Is using video Edition software and then FX software not affecting the quality?

This is general question. I have been editing some family and music video movies but never entered the 'FX after area'.

I come from 2d graphic design background and every graphic designer knows or should know that opening and saving JPG file repeatedly lowers the quality as this applies copression on top of already compressed file thus downgrading the source material every single time.

When I started hearing about After Effects, Hitfilm etc. I was surprised there is a separate software that applies special effects or even titles I believe separatelly to the main editing/cutting project.

Can someone explain briefly how does the process looks like and does it not affect the quality to render the movie from one software and then open and render it again from another program.

Comments

  • Aladdin4dAladdin4d Moderator

    Loaded question! The shortest answer is "it depends" ;) A longer answer is it depends on the whole process and what all you need to do with different strategies being employed based on the requirements. Really serious VFX work generally relies on image sequences using lossless image formats. 

    Another strategy is what's known as an offline workflow. You use lower quality proxies to do all your layout work until you're ready for a final render at which point you swap out the media for the high quality version.

    Yet another is to transcode your media to what's known as an intermediate or mezzanine codec. Even though many of the codecs in this class are lossy they are designed to have minimal generational loss and some are truly lossless.

    These are just some examples and all of these can and usually are combined into workflows with an eye on minimizing generational loss.

  • Triem23Triem23 Moderator

    It actually doesn't. Your stills/JPEG analogy works well. 

    Most video can be thought of (for purposes of explaining) as a series of JPEGS. If you compress a Jpeg to a low quality setting it looks terrible. Compressed at a high quality rate and it looks good. 

    Kind of the same with video. Mp4 in particular--the footage from most DSLRs/MFTs and consumer cameras--is prone to generation loss. You have to know your original footages bitrate and save at that or higher to minimize generation loss. 

    You'll hear about "intermediate codecs."These are still lossy, but hold up at lost better than mp4, and are usually all you need. This is probably the best option. In Hitfilm 4 Express ProRes on Mac or DNxHD on Windows are probably your best options. Hitfilm Pro 2017 accepts Cineform.

    There are options to work with Raw, uncompressed footage. Fir Hitfilm this requires converting video into PNG or EXR image sequences. This is disk intensive and requires a beefy computer, but it's possible. Not worth the effort. In this case you would work/edit on the intermediate codec and swap in the RAW files later anyway.

    Finally, if you are putting your footage on YouTube or Vimeo your footage is going to get downshifted to a lower bitrate anyway. Normal back and forth won't make your final project worse with proper encoding. 

  • Also keep in mind that your source doesn't actually change; opening a jpg doesn't affect the original file.

    If you save it as a NEW jpg, then you are throwing additional data away. That's called generation loss; that's what you want to avoid.

    For most purposes, ProRes 422 HQ is enough even for VFX. If you need to pull a detailed chroma key (like with moving hair) you'd want to capture with 444 chroma subsampling or raw, plus with a higher shutter speed than the standard 1/48th of a second.

     

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