerably confused... Like most things it depends on what you want to do. If you want to master on HDV then editing HDV natively might be the way to go. One thing I've noticed in FCP6 is that outputting HDV takes considerably longer than it did in 5.1.4. Interestingly enough I believe it has to do with the mixed format timeline. In 5x many of the changes you made to HDV timelines required rendering so when it came to output much of the timeline was already conformed correctly [render-as-you-go] so it didn't seem to take as long. In FCP6 if its not too complicated and doesn't require rendering then the conform seems to take for ever. But I bet the aggregate render/conforming time is about the same in both versions. Using Apple's intermediate codec will significantly reduce render times to output to any other format other than HDV. There are several things to keep in mind with this workflow: 1. The data rate and file sizes are considerably higher, the same 15s file: a. HDV file is 54.3MB -- data rate of 3.3MB/s b. AIC is 175.3MB -- data rate of 11.6MB/s c. ProRes 216.4MB [That's the 14.4MB/s, not the 220Mb HQ] 2. At the moment there is no way to capture via firewire directly to DVCProHD or ProRes. I used media manager to batch convert from HDV to both formats which consumes more hard disk and takes a considerable amount of time. It would be nice of you could use the new log and transfer window to or the log and capture window to capture HDV with the AIC. 3. If you plan on mastering back to HDV tape then I don't see any reason to use ProRes or AIC, any times savings you might have gained will be lost converting it back to HDV. I'm on a Mac Pro 2.66 and I have not had any issues with AIC and Unlimited RT. Regarding the scaling issue, I have only gone the other way DVCProHD 1280x1080 to 1920x1080 output which required rendering. [Obviously it outputs real time to DVCProHD tape where the deck takes care of the up-convert]. But if I did it in the timeline it required rendering and I don't know if there would be much of a difference going from 1440 vs 1920... It appears from the nature of your questions that you're concerned with quality, remember both the ProRes and DVCProHD codecs are lossy, if you want a lossless codec check out SheerVideo. Again a considerable jump in file size but much less demand on the processor. But this would only be useful if you are trying to mix uncompressed with compressed HD formats. Its been my experience that the DVCProHD coedc does not hold up well to multi generational encoding and I have not used the ProRes codec enough to say for certain but I would us it before the DVCProHD codec.