Video Core Next is AMD's successor to both the Unified Video Decoder and Video Coding Engine designs,[1] which are hardware accelerators for video decoding and encoding, respectively. It can be used to decode, encode and transcode ("sync") video streams, for example, a DVD or Blu-ray Disc to a format appropriate to, for example, a smartphone. Unlike video encoding on a CPU or a general-purpose GPU, Video Core Next is a dedicated hardware core on the processor die. This application-specific integrated circuit (ASIC) allows for more power-efficient video processing.[2][3]
Feature set
All versions of VCN support: MPEG-2 Decode, MPEG-4 Decode, H.264/MPEG-4 AVC Encode/Decode, HEVC (H.265) Encode/Decode, and VP9 Decode. 10-bit color depth in the P010 format is supported. VCN 1.0 supports up to 4K resolution. VCN 2.0 and beyond supports up to 8K.[4] Support for H.264 and H.265 Encode methods differ among generations (see below). VC-1 Decode is supported until VCN 3.0.33.[4]
VCN 2.0 is implemented with Navi products and the Renoir APU. The feature set remains the same as VCN 1.0.[4]
VCN 3.0 is implemented with Navi 2 products.[5] VCN 3.0 implements H.264 B-frames, which was present in Video Coding Engine 2.0 but taken out with VCE 3.0.[6]
VCN 4.0 adds AV1 encode.[7] H.264 quality is higher with VCN 4.0 (as part of RDNA 3) compared to previous generations, but still lags behind Intel and Nvidia hardware codecs.[8]
There is no support for encoding or decoding in YUV422 and YUV444 in H.264 and H.265.
Video Core Next Video decoding/encoding support[4]
AMD VCN has lower overall quality (VMAF) compared to offerings from Intel and Nvidia. B-frame narrows the gap, but does not eliminate it.[8] With pre-analysis enabled too, the gap is almost closed.[9]
Despite a lack of B-frame support, H.265 provides better quality (VMAF) and near-identical speed for the same bitrate compared to H.264 on VCN 2.0, 3.0, and 4.0.[19]
^B-frames allow for higher-quality I and P frame to be used, improving the overall video quality in high-motion sections. There is no B-frame support for H.265 at any version.[6]
^Pre-analysis improves quality in high motion scenes at the cost of latency.[9][10] This pass works in both H.264 and H.265.