GB2236451A - Reproducing combined video and graphics images from a recording - Google Patents

Abstract

In reproducing a picture from a recording such as a videodisc which comprises both a video signal which may be according to different line scanning standards and a coded graphics information signal which is stored 55 and then read out for mixing with the video signal, the graphics image will be distorted for at least one of the scanning standards. Accordingly the scanning standard of the recorded signal is detected 17 and reading of the stored graphics signal is correspondingly adjusted to alleviate such distortion. The apparatus includes a first counter 11 controlled by the horizontal sync signal, and a second counter 12 controlled by a higher frequency clock 13. For the format having more lines the supply of horizontal sync to counter 14 is periodically halted for a time determined by the difference in the line standards, so that the same graphic code is repeatedly read from the memory 55 and so that the graphic image occupies more scan lines. <IMAGE>

Description

RECORDING MEDIUM PLAYING APPARATUS The present Invention relates to a

recording medium playing apparatus for playing a recording medium such as a video disc or a digital audio disc. - A system has been proposed in which picture information is recorded and reproduced in the form of a subcode on and from a digital audio disc having a diameter of 12 cm. generally called compact disc (abbreviated as CD hereinafter). The subcode is made up of eight subcode bits, and bit groups forming the subcode are divided into eight channels denoted respectively by letters Pr Q, R, S, T, U, V, and W. In the method in which the picture information is recorded and reproduced in the form of the subcode, data corresponding to picture information is configured such that a symbol is formed by 6 bits of channels R through W out of the 8 bits forming the subcc>de. and 98 symbols are treated as one block, as illustrated in Fig. 1. Two symbols in the 98 symbols are used as a sync signal, and 24 symbols obtained by dividing the remaining 96 symbols by four are treated as 2 a minimum unit of data, i.e. a "pack", which constitutes one instruction of picture processing.

More specifically, the first symbol (referred to as symbol 0 hereinafter) of the 24 symbols shows one of several modes. A symbol 1 following this symbol 0 forms "instruction" which indicates the sort of the instruction. Symbols 2 and 3 following the symbol 1 constitute a "parity Q" which is an error correction code. Symbols 4 through 19 following the parity Q constitute a data field, and include information such as color information. Finally, symbols 20 through 23 following the data field constitute a parity P which is an error correction code for protecting the information in the "pack".

There are four modes, i.e. "zero model', Illine- graphics model,, 'ITV-graphics model', and "user model'. The "zero model, is provided for a case where no operation is required for pictures on the display screen, that is, the original image is to be maintained, and all data in the 11packo are 0 for this mode.

The "line-graphics mode" is provided for such a case that a liquid crystal display is provided on the front face of the player, to display notes such as an explanation of a music piece. As shown in Fig. 2, a picture area elongated sideways is formed by pixels which 3 are arranged in 288 columns and 24 rows. In other words, each row includes 288 pixels and each column includes 24 pixels. The term 11pixell, stands for the minimum display element of a picture, and it is general that the picture processing is performed by using picture composing units designated as "fonts" each of which is made up of pixels divided into 6 columns and 12 rows.

The number of "fonts" which can be"displayed in the,,line-graphics model, is 48 in the lateral direction,, and 2 in the column direction, and this area is designated as "screen area". For providing the scroll function, a line of "fonts" is added to the upper and lower outer peripheries and the right and left peripheries of the Screen area, to form a picture area having 50 "fonts" in the direction of row, and 4 "fonts" in the direction of column. The subcode is formed so that the picture processing is performed by using a memory having addresses each corresponding to a pixel in this picture area. In addition. the area outside the "screen area" is designated as "border".

The "TV-graphics mode" is a mode for displaying images on the TV screen. and a picture is formed by pixels arranged in 192 rows and 288 columns as illustrated in Fig. 3. The number of "fonts" which can be displayed in the ',TV-graphics mode" is 48 in the 4 direction of row, and 16 in the direction of column. Also in this 'ITV- graphics model,, the subcode is formed so that the picture processing is performed by using a memory having addresses each of which corresponds to a pixel in a picture area having 50 "fonts" in the direction of row, and 18 "fonts" in the direction of column,. made by adding a line of "fonts" to the upper and lower peripheries as well as the right and left outer peripheries of the "screen area".

