Ultra-HD / 4K Blu-ray Disc specifications leaked

A Japanese website has leaked the specifications of the upcoming Ultra High Definition Blu-ray format. The specifications contain several surprises. In September last year the Blu-ray Disc Association announced it was developing a format for Ultra-HD content and stated that players and discs for the format would become available at the end of 2015.

Panasonic already showcased a prototype player at CES this year, however the device was behind glass and Panasonic didn’t provide much information about it.

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The Japanese website AV Watch today posted an image showing the expected specifications of the new Blu-ray format. The table confirms most of the information already available, such as usage of the HVEC codec and a maximum peak video bit rate of 100 Mbps.  Nevertheless, the posted specifications also show some surprises.   The new Ultra-HD Blu-ray discs will only support 3840 x 2160 pixels, which matches the resolution of Ultra-HD displays. The cinema 4K resolution of  4096 x 2160 pixels won’t be supported.

Ultra HD movies can offer frame rates of up to 60 frames per second, while current Blu-ray normally plays video at 23.976 or 24fps, but also offers up to 29.97 frames per second with interlaced video.  This new chart shows no interlaced resolutions for Ultra HD.  It’s surprising that the “Ultra-HD Blu-ray Disc”, which still doesn’t have an official name, only offers chroma subsampling of 4:2:0. and that Ultra-HD Blu-ray players will be required to have an HDCP 2.2 protected HDMI output. This would be a big advantage for Onkyo which sells 4K-compatible audio/video receivers with an HDCP 2.2 protected HDMI 2.0 input and which only support 4:2:0 chroma subsampling.  All other manufacturers of AV receivers currently rely on a higher color scanning and have no HDCP 2.2 support.

Ultra HD movies in 3D will probably not be part of the Ultra-HD Blu-ray specification. That isn’t really surprising, because Panasonic’s chief developer Kazuhiko Kouno has already stated no suitable chip is available.

The Ultra HD Blu-ray discs will support both a higher dynamic range by increasing the color depth to 10-bit per color, and a greater color gamut by using the Rec. 2020 color space. At CES, Netflix already demonstrated 4K video with HDR. The additional data required for HDR can be added to a HVEC stream which allows playback of both formats from a single disc, players without HDR support will simply ignore the additional data.