TWI406561B - Video processor and its automatic selection filter of the video filter driver - Google Patents

Abstract

Disclosed is a video filter driving apparatus automatically selecting a filter, which comprises a signal format judging unit, a first video signal filtering unit, a second video signal filtering unit, and a third video signal filtering unit. The signal format judging unit receives a first video signal and detects the frequency of its horizontal synchronous signal as a first frequency or a second frequency, and sends out a control signal. The first, second and third video signal filtering units separately include a filter set having a first filter and a second filter and a change-over switch. Each change-over switch controls, according to the control signal, the video signal to be inputted into the first filter or the second filter, so as to carry out filtration towards the video signal. In addition, the present invention also provides a video processor having the abovementioned video filter driving apparatus.

Description

Video processor and video filter driver for its automatic selection filter

The invention relates to a driving device, in particular to a video filter driving device capable of automatically detecting a format and automatically switching a filter according to a format.

With the pursuit of high image quality in the era, high-quality original sound reproduction is the ultimate demand for human visual sense. Therefore, video processing technology has evolved from the analog technology to the current digital technology. Moreover, in terms of video signal format, it is also developed from Standard-Definition (SD) to High Definition (HD), in which the standard image quality (SD) video signal format contains composite (Composite). ) Signals, S-Video (Y/C) signals, etc., and high-definition (HD) video signal formats include DVI and HDMI. However, the TV (TV) and player (Player) currently used by the public do not necessarily support high-definition video signal formats, so existing TVs or players must be designed. Handle various video signal formats and backward compatibility.

Referring to FIG. 1, for the main chip 1 of the television and the player, in order to satisfy various video signal formats, it is necessary to simultaneously support various image resolution formats to ensure the elasticity and phase of the actual application. Capacitance. The current common video signal formats include CVBS+S-Video (Y/C) for SD video signals and R/G/B or Y/Pb/Pr for HD video signal formats, and are internal to Main chip 1. The video decoder 11 synthesizes an analog video signal output through a digital analog converter (DAC) 12 in the form of digital data. Therefore, in terms of video signal output, in order to output the currently widely used video signal format, the main chip The video decoder 11 of (Main chip) 1 needs to be equipped with six sets of digital analog converters (DACs) 12 at the same time, and the external video filter driver (Video Filter Driver) 2 must have six separate analog converters for each digital bit. 12 video signal filtering unit, and since the SD video signal format is different from the video signal filtering unit required for the HD video signal, the video signal filtering unit is divided into an SD video signal filtering unit 21 that accepts CVBS, Y, C inputs, and The HD video signal filtering unit 22 that accepts the R/G/B or Y/Pb/Pr input.

Further, referring to FIG. 2, the SD video signal filtering unit 21 has a DC Clamping 211, a low-pass filter (LPF) 212 with an analog bandwidth of 9 MHz, and a 6 dB gain mode. Group 213. Referring to FIG. 3, the HD video signal filtering unit 22 has a DC Clamping 221, a low-pass filter (LPF) 222 having an analog bandwidth of 36 MHz, and a 6 dB gain module 223. . In contrast, the difference between the SD video signal filtering unit 21 and the HD video signal filtering unit 22 is only that the frequency cutoff points of the low pass filters of the two are different (that is, the bandwidth is different), but the difference is caused by the television and the playback. The cost of the device increases and the space is wasted. For example, if the output video signal is CVBS+S-Video(Y/C), only three digital analog converters 12 and three SD video signal filtering units 21 are actually used at the same time. On the other hand, if the output video signal is R/G/B, only three digital analog converters 12 and three HD video signal filtering units 22 are actually used at the same time, which means that the video signal format of the output is SD. Or HD will have three digital analog converters 12 and three video signal filtering units not used.

In view of this, if the SD video signal filtering unit 21 and the HD video signal filtering unit 22 can be integrated, the cost and space of the main chip and the video filter driving device of the TV and the player can be effectively reduced. The direction to be solved.

Accordingly, it is an object of the present invention to provide a video filter driving apparatus that automatically selects a filter.