As instructions for the picture processing, there are an instruction for painting out the whole picture area by one certain color, an instruction for drawing a picture in one "font" on the screen by using two different colors, an instruction for moving the whCe picture upward or sideways. and so on.

Additionally, in the 8-bit groups forming the subcode, the Q bits forming the channel Q include time information corresponding to the track length to a certain position of each information data which is recorded from the beginning of the program area of the CD, and form address time data which can be used as positional data representing the recording position. on the other hand, the P bits forming the channel P form data including information relating to a pause between two music pieces.

In the case of the above-described system for recording and reproducing picture information as the subcode, at most nineteen picture channels can be designated. Specifically, a "write font foreground/back- ground" instruction is used in the 'ITV-graphics model', which has such a structure as illustrated in Fig. 4. This is an instruction for writing font data of the symbols 8 through 19 in positions having a row address defined by the symbol 6 and a column address defined by the symbol 7. For the pixels whose font data is 11011, a color of a color number determined by the 11color 011 is designated as a background color. For the pixels whose font data is 11111, a color of a color number defined by 11color 111 is designated as a foreground color. At the same time, sub- picture channels can be designated by using four bits of the channels R and S of the symbols 4 and 5. By this feature, as many as sixteen picture channels can be designated. Sixteen sorts of picture are previously recorded on a disc for example, and on the playing side, a desired picture channel can be selected at the time of playback by this scheme of designating the picture channel.

In addition, the sixteen colors indicated by the color number 000 through 01511 are set by a "load CLUT color 0 through color 15 (load color look-up table color 6 0 through color 15)11 instruction. The "load CLUT color 0 through color 15" instruction is an instruction having a structure illustrated in Fig. 5, and setting the contents of a color look-up table showing the color of pre-set color numbers or foreground/background color numbers. It is necessary to designate sixteen colors in total. However. since four bits are used respectively for each of RGB to indicate a color, two symbols are required for setting one color. Therefore, eight colors are set by one "pack,' at most. In these circumstances, this instruction is divided into two instructions respectively designating eight colors of the first half, and eight colors of the second half.

The instruction code for the colors of t'-;: first half, i.e. the color 0 through the color 7, is determined to be "30", and the instruction code for the colors of the second half, i.e. the color 8 through color 15 are deterTained to be "310. The mixing of colors for each of the color numbersis as follows. Red color is represented by four bits of the channels R through U of even symbols allotted to the color number. Green color is represented by four bits. i.e. two bits of the channels V and W following the channels R through U of the even symbols. and two bits of the channels R and S of odd symbols. Blue color is represented by four bits of channels T through W 7 following the channels R and S of the odd symbols.

Therefore, 24 (=16) sorts of gray scales are available for each color, and preparation of 163 (=4096) colors is possible since three colors (RGB) are used. In addition, a gray scale 1,000011 corresponds to the darkest state, and a gray scale 1111111' corresponds to the brightest state.

The inventors of the present invention have invented a system for recording on a recording medium an FM modulated video format signal in addition to a digital audio signal in which graphic codes including picture information are inserted according to the above-described system for recording and reproducing picture information as the subcode, so that the image obtained by the subcode can be inserted into the picture obtained by the video format signal at the time of play of the recording medium. The system is disclosed in Japanese Patent Publication No. H1-221072.

In order that the picture represented by the FM modulated video format signal and the picture represented by the subcode can be displayed in the same screen at the same time,, the system of this prior application uses a new code as illustrated in Fig. 6 to be inserted as the symbol 0 to designate an additional mode, that is, "graphic mode with motion picture" in addition to the "zero mode" the,line-graphics mode", the "TV-graphics model' and the ',user model, which are also used in the conventional method for recording and reproducing picture information using the subcode.

The structure of a picture in the "graphics mode with motion picture,, is identical with that in the 'ITVgraphics mode", and an instruction designated as,load transparency control table,, as illustrated in Fig. 7 is provided. This 'load transparency control table" instruction is an instruction for designating the mode for each pixel in the picture area. Three modes are designated by this instruction, and those are namely. "transparent model'. "mixing model', and "non-transparent mode". In these three modes, different values are selected for the mixing ratio between a video format signal obtained by the subcode and a video format signal which is recorded by multiplexing operation together with the coded information signal including the subcode.

