46 results about "SECAM" patented technology

An audio/video production system facilitates professional quality image manipulation and editing using an enhanced general-purpose hardware. A program input may be translated into any of a variety of graphics or television formats, including NTSC, PAL, SECAM and HDTV, and stored as data-compressed images, using any of several commercially available methods such as Motion JPEG, MPEG, etc. While being processed, the images may be re-sized to produce a desired aspect ratio or dimensions using conventional techniques such as pixel interpolation. Frame rate conversion to and from conventional formats is performed by using the techniques employed for film-to-NTSC and film-to-PAL transfers, or by inter-frame interpolation, all well known in the art. By judicious selection of the optimal digitizing parameters, the system allows a user to establish an interrelated family of aspect ratios, resolutions, and frame rates, yet remain compatible with currently available and planned graphics and television formats.

A SECAM video signal is decoded by selecting different combinations of chrominance signals according to the luminance difference between the current line and the preceding line. The chrominance signals from the current line and the preceding line are selected when this difference is smaller than a threshold. The chrominance signals from the current line and the next line are selected when the difference is greater than the threshold. The average value of the chrominance signals in the preceding and following lines may be calculated and selected in place of the chrominance signal from the preceding line.

We describe an apparatus and method for decoding a SECAM chrominance signal. The apparatus may include a band-pass filter to separate the chrominance signal from the composite video baseband signal. A down-mixer down mixes the chrominance signal from a high to a low frequency band to generate two signals having a substantially 90° phase difference. A cloche filter filters the two signals. A differentiator differentiates the cloche filtered signals. A multiplier squares each differentiated signal. An adder sums the squared result while a square root takes the square root of the sum.

In a receiver capable of receiving a plurality of television systems, a color transmission system discrimination circuit is provided, which is capable of exactly and rapidly determining a color transmission system which is being received. The color transmission system discrimination circuit includes: a killer state change detection circuit 23 for detecting a change in three kinds of color killer signals corresponding to a burst signal component in a 90° phase, a burst signal component in a 180° phase, and a SECAM discrimination signal; a sequencer 22 which is driven with an output signal of the killer state change detection circuit 23 and performs the first, second, and third stages in this order respectively for a predetermined period of time; first latch circuits 29 to 31 for latching the color killer signal captured in the first stage; second latch circuits 32 and 33 for latching the color killer signal captured in the second stage; and a discrimination decoder 34 for outputting a discrimination signal of a color system and a discrimination signal of a frequency of a reference sub-carrier signal, based on the color killer signal captured in the third stage and the output signals of the first and second latch circuits 29 to 33.

A time-based, digital FM demodulator circuit receives a stream of digital samples corresponding to an analog FM waveform. The samples are provided to a zero crossing detector, which allows a counter to determine a number of clock cycles between zero crossings. The resolution of this coarse period determination is further refined by an intercept calculation, which further localizes the zero crossing of the FM waveform based on interpolation between samples on either side of the zero crossing. Accuracy of the period determination may be further enhanced by use of a sinusoidal correction filter, which minimizes error caused by the linear interpolation performed on the sinusoidal waveform. Although the FM demodulator circuit is particularly suitable for demodulation of the chroma component of a SECAM video signal, it may advantageously be applied in a wide variety of FM demodulation applications.

An apparatus for recovering a chrominance signal from a sequential color with memory (SECAM) composite video baseband signal (CVBS), and more particularly, an apparatus and method of recovering a SECAM chrominance signal to simplify a circuit configuration of a frequency demodulator since a phase different calculation scheme is simplified is provided. The apparatus for recovering a chrominance signal from a CVBS includes: a frequency demodulator calculating a phase difference between neighboring samples by using an arctangent approximation from an input signal; and a direct current (DC) compensation unit eliminating a DC offset from the calculated phase difference, wherein the phase difference corresponds to the chrominance signal.

