Digital recording formats
Television video equipment using digital tape recording methods has been supplied for several years.
However, the majority of television workers in the world still do not have a sufficiently clear idea of what a “digital” is, why it is needed and if it is worth working on it. The media specializing in television technology have focused on image quality, comparing the quality of digital formats, digital compression, artifacts, etc. Communication with television engineers shows that negative opinion often comes from the experience of working in incorrect settings, faulty equipment, or due to ignorance of the features and subtleties of the latest technology. That is why those who are now dedicated to television continue to be confused with the new concepts and prefer to use the old Betacam SP or the inferior, but familiar S-VHS. And some television executives, wanting to keep up and trying to make sense of the new teams, get misconceptions due to lack of information and focus their attention on insignificant details, missing highly profitable opportunities. Meanwhile, digital formats are developing rapidly, the range of relevant equipment is expanding,
So, in the process of developing video recording formats, the following main features have been improved:
– picture quality;
– operational capabilities;
– recording density and cost of 1 minute of recording;
– weight and size parameters of the videotape;
– the cost of purchasing and operating the equipment.
Image quality
Image quality generally refers to resolution, that is, the number of vertical lines reproduced. Of course, this is a cursory assessment, as there are many other, no less important parameters that are as perceptible to the human eye as the readability of the line. This review will also take into account the signal-to-noise ratio of the path, the quality of the composite, Y / C and component encoders / decoders, the effectiveness of the fight against tape drops. To a large extent, the evaluation of this parameter was quite subjective.
Operational capabilities
This concept includes everything related to the operation of the device in the system, operational functions, ease of use, integration capabilities, presence of interfaces and inputs and outputs, certain configuration characteristics, etc.
Recording density, cost per minute of recording, and video tape size and weight parameters
These are important parameters for the video recording format. They take into account three factors: the size and weight of the videotape, the duration of the recording, and the unit cost of one minute of recording. The higher the capacity of the cassette and / or the smaller its size, and / or the lower the unit cost, the higher the estimate.
Expenses
This parameter takes into account the cost of equipment, maintenance and spare parts. According to our system, a high score corresponds to a lower total cost of ownership and maintenance of equipment of one format or another.
In each new video format, developers strive to improve these indicators, but improvement in one indicator often occurs at the expense of others. But it must be admitted that the total level of indicators for all categories is growing from format to format.
Let us consider the video formats that are used in television centers in our country. Format features are rated on a 10-point scale, with ratings in parentheses after each feature. The effectiveness of the format will be determined by the total score.
Analog formats
Format Q (Ampex, NZTM)
Home television switched to video recording, using Q-format Kadr-3PM video recorders, using 2 “wide tape videotape as the carrier. Naturally, there was no Q-format camcorder at all. : mobile TV stations and cameras Format features:
1. The Q format provides high image quality (6 MHz bandwidth). Signal / noise ratio 40 dB. A complete composite video signal is recorded on tape in the SECAM standard, so no transcoding is required for broadcast playback. (Score 8)
2. The opportunities are minimal. VCRs can only be used by qualified engineers; preparing for playback requires at least five minutes of careful adjustment of the CAP modes and parameters of each of the four video heads. There is no search for an image with preview, markup editing is done in motion only.
