“The Hobbit” 1920×1080@48 per-view Cannot be Viewed from Blu-Ray 3D

The Hobbit: Too much bandwidth for HDMI receiver?

The HDMI 1.4a specification that is used as the uncompressed interface of most 3D Blu-ray players is defined thusly by HDMI:

3D Mandatory Formats

  • For movie content:
    • Frame Packing
      • 1080p @ 23.98/24Hz
  • For game content:
    • Frame Packing
      • 720p @ 50 or 59.94/60Hz
  • For broadcast content:
    • Side-by-Side Horizontal

      • 1080i @ 50 or 59.94/60Hz
    • Top-and-Bottom
      • 720p @ 50 or 59.94/60Hz
      • 1080p @ 23.97/24Hz

We can see here that Frame Packing at 1080p per-view tops out at 24Hz, or 48Hz total for both eyes combined, while  720p content can be viewed at 60Hz, or 120Hz total.

Silicon Image HDMI Processor

Silicon Image HDMI Processor

 

What is the reason for this? It’s not only that the HDMI TX transmitter found in the source device is limited to 60Hz output but that most HDMI RX receivers found in HD televisions are also limited to 60Hz (59.94) input.

So, while the Hobbit could possibly, with a firmware update, be played back with existing equipment at 48Hz x2=96Hz total at 720p, the processing speed of the HDMI transmit and receive simply cannot handle 1920×1080 at anything faster than 29.98Hz per-view.

The actual HDMI cable itself is clearly possible of supporting higher frame rates in 3D, meaning users would be able to retain their existing HDMI cables, however, devices would require updated HDMI hardware to handle the increased bandwidth processing.

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