Therefore, the video filter driving device of the present invention can receive a first video signal, and includes a signal format determining unit and a first video signal filtering unit. The signal format determining unit receives the first video signal, and includes a synchronization signal separation module and a frequency detection module. The synchronization signal separation module separates a synchronization signal component from the first video signal; the frequency detection module is coupled to the synchronization signal separation module and receives the synchronization signal component, and the frequency detection module is configured to detect The frequency of the synchronization signal component is a first frequency or a second frequency, and a control signal is issued. The first video signal filtering unit includes a filter bank and a switch. The filter bank has a first filter and a second filter; the switch is coupled to the frequency detection module and the filter bank, and receives the first video signal and the control signal, and the switch is controlled according to the control The signal controls the first video signal to be input to one of the first filter or the second filter to filter the first video signal.

Preferably, the synchronization signal component is a horizontal synchronization signal.

Preferably, the signal format determining unit further includes a luminance chrominance separation module configured to separate the luminance signal in the video signal and coupled to the synchronization signal separation module, and the first video signal passes the synchronization signal Before the module is separated, the brightness chroma separation module is first passed.

Preferably, when the frequency detecting module detects that the frequency of the synchronization signal component is the first frequency, the control signal is a low potential signal, and the switching switch controls the first video signal input to the first The filter performs filtering; when the frequency detecting module detects that the frequency of the synchronization signal component is the second frequency, the control signal is a high potential signal, and the switching switch controls the first video signal input to the first The second filter performs filtering.

Preferably, the video filter driving device further includes a second video signal filtering unit for processing a second video signal, the second video signal filtering unit includes the filter group and the switching switch, and the switching switch is coupled. Connecting the frequency detecting module and the filter bank, and receiving the second video signal and the control signal, the switching switch controls the second video signal to input the first filter or the second filter according to the control signal One of them filters the second video signal. In addition, the video filter driving device further includes a third video signal filtering unit for processing a third video signal, the third video signal filtering unit includes the filter group and the switching switch, and the switching switch is coupled to the a frequency detecting module and the filter group, and receiving the third video signal and the control signal, wherein the switching switch controls the third video signal to input the first filter and the second filter according to the control signal First, filtering the third video signal.

Furthermore, the first video signal filtering unit, the second video signal filtering unit and the third video signal filtering unit respectively comprise a gain coupled to the filter group for increasing the intensity of the filtered video signal. Module. And the first video signal filtering unit, the second video signal filtering unit and the third video signal filtering unit respectively comprise a DC clamp circuit for clamping the signal to a DC level as a back-end line. The signal intercepts the reference voltage.

Preferably, the first frequency is a frequency of a horizontal synchronization signal in a standard image quality video signal, and the second frequency is a frequency of a horizontal synchronization signal in the high quality video signal.

Further, another object of the present invention is to provide a video processor having the above-described video filter driving device and which is cost-effective and space-saving.

The method of the present invention is to determine the video signal format of the first video signal by the signal format determining unit, and the first video signal filtering unit, the second video signal filtering unit and the third video signal filtering unit are based on the frequency detecting mode. The control signal sent by the group switches using different filters, thereby integrating the first filter and the second filter of different bandwidths into the same video signal filtering unit. Furthermore, the main chip only needs to be set correspondingly. The three digital analog converters save the cost and space of the video processor compared to conventional ones.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Referring to FIG. 4, a preferred embodiment of the video processor of the present invention is shown. The video processor is suitable for a television (TV) or a player (Player), and has a main chip 4 and a video filter driver 5, and a video filter driver. The device 5 serves to cooperate with the main wafer 4. The main chip 4 has a video decoder 41 and a first digital analog converter (DAC) 421 connected to the video decoder 41, a second digital analog converter (DAC) 422 and a third digital analog conversion. (DAC) 423. The video decoder 41 processes the video signal in the form of digital data, and the digital analog converters 421, 422, and 423 are used to convert the digital data output by the video decoder 41 into an analog video signal. Moreover, it can be seen from FIG. 4 that the video signal format output by the digital analog converters 421, 422, and 423 can be a set of standard picture quality (SD) video signals CVBS, Y, and C, or a group of high. Image quality (referred to as HD) video signal Y, Pb, Pr, or a set of SD / HD video signal G, B, R. For the following description, the signal output by the first digital analog converter 421 is defined as the first video signal S1, such as CVBS or Y or G; and the signal output by the second digital analog converter 422 is defined as the second video signal S2, such as Y or Pb or B; the signal output by the third digital analog converter 423 is defined as a third video signal S3, such as C or Pr or R.

