Library of Congress Moving Image File Specifications.docx

NAVCC 11/22/2021

Library of Congress Moving Image File Specifications

Two types of files are required: the archive file (AF)and the viewing file (VF):

Library of Congress NAVCC moving image archive file specifications

Wrapper: MXF OP1a (SMPTE 377 & associated standards).

SMPTE RDD48 compliant

Image essence coding: JPEG2000 reversible 5/3 (aka “mathematically lossless”) (ISO/IEC standard 15444) Native resolution: the entire active picture area of the source video shall be captured in the Archive File JPEG2000 coded essence (eg. The resolution of the source images shall be JPEG2000 coded at exactly the same resolution without conversion or truncation) Native color components: the color standard of the source video shall be captured in full in the Archive File JPEG2000 coded essence (eg: if the source material is RGB, the JPEG2000 coded essence shall be RGB). For analog-sourced material not originally RGB, the color components shall be YCbCr, 10 bit sampled, ITU-R Rec. 601 for SD, ITU-R Rec. 709 for HD.

Native bit depth: the bit depth of the source video shall be captured in full in the Archive File JPEG2000 coded essence (if the source file is 16 bits per channel the JPEG2000 coded essence shall be 16 bit). For analog-sourced material the bit depth shall be no less than 10 bits per color channel, with the option of up to 16 bits per color channel.

Native frame rate: the frame rate of the source video shall be captured in full in the Archive File JPEG2000 coded essence. No inter-frame coding permitted.

Native interlace/progressive raster: Interlace material shall be captured as interlaced, odd field first. For progressive source material the video shall be captured as progressive. For segmented frame source material the video shall be captured as progressive at the non-interlace frame rate.

Aspect ratio: the aspect ratio of the source video shall be faithfully reproduced in the Archive File JPEG2000 coded essence. If AFD (Active Format Description; SMPTE 2016-1) codes are present in the original, they shall be carried into the space for such codes in the Archive File JPEG2000 Tile: single tile JPEG2000 cadence: the cadence shall default to LRCP.

For files whose content is interlaced video: JPEG2000 interlace KLV metadata type shall be a configurable menu choice of I1 or I2.

Audio essence:

Audio coding: the audio track(s) shall be captured in the Archive File audio tracks essence(s) as PCM sampled BWF (Broadcast WAV) RF64 format at 96 kHz, 24 bit sampling. The number of tracks shall match the number of tracks in the source material.

Time codes:

Time code(s): SMPTE time code, where in the original, shall be preserved as a timecode track within the MXF OP1a SMPTE RDD48 compliant wrapper. LTC (Linear Time Code) shall be time code track 1. VITC (Vertical Interval Time Code) shall be time code track 2. Should a timecode track also exist as an audio track, that timecode track shall be carried as BOTH a timecode track AND the audio track that timecode was located within.

Statutory metadata: (metadata required by U.S. Federal law) Closed captioning: should closed caption or caption data exist for the original video essence, either included in the image essence or as a sidecar file, that data shall be included in the MXF standardized location for such data

Library of Congress NAVCC moving image viewing file specifications Video parameters Video codec: H.264 Resolution: same as source material Frame rate: same as source material Color space: MPEG-4 YCbCr Audio parameters MPEG audio coding 48 kHz sampling, variable bitrate Included Metadata FCC Timed Text audio captions shall be included matching the captions in original source material and the Archive File Format Choice of one of the Archive File timecodes