High-Quality Video Renders from your CG Work

high quality image formatsWhen working in a 3D/CG program, such as Maya, Blender or Unreal Engine, and aiming for the best quality video renders then I recommend to always export out the video as an EXR image sequence.

If you are not doing so already, the best approach to render out your video is as an image sequence and then import (the combined images) into a video editing or compositing software program, such as DaVinci Resolve or Adobe After Effects.

The image format you use (if different from EXR) depends a lot on what the video is required for, how much space you have on your hard drive(s) or what information you want to keep. For example Jpg is a good format for compressed images used online, but it will not deliver the best results for high-quality video or static image renders as it’s a highly compressed lossy file format.

Best to start with the highest quality export possible (such as EXR) and you can always compress the final video export if required.

So for producing high quality video renders I work primarily using two image formats: PNG and EXR. These are my preferred image formats, they produce great quality and are recognised industry standards.

EXR and PNG

EXR stores a lot of data, including the alpha channel, a deep colour depth of 32 bit, high dynamic range, and z-buffer distance from camera info. The main challenge with EXR is that they are large files and one EXR image could easily be 50mb or larger. I recently was doing some exports in EXR from Unreal engine and each image was 62mb, so as you can imagine that took up a lot space when thousands of frames (images) have been rendered. But, don’t fear, as some programs have an option to compress EXR images which can save a lot of space.

Also EXR is not a common file format, such as PNG or Jpeg, so you need software that understands the format, but Blender, Unreal Engine, Photoshop, Affinity Designer/Photo all recognise the format.

PNG produces good quality exports and is a lossless format, so you will not lose quality when you compress the image files. It also supports an alpha channel and 16 bits per channel, which is more than the TGA (targa) format which only supports 8 bits per channel.

Image Formats

There are many options to choose from when exporting out images or image sequences, but below I have listed 4 that are very common and that I also use (aside from PNG and EXR). It’s worth noting that PNG and TGA are similar file formats, but whilst in the past I have used TGA I now use PNG more commonly.

.PNG (Portable graphics network file format)

  • Supports up to 48-bit true colour images
  • Supports up to 16 bit per channel.
  • Lossless and will not degrade in quality after multiple duplications.
  • Supports an Alpha Channel.

.EXR

  • EXR format was created by ILM (industrial light and magic) for the film VFX industry.
  • Supports lossy and lossless compression, and 16-bit and 32-bit pixels
  • Supports HDR.
  • Supports an Alpha Channel.

.TIFF

  • Can support multiple layers and images within one file.
  • Supports both 8 and 16 bits per channel.
  • Lossless and can be compressed.
  • This can create compatibility issues when opening the files within different programs. There also can create very large files.
  • It’s very commonly used by Artists or Designers when creating images and also for high-quality prints.
  • Supports an Alpha Channel.

.TGA or Targa (Truevision Advanced Graphics Adapter):

  • It can store 32-bit images.
  • TGA only allow for 8bits per channel bpc (Green 8 Red 8 Blue 8 and Alpha 8). Can only support up to 32 bit images.
  • Lossless and supports 32-bit deep colour images and this allows for varying transparency.
  • Doesn’t support HDR
  • Supports an Alpha Channel.

Industry Example

Quixel Megascans provide high-quality industry used (movies, ads, video games and music videos) textures and other CG assets. Below is a screenshot is taken from a tool they provide called Bridge, and as you can see below the options (on the right-hand side) include JPG, EXR, PNG or TGA.

The main reason for providing JPG is that it’s a format that can be compressed, but still maintain decent quality and such compressed assets are used in video games. As running video games (especially mobile games) can be a resource intensive process and using EXR is not an option as it will eat video memory and processing power alive!

Formats to avoid for best quality video renders

Formats such as Giff or Jpg should generally be avoided when rendering out images or image sequences for video. They do not produce the best quality, although if you want to produce a compressed file that is for use in a website or social media, then Jpg is a good format to use or if you are just doing some test renders before you get to the final export.

Video Export Rendering

Once you have exported out your image sequence (PNG or EXR) and imported into a video editing/composition program there will be multitude of export options available in any professional video editing/composition program. Listed below is a high level overview of key recommended rendering export options (but there are of course other high quality export options you could use).

  • MP4 h264 or h265 Codec: When you come to exporting out your videos it again really depends on what the final delivery medium will be. So if you are exporting out for Youtube then you are okay with MP4 with a h264 or h265 encode. This is a compressed video format though, so it won’t produce the best quality export., but its still pretty decent. Youtube will compress your video to MP4 whatever file format you use/

  • QuickTime and h264 or h265: To produce higher quality video exports use QuickTime and h264 or h265.

  • DCP: Let’s remember though that Youtube is not the only place for video! ;) If exporting for cinema projection or a film festival then you will (most of the time) need DCP. It produces great quality and also Davinci Resolve (paid version) has an easy export option for DCP.

  • DNxHR: If you want a really high quality export, use Quicktime and DNxHR. Remember a lot of programs will not recognise this format, and whilst it will produce a high quality video export it will be best used as an archive format and something yon can return to in the future if you want to export out in another delivery format, or use for further editing or colour correction.

A note on why to export out image sequences?

There are multiple benefits for rendering Image sequences for video:

  • The primary benefit is that if the program crashes during the render, then there will still be the rendered images up until that point and you will not need to render them out again.
  • The render can be stopped early if required, but the rendered images up to that point will still be usable for a video sequence.
  • It provides a high-quality initial output that can be compressed further if needed.

A great video providing further insights on the EXR Format from Polyfjord