A video signal processing circuit. includes: a bell table, a first switch, a carrier generating unit, a second switch and a calculation processing unit. The bell table inputs a color difference signal to output a modulation signal having an amplitude defined by the SECAM Standard of the color difference signal. The first switch selects one of the color difference signal and the modulation signal to output a first signal. The carrier generating unit inputs the color difference signal to generate a carrier signal having a frequency defined by the SECAM Standard of the color difference signal. The second switch selects one of the carrier signal and a carrier signal having frequency defined by the PAL Standard and/or the NTSC Standard to output a second signal. The calculation processing unit calculates the first and second signals to output a color difference modulation signal.

The invention discloses a streaming media playing method based on a DireotShow platform, which comprises the following steps of: selection of a video system, in which a system of a video stream input source is identified, the identified system is compared with a system of an initial input source, an equipment controller stops working if the system has been changed, equipment parameters are modified to ensure that the system is the same as that of the corresponding input source, and video steam continues to be transmitted according to the modified system standard; and selection of a sound system, in which an original sound is produced according to each country code with a PAL or SECAM system during channel scanning, each original sound corresponds to a frequency, a plurality of the sounds and a plurality of the frequencies form a channel list, whether the system of the video stream input source is the PAL or SECAM system is judged, if so, the sound corresponding to the frequency which corresponds to the country code is read from the channel list according to the country code corresponding to the video stream input source, and is sent to a current equipment drive, and corresponding audio is modulated by current equipment.

When a video signal type detection section detects a video signal of the PAL method or the SECAM method (50Hz), it subjects the input image data to emphasis conversion processing with a smaller emphasis conversion degree than the NTSC method (60Hz), thereby improving the liquid crystal response speed, preventing generation of a video noise by excessive emphasis, and suppressing the image deterioration. As a result, it is possible to perform emphasis conversion for the input image data so as to compensate the optical response characteristic of the liquid crystal display panel and to prevent generation of a video noise by an excessive emphasis conversion for the image data of the PAL method or the SECAM method (50 Hz), thereby displaying a high-quality image.

The key component of a digital PAL or NTSC color decoder is a quadrature demodulator for these AM modulated signals. For a SECAM color decoder, however, an FM demodulation is required which is conventionally implemented using a Hilbert filter which is followed by a CORDIC processor and a differentiation stage. It would be advantageous if for multi-standard applications a general-purpose color demodulator for PAL, NTSC and SECAM systems could be implemented on one chip having as much as possible common demodulation processing stages. According to the invention a single common quadrature mixer is used for all three color systems. A resulting bias effect caused by the use of a single mixing frequency is corrected in a clamping stage. The bias effect can also be used for line identification.

The invention provides a system for reconstructing chroma of a television signal, a brightness chroma separation and color decoding device in the system generates brightness and color difference corresponding to a Kth pixel in the (N+1)th image line via filtration of the television signal. A first line buffer device temporarily stores the brightness of the Kth pixel in at least one adjacent image line prior to the (N+1)th image line. A second line buffer device temporarily stores the color difference of the Kth pixel in the Nth and the (N-1)th image line. A vertical direction similarity calculation device generates, in accordance with the brightness corresponding to the Kth pixel in the (N+1)th image line and the (N-1)th image line, an upper similar parameter and a lower similar parameter. The reconstruction device implements weighting to color difference signals of the (N+1)th image line and the (N-1)th image line by taking the upper similar parameter and the lower similar parameter as weights, so as to obtain a reconstruction color difference signal of the Kth pixel in the Nth image line. The invention also provides a method for reconstructing chroma of a television signal, the color difference signal can be reconstructed precisely in a SECAM television system using the invention.

The embodiment of the invention discloses an SECAM (Sequential Colour and Memory) system detection method which comprises the following steps of: inputting video signals line by line; setting a window in a color synchronization signal area of each line of video signals, and grouping every six adjacent lines of video signals as one; in the window area, adding data of every two lines of odd-numbered lines or even-numbered lines in each group to obtain three sum values, judging whether the amplitude of the three sum values satisfies two small values and one big value, voting for the satisfaction condition of the three sum values, judging whether one value is larger than the other two in three voting values M1, M2 and M3 and the difference of the other two is larger than a set threshold value, if yes, the current system is an SECAM system. The invention further discloses a corresponding SECAM system detection device. The method and device disclosed by the invention are simpler and can be realized conveniently.