A high-quality GPU powered codec for VFX

NotchLC is now available for Adobe CC, with plugins for After Effects, Premiere and Adobe Media Encoder

Why did we make this?

Simply put, we were dissatisfied with the lack of high-quality codecs for content creators that exploited the power of modern GPUs. So, we created NotchLC; a codec capable of being used as both an intermediary codec as well as a playback codec.

NotchLC brings the equivalent of 10bit accuracy in a scrubbable codec that is extremely fast to encode and decode, with a compression ratio of 8:1 to 5:1.

In an independently conducted test of 10bit codecs, design and technology house dandelion + burdock says:

Combining all the above quality and speed factors, we can strongly suggest ProRes 4444 and NotchLC (best and optimal) as equivalent intermediate codecs. All three have 10bit or higher depth and are only moderately space demanding.

Read the full test here.

NotchLC plugins for Adobe CC and Quicktime & AVI are available as free downloads from the Notch website.

Luma, Chroma, Bit Depths & Compression

The LC in NotchLC stands for Luma & Chroma. NotchLC breaks colour data down into luma and chroma (YUV). 12bits of depth are assigned to luma data, as in many scenarios this is where bit depth is most perceivable. 8bits are assigned to each of the U & V channels. Total (28 bits per pixel). Alpha data is stored at 8bit depth. This is compared to HAP & DXV that encode colour data in RGB at bit depths of 5 or 6 bits per channel (total 16 bits per pixel).

Quality Levels & Bit Rates

Rather than specify target bitrates and end up with undetermined quality outcomes, NotchLC takes the reverse approach. When encoding you set a quality level, which is essentially an allowable ‘error level’ in encode. The encoder then searches for best fit compression in each block that meets this quality threshold. These defined coefficients of error give confidence in the quality of the resulting encoded video.

Typically our users are seeing compression ratios between 5:1 and 8:1 when compared to raw video. And as a general rule of thumb Notch tends to be 30% larger than HAPQ (for a significant quality uplift).

Detail when you need it

Unlike other mainstream GPU codecs, NotchLC uses variable block size and variable control point bit levels to provide extra detail in areas of the image that need it, while allowing greater compression in areas of flatter colours.

Quality Measurement

During development and testing the modern SSIM measurement method was used to test the accuracy of the NotchLC against raw lossless sources. Below is a sample of the types of test content:

We used a wide range of images to quality test against.

SSIM is a coefficient of error. The lower the SSIM result the lower the error. Across the range of samples the following results were achieved:

Subjective performance is always in the eye of the beholder. But in a full 10bit pipeline (content through display output), a very picky leading content creator said the difference in NotchLC vs RAW lossless is “very difficult to see and only possible to the most incredibly discerning of eyes”.

Encoding Performance

NotchLC utilises the full power of the GPU to accelerate the encoding process.

Test video:

  • Big Buck Bunny
  • Duration: 9min 57 secs
  • Format: 1080p24

NotchLC encode duration: 1min 44secs on a NVIDIA 1080 Ti.

On average it is:

  • 7x — 20x faster than HAP
  • Up to 2.9x faster than HAPQ

Decoding Performance

As a GPU powered codec, performance is heavily related to the power of your GPU. However, as an indication of what can be achieved with a modern GPU, it is possible to play 24 layers of 4K@30fps video with an NVIDIA 2080 Ti.

Tools / Encoders / Decoders

We are now shipping an Adobe plugin that provides import and export support to Adobe Premiere, After Effects & Adobe Media Encoder, as well as QuickTime and AVI plugins as well. These plugins are available outside of Notch, free of charge, and can be downloaded from the Notch website.

Currently, the plugins are just available for Windows, but there are plans in place for a macOS version. Additionally, there is a legacy Quicktime Player plugin for Windows. Future plans may include FFMPEG and VLC support, and for media professionals, NotchLC support is coming to the new version of disguise and other media server are implementing it at present.