8K-Optimized Transcoder Released by Spin Digital

Spin Digital is releasing a new transcoder suite of software-based applications designed to run on workstation-class servers in a cloud environment.  Called Spin Enc File v2.0, it is based on a new version of Spin Digital’s software HEVC encoder that has been extensively optimized for high encoding speed while at the same time producing very high quality and compression efficiency. Spin Digital says that for 8K video the optimized transcoder produces similar quality and compression levels when compared to open-source HEVC solutions (i.e. x265 encoder with slow preset) but achieves significantly higher transcoding speeds.

In transcoding applications, a high-quality source file that has been compressed using a mezzanine codec such as ProRes, DNxHR, or Cineform, is converted into a distribution format such as HEVC. Optionally, some conversion operations such as chroma subsampling, resolution scaling, and tone mapping are applied before encoding. The entire transcoding application, therefore, includes decoding the mezzanine file, performing video processing filters, and encoding in distribution format.

The address these needs, the Spin Enc File includes three main components for high-end transcoding applications:

  • SpinDec: a high-performance HEVC decoder with support for professional formats. It supports the HEVC Range Extensions profiles for professional video formats (4:2:2 and 4:4:4, up to 12-bit).
  • SpinFilter: a set of high-precision and high-performance pre-processing filters for video processing tasks including resolution scaling, color space, and HDR transfer function conversion, tone mapping, as well as 360°/VR content processing including spherical format conversions.
  • SpinEnc: a high-performance and high-quality HEVC encoder

All these modules have been integrated into the FFmpeg media framework facilitating their use in transcoding workflows and supporting several input and output formats included in FFmpeg.  “What we have done is to include our HEVC decoder, encoder, and video processing filters as binary plugins into FFmpeg,” explained Mauricio Alvarez-Mesa, CEO of Spin Digital. “Our libraries are proprietary modules linked to FFmpeg, and we provide our customers a custom-made version of FFmpeg called spinffmpeg. The main benefits of using FFmpeg instead of creating our own transcoder are:

  • Reuse FFmpeg workflows: Many transcoding workflows are based on FFmpeg, so people familiar with FFmpeg interface can use our codecs in a well-known environment
  • Reuse FFmpeg input and output formats: we use existing FFmpeg modules for muxing and demuxing (MP4, HLS, etc.) and audio coding.”

Spin Enc File v2.0 makes 8K transcoding in the cloud cost-effective and, at the same time, produces the quality at bitrate needed for 8K streaming over the internet.

As shown in the table below, Spin Enc File v2.0 is able to transcode up to 15.4 8K frames per second (fps) from ProRes to HEVC and 21.4 fps from HEVC-4:4:4 to HEVC. The output files have a very similar objective quality and file size. The experiments were conducted on a 64 core CPU workstation with Ubuntu Linux 20.04 and using FFmpeg v4.3.1. As a result, with Spin Enc File a feature-length 1.5-hour 8K movie at 60 fps can be transcoded in around 4 hours.

Encoder

Input: ProRes 4:4:4 12-bit
Output: HEVC 4:2:0 10-bit
Input: HEVC 4:4:4 10-bit
Output: HEVC 4:2:0 10-bit
Spin Enc File – balanced 15.4 fps 21.4 fps
x265 – slow 3.3 fps

3.2 fps

When compared to other HEVC encoders such as SVT-HEVC and Nvidia’s NVenc, Spin Digital’s Spin Enc File v2.0 results in higher transcoding speeds and, in addition, higher compression efficiency. More details of a codec comparison analysis will be revealed soon.

As a flexible software solution, Spin Enc File supports multiple HEVC formats compatible with different 8K software and hardware media players. These formats include single-slice encoding and the ARIB STD-B32 standard used for 8K broadcast in Japan.

Spin Enc File v2.0 is available now for licensing. For more information visit the Spin Enc File webpage.