Referring to FIG. 4, the video filter driving device 5 includes a signal format determining unit 50, a first video signal filtering unit 51 connected to the first digital analog converter 421, and a second video connected to the second digital analog converter 422. a signal filtering unit 52, and a third video signal filtering unit 53 connected to the third digital analog converter 423, wherein the first video signal filtering unit 51 receives the first video signal S1, and the second video signal filtering unit 52 receives the second The video signal S2, the third video signal filtering unit 53 receives the third video signal S3, and the above-described video signal filtering units 51-53 have the same configuration except that the received video signals are different. Furthermore, each of the video signal filtering units 51-53 is externally connected with a resistor 9 for impedance matching with the back-end line.

First, the present embodiment is characterized in that the filter bandwidth of the video signal is selected by using the SD video signal and the frequency of the horizontal sync signal of the synchronization signal in the HD video signal. Further, the frequency of the horizontal synchronization signal of the synchronization signal in the SD video signal is 15 kHz, and the frequency of the horizontal synchronization signal of the synchronization signal in the HD video signal is 45 kHz. Therefore, the present embodiment uses the SD video signal and the HD video signal. The frequency of the horizontal synchronizing signal is different to judge whether the video signal format is SD or HD, and thereby select a suitable filter, which is described in detail below.

Referring to FIG. 5, the signal format determining unit 50 of the video filter driving device 5 includes a chrominance chroma separation (Y/C separation) module 501 for receiving the first video signal S1, and a coupling luminance chromaticity separation. The Sync signal separation module 502 of the module 501, the frequency detection module 503 coupled to the synchronization signal separation module 502, and the level shift of the coupled frequency detection module 503 A level shift module 504, and each of the above modules is implemented by a circuit. In addition, it should be noted that, since the first video signal S1 (CVBS or Y or G) includes a synchronization signal, the first video output by the first digital analog converter 421 is buffered by a buffer (not shown). The signal S1 is divided into two separate input signal format determining units 50 and a first video signal filtering unit 51.

The luminance chroma separation module 501 receives the first video signal S1 and separates the luminance signal (Y) in the first video signal S1 (such as CVBS), but also does not function due to the difference of the video signal. For example, If the input first video signal S1 is Y or G, the luminance chrominance separation module 501 does not function. Then, the synchronization signal separation module 502 is configured to separate the synchronization signal in the first video signal S1 into a synchronization signal component (if the first video signal S1 is CVBS, the signal input to the synchronization signal separation module 502 is a luminance signal) In this embodiment, the synchronization signal component is a horizontal synchronization signal. In addition, a capacitor may be added in the synchronization signal separation module 502 to deform the output horizontal synchronization signal, so that the frequency detection module 503 can more easily recognize the frequency of the horizontal synchronization signal.

The frequency detecting module 503 receives the horizontal synchronization signal, and detects that the frequency of the horizontal synchronization signal is a first frequency (15 kHz) of an SD video signal format, or a second frequency (45 kHz) of an HD video signal format. And a control signal CS for controlling the video signal filtering units 51-53 is issued. In this embodiment, the frequency detecting module 503 detects that the horizontal control signal is at the first frequency, and causes the generated control signal to be low; the frequency detecting module 503 detects the level. When the frequency of the synchronization signal is the second frequency, the issued control signal is at a high potential, whereby when the control signal CS is at a high potential, the input video signal format is SD; when the control signal CS is at a low potential, the input is indicated. The video signal format is HD. The function of the level shift module 504 will be described later.

