HEVC Interlaced timeline.png

The goal of this blog entry is to clarify that HEVC/H.265 does indeed support interlace video efficiently, and that in reality, it does perform substantially better than AVC/H.264 and MPEG-2 for interlace content.

Let’s take a brief look back at HEVC/H.265 development.  Support for interlace content was always an HEVC/H.265 requirement, dating back to 2009 [1][2].  While the initial test material was progressive, this was in keeping with the desire to start from a simple design.

In November 2011, eleven companies proposed that JCT-VC work on the efficient implementation of interlace coding in HEVC/H.265[3].  Legacy content and legacy camera equipment were cited as a rationale.  As a result, JCT-VC established an ad-hoc group (AhG) tasked with adding interlace support to the HEVC/H.265 specification [4].

At the following JCT-VC meeting (February 2012), after discussing several possible approaches, it was decided that efficient compression of interlace video could be achieved by adding an SEI message to the specification without needing to change the basic design or coding tools of HEVC/H.265 [5].  During 2012, dozens of proposals were made to JCT-VC with the objective of further refining HEVC/H.265’s handling of interlace material.

That brings us to the present situation: HEVC/H.265 does support efficiently compression of interlace material. Furthermore, numerous tests, including those performed by some companies that initially requested interlace support; have indicated that the performance achieved is satisfactory [6].  The European Broadcasting Union has stated “…the need for low-level interlaced coding tools will not be necessary anymore as some type of interlaced coding is already supported in HEVC…” [7], and the UK National Body welcomed “…the approach that has been followed in providing signaling of field coding, which it considers to be sufficient to satisfy the immediate market requirements for the coding of interlaced content using HEVC” [8].

Naturally, HEVC/H.265 could be further improved for both progressive and interlace content.  Given that HEVC/H.265 already has profiles that supports interlace coding efficiently, the improvement must generally be significant in order to clearly differentiate a new profile from existing ones and justify the cost of its implementation.

If you would like to see a follow up post on how HEVC/H.265 support Interlaced video than please leave a comment below.

Interlaced Video

Interlaced Video

1. ITU-T VCEG and ISO/IEC MPEG, “Joint Call for Proposals on Video Compression Technology”, document VCEG-AM91 of VCEG. Jan 2010.
2. “Draft Requirements for next-generation video coding project”, document VCEG-AL96. Jul 2009.
3. "Request to establish AHG on interlaced format support in HEVC standard”, document JCTVC-G912. Nov 2011.
4. JCT-VC Meeting Notes, November 2011 
5. "Interlace indication”, document JCTVC-H0013. Feb 2012.
6. "HEVC performance evaluation on interlaced video sequences”, document JCTVC-K0331. Oct 2012
7. "EBU Liaison to MPEG on Low-Level Interlaced Coding tools support in HEVC”, document JCTVC-K0355. Oct 2012
8. "UKNB Comment on Interlaced support in HEVC”, document JCTVC-K0303. Oct 2012.

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