In response to that request, MPEG issued a set of requirements for a new video coding standard and a Call for Proposals for those companies and organizations that have developed video compression technology that they believe address the requirements.
The Requirements set define a codec that allows a full resolution encoded/decoded stream being formed from enhancing a stream encoded/decoded with a hardware codec and a data stream which, when added to the coded/decoded stream, would bring the video to the full resolution.
In particular, the key performance requirements were defined as follows:
- When enhancing an n-th generation codec (e.g., AVC), compression efficiency for the aggregate stream is appreciably higher than that of the n-th generation MPEG codec used at full resolution and as close as possible to that of the (n+1)-th generation codec (e.g., HEVC) used at full resolution, at bandwidths and operating conditions relevant to mass market distribution; and
- Encoding and decoding complexity for the aggregate full resolution video (i.e., base plus enhancement) shall be comparable with that of the base encoder or decoder, respectively, when used alone at full resolution.
The key implementation and non-technical requirements for the video coding project were:
- The video stream should be decodable without specific firmware or OS support by all devices capable to decode the base codec, with equivalent resource utilization (e.g., processing power, battery consumption, etc.) as the base decoder at full resolution decoded in hardware;
- The additional data stream should be compatible with the existing ecosystem, e.g. ad insertion, metadata management, CDNs, DRM/CA and network protocols such as DASH, HLS, MMT and SS;
- The overall processing power requirement to encode a video stream should be comparable with that of the base codec when used alone at full resolution.
Multiple independent tests and cross-checks conducted during the MPEG collaborative phase of standardization demonstrated that LCEVC successfully satisfies its requirements (see technical documentation and performance evaluations in the Resources section for a summary of tests performed and LCEVC performance results).