Audio-Visual Prototyping Project

AudioMD Data Dictionary

# Table Name Field Name Field Definition Data Type Enumerated Values
1 audiomd audio_block_size Size of an audio block in bytes. Large signed number NONE
2 audiomd audio_data_encoding Structure for audio data; current known types are pulse code modulation (PCM) and SONY's DSD structure. Suggested Enumerated Type NONE
3 audiomd bits_per_sample Number of bits per audio sample, e.g., 16, 20, 24, etc. Large signed number NONE
4 audiomd calibration_ext_int Indicator that the calibration information is contained within the file or externally. SBCS(255) NONE
5 audiomd calibration_location Temporary location of the calibration file if it is external, e.g. URL. SBCS(255) NONE
6 audiomd calibration_type Type of calibration, e.g., the ITU test sequences known as CCITT 0.33.00 (mono) and CCITT 0.33.01 (stereo). SBCS(255) NONE
7 audiomd data_rate Data rate of the audio in an MP3 or other compressed file, expressed in kbps, e.g., 64, 128, 256, etc. Large signed number NONE
8 audiomd data_rate_mode Indicator whether the data rate is fixed or variable. Enumerated Type Fixed, Variable
9 audiomd duration Elapsed time of the entire file, expressed using ISO 8601 syntax; see http://www.w3.org/TR/NOTE-datetime. SBCS(255) NONE
10 audiomd first_sample_offset Location of the first valid sound byte in the file. Large signed number NONE
11 audiomd first_valid_byte_block Location of the first valid sound byte in the block. Large signed number NONE
12 audiomd last_valid_byte_block Location of the last valid sound byte in the block. Large signed number NONE
13 audiomd note Additional information or comments about the audio file. SBCS(2000) NONE
14 audiomd num_channels Number of audio channels, e.g., 1, 2, 4, 5, etc. See also sound_channel_map. Large signed number NONE
15 audiomd sampling_frequency Rate at which the audio was sampled, expressed in kHz, e.g., 22, 44.1, 48, 96, etc. Large signed number NONE
16 audiomd sound_channel_map Information about the channel configuration, e.g., mapping the audio channel to their intended aural position/loudspeakers. The values represent parseable compound metadata using commas as separators, e.g., 1=left_front, 2=right_front, 3=center, 4=left_ Suggested Enumerated Type NONE
17 audiomd sound_field Indicates aural space arrangement of the sound recording, e.g., monaural, stereo, joint stereo, surround sound DTS 5.1, etc. MAVIS codes exist. Suggested Enumerated Type NONE
18 audiomd word_size Number of bytes that comprise a single sample of audio data, which generally maps to bits_per_sample. Files with a bit depth of 24 will usually be expressed as a 3-byte word_size; however, some applications may store 24-bit audio in a 4-byte word. Large signed number NONE
2/25/03
Library of Congress
Comments: AV Prototype Coordinator (cfle@loc.gov)
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( August 31, 2010 )