The bits in the channels R through W of each of the symbols 4 through 8 and the channels R and S of the symbol 9 constitute a series of codes TW-0 through TCB 15 which respectively designate one of modes which will be described later for each of the group of pixels to which one of colors, which are registered as color number 0011 through color number 111511, is allotted. Fig. 8 shows the relationship between bit patterns of the codes TW-0 through TCB-15 and the modes designating the mixing ratio, and the mixing ratio in each mode.

A recording medium playing apparatus for playing a recording medium on which information is recorded by the system of the prior application described above, is also disclosed in Japanese Patent Publication No. H1-221072. This recording medium playing apparatus is constructed such that the picture signal obtained by'the subcode and the video format signal recorded in the FM modulation lo form are mixed and output at a mixing ratio according to the graphic codes representing the color of each pixel in the display area of the image by the subcode.

As for the video format signal recorded on the disc. there is a video format signal of the PAL video format as well as a video format signal of the NTSC video format. The number of scanning lines is 525 for the NTSC format, while the number is 625 for the PAL format. However, the number of picture elements in a displayed picture of the subcode image is 288 in the vertical direction. In these circumstances,, there has been a problem that the relative size of the subcode image with respect to the picture by the video format signal in the vertical direction differs between cases in which the subcode image is combined with the picture of the NTSC format video signal and in which the subcode image is combined with the picture of the PAL - 10 format video signal.

In order to solve the problem mentioned above, a method has been investigated in which the contents of the picture processing instructions to be recorded as the subcode is changed depending on the signal format of the video format signal. However, a problem arises in such a method that the number of image processing instructions are increased for the recording medium on which the PAL format video format signal having more horizontal scanning lines is recorded.

The present invention is based on the point described above, and an object of the present invention is to provide a recording medium laying apparatus in which the relative size of the subcode image in the is vertical direction will not change depending on the signal format of the video format signal being recorded by the FR modulation process.

In order to attain the above object, a recording medium playing apparatus according to the present invention is provided with a first counting means whose count value varies with the horizontal sync signal of the video format signal in the read-out signal, and a second counting means whose count value varies with a clock signal of a frequency higher than that of the horizontal sync signal. Depending onthe signal format of the video format signal the supply of the horizontal sync signal to the first counting means is periodically inhibited for a time interval corresponding to the difference in number of horizontal scanning lines between two types of video format signal. at a predetermined periodic rate. After the graphic code is extracted from the coded information signal in the read-out signal and in turn stored into a memory, the graphic code is sequentially read-out from the memory in the order of addresses indicated by the outputs of the first and second counting means. A picture signal is generated according to the read-out graphic code and mixed to the video format signal.

By the recording medium playing apparatus constructed as described above, the count value of the first counting means is made unchanged periodically for the time interval corresponding to the difference in number of horizontal scanning lines between two types of video format signals at a predetermined periodic rate, so that the same graphic code is repeatedly read-out. The interpolation is performed by the graphic code read-out repeatedly, and the subcode image is expanded in the vertical direction at anexpansion factor corresponding to the difference in the number of horizontal scanning lines between the two types of video format signals.

- 12 BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a diagram showing the recording format of subcode data; Fig. 2 is a diagram showing the structure of a picture in the,line-graphics model,; Fig. 3 is a diagram showing the structure of a picture in the "TVgraphics mode"; Fig. 4 is a diagram showing the construction of a "write font foreground/background', instruction;

Fig. 5 is a diagram showing a "load color look-up table color 0 through color 711 instruction; Fig. 6 is a diagram showing the sortsof recording modes; Fig. 7 is a diagram shwing the construction of is "load transparency control table', instruction; Fig. 8 is a diagram showing the correspondence between the bit pattern of TCB and the mixing ratio; Figs. 9A through 9C, when combined, are a block diagram showing an embodiment of the playing apparatus according to the present invention; Fig. 9 is a diagram showing the arrangement of Figs.

