VC-2 HQ

SUPERIOR LIGHTWEIGHT SLICE-BASED VIDEO CODEC

The high quality profile and low delay syntax of VC-2 is used to achieve low compression ratio, typically up to 4 times visually lossless. The algorithm is lightweight and works without external memory allowing cost-effective implementation. The VC-2 High Quality codec has ultra-low latency due to its slice-based processing.

 

VC-2 HQ – MAXIMUM FLEXIBILITY

Did you know?
British Broadcasting Corporation (BBC) developed and open sourced a Wavelet-based video codec named Dirac. A low-complexity profile of the Dirac codec named Dirac Pro, which does not use motion compensation, was standardized by SMPTE as the VC-2 codec. Silex Insight’s VC-2 HQ IP implements the VC-2 codec and associated support for handling the compressed bitstream.

 

EXTENSIVE USE CASES

 

FEATURES IN VC-2 HQ

The slice-based processing allows a high level of parallelization. In combination with small slices, a sub-frame level pipelining can be put in place and lead to an end-to-end latency of 2 stripe height lines. With 8 lines of latency in 4K60, VC-2 HQ has a latency of only 0.0593 milliseconds.

 

The slice-based processing allows to update any slice directly in the compressed picture! This is ideal for picture in picture (see example below), logo insertion or video content update without the decoding and re-encoding of the full resolution picture, saving power. VC-2 HQ is a hyper-flexible codec.

 

With ROI coding, only the useful slices determined by the user are encoded. This allows saving power and bandwidth.

 

PROCESSING LATENCY OF VC-2 HQ

By far the lowest latency for any codec in the market with such a low complexity

The slice-based processing also results in extremely low encoding latency with the encoded bits becoming available for transport and decoding even as other slices in a frame are yet to be encoded.

Low latency processing is also supported by the Constant Bit Rate (CBR) encoding option which allows for predictable data transfer rates across the entire system from sensor to encoder to decoder to processor. In applications that require real-time analysis of the video, the CBR mode could be a key asset.

For example, in the lowest latency configuration of VC-2 HQ, 8 lines of processing latency in a 4K60P frame (comprised of 2250 lines including blanking) computes to just 59.3 microseconds which is by far the lowest latency for any codec in the market with such a low complexity.

 

WHEN LOW COMPLEXITY VIDEO CODEC MATTERS

 

VC-2 HQ vs. OTHER CODECS

Many options exist for performing Intra-frame only coding of video including popular and more complex codecs such as H.26x and JPEG. However,  VC-2 HQ offers a number of superior features:

  1. Lossless and near-lossless quality options
  2. Low complexity in terms of both gate count and memory footprint
  3. Low latency throughput using slice-based processing
  4. Standards based via SMPTE & IETF
  5. Widely supported in popular video software frameworks such as FFMpeg & GStreamer

Even among codecs targeting lightweight encoding such as JPEG-XS, VC-2 HQ offers unique capabilities:

  1. Slice-based processing allowing for flexible compressed frame buffer and region of interest
  2. Supports 4:2:0 color subsampling