J2 - LOC Moving Image File Specifications.docx

NAVCC 09/18/2024

Library of Congress Moving Image File Specifications

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

Archival File Specification Wrapper: MKV Matroska Media Container Format Specification (IETF Standard: draft-ietf-cellar-matroska-23) Video Essence Video essence coding: FFV1 Video Coding Format Version 0, 1, and 3 (IETF Standard RFC 9043) Native resolution: the entire active picture area of the source video shall be captured in the Archive File FFV1 coded essence (eg. The resolution of the source images shall be FFV1 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 FFV1 coded essence (eg: if the source material is RGB, the FFV1 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 FFV1 coded essence (if the source file is 16 bits per channel the FFV1 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 FFV1 coded essence. No inter-frame coding permitted.

Native interlaced/progressive raster: Interlace material shall be captured as interlaced, with the field dominance matching the original signal. 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 FFV1 coded essence.

FFV1 Version: 3.4 or greater GOP Size: 1 CRC Slices: Each frame of the FFV1 video essence shall be split into slices, with CRC checksum information calculated for each slice. The number of slices shall be user selectable as any of the following values: 0, 4, 6, 9, 12, 16, 24, 30

Audio essence Audio coding: the audio track(s) shall be captured in the Archive File audio tracks essence(s) as Linear PCM sampled WAV RF64 format at 48 kHz, 24-bit sampling. The number of tracks shall match the number of tracks in the source material.

Additional Streams Time code(s): Any time timecode present in the source material should be stored in the MKV wrapper according to the MKV specification.

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 MKV wrapper location for such data Viewing File Specification Video parameters

· Video codec: H.264/AVC

· Resolution: same as source material

· Frame rate: same as source material

· Bit Rate: Constant Rate Factor: 18

· Color space: YUV

· Chroma Subsampling: 4:2:0

· Bit Depth: 8

· Scan Type: Progressive Audio parameters

· Encoding: AAC

· Sampling Rate: 48 kHz

· Bit Rate: Variable

· 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