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Explore filmmaking terms starting with 7, from 70mm film and 720p video to 75-ohm cable and immersive-sound layouts. Many are equipment or signal specifications, where the number is useful only when you also know the format, connection or channel arrangement.
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7.1 Surround Sound
A sound format with seven main channels plus a low-frequency effects channel. A common layout adds separate rear surrounds to the left, centre, right and side-surround channels of a 5.1 arrangement. Other historical 7.1 configurations exist, so channel names and routing matter as much as the count. Seven main channels do not automatically mean overhead sound or an Atmos mix. See 7.1.4.
7.1.2
In speaker-layout notation, seven ear-level channels, one LFE channel and two height positions. In Dolby Atmos production, 7.1.2 can also describe a channel-based bed inside a larger mix. A bed’s channels and a room’s physical loudspeakers are different things; the notation does not tell you the number of audio objects. Confirm whether the discussion concerns a mix bed, monitoring layout or delivery specification.
7.1.4 Speaker Layout
A monitoring or playback layout with seven ear-level channels, one low-frequency effects channel and four overhead positions. The last number identifies the height layer. It describes the listening arrangement, not a fixed maximum number of objects in an Atmos production. The LFE channel can feed more than one physical subwoofer, and bass-management arrangements are separate. Compare 7.1.2.
7.5 IRE Setup
A historical analogue NTSC black-level pedestal used in North America and some other territories, placing black above the 0 IRE blanking reference. It was not universal across all NTSC systems. Digital component video and modern file workflows should not receive a blanket 7.5 IRE offset merely because a project uses a fractional NTSC-derived frame rate. Follow the actual signal specification and monitor configuration. See 0 IRE and colour bars.
7K Resolution
A camera-resolution label for an image with roughly seven thousand horizontal pixels. One cinema-camera implementation uses 7168 × 3780, but that is an example rather than a universal delivery standard. The selected mode may crop a larger sensor and change field of view or available frame rates. Specify the actual raster, crop and codec rather than assuming every “7K” setting behaves identically. Compare 6K and 8K.
70mm Film
A large-format release-print gauge commonly associated with photography on 65mm negative. The extra width historically allowed room for sound information beside the picture. Conventional vertical 5-perf and horizontal 15-perf IMAX presentations use different frame arrangements and image sizes. “70mm” therefore does not identify one aspect ratio, camera or projection system. Confirm the capture format and exhibition format separately.
720p
A progressive HD video format with 720 picture lines, conventionally 1280 × 720 pixels in a 16:9 image. The “p” means progressive scanning; it does not state the frame rate. A 720p50 feed and a 720p59.94 feed have different timing and must be supported by the connected equipment. Resolution alone is not enough information to configure a complete video signal path. Compare 4K.
75mm Tripod Bowl
A tripod interface with a nominal 75mm bowl, used with a compatible half-ball head or levelling adaptor. It allows the head to be levelled without repeatedly adjusting all the legs. Bowl diameter is an interface size, not a payload rating. The head, legs, attachment method and camera package must be compatible; a 100mm head does not directly become a 75mm system without suitable hardware.
75-Ohm Video Cable
A coaxial video cable with a nominal characteristic impedance of 75 ohms, used in SDI and other video systems. Characteristic impedance is not the same as measuring end-to-end DC resistance with a multimeter. A BNC connector can fit without proving the cable is suitable for the required data rate or distance. Use cable and connectors rated for the actual 3G-SDI, 6G-SDI or other signal being carried.
Signal paths, camera supports and sound layouts all depend on compatible components and clear communication. Check the complete specification before treating matching numbers as matching equipment. Continue with terms starting with 8, or return to the filmmaking dictionary.
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