In this episode of Production Bot 101 we will be talking about Codecs. Codecs are critical in live streaming and video production in general. Today we will be covering some pros and cons for popular codecs so you can decide what works best for your production.
What is a codec?
Short for compress decompress, meaning it takes a big file (like your video) breaks it down into a bunch of pieces, sends them, and assembles them back together again.
What are the common codecs?
- AVC or H.264: this is the go to codec for RTMP streaming as well as a ton of video online. It is a great way of shrinking video down to a manageable size without sacrificing quality too much. You can use any resolution in H264 and most every platform and browser is compatible with it; but if you want high quality, ProRes is the way to go.
- HEVC or H.265: this codec is license based (so developers need to pay to allow it on their application), but it promises to deliver the same quality at half the bit rate of H.264. But the rate on the CPU power it needs is way higher than H.264, meaning you can overload your system much more easily.
- AV1: The free competitor to H.265 that is soon to be fully released. AV1 is based on VP9 and will be free to license. Most browsers have adopted this codec.
- HAP: This codec is open source was developed as a free alternative that takes advantage of Graphics Cards. Since those are getting bigger and better by the day, the HAP codec takes advantage of this, and renders video less on the CPU and more on the GPU.
What if my video asset has an alpha channel?
Alpha: this is any part of a video or graphic that has some degree of transparency. Only some formats can handle Alpha. Unfortunately, H.264 does not contain an alpha channel, so those animated lower thirds will need to be rendered some other way. HAP has an alpha codec and Quicktime is also an option, but beware of the giant file sizes. ProRes 4444 can contain alpha, but only certain applications will let you use it.
On Production Bot, vMix comes preinstalled, so that means you can play any H.264, ProRes (including 4444), or Quicktime Animation file. One thing you can’t play yet is H.265, so make sure you convert any H.265 assets before importing them.
HAP: Download the codec here. The best way to do it is to download the VDMX software and run the installer. It will download the software and the codec, and you can uninstall the software and keep the codec. One important drawback with HAP is that currently, Adobe Media Encoder 2018 cannot render it. There are some extensions that could be used, but are of course third party, so you should test them out before transcoding any important assets.