• Science Slideshow

AFDI Dome Standards Group

AFDI, the Association of Fulldome Innovators is a special interest group operating under the auspices and government of IMERSA. AFDI supports community-wide, professional standards to facilitate convergence of film domes and digital domes, and move the immersive dome medium forward.

AFDI has gathered engineers from major fulldome system providers including Evans & Sutherland, Sky-Skan, SCISS, RSA Cosmos, Zeiss, Konica-Minolta and Goto. Producers, artists, planetarium vendors and all interested members of the community are invited to participate and help shape the future standards of the industry.

About the Standards Foundation Process

  1. Establish volunteer Standards Committee from IMERSA Supporting Members and Affiliates.
  2. Disseminate Draft Standards for comment on work group web site (fulldome.org).
  3. Broad-based public, member and allied organization review and comment on Draft Standards.
  4. Standards Committee consideration of and response to submitted comments.
  5. Incorporation of approved changes (via formal Standards Committee vote) into a Draft Standard.
  6. Phase 2 of dissemination, comment, review and revisions.
  7. Incorporation of approved changes into a Working Standard.
  8. Standards Committee consensus on Working Standard and ratification recommendation.
  9. Ratification of Working Standard by IMERSA Board and other user organizations.
  10. Continued review of comments, concerns and revisions as required by Standards Committee.

Overall Goals

  1. Develop a standard data format and procedure for transferring fulldome programs between users.
  2. Facilitate the automated display of fulldome programs with minimal human interaction.
  3. Define metadata and Intellectual Property identification procedures.
  4. Allow for the expansion of the Working Standard to include 3D datasets, spatialized audio and future technologies.

 

  • I. Metadata Specifications

    Sufficient information for future automated reading and processing of program files, including important owner information about the program.

    1. A description document file should describe all drive/DVD contents and program specifications
      1. must include plain text version of the document file
      2. may include XML version of the document file

    2. Show name, version, producer, copyright statement, and other intellectual property data
    3. Total number of Dome Master frames, including number of files and/or length of encoded video file
    4. Resolution of Dome Master frames (diameter in pixels)
    5. Dome Master file format — e.g., “TGA” or “JPEG”
    6. First frame designation — e.g., “00001” or “0001”
    7. Number of audio tracks —e.g., “2” or “6”
    8. Audio file format — e.g., “WAV” or “AC3”
    9. Audio file format parameters including sample rate and bit depth — e.g., “48Khz 16bit”
    10. Audio track parameters including track designation — e.g., 5.1 or stereo, or virtual tracks
    11. Time code start and end value — e.g., “00:00:00 - 23:50:00”
    12. Frame rate — e.g., “30 fps”, “29.97 fps”
    13. Media structure — location of files, number and names of folders, etc.
    14. Other program data needed for identification or proper playback
  • II. Dome Master Working Specification

    The “Dome Master” refers to the individual images projected by the fulldome system. For purposes of this working specification, only circular dome masters (i.e., a square source frame) are considered.

    1. Geometry – equidistant azimuthal “fisheye” render representing up to full sphere with bottom of the frame representing the front bottom of the dome screen, and the right and left hand sides of the dome master corresponding with the respective right and left sides of the dome to a viewer sitting at dome center within the theater. Top and sides of polar image are tangent to edges of image frame.
    2. Recommended file formats: sequentially numbered lossless files — e.g., PNG, TIFF or TARGA with RLE compression
      1. other sequentially numbered files — e.g., JPEG at highest-quality setting
    3. Recommended file name format — e.g., “Name_00001.jpg”, “Name_000001.jpg”
    4. Recommended folder name format “filename_000001_010,000”
    5. Color Bit Depth — e.g., 8, 10, or 12 bits/color
    6. Frame Size, frame must be square, with standard diameter resolutions of 720x720, 1024x1024, 1536x1536, 2048x2048, 3200x3200, 3600x3600, 4096x4096, 8192x8192
    7. Recommended frame rates — 30 fps or 60 fps,
      1. other frame rates — 24 fps, 25 fps, 29.97 fps, 30 fps, 48 fps, 59.94 fps, 60 fps
    8. Alignment Frames — set of standard frames included in dome master that establish synch and test proper geometric alignment, gamma, color balance, etc.
    9. Other design recommendations:
      1. Unidirectional “Safe Action” area approx. ±50° longitude (measured from dome front/center), and ranging from 10–60° latitude (altitude)
      2. Nominal camera tilt of 15° great circle (cf. reference frame)

    10. Exterior to active pixel area:

    1. region colored black (except for time and frame data)
    2. user-defined show name, timecode, and frame number text
    3. recommended arrangement: timecode (top line), frame number (second line), and frame rate (third line) in upper left-hand corner, with show name in upper right-hand corner.
  • III. Audio Files

    Audio Format. To accommodate for variations in sound systems in different venues, the original digital “stem” tracks can be available for re-mixing or encoding for individual venues. A “generic” 5.1 mix is derived from these files as well as a number of odd formats such as 16.1. It is preferable to re-mix the sound in each venue when possible utilizing a portable editing system.

