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CTL Timecode
Control track longitudinal timecode, or CTL timecode, developed by JVC in the early 1990s, is a unique technique for embedding, or ''striping'', reference SMPTE timecode onto a videotape. Similar to the way VITC timecode is embedded in the vertical interval area of a video signal, CTL timecode embeds SMPTE timecode in the '' control track'' area of helical scan video recordings. The advantage of both VITC and CTL timecode is that an audio track does not have to be sacrificed for linear timecode. Though a very effective technology, and still probably in limited use today, CTL timecode never really caught on. JVC is apparently the only manufacturer that included CTL timecode capability in their video products, and this was limited to select professional S-VHS equipment. When it was introduced, there was much negativity about CTL timecode, because people misunderstood how it worked. Many incorrectly assumed that CTL timecode was nothing more than a ''control track pulse'' signal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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SMPTE Timecode
SMPTE timecode ( or ) is a set of cooperating standards to label individual frames of video or film with a timecode. The system is defined by the Society of Motion Picture and Television Engineers in the SMPTE 12M specification. SMPTE revised the standard in 2008, turning it into a two-part document: SMPTE 12M-1 and SMPTE 12M-2, including new explanations and clarifications. Timecodes are added to film, video or audio material, and have also been adapted to synchronize music and theatrical production. They provide a time reference for editing, synchronization and identification. Timecode is a form of media metadata. The invention of timecode made modern videotape editing possible and led eventually to the creation of non-linear editing systems. Basic concepts SMPTE timecode is presented in ''hour:minute:second:frame'' format and is typically represented in 32 bits using binary-coded decimal. There are also ''drop-frame'' and ''color framing'' flags and three extra ''bin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Control Track
A control track is a track that runs along an outside edge of a standard analog videotape (including VHS). The control track encodes a series of pulses, each pulse corresponding to the beginning of each frame. This allows the video tape player to synchronize its scan speed and tape speed to the speed of the recording. Thus, the recorded control track defines the speed of playback (e.g. SP, LP, EP, etc.), and it is also what drives the relative counter clock that most VCRs have. Significance and use The control track is used to fine-tune the tape speed during playback, so that the high speed rotating heads remained exactly on their helical tracks rather than somewhere between two adjacent tracks (known as "tracking"). Since good tracking depends on precise distances between the rotating drum and the fixed control/audio head reading the linear tracks, which usually varies by a couple of micrometers between machines due to manufacturing tolerances, most VCRs offer tracking ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Helical Scan
Helical scan is a method of recording high-frequency signals on magnetic tape, used in open-reel video tape recorders, video cassette recorders, digital audio tape recorders, and some computer tape drives. With this technique, magnetic tape heads (or head chips) are placed on a rotating head drum, which moves the chips at high speed by due to its high angular velocity. The speed of the head chips must be higher than the linear speed of the tape. The tape is wrapped tightly around the drum. The drum and/or the tape is tilted at an angle that allows the head chips to read the tape diagonally. The linear speed of the tape is slower than the speed of the head chips, allowing high frequency signals to be read or recorded, such as video. As the tape moves linearly or length-wise, the head chips move across the width of the tape in a diagonal path. Due to geometry, this allows for high head chip speeds, known as writing speeds, to be achieved in spite of the low linear speed of the tap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Linear Timecode
Linear (or Longitudinal) Timecode (LTC) is an encoding of SMPTE timecode data in an audio signal, as defined in SMPTE 12M specification. The audio signal is commonly recorded on a VTR track or other storage media. The bits are encoded using the biphase mark code (also known as ''FM''): a 0 bit has a single transition at the start of the bit period. A 1 bit has two transitions, at the beginning and middle of the period. This encoding is self-clocking. Each frame is terminated by a 'sync word' which has a special predefined sync relationship with any video or film content. A special bit in the linear timecode frame, the ''biphase mark correction'' bit, ensures that there are an even number of AC transitions in each timecode frame. The sound of linear timecode is a jarring and distinctive noise and has been used as a sound-effects shorthand to imply ''telemetry'' or ''computers''. Generation and Distribution In broadcast video situations, the LTC generator should be tied into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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S-VHS
