Agency Based Discussion > VideoBlocks

Minimum bitrate requirement seems really high

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dragonblade:
It's been a while since Ive read Videoblock's technical requirements. I read them when I first signed up but have since forgotten some of the finer details. I read them again just now and was surprised to read that the minimum bitrate they accept is 50,000 kbps. That seems unusually high if you're submitting HD content. None of my HD cameras capture bitrates anywhere near that figure and I wouldn't exactly call them cheap cameras. They're definitely not point and shoots. Among them is a Panasonic G6 which has a fairly good reputation for HD video and produces a bitrate on average about  23,629 kbps or thereabouts. I have an older GoPro model that boasts a lower bitrate than that.

Thinking about this some more, I'm curious why they accepted a 1280 x 720 video from my Panasonic G2 since the bitrate for that clip would have been around 5,812 kbps.

increasingdifficulty:
In a professional situation, 50 mbps is on the low side. I know lots of cameras encode harder than that, and it looks fine, but just use ProRes or encode a new 50+ file and the problem is solved.

The thing with a 28 mbit file is that, while it may look perfectly fine, it leaves little room for grading since the invisible information has been thrown away.

SuperPhoto:
Speaking of which - can someone please explain to me the advantage of a 'higher' bit rate?

I have a large monitor (25") as well as large TV (60") - and if I view HD/4K video on them at say 20MPS as opposed to 150MPS - they look pretty much identical to me.

So I don't get/see the advantage of a higher bit rate.

increasingdifficulty:
Higher bitrate means less compression.

The goal of compression is to minimize file size while keeping an acceptable level of image quality. What is acceptable will differ from application to application, and from person to person. An untrained eye will not notice heavy compression, while a professional editor can spot it right away.

Modern compression algorithms are really good, and for simply VIEWING a video, you can get away with quite heavy compression.

But when you're selling stock footage, you're not selling it to be viewed directly. You're selling it to be EDITED, or at least to have the option to be graded and changed.

Heavy compression removes the ability to grade and change colors, as what you see is the only information still present. In an uncompressed file, there is A LOT of information that you simply don't see, but that is necessary when you want to change something.

Compare a RAW file to a JPG. They can look identical if you have JPG compression set at 100%, but as soon as you want to make changes, like raise shadows or change the colors, you will quickly notice that the RAW file has A TON more information and the JPG will quickly fall apart and look terrible.

SuperPhoto:
Hmm, okay - 'kind' of making a bit more sense - but can you give me an example of a specific color change (i.e., say premiere pro) - where it would look bad in one but good in the other? I do editing myself (on both say 50kpbs, and 10kpbs) - and for the most part - looks identical.

The 'only' time I would say notice a difference is if you had gradients (i.e., a timelapse with a blue sky). *Then* yes, I admit I definitely notice the 'banding' on a lower kpbs/more compressed item...

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