    1. Surround Format – e.g., stereo, 5.1, 7.1, stem tracks, or other
    2. File Format – e.g., WAV, AIFF, other
    3. Leader with test tones at -18dBV
    4. Handles and pips for sync at installation
      1. recommend ten seconds on front, 5 seconds after end of picture[RJW1] 
    5. Sampling Frequency and bit depth — e.g., 48-kHz 16-bit
    6. Frame rate for video sync — e.g., 25, 29.97 or 30 fps
    7. Start frame of either “01:00:00:00” or “00:00:00:01”
    8. Basic audio file naming convention for discrete channels[RJW2] :

    9. Front Left: filename_L.wav
      1. Front Right: filename_R.wav
      2. Rear Left Surround: filename_Ls.wav
      3. Rear Right Surround: filename_Rs.wav
      4. Center Front: filename_C.wav
      5. Center High (Top): filename_T.wav
      6. Low-frequency channel (Sub-bass): filename_LFE.wav
      7. Other: filename_XXX.wav
  • IV. Standard Tech Trailer

    Common test program including:

    • Test patterns
    • Audio files
    • Media synchronization file
    • Color balance
    • Black-and-five
    • Pink noise
    • Annunciated channel check
  • V. Program Distribution Medium (same metadata should appear on all program media)

    1. Content should be delivered on either DVDs or hard drives:
      1. Media < 4GB delivered on DVDs
      2. Media > 4GB delivered on PC-formatted (NTFS file system) 6-pin, Firewire + USB 2.0 drives
    2. When multiple drives are used, the same metadata should appear on each drive
    3. Video should be organized into folders according to frame numbers, typically with a maximum of 10,000 frames per folder
    4. Audio should be organized into folders according to frame rate (e.g., 25fps, 29.97fps, and 30fps folders), with sub-folders for stereo and x.x surround mixes
    5. Top level directories: “Frames”, “Audio”, “Extra”, etc.
  • VI. Digital Rights Management: Encryption, etc.

    VI. Digital Rights Management: Encryption, etc.

 

Dome Master Standards

The current revision of the complete standards document is available for download here. To date, the following standards have been defined.

 

  • Metadata standards for Fulldome show delivery

    This metadata standard defines an xml schema that should be saved into a file with extension *.dml (dome master markup language / dome original markup language) that accompanies frames in distributions. The purpose of the metadata is to describe the contents of a hard drive or other distribution medium, and the intention is that a metadata file is associated with all distributed files from all major distributors, old and new titles alike.

  • A common 2K fisheye video standard

    The Encoded Movie and Audio file for direct playback is a standard to allow sharing of medium resolution media for direct playback without pre-processing, across sites using any compliant system.

 

Process

AFDI is developing a process by which the vendors will work together to develop standards and enhanced capabilities that all fulldome systems can share. Individuals and organizations willing to participate are welcome to join this effort, more information will follow.

 

  • Specifications

    There are several ongoing efforts and conversations regarding technical specifications and standards, such as recommendations for resolution, brightness and contrast. IMERSA and AFDI will continue to support and participate in the DIGSS (giant flat screen and dome) and fulldome (all dome sizes) standards efforts and encourages participation in conversations taking place on the fulldome ning, dome-l, fulldome and various online usergroups and community blogs.

  • Capabilities Standards

    AFDI exists primarily to define and implement shared capabilities standards. The first two published standards were metadata for fulldome show delivery and a common 2K fisheye video standard, both highly achievable goals that AFDI was able to establish through great consensus within the organization. To move the immersive dome medium forward, AFDI and its associated vendors will continue to review, and prioritize important system capabilities that all fulldome systems can share. AFDI will develop and implement these capabilities in a joint effort between the AFDI’s vendors and interested members of the community. By nature, this shared development process will be careful and thoughtful with the ambition to put AFDI’s limited engineering time to the best possible use to serve the community at large.

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