The first video signal filtering unit 51 of the video filter driving device 5 is first described. Referring to FIG. 5, the first video signal filtering unit 51 includes a DC clamping circuit coupled to the first digital analog converter 421. DC Clamping 601, a switch 602 coupled to the DC clamp circuit 601, a filter bank 603 coupled to the switch 602, and a Gain up module 604 coupled to the filter bank 603, And the above modules are implemented by circuits. The DC clamp circuit 601 is used to clamp the signal to a DC level as a signal for the back-end line to intercept the reference voltage. The filter bank 603 has a first filter 61 adapted to filter the SD video signal and a second filter 62 adapted to filter the HD video signal, the filter for passing the video signal (the first video signal S1) The noise is removed, and, in the present embodiment, the first filter is a low pass filter (LPF) having a bandwidth of 9 MHz, and the second filter is a low pass filter (LPF) having a bandwidth of 36 MHz. The changeover switch 602 receives the control signal CS from the signal format determination unit 50 to selectively switch to a suitable filter within the filter bank 603. In this embodiment, the switch 602 is a digital switch. When the control signal CS is low (that is, the first video signal S1 is in the SD format), the switch 602 is switched to the first suitable for the SD video signal. The filter 61; when the control signal CS is high (that is, the first video signal S1 is in the HD format), the switch 602 is switched to the second filter 62 suitable for the HD video signal. It is further noted that the level displacement module 504 is configured to adjust the potential of the control signal CS such that the high potential and the low potential of the control signal CS meet the switching criteria of the switch 602. Moreover, the filtered first video signal S1 is passed through the gain module 604 to increase its signal strength by about 6 db for impedance matching (eg, the TV input impedance is 75 ohm), but is not limited thereto.

Referring to FIG. 6, the difference between the second video signal filtering unit 52 and the first video signal filtering unit 51 is that the DC clamp circuit 601 of the second video signal filtering unit 52 receives the second video signal S2, and the rest of the configuration is the same as the function. Therefore, do not add more details. Referring to FIG. 7, the difference between the third video signal filtering unit 53 and the first video signal filtering unit 52 is that the DC clamp circuit 601 of the third video signal filtering unit 53 receives the third video signal S3, and the rest of the configuration is the same as the function. Therefore, do not add more details.

In general, if the video signal format of the first video signal S1, the second video signal S2, and the third video signal S3 outputted by the main chip 4 is SD, the frequency detecting module 503 of the signal format determining unit 50 detects The frequency of the horizontal synchronizing signal in the first video signal S1 is the first frequency (15 KHz), and the issued control signal CS is low, so that the first video signal filtering unit 51, the second video signal filtering unit 52 and the third The switch 602 of the video signal filtering unit 53 switches the first filter 61 according to the control signal CS for filtering the SD video signal. On the other hand, if the video signal format of the first video signal S1, the second video signal S2, and the third video signal S3 outputted by the main chip 4 is HD, the frequency detecting module 503 of the signal format determining unit 50 detects The frequency of the horizontal synchronizing signal in the first video signal S1 is the second frequency (45 KHz), and the issued control signal CS is at a high potential, so that the first video signal filtering unit 51, the second video signal filtering unit 52 and the third The switch 602 of the video signal filtering unit 53 switches the second filter 62 according to the control signal CS for filtering the SD video signal. Therefore, the main chip 4 of the embodiment only needs three sets of digital analog converters, and the video filter driving device 5 only needs three sets of video signal filtering units, which saves the cost of the video processor compared with the conventional one. space.

Incidentally, referring to FIG. 8, a usage interface 900 is displayed on a display screen of a television or a player. The user can select the video signal output by the main wafer 4 by using the interface 900 to meet the desired visual experience. For example, if the user wants to view the image in the HD video signal format, the user can select the Y, Pb, and the digital analog converters 421, 422, and 423 of the main chip 4 by using a remote controller. Pr or G, B, R to the first video signal filtering unit 51, the second video signal filtering unit 52 and the third video signal filtering unit 53 of the video filter driving device 5, and then by the first video signal filtering unit 51, The second video signal filtering unit 52 and the third video signal filtering unit 53 output Y, Pb, Pr or G, B, R to the display screen, so that the user can view the desired picture quality.

In summary, the video filter driving device 5 of the present embodiment determines the video signal format of the first video signal S1 by the signal format determining unit 50, and the first video signal filtering unit 51 and the second video signal filtering unit. 52 and the third video signal filtering unit 53 switch different control filters according to the control signal CS sent by the frequency detecting module 503, thereby integrating the first filter 61 and the second filter 62 of different bandwidths. In a video signal filtering unit, in addition, the main chip 4 only needs to set three digital analog converters 421, 422, and 423 correspondingly, which saves the cost and space of the video processor compared with the conventional one. The object of the invention is achieved.