S-VHS, the common initialism for Super VHS, is an analog video cassette format introduced by JVC in 1987 as an improved version of the VHS (Video Home System) format. S-VHS improved image quality by increasing the bandwidth of the luminance (brightness) signal, allowing for a horizontal resolution of approximately 400 lines, compared to the 240 lines typical of VHS. The format used the same physical cassette shell as VHS but required higher-grade magnetic tape and compatible recording and playback equipment. S-VHS decks are backward-compatible with standard VHS tapes, allowing them to play and record in VHS format. However, S-VHS tapes generally cannot be played in VHS-only machines, due to differences in the signal encoding. Despite its technical advantages, S-VHS struggled to gain widespread consumer adoption due to the higher cost of equipment and tapes, along with the limited availability of pre-recorded content. The format found moderate success in professional, educa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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AES-EBU Embedded Timecode
AES3 is a standard for the exchange of digital audio signals between professional audio devices. An AES3 signal can carry two channels of pulse-code-modulated digital audio over several transmission media including balanced lines, unbalanced lines, and optical fiber. AES3 was jointly developed by the Audio Engineering Society (AES) and the European Broadcasting Union (EBU) and so is also known as AES/EBU. The standard was first published in 1985 and was revised in 1992 and 2003. AES3 has been incorporated into the International Electrotechnical Commission's standard IEC 60958, and is available in a consumer-grade variant known as S/PDIF. History and development The development of standards for digital audio interconnect for both professional and domestic audio equipment, began in the late 1970s in a joint effort between the Audio Engineering Society and the European Broadcasting Union, and culminated in the publishing of AES3 in 1985. The AES3 standard has been revised in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Burnt-in Timecode
Burnt-in timecode (often abbreviated to BITC by analogy to VITC) is a human-readable on-screen version of the timecode information for a piece of material superimposed on a video image. BITC is sometimes used in conjunction with "real" machine-readable timecode but more often used in copies of original material onto a nonbroadcast format such as VHS so that the VHS copies can be traced back to their master tape and the original timecodes easily located. Many professional VTRs can "burn" (overlay) the tape timecode onto one of their outputs. This output (which usually also displays the setup menu or on-screen display) is known as the ''super out'' or ''monitor out''. The ''character'' switch or menu item turns this behaviour on or off. The ''character'' function also displays the timecode on the preview monitors in linear editing suites. Videotapes that are recorded with timecode numbers overlaid on the video are referred to as ''window dubs'', named after the "window" that di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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MIDI Timecode
MIDI time code (MTC) embeds the same timing information as standard SMPTE timecode as a series of small 'quarter-frame' MIDI messages. There is no provision for the user bits in the standard MIDI time code messages, and SysEx messages are used to carry this information instead. The quarter-frame messages are transmitted in a sequence of eight messages, thus a complete timecode value is specified every two frames. If the MIDI data stream is running close to capacity, the MTC data may arrive a little behind schedule which has the effect of introducing a small amount of jitter. In order to avoid this it is ideal to use a completely separate MIDI port for MTC data. Larger full-frame messages, which encapsulate a frame worth of timecode in a single message, are used to locate to a time while timecode is not running. Unlike standard SMPTE timecode, MIDI timecode's quarter-frame, and full-frame messages carry a two-bit flag value that identifies the rate of the timecode, specifying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Rewritable Consumer Timecode
The Rewriteable Consumer Timecode (RCTC, RC Timecode, or RC Time Code) is a nearly frame accurate timecode method developed by Sony for 8mm and Hi8 analog tape formats.Sony CCD-V801 Manual Page 9 covers RC Timecode and Data Code formats. The RC timecode tags each frame with the hour, minute, second and frame for each frame of video recorded to tape. Officially, RCTC is accurate to within ±2 to 5 frames. The RC timecode can be used in conjunction with the datacode to record the date and the time. The data and RC codes are written between the video and the PCM audio tracks. It may be added to any 8-mm tape without altering the information already on the tape, and is invisible to machines not equipped to read it. On several video camera models, |