The constant rendering nightmare

N

Nchanta

Member
Hello all. I will save the pleasantries and introdictions for another time when I am less 'worked up'! ;)

I am trying to render out of AE CS5 in the best quality I can in a compressed scenario. I have done some pretty heavy grading on a film I am working on that was shot last year with some HV20s. Image is beautiful in full rez but no matter what I do, differenct codecs destroy it in different ways.

I am having serious banding issues eventhough I am working at 16bpc.

The closest I got to 'pretty damn good' was a H.264 (within a MP4 wrapper). I don't understand why that would look better than QT MPG2 unless the lower quality was masking the isssues.

I understand the necessity to compress for DVD but I am fed up with losing so much in the conversion.

Forgive the rant.

Anyone got any hints and tips for compressions out of AE and getting rid of banding would be much appreciated.

Also one last question can you render a H.264 for DVD or is H.264 just standardised for Blu-Ray only?

Peace

Tim
 
Don't render your H264 or MPEG2 out of After Effects. It takes forever and that's probably the sore source of your quality issues. Render out a Lossless format then compress it in a different program like Compressor, Squeeze, Episode, etc.

Others on here will probably say that you can render out from AE just fine, and while you may be able to, that's just stupid.
 
To answer your other question , DVD-video (for regular DVD video players) is MPEG2 only and standard definition.

You can make AVCHD discs on DVD media , which use h.264 compression , but you need blu-ray player (or ps3) to play it back

Banding from 8-bit video is difficult to get rid of , especially if it's already been baked into your source footage (as opposed to generated ramps or gradients in AE which you can alleviate with higher bpc projects) - but dithering can help . Dithering is essentially noise so will require enormous amounts of bitrate to compensate if you want it to be effective, and may not be feasible if you have fixed capacity or bandwidth limitations. There are many was to do this, and with other software, but here is a tutorial specific to AE

http://greyscalegorilla.com/blog/2009/10/how-to-remove-banding-artifacts-in-after-effects/

I 100% agree with oneinfinte's comments. I would definitely recommend using other software for your final format goal. You can use multiple passes, and better encoders which feature more efficient compression. Unfortunately if you are making a standard DVD, MPEG2 compression is really crappy and doesn't handle noise (or dithering) very well. Most people in this case would denoise or prefilter then dither after, depending on your source content.
 
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Thanks for the feedback.

To be honest I don't remember the settings, or how much the settings can be manipulated on Cineform (which is how I loaded the footage at the time) might go back and have a look. At the end of the day it is HV20 footage and there is only a certain that can be done to the footage. It has been denoised at varying levels throughout the film. Apart from the banding which tends to come more from Colorista masks than from the original footage. If I am working in a 16bpc in AE the banding from colorista should be relatively smooth I would have thought...

Will have a play and try what you have suggested. I did try exporting a section out through Procoder but it didn't do a lot differently. The biggest annoyance obviously (apart from the banding) is the conversion from REC 709 to REC 601. I will try turning off color management in AE and see is the default ICC profiles does a better job at converting.

Thanks again for your help.

Tim
 
I had used cineform for a few years, but not recently . It interpolates to 10-bit 4:2:2 for the lower end versions (there are 4:4:4 12 bit derivatives), but I noticed in AE, it actually doesn't "act" like real 10-bit footage (at least the version I used didn't) . You can notice this when you grade , the histogram or waveform monitor has quantized peaks, and you see corresponding banding in the footage. Other 10 bit or higher footage (e.g. v210) can act like real 10-bit+ and the histogram is smooth, and you have less banding when using a 16 or 32bpc project. I'm not sure if they have fixed it in more recent versions

I don't use colorista, but does it have 16bit and 32-bit compatibility , or are you using a filter in your chain that works in 8bit mode ? You can introduce more banding if you manipulate using a 8bit filter, despite having project set at 16/32bpc

Denoising shouldn't be done at the end, because it will get rid of the dithering (which adds noise to get rid of the banding) , but again dithering is very difficult to do properly with DVD-video , because of MPEG2 compression and bitrate limitations. It will depend on how compressible your material is. If it's something like an action piece, you can forget about even trying to dither. Something like a slow moving drama you might be able to dither slightly. With blu-ray and higher bitrate limitations, you have a lot more headroom

The difference between rec709 to rec601 is negligible for your average viewer. The colors (especially red & green) will appear slightly different and some viewers may notice, but there should be nothing drastic like a levels shift . Perhaps you are experiencing somthing else ? IIRC, Procoder has very quircky behaviours when fed different colorspace inputs. For example if fed YV12 input it will crush your black level
 
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