However, the above description is only a preferred embodiment of the present invention. The universal pointer automatically detects the corresponding horizontal synchronization signal detection using different video formats, and cannot limit the scope of implementation of the present invention. The simple equivalent changes and modifications made by the present invention in the scope of the invention and the scope of the invention are still within the scope of the invention.

4. . . Main wafer

41. . . Video decoder

421. . . First digital analog converter

422. . . Second digital analog converter

423. . . Third digit analog converter

5. . . Video filter driver

50. . . Signal format judgment unit

501. . . Luminance chroma separation module

502. . . Synchronization signal separation module

503. . . Frequency detection module

504. . . Level shift module

51. . . First video signal filtering unit

52. . . Second video signal filtering unit

53. . . Third video signal filtering unit

601. . . DC clamp circuit

602. . . Toggle switch

603. . . Filter bank

604. . . Gain module

61. . . First filter

62. . . Second filter

900. . . Use interface

9. . . resistance

S1. . . First video signal

S2. . . Second video signal

S3. . . Third video signal

CS. . . control signal

Figure 1 is a block diagram showing a conventional main chip and video filter driving device;

2 is a block diagram showing an SD video signal filtering unit of the video filter driving device;

3 is a block diagram showing the HD video signal filtering unit of the video filter driving device;

4 is a block diagram showing the main chip and video filter driving device of the video processor of the present invention;

Figure 5 is a block diagram showing the signal format determining unit and the first video signal filtering unit of the video filter driving device;

Figure 6 is a block diagram showing the second video signal filtering unit of the video filter driving device;

Figure 7 is a block diagram showing a third video signal filtering unit of the video filter driving device; and

Figure 8 is a schematic diagram showing the use interface of a television or player.

4. . . Main wafer

41. . . Video decoder

421. . . First digital analog converter

422. . . Second digital analog converter

423. . . Third digit analog converter

5. . . Video filter driver

50. . . Signal format judgment unit

51. . . First video signal filtering unit

52. . . Second video signal filtering unit

53. . . Third video signal filtering unit

9. . . resistance

S1. . . First video signal

S2. . . Second video signal

S3. . . Third video signal

CS. . . control signal

Claims (18)

