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Why does After Effects need to render unmodified footage?

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Will BlankWhy does After Effects need to render unmodified footage?
by on Nov 21, 2011 at 8:07:38 pm

No matter if I am viewing footage by double clicking it in the project browser or in a composition, the video will generally play smoothly with fits of stuttering. This is without any effects applied.

I am an FCP/Avid user, and whenever you import unmodified footage into those programs, there is never any issue with it playing back smoothly-- at least until you decide to go crazy with effects.

Please do not respond with 'After Effects is not an editing program' because I am well aware of that. It just seems strange to me that unmodified, correctly interpreted footage whether it be from an HVX200 or any other camera, can't be played back 100% smoothly in After Effects... without 'rendering'. Why is that? Thanks!


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Michael SzalapskiRe: Why does After Effects need to render unmodified footage?
by on Nov 21, 2011 at 8:23:57 pm

"Please do not respond with 'After Effects is not an editing program' because I am well aware of that. It just seems strange to me that unmodified, correctly interpreted footage whether it be from an HVX200 or any other camera, can't be played back 100% smoothly in After Effects... without 'rendering'."

Sorry, but that's the real answer. It treats footage completely differently. Perhaps this response to another's question from Rick Gerard will help:

Sony Vegas, Premiere Pro, Final Cut, Avid are all NLE's (Non Linear Editors) and they are specifically designed to playback a video stream. With any of them, if you stack enough layers or effects on the video they will have to render a new video stream based on pixel based calculations for every pixel in the stack. This rendering, especially for HD sources or for complex plug-ins, will take quite a bit of time.

After Effects, Flame, Fusion, Shake -- are all pixel based image processing applications that act very much like Photoshop. They calculate the values of every pixel in every frame, come up with a new pixel, and then play those pixels back as a video stream. More importantly, AE and all the other pixel based compositing apps, always work internally with completely uncompressed pixel data. NLE's rely on codecs and in some cases, hardware, to playback the video. It's an entirely different way of working with moving images.

In After Effects you enable the preview by loading a bunch of frames into RAM then the video stream is played back. You start the process with the 0 key on the numeric keypad and not with the Space Bar as you do in nearly every NLE ever created. The length of the preview depends entirely on how much free ram you have available and it takes some time to generate these new pixels. The more layers, the more effects, the more calculations that need to be performed the longer it will take to process the RAM preview. There's currently no way around this rendering time. A modern NLE will handle an amazing number of video streams simultaneously, but as soon as you exceed the capability of the system you're stuck with a render. Most NLE's, given the same number of calculations, actually take a little longer than After Effects to do the same kind of effects. Open GL, and other GPU acceleration helps many NLE's achieve higher performance but it has yet to be implemented into a pixel based compositing app. The sad truth of the matter is that if you want to do compositing in any of the available compositing apps, you have to wait for renders. They are getting better. Memory management and efficiency is improving. GPU accelerated effects are being added, but for now, that's about as good as it gets.

I hope this helps. As long as you use After Effects to create shots and don't try to make it do the work of a NLE you should be fine. Movies come from NLE's, amazing shots come from AE.

- Rick Gerard


- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.


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Will BlankRe: Why does After Effects need to render unmodified footage?
by on Nov 21, 2011 at 8:30:59 pm

That was a really great, comprehensive answer. Thank you!


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Michael SzalapskiRe: Why does After Effects need to render unmodified footage?
by on Nov 21, 2011 at 10:55:19 pm

You're welcome! And, if you ever see Rick Gerard about (the Adobe Forums, NAB, etc.) be sure to thank him too. :)

- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.


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Kevin CaminRe: Why does After Effects need to render unmodified footage?
by on Nov 22, 2011 at 10:13:11 am

When I do an audio preview with the '.' key on the numeric keypad, why does it seem to think extremely hard about it and often limit me to a very short preview. I understand the variables involved with a clean running machine, but REALLY, audio? Just audio? As far as I can see, it has no reason to render video to RAM or anything complicated.

Any explanation will be soothing.

Best regards,

Kevin

Best regards,

Kevin Camin


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Roland R. KahlenbergRe: Why does After Effects need to render unmodified footage?
by on Nov 22, 2011 at 12:23:47 pm

You should set your audio settings such that they are similar to the audio file that you use. Do not mix audio files with different inherent profiles. As for audio previews, they used to default to 8 seconds although I'm not sure if this is the case with the latest version. You can change the audio settings and default audio duration within AE's prefs window.

HTH
RoRK

Intensive AE & Mocha Training in Singapore and Malaysia
Adobe ACE/ACI (version 7) & Imagineer Systems Inc Approved Mocha Trainer


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Steve BlackerRe: Why does After Effects need to render unmodified footage?
by on Nov 22, 2011 at 1:34:59 pm

And use .wav files, not MP3s...

