VP9-next generation open source codec

March 20, 2014
Google’s VP9 is a new codec, which supports high resolution coding at over half the rate when compared to VP8, and is expected to give fierce competition to HEVC codec. VP9 is fundamentally no different from HEVC since both the codecs employ similar techniques of compression such as larger block size, transform, intra & inter predictions and CABAC based entropy coding. However, there are differences with respect to the usages & limitations of the techniques.
Comparison of features supported by VP9 & HEVC are tabulated below
Features VP9 HEVC
YUV format 420, 422, 444 420, 422, 444
Entropy CABAC CABAC
Number of reference frames 3 (Last frame, Golden frame, AltRef frame) - DPB size is 8 frames 16
Bi-Prediction Yes Yes
Block Size 4x4 to 64x64 including rectangular partitions (such as 4x8, 16x8 etc…) 4x4 to 64x64 including rectangular partitions (such as 4x8, 4x16 etc..)
MV precision 1/8th for luma, 1/16 th for chroma 1/4th for Luma & 1/8th for Chroma
Motion Compensation 8-tap filter for 1/8th, 1/4th,1/2 pels 8 tap for ½ pel & 7 tap for ¼ pel
Intra prediction 10 modes 35 modes
In loop deblocking Yes Yes
Transform Sizes 32x32,16x16,8x8,4x4 32x32,16x16,8x8, 4x4
Tools Tiles, Segmentation Tiles, WPP, SAO
 
VP9’s compression ratio will be on the lines of HEVC, but, the efficiency of the VP9 is not truly reflected in the reference encoder from WebM since HEVC’s reference encoder is better than VP9’s WebM reference encoder as of today. However, the VP9 codec is patent free and available under BSD license, hence, VP9 is suitable for commercial applications as well open source community. VP9 will occupy the place for high resolution video encoding in youtube down the line (VP9 is already supported in Chrome browsers through libvpx). Google has released hardware IP for VP9 –G2 VP9 decoder IP- for semiconductor companies which would like to ship products with VP9.

Code

VP9 is available from two places

Conclusion

VP8 could not challenge H.264 because of several reasons such as
  • VP8 entered video market very late when compared to the that of H264 (H264 came 6-7 years before VP8). When VP8 entered, H264 was widely accepted & deployed by the industry
  • Lack of clarity on the patent rights of VP8 in the initial years
  • No significant differentiation over H264
However, VP9 has entered scene at almost the same time as that of HEVC. In addition, VP9 is released under BSD license and claimed to be patent free. Also, VP9 is getting deployed in the industry through collaboration and strategic push by google. Hence, VP9 will give strong competition to HEVC. But, only time will tell on who is going to win the battle. For now, let us enjoy the battle!!!!
Pathpartner author Ajay
Ajay Basarur
Business Development Manager - I