9A through 9C; Fig. 10 is a diagram showing the recording area of a composite disc; Fig. 11 is a block diagram showing a specific configuration of video format signal processing circuit 30 in the apparatus shown in Pigs. 9A through 9C; Fig. 12 is a flowchart showing the operation of the processor in the system controller of the apparatus shown in Figs. 9A through 9C; Fig. 13 is a diagram showing pictures obtained by the apparatus shown in Figs. 9A through 9C; Fig. 14 is a diagram showing an image obtained by the subcode when the NTSC format video format signal is demodulated in the apparatus shown in Figs. 9A through 9c; Figs. 15A through 1SE are timing charts showing the operation of each part of the apparatus shown in Figs. 9A through 9C; and is Fig. 16 is diagram showing an image obtained by the subcode when the PAL format video format signal is demodulated by the apparatus shown in Figs. 9A through 9C.

An embodiment of the invention will be explained by way of example only with reference to Figs. 9 through 16 of the accompanying drawings.

In Figs. 9A through 9C and 10. the reference numeral denotes a disc as the recording medium. As shown, the composite disc 20 has a first area 20a disposed in an 14 inner peripheral area of the disc (this area being referred to hereinafter as the CD area) in which is recorded a digital audio signal with the subcode including picture information for example being inserted, and a second recording area 20b (this area being referred to hereinafter as the video area) containing an FRmodulated video format signal and a superimposed digital audio signal with the subcode including picture information being inserted, wherein the superimposition jo is performed by using a frequency multiplexing system. Since the video format signal contains higher frequency components than the PCA signal, it is necessary to rotate the disc at a higher speed of rotation during the recording of signals -n the video area 20b, than during the recording of the signal in the CD area 20a. Therefore of course it is necessary, at the time of playback. to reproduce the signal by rotating the disc at the higher speed during the playback of video area 20b, than during the playback of CD area 20a. The speed of disc rotation during the playback of CD area 20a is several hundred r.p.m., whereas during the video area playback the speed of rotation is two thousand plus several hundred r.p.m. for playback from the innermost periphery of that area, and is one thousand plus several hundred r.p.m. for playback from the outermost periphery of that area, so that the speed of rotation is extremely high during video area playback.

In the head portions of the CD area 20a and the video area 20b, there respectively are provided a lead-in area in which are recorded, as the subcode, index codes relating to the contents recorded in each area. such as first and second code groups formed correspondingly to each area by the repetition of index codes which respectively indicate start and end times of small portions which together constitute each area. In addition. the index codes of the audio lead-in area include disc type information indicating whether the disc itself is a composite disc or a disc of other type.

The disc 20 is rotated by a spindle motor 21, and information recorded thereon is read-out by means of a pickup 22. The pickup 22 incorporates therein an optical system including a laser diode, an objective lens, and photo detectors. a focus actuator for driving the objective lens in a direction of its optical.axis with respect to the information recording surface of the disc 20, a tracking actuator for biasing the beam spot (information detecting point) issued from the pickup 22 with respect to the recording tracks in a direction of disc radius, and so on. The pickup 22 is mounted on a slider 23 which is movable in the direction of disc 16 radius by a direct drive of a'transmission mechanism 25 which in turn has a slider motor 24 as a source of driving force, and made by a combination of rack and pinion gears. A read-out RF (radio frequency) signal output by the pickup 22 is supplied to a video format signal demodulating and processing circuit 30 and a coded information demodulating and processing circuit 31 through an RF amplifier 26.

The video format signal demodulating and processing circuit 30 includes a demodulation circuit which for example demodulates the RF signal and converts it to a video format signal and a memory which stores the video format signal after digitizing it, and configured to selectively outlat one of the video format signal output by the demodulation circuit and the video format signal read-out from the memory in accordance with a changeover command from a system controller 32. The video format signal output by the video format signal demodulating and processing circuit 30 is supplied to a video switch 33.

In addition, the video format signal demodulating and processing circuit 30 is further provided with a separating circuit which separately extracts a horizontal sync signal h, a vertical sync signal v, and control data c from the demodulated video format signal, and the separated horizontal and vertical sync signals h and v, and the control data c are supplied to each part such as the system controller 32.

