Help with compressing short film for web

[Thrash632]

Ive been up all night messig with compression settings for my short film so I can upload it to Vimeo.

The film was edited in premiere usin 5dnmark ii footage converted to pro res hq.

I am using adobe media encoder 5.5 to encode an uncompressed master to an h264 mp4.

Something weird was happening where certain sections looked fine and others were extremely pixelated and full of artifacts. To make a long story short, I figured out that the key frame distanxe option had a lot todo with this.

My short has some sections that are fairly static and don't have a lot of movement and there are some sections with a lot of movements and really fast cuts between clips.

When i set the key frame distance to 24, the static shots look great but the quick scenes are full of artifacts and pixelated. When I set the key frame distance to 1, the fast scenes look good but the static scenes look bad.

When I set the key frame distance to 12, the whole thing looks meh...

Is there anyway to manually set key frames? I think I've read something about this bit do not see any way to do this in premiere or media encoder. I am at my wits end and news toauit this video tonight. Any advice?

 

[wheatgrinder]

your post is a bit confusing.

If you watch the effects (key frames) shots in your editor\tool (Premiere AE, what ever) does it look pixelated?

Im guessing your final render has the artifacts.

If you render quicktime movie motion jpeg at 100% do you still see the artifacts? I bet not.

Be sure to compare you h264 settings to viemos guidelines, I bet your bitrate is way low..

https://vimeo.com/help/compression

 

[Hanes]

1. question is, what format are your source file, is it all the same? If the one used now is good for editing in Premiere I recommend to edit your timeline as you wish, then convert all the source files into h.264 put in another folder but with the same reel names and reconnect.

Also while converting the source file, make all the same settings, including keyframes, you can see if any of them are still broken after it, if you scceed and convert them in the same codec and setting. There shouldnt be problem then, to reconnect sources in Premiere and Export


GL
Hope it Helps

 

[ItDonnedOnMe]

What data rate are you compressing to? I suspect that has far more to do with the pixelation you're seeing than the key frame distance, and I also suspect it's far too low based on what you've described.

When you're uploading to vimeo or youtube, etc, they're going to recompress your video anyway, so your goal should be to use the highest data rate that keeps your total file size under the upload limit for whatever service you are uploading to - I believe youtube is 2Gb, Vimeo is 500mb for basic accounts and 5Gb for plus accounts. So the max data rate you use will depend on the length of your video - take the max size you can upload, divide by the total seconds of your video, and that's the maximum data rate you can use.

So if you have a 10 minute video, and you're uploading to a basic vimeo account, the max you can use is 0.8 megabytes/second - 800kb per second. Data rates for compression are usually expressed in megabits though, so multiply that by 8 (there's 8 bits per byte) and you get 6.4 megabits/second. For an HD video that may be plenty, although if you have a lot of action that could still be a problem. If you have a plus account you could go 10x as high - so over 60 megabits/second - but in practical terms you're not likely to see much gain going over the 10-20mbits range.

You also want to make sure you're using 2-pass encoding, as that will use less data for the static scenes and apply the extra to the scenes with more motion.

Of course, once you upload it and they re-compress it's going to drop down to whatever their limits are - I don't know the current values each service uses, but it's likely to be in the 2-5mbit/s range for HD - so your final video on Vimeo may still have some pixelation during fast motion that you can't do anything about. All you can do is upload the cleanest copy you can produce and hope it works out in their encoder.