2-pop
Encyclopedia
Used in television production and filmmaking
post-production
, a 2-pop is a 1 kHz tone that is one frame
long and placed 2 seconds before the start of program. It is a simple and effective method of ensuring synchronization between sound and picture in a video or film.
A 2-pop is typically placed at the end of a visual countdown. Only the first frame of the "2" is shown, and the remainder of the 2 seconds prior to the program is black. This provides a unique point of reference where the frame-long image and frame-long sound should align, similar to the way a film clapperboard
is used to generate a synchronization point.
For example, in a video program the first frame of action (FFOA) starts at one hour (typically timecode
of 01:00:00:00 in the US, and 10:00:00:00 in the UK), preceding that, 1 frame (or the 2-pop) of tone would be placed at timecode 00:59:58:00 or exactly 2 seconds before first picture.
A 2-pop is useful whenever picture and sound are handled separately. For example, projecting work-in-progress in the pre-video days involved a film projector linked to a magnetic dubber
, onto which the separate soundtrack reel was loaded. Aligning them by the 2-pop would ensure proper synchronization during playback. A modern scenario would involve sending a soundtrack to a separate facility for a sound mix. The returned product is a computer audio file which then needs to be synchronized again with the picture.
levels on the tape, the 2-pop is primarily used for picture and sound synchronization
. Therefore, while the loudness
of the 2-pop may be the same as the bars and tone audio level in use, this is not a requirement. The loudness level should be sufficient to be heard clearly.
Filmmaking
Filmmaking is the process of making a film, from an initial story, idea, or commission, through scriptwriting, casting, shooting, directing, editing, and screening the finished product before an audience that may result in a theatrical release or television program...
post-production
Post-production
Post-production is part of filmmaking and the video production process. It occurs in the making of motion pictures, television programs, radio programs, advertising, audio recordings, photography, and digital art...
, a 2-pop is a 1 kHz tone that is one frame
Film frame
In filmmaking, video production, animation, and related fields, a film frame or video frame is one of the many still images which compose the complete moving picture...
long and placed 2 seconds before the start of program. It is a simple and effective method of ensuring synchronization between sound and picture in a video or film.
A 2-pop is typically placed at the end of a visual countdown. Only the first frame of the "2" is shown, and the remainder of the 2 seconds prior to the program is black. This provides a unique point of reference where the frame-long image and frame-long sound should align, similar to the way a film clapperboard
Clapperboard
A clapperboard is a device used in filmmaking and video production to assist in the synchronizing of picture and sound, and to designate and mark particular scenes and takes recorded during a production...
is used to generate a synchronization point.
For example, in a video program the first frame of action (FFOA) starts at one hour (typically timecode
SMPTE time code
SMPTE timecode is a set of cooperating standards to label individual frames of video or film with a time code defined by the Society of Motion Picture and Television Engineers in the SMPTE 12M specification...
of 01:00:00:00 in the US, and 10:00:00:00 in the UK), preceding that, 1 frame (or the 2-pop) of tone would be placed at timecode 00:59:58:00 or exactly 2 seconds before first picture.
A 2-pop is useful whenever picture and sound are handled separately. For example, projecting work-in-progress in the pre-video days involved a film projector linked to a magnetic dubber
Reel-to-reel audio tape recording
Reel-to-reel, open reel tape recording is the form of magnetic tape audio recording in which the recording medium is held on a reel, rather than being securely contained within a cassette....
, onto which the separate soundtrack reel was loaded. Aligning them by the 2-pop would ensure proper synchronization during playback. A modern scenario would involve sending a soundtrack to a separate facility for a sound mix. The returned product is a computer audio file which then needs to be synchronized again with the picture.
Sample sound
Whereas laying down bars and tone prior to program start establishes video and audio calibrationCalibration
Calibration is a comparison between measurements – one of known magnitude or correctness made or set with one device and another measurement made in as similar a way as possible with a second device....
levels on the tape, the 2-pop is primarily used for picture and sound synchronization
Synchronization
Synchronization is timekeeping which requires the coordination of events to operate a system in unison. The familiar conductor of an orchestra serves to keep the orchestra in time....
. Therefore, while the loudness
Loudness
Loudness is the quality of a sound that is primarily a psychological correlate of physical strength . More formally, it is defined as "that attribute of auditory sensation in terms of which sounds can be ordered on a scale extending from quiet to loud."Loudness, a subjective measure, is often...
of the 2-pop may be the same as the bars and tone audio level in use, this is not a requirement. The loudness level should be sufficient to be heard clearly.