- April 17, 2014 at 6:14 pm
Trying to figure out the best way to handle compression when you know you are going to have to compress and recompress over and over because you don’t have a suped up enough system to go uncompressed. For example:
1. Shoot video
I gather some cameras can shoot completely uncompressed, usually this involves recording to an external hard drive, and is many GBs per minute. I don’t think my computer and NLE is even fast enough to play back these kinds of files in realtime with no frame drops, lags, etc. So in reality, unless you have access to a very high quality system, most of us will shoot footage that gets compressed in camera as it is shot, so that’s the first compression.
2. Video “polishing”
These are processes done with the original footage, which remember is already compressed. Things like, color grading, noise reduction, perhaps even image enlargement and sharpening. Again, because we probably don’t have a high end system, once these corrections are made, the video is re-compressed again, so it can be edited.
Really, no compression takes place here until the final cut is ready, the video is “locked,” and video is rendered out.
4. Final touches
There are many standalone pieces of video software that provide certain benefits over most NLEs. For example I’m thinking of Video Enhancer here. If you have 640 x 480 footage you want to enlarge to 1280 x 960, you’ll get a better result first rendering the footage from your NLE at 640 x 480 and then using Enhancer to blow it up to 1280 x 960, rather than just telling your NLE to render out at 1280 x 960.
5. Uploading online
While we are not really in control of what sites like Youtube and Vimeo do to our video after we upload, there are certain codecs and settings that work best because once the upload site recognizes these codecs it will do little or no recompression.
So there are 5 times our video will be compresssed here. My question is what is the best type of compression to use at each step? I’d probably use something like HuffYUV, which is a lossless compression, but it results in pretty large file sizes, something like 1 GB per minutes. So I’d probably want to use something else if possible. Is it best to use the exact same codec at the same settings for each of these steps? Or should I use a different one for each step? Maybe there is a way to use uncompressed footage with a light CPU and Hard drive load? I know so little about compression that I’m really not sure even what to ask here. I just know that a lot of times our already compressed footage will need to be compressed again, and that there must be some kind best method to handle this. Thank for any advice.
- April 17, 2014 at 6:40 pm
It really depends on your cameras, your system, your NLE. There is no “best”
Some cameras and many external recorders use Apple ProRes. While the file sizes are large, the codec is very easy to handle since it’s not GOP based. Some recorders may use MPEG2 iFrame and those are often easily handled on Windows NLEs.
If your recording in camera that uses an H.264 GOP variant and your NLE can’t handle it you can encode those to Apple ProRes or DNxHD depending on your NLE.
- April 17, 2014 at 7:12 pm
But then what would I then use for compression when I’m rendering out of After Effects (which I use for color grading) and then what would I use to render out from Sony Vegas (that I use for editing) and then what would I use for my final render from Enhancer, which I use for final polishing of the video? How would (should?) the codec used change if I was going to upload to Youtube, vs. if I wanted to burn a DVD?
You see I’m talking about the best way to handle MULTIPLE recompressions of the same material.
Thank you for your answer though!
- April 17, 2014 at 7:19 pm
On Windows you could render out DNxHD I’d think.
YouTube has H.264 recommendations for upload
- April 17, 2014 at 8:35 pm
Stick with your codec the entire way through, whether it’s ProRes or DNxHD. Additionally, most workflows edit footage first, then color correct and add effects. Then encode to H264 for upload to YouTube as Craig says.
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