H.265 was initially foreseen as an entirely new standard and not an extension of H.264 like HVC by the ISO/IEC Moving Picture Experts Group (MPEG). Although some agreements about the goals of an H.265 project have been reached, e.g. computational efficiency and high compression performance, the current state of technology does not yet seem mature for creation of an entirely new H.265 standard, and all contributions are modifications to KTA JM11, a reference H.264 encoder by the MPEG/VCEG Joint Video Team. In April 2009, the scope of the project was changed to NGVC, with a H.264+standard being the most likely outcome; in July 2009, a joint meeting of MPEG and VCEG discussed future collaboration on NGVC and HVC, similar to the Joint Video Team effort.
The preliminary requirements for NGVC are bit rate reduction of 50% at the same subjective image quality and computational complexity comparing to H.264 High profile, with computational complexity ranging from 1/2 to 3 times as that of H.264. NGVC should be able to provide 25% bit rate reduction along with 50% reduction in complexity at the same perceived video quality as H.264 High profile."
The ITU discussion can be found in
Prof. Dr. Touradj Ebrahimi mentioned
Though the necessary scope of H.265 is yet largely to be determined, it is agreed that among the goals will be:
- High coding efficiency, e.g., two times compared with H.264/AVC
- Computational efficiency, considering both encoder and decoder
- Loss/error robustness
- Network friendliness
So far, contributions to VCEG have mainly focused on improving coding efficiency.
To better evaluate these contributions and retain progress, the KTA (Key Technical Area) has been developed as the software platform, using JM11 as the baseline and continuously integrating promising tools.