Technicolor DTMF sequences: Difference between revisions
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Many videotapes duplicated at [[Technicolor Video Services]] in Livonia using either industrial duplicators or Otari TMD systems, beginning in 1989 and ending in 2006, included a sequence of DTMF tones at the start and/or end of the tape. It is not yet known exactly what each tone in the sequence indicates, except there's usually a pause between the first and second tones, the second tone is always 1, the third tone is always #, and the fourth tone is always D. This sequence was used to encode audio and video on the master tape by providing information on settings such as format, running time, audio level balance, volume control, etc. to the duplication machines, allowing better replication. On most tapes, the tones are audible on the left channel of the hi-fi audio track. However, on some tapes, the tones are audible either on the right channel of the hi-fi track or exclusively on the linear audio track. Disney videotapes are the most notable tapes to use these sequences. |
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For a list of tapes using variations of these sequences, see [[Technicolor test patterns]]. |
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== Video examples == |
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# [https://www.youtube.com/watch?v=CrMiiNdjnbY Spooky!! Phone dialing sound on Disney VHS tapes!?] |
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# [https://www.youtube.com/watch?v=0LyLq_cmetM VHS Phone Dialing Sound] |
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# [https://www.youtube.com/watch?v=-6ygY98jq64 VHS Dialing Sound Effect] |
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# [https://www.youtube.com/watch?v=hzv3ZQQF78A&list=PLKcNH5J_u70wzF2JxfsCCuB5g1-7V13XW&index=39 Creepy Phone Dialing in the beginning of Disney VHS tapes] |
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Latest revision as of 14:59, 6 May 2024
Many videotapes duplicated at Technicolor Video Services in Livonia using either industrial duplicators or Otari TMD systems, beginning in 1989 and ending in 2006, included a sequence of DTMF tones at the start and/or end of the tape. It is not yet known exactly what each tone in the sequence indicates, except there's usually a pause between the first and second tones, the second tone is always 1, the third tone is always #, and the fourth tone is always D. This sequence was used to encode audio and video on the master tape by providing information on settings such as format, running time, audio level balance, volume control, etc. to the duplication machines, allowing better replication. On most tapes, the tones are audible on the left channel of the hi-fi audio track. However, on some tapes, the tones are audible either on the right channel of the hi-fi track or exclusively on the linear audio track. Disney videotapes are the most notable tapes to use these sequences.
For a list of tapes using variations of these sequences, see Technicolor test patterns.