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Exported video from AE - black color looks bad.

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Mckelvie Wilder
Exported video from AE - black color looks bad.
on Apr 26, 2010 at 3:01:21 am

First time poster here, so if I do this wrong sorry. I am a newer user to AE. I've keyed some DV footage. The key looks as good as I think I can get it. The problem is when I export the video as a Quicktime video all looks fine. When I use compressor to convert to mpeg file for DVD burn, the solid black color looks horrible. In the clothing of the people especially. It looks as if the key was trying to take out this color, but didn't. I have reworked the key a hundred times, it changes nothing. Any clue what would be affecting this black color level? I am not a video expert, so keep that in mind when responding. Thanks for any help.

ps .. is there a way to get compressor to export an mpeg dvd file WITH audio imbedded?

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Tudor "Ted" Jelescu
Re: Exported video from AE - black color looks bad.
on Apr 26, 2010 at 7:22:09 am

Render your original footage to an uncompressed format. Then pull the key.
Here's a great tip from Dave LaRonde:
"Dave's Stock Answer #1:

If the footage you imported into AE is any kind of the following -- footage in an HDV acquisition codec, MPEG1, MPEG2, AVCHD, mp4, mts, m2t, H.261 or H.264 -- you need to convert it to a different codec.

These kinds of footage use temporal, or interframe compression. They have keyframes at regular intervals, containing complete frame information. However, the frames in between do NOT have complete information. Interframe codecs toss out duplicated information.

In order to maintain peak rendering efficiency, AE needs complete information for each and every frame. But because these kinds of footage contain only partial information, AE freaks out, resulting in a wide variety of problems. "

Tudor "Ted" Jelescu
Senior VFX Artist
Bucharest, Romania

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Larry S. Evans II
Re: Exported video from AE - black color looks bad.
on Apr 27, 2010 at 8:03:16 pm

There are potentially a number of issues here, which I don't think have to do with compression at all. Ideally I need to know more about how you are keying this footage before being able to give you a specific answer, because simply picking the wrong kind of key or key settings can cause these problems. However, here are some basic things you can try first.

1. Before you start to pull the key, apply the Effect>Color Correction> Broadcast Colors to your clip. This limits the colors in the clip to that which can be reproduced by NTSC or PAL televisions (which are fewer colors than are produced by computer monitors). This should address any issues of "weird blacks" to begin with.

2. If the problem appears to be that the key you applied is removing the black color -as you are describing it- then it may be helpful to try and set your key against a background solid rather than an image or other background. I would try to pick a solid color that is not featured in the foreground image. White is actually usually a good choice for this because true pure white rarely exists in taped footage. At any rate, if you set your key against this and see the bleed through on the blacks, then you are using some setting that is too broad.

Again, without knowing how you are creating this key, I can't be more specific, but the Keylight plug-in has features that act like the Color Correction>Levels effect that allows you to expand or contract the range of the keyed out values (this is a significant oversimplification). If you expand the "bottom" black too much it can start to take out the blacks in the image.

Additionally you can get "fringing" or "spill" effects where colors appear to be clean but actually pick up enough reflected color off the background to start keying out. these all can be corrected to some degree but first you have to see them and then identify the source. Using a solid background instead of a background image may help do this.

3. Finally, if I have misunderstood and you are trying to compress a final MPEG-2 format directly out of After Effects or are trying to re-compress a Quicktime file to MPEG-2, then there could very well be some problem in the compression. First, you'd want to output uncompressed AVI or Quicktime as the final state and then use something like the Adobe Media Encoder to conform it to MPEG-2 for DVD. If you are using Encore for DVD creation, the application will actually select the Media Encoder and set the most standard requirements for you (these may not be the best, but let's go with the basics). If you are creating your DVD using a different software and need to create the MPEG-2 file first, I would recommend finding something other than After Effects to do the compression. In any case, never re-compress a compressed file of any format.

In answer to your other question, the MPEG-2 DVD format is designed to have the audio as a separate channel. This facilitates multiple language editions of the DVD, the addition of audio commentaries, etc. I believe you can create an MPEG2 format out of Media Encoder that embeds the audio, but it is not the proper way to do it for making a DVD with a DVD authoring program. -R

Larry S. Evans II

Executive Producer

Digital I Productions

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