On the other hand, the coded information demodulating and processing circuit 31 is provided with a selector switch 35 which changes its switch position in accordance with the area to be played (the CD area or the video area) during the playing of a composite disc. The selector switch 35 is operated to a position a during the playing of the CD area, and to a position b during the lo playing of the video area. and the changeover is performed in response to a changeover command issued from the system controller 32. In the case of the composite disc, the speed of disc rotation changes greatly between the CD area and the video area, and the PCM audio signal is for example an EFX (Eight to Fourteen Modulation) signal. For the video area, the EFM signal will adversely affect the low frequency component of the video signal treated by the FM modulation process if the digital signal is directly superimposed on the FM video signal at the time of recording. Therefore, the digital signal. i.e. the EFM signa: is recorded at a level which is lower than the video carrier level by several tens of dB, although the degree of modulation is almost the same for the EFM and video signals. Thus the frequency characteristic and amplitude of a playback EFX 18 signal will both be different, for the cases of CD area playback and video area playback respectively. However, a common demodulating system is used for the CD area playback and the video area playback. This is made possible by switching signal processing systems for the playback EPM signals of the CD area and the video area respectively.

Specifically, during playback of the CD area. the - playback RF signal is an EFM signal, which is subjected to frequency characteristic compensation by an equalizer circuit 36 having a predetermined equalizing characteristic, and is amplified at a predetermined amplification factor by an amplifier 37. During the playback -f the video area, on the other hand, the playback RF signal is an PM video signal which is combined with an EFM signal. The EFX signal is extracted by an EPM signal extracting circuit 38 which is made up of an LPF and so on, then is subjected to frequency characteristic compensation by an equalizer circuit 39, which has a different equalization characteristic from the equalizer circuit 36, to be then amplified by an amplifier 40, which has a higher gain than that of the amplifier 37. In this way, an EFR signal is derived whose frequency characteristic and amplitude are almost the same as the EFM signal obtained during CD area playback.

During playback of a.CD disc, the selector switch 35 is held in position a.

The playback EFM signal selected by the selector switch 35 is supplied to an EFM demodulation circuit 42 which performs the demodulation process. to obtain a PCM data that is digital data including audio information of left and right channels which is for example timedivision multiplexed, and the subcode. The digital data including audio information output by this EFM demodulation circuit 42 is supplied to a de-interleave and interpolating circuit 43. The de-interleave and interpolating circuit 43 is configured to change back, in cooperation with the RAM 44, the order of the digital data which was rearranged by the interleave operation during the recording, in turn send it to an error correction circuit 45, and to effect the interpolation of erroneous data in the output data of the error correction circuit 45 by the average value interpolation method for example, when a correction inability signal is output.

The error correction circuit 45 is configured to perform the error correction operation by using the CIRC (Cross Interleave Reed Solomon Code), and supply the digital data to the de-interleave and interpolating circuit 43, or supply the digital data to the de-interleave and interpolating circuit 43 together with the correction inability signal when the-error correction is not possible.

The output data of the de-interleave and interpolating circuit 43 is supplied to a D/A (Digital to Analog) converting circuit 46. The DIA converting circuit 46 includes a de-multiplexer which separates from each other the digital data of left and right-channel audio information combined by the time division multiplexing, and left and right-channel audio signals are reproduced.

After their unnecessary components are removed at LPFs (Low Pass Filters) 47 and 48, the reproduced left and right-channel audio signals are supplied to audio output terminals OUT1 and OUT2 through amplifiers 49 and 50.

In the subcode output by the EFM demodulating circuit 42. two bits of the channels P and Q are supplied to the system controller 32, and six bits of the channels R through W are supplied to a de-interleave and error correction circuit 52 in which the de-interleave of the six bits of the channels R through W and the error correction using the parity Q and P are performed. Output data of the de- interleave and error correction circuit 52 is supplied to a modelinstruction decoder 53. The modelinstruction decoder 53 is configured to decode the mode represented by the three bits of the channels R through T of the symbol 0 of each pack. the mode designated by the item represented by the three bits of the channels U through W of the symbol 0 of each pack, and the instruction represented by the six bits of the channels R through W of the symbol 1 of each pack, and to supply to each part signals respectively indicative of the mode and instruction.

Furthermore, the output data of the de-interleave and error correction circuit 52 is supplied to a picture memory device 55. The picture memory device 55 includes sixteen RAMs 56a through 56p having addresses respectively corresponding to all pixels on a picture having 50 "fonts" by 18 "fonts" in the row and column directions, and four bits of data can be stored in each address, and a memory control circuit 57 for sensing data indicating the color number of each pixel of each picture channels in the output data of the de-interleave and error correction circuit 52 by using the kind of the modes and the instruction indicated by the output of the modelinstruction decoder 53 and writing them.in the corresponding addresses of the RAMs 56a through 56p, and for reading out the memory content of one of the RAMs 56a through 56p corresponding to the picture channel designated by a data d by the key operation in an operating part 60, from addresses indicated by reading address data.

22 Reading clocks are supplied to the memory control circuit 57 from a reading clock generating circuit 10, and the reading address data is supplied to the memory control circuit 57 from counters 11 and 12. The reading clock generating circuit 10 is constructed to detect, by using the horizontal and vertical sync signals for example, a first time interval slightly shorter than a 1H period excluding the horizontal fly-back time, and a second time interval corresponding a 288H period in the middle of a vertical sync period excluding the vertical flyback time, and to provide, as the reading clocks, clocks issued from a clock generating circuit 13 described later only during the first and second time intervals. Clocks issued from the clock generating circuit 13 are supplied to a clock input terminal of the counter 12. The horizontal sync signal h is supplied to the clock generating circuit 13. The clock generating circuit 13 is made up of a PLL (Phase Locked Loop) circuit for example. and configured to be synchronized with the horizontal sync signal. and to generate clocks at a frequency N (N is an integer equal to or greater than 2) times the frequency of the horizontal sync signal h.

In addition, the horizontal sync signal h is supplied to the reset input terminal of the counter 12.

To the clock input terminal of the counter 11, there is connected anoutput signal of an AND (logical product) gate 14. The horizontal sync signal h is connected to one of two input terminals of the AND gate 14. To the other input terminal of the AND gate 14, there is connected through a switch 15 an output signal of a modulo-6 counter-16. The horizontal sync signal h is connected to a clock input terminal of the modulo-6 counter 16. The modulo-6 counter is configured to generate anoutput signal of a low level only when its count value is equal to "S". To a control input terminal of the switch 15, there is connected an output signal of a signal format discrimination circuit 17. The signal format discrimination circuit 17 is constructed, for example, to count the number of horizontal scanning lines by a counter counting up by the horizontal sync signal h and reset by the vertical sync signal v, and to discriminate the signal format of the video format signal issued from the video format signal demodulating and processing circuit 30 by using the counted number of horizontal scanning lines. The discrimination circuit 17 produces a high level signal as a signal format discrimination signal when the video format signal is of the PAL format, and a low level signal as the signal format discrimination signal when the video format signal is of the NTSC format. The vertical sync signal v is supplied - 24 to a reset input terminal of the counter 11.

The output data of the counters 11 and 12 are supplied to the memory control circuit 57 respectively as a high-order bit group and a low-order bit group of the reading address data.

The data output by the picture memory device 55 is supplied to a color lookup table 58 (this table being referred to hereinafter as the CLUT). The CLUT 58 is configured to detect the "load CLUT color 0 through color 70 instruction and the "load CLUT color 8 through color 150 instruction from the output data of the de-interleave and error correction circuit 52 in accordance with the kind of the modes and the instruction indicated by the output signal of the mode/instruction decoder 53. and hold the color data corresponding to each color number, and configured to select and output color data of the color number designated by the data read-out from the picture memory 55.

The output data of this CLUT 58 is made up of three data respectively representing the level of one of the R, Gi B color signals by using four bits. The three data output by the CLUT 58 and indicating the levels of the R, Gi B color signals are supplied to DIA converting circuit 61, 62, and 63, and converted to analog signals. Output signals of these DJA converting circuits 61 through 63 - are supplied to an analog-to-video converting circuit 65. The analog-to- video converting circuit 65 is configured. for example. to form a video signal of the NTSC format or the PAL format by the steps of obtaining a luminance signal and two color difference signals by the output signals'of the D/A converting circuits 61 through 63, generating a color carrier signal by processing the two color difference signals in accordance with the output signal of the signal format discrimination circuit 17, combining the color carrier signal and the luminance signal by the summation, and adding sync signals thereto. By this analog-to-video converting circuit 65, the output signals of the DIA converting circuits 61 through 63 are converted to a video signal and forwarded subsequently.

In addition, the output data of the de-interleave and error correction circuit 52 are also supplied to a transparency control table 66