It's only work if you'd rather be doing something else...


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Todd KoprivaRe: Why does After Effects need to render unmodified footage?
by on Nov 24, 2011 at 3:22:13 am

> And use .wav files, not MP3s...


AIFF works as well as WAV.

---------------------------------------------------------------------------------------------------------
Todd Kopriva, Adobe Systems Incorporated
Technical Support for professional video software
After Effects Help & Support
Premiere Pro Help & Support
---------------------------------------------------------------------------------------------------------


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Roland R. KahlenbergRe: Why does After Effects need to render unmodified footage?
by on Nov 24, 2011 at 4:08:19 am

Hi Todd, kinda curious over here - when hooking up to an AIFF, does AE have to access QT's 32-bit engine?

BTW, how much of an issue, speed-wise, does a 32-bit QT impose on rendering times, relative to ... say, a TIFF image sequence.

Additionally, which video architecture/format provides for full-on 64-bit workflow within AE?

Cheers
RoRK

Intensive AE & Mocha Training in Singapore and Malaysia
Adobe ACE/ACI (version 7) & Imagineer Systems Inc Approved Mocha Trainer


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Todd KoprivaRe: Why does After Effects need to render unmodified footage?
by on Nov 24, 2011 at 3:23:38 pm

> when hooking up to an AIFF, does AE have to access QT's 32-bit engine?


No.

> BTW, how much of an issue, speed-wise, does a 32-bit QT impose on rendering times, relative to ... say, a TIFF image sequence.


That's not a useful comparison, since you've got two variables: 1) 32-bit QT or not and 2) movie or image-sequence.

I think that a better comparison is between something that has to go through 32-bit QuickTime and something that can go straight through MediaCore (our native media encoding/decoding engine). The difference can be very large, making the difference between stuttery playback/scrubbing and smooth playback/scrubbing.

That difference is responsible for the bug describe here:
http://kb2.adobe.com/cps/915/cpsid_91558.html

> Additionally, which video architecture/format provides for full-on 64-bit workflow within AE?


Anything but QuickTime.

---------------------------------------------------------------------------------------------------------
Todd Kopriva, Adobe Systems Incorporated
Technical Support for professional video software
After Effects Help & Support
Premiere Pro Help & Support
---------------------------------------------------------------------------------------------------------


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Roland R. KahlenbergRe: Why does After Effects need to render unmodified footage?
by on Nov 25, 2011 at 4:57:58 am

Good stuff Todd. Is there a page/site where we can find out more on Adobe's MediaCore?

Other than getting more info on MediaCore, I feel that there is a need for users to have a better understanding of the issues involved with the different video architectures/formats/containers and how best to have a really doped-up workflow from acquisition, digital intermediaries and on to final delivery.

Cheers
RoRK

Intensive AE & Mocha Training in Singapore and Malaysia
Adobe ACE/ACI (version 7) & Imagineer Systems Inc Approved Mocha Trainer


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Todd KoprivaRe: Why does After Effects need to render unmodified footage?
by on Nov 25, 2011 at 5:21:51 am

No, I don't think that we have any pulicly-facing documentation about MediaCore.

---------------------------------------------------------------------------------------------------------
Todd Kopriva, Adobe Systems Incorporated
Technical Support for professional video software
After Effects Help & Support
Premiere Pro Help & Support
---------------------------------------------------------------------------------------------------------


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Roland R. KahlenbergRe: Why does After Effects need to render unmodified footage?
by on Nov 25, 2011 at 1:34:47 pm

Hmmm, I thought so too. Is there any reason for the lack of publicly-accessible information on MediaCore?

In terms of workflow, with respect to video formats/architectures/containers, we can lay them out in terms of the following processes -
1) acquisition
2) work space
3) delivery

I believe that process (1) is pretty much out of our hands although I prefer to work backwards; starting from delivery BUT that's a non-issue for now and the necessary requirements can be accessed by aggregating and then interpolating the information, henceforth.

On delivery; on its various mechanisms and preferred routes, I believe that we do have a nuts and bolts solution.

It's (2), as per above, where there seems to be a deficiency, with information, on how we can maximize efficiency, not only within AE but also across PPro and AME.

I bring this issue up because there seems to be a high preference towards QT (ProRes, DNxHD, Animation, Photo JPEG, PNG - CODECs) as a work space (digital intermediary) format.

I feel that users should be placed in a position where they will have a better idea how a choice for a DI will affect their workflow.

Cheers
RoRK

Intensive AE & Mocha Training in Singapore and Malaysia
Adobe ACE/ACI (version 7) & Imagineer Systems Inc Approved Mocha Trainer


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