A video filter driving device for automatically selecting a filter, can receive a first video signal, the video filter driving device comprises: a signal format determining unit, receiving the first video signal, and comprising: a synchronization signal separating module Separating a synchronization signal component from the first video signal; a frequency detection module coupled to the synchronization signal separation module and receiving the synchronization signal component, the frequency detection module for detecting the synchronization The signal component has a frequency of a first frequency or a second frequency and emits a control signal; and a first video signal filtering unit, comprising: a filter bank having a first filter and a second filter a switching switch coupled to the frequency detecting module and the filter bank, and receiving the first video signal and the control signal, the switching switch controlling the first video signal to input the first filter according to the control signal Or one of the second filters to filter the first video signal. The video filter driving device according to claim 1, wherein the synchronization signal component is a horizontal synchronization signal. The video filter driving device of claim 1, wherein the signal format determining unit further comprises: a brightness signal for separating the first video signal and coupling the brightness of the synchronization signal separating module The chroma separation module, and the first video signal passes through the luminance chroma separation module before passing through the synchronization signal separation module. According to the video filter driving device of claim 1, wherein the frequency detecting module detects that the frequency of the synchronization signal component is the first frequency, the control signal is a low potential signal, And the switching switch controls the first video signal to input the first filter for filtering; when the frequency detecting module detects that the frequency of the synchronization signal component is the second frequency, the control signal is a high potential signal And the switch controls the first video signal to input the second filter for filtering. The video filter driving device according to any one of claims 1 to 4, further comprising a second video signal filtering unit for processing a second video signal, the second video signal filtering unit The filter set and the switch are coupled to the frequency detection module and the filter bank, and receive the second video signal and the control signal, and the switch controls the second according to the control signal The video signal is input to one of the first filter or the second filter to filter the second video signal. The video filter driving device according to claim 5, further comprising a third video signal filtering unit for processing a third video signal, wherein the third video signal filtering unit comprises the filter group and the switching a switch, the switch is coupled to the frequency detecting module and the filter bank, and receives the third video signal and the control signal, and the switch controls the third video signal to input the first filter according to the control signal And one of the second filters, filtering the third video signal. The video filter driving device of the sixth aspect of the invention, wherein the first video signal filtering unit, the second video signal filtering unit and the third video signal filtering unit respectively comprise a coupling The device group is used to increase the intensity of the filtered video signal as a gain matching impedance module. The video filter driving device of the seventh aspect of the invention, wherein the first video signal filtering unit, the second video signal filtering unit and the third video signal filtering unit respectively comprise a DC clamp circuit The reference voltage is intercepted by a signal that clamps the signal to a DC level as a back-end line. The video filter driving device according to claim 8, wherein the first frequency is a frequency of a horizontal synchronization signal in a standard image quality video signal, and the second frequency is a horizontal synchronization in a high quality video signal. The frequency of the signal. A video processor includes: a main chip, including a video decoder, and a first digital analog converter coupled to the video decoder, the first digital analog converter outputs a first video signal; and a video The filter driving device comprises: a signal format determining unit, receiving the first video signal, and having: a synchronization signal separating module, separating a synchronization signal component from the first video signal; and a frequency detecting module The synchronization signal separation module is coupled to receive the synchronization signal component, and the frequency detection module is configured to detect that the frequency of the synchronization signal component is a first frequency or a second frequency, and issue a control signal. a first video signal filtering unit, comprising: a filter bank having a first filter and a second filter; a switch, coupled to the frequency detecting module and the filter bank, and receiving the a first video signal and the control signal, the switch is configured to control the first video signal to be input to one of the first filter or the second filter according to the control signal, so that the A video signal is filtered. The video processor according to claim 10, wherein the synchronization signal component is a horizontal synchronization signal. The video processor of claim 10, wherein the signal format determining unit further comprises a luminance chrominance for separating the luminance signal of the first video signal and coupling the synchronization signal separation module. The module is separated, and the first video signal passes through the luminance chrominance separation module before passing through the synchronization signal separation module. The video processor of claim 10, wherein when the frequency detecting module detects that the frequency of the synchronization signal component is the first frequency, the control signal is a low potential signal, and the The switch controls the first video signal to input the first filter for filtering; when the frequency detecting module detects that the frequency of the synchronization signal component is the second frequency, the control signal is a high potential signal, and The switch controls the first video signal to be input to the second filter for filtering. The video processor according to any one of the preceding claims, wherein the main chip further comprises a second digital analog converter coupled to the video decoder and outputting a second video signal. The video filter driving device further includes a second video signal filtering unit coupled to the second digital analog converter for processing the second video signal, the second video signal filtering unit including the filter group and the a switching switch coupled to the frequency detecting module and the filter bank, and receiving the second video signal and the control signal, wherein the switching switch controls the second video signal to input the first filtering according to the control signal Or one of the second filters to filter the second video signal. The video processor of claim 14, wherein the main chip further includes a third digital analog converter coupled to the video decoder and outputting a third video signal, the video filter driving device further a third video signal filtering unit coupled to the third digital analog converter and configured to process the third video signal, the third video signal filtering unit includes the filter bank and the switch, and the switch is coupled The frequency detecting module and the filter bank receive the third video signal and the control signal, and the switching switch controls the third video signal to input the first filter and the second filter according to the control signal. One of them filters the third video signal. The video processor of claim 15, wherein the first video signal filtering unit, the second video signal filtering unit, and the third video signal filtering unit respectively comprise a filter bank coupled to the filter unit. And used to improve the intensity of the filtered video signal as a gain matching impedance module. The video processor of claim 16, wherein the first video signal filtering unit, the second video signal filtering unit, and the third video signal filtering unit further comprise a DC clamp circuit, respectively. The signal is clamped to a DC level as a signal for the back-end line to intercept the reference voltage. The video processor according to claim 17, wherein the first frequency is a frequency of a horizontal synchronization signal in a standard image quality video signal, and the second frequency is a horizontal synchronization signal in a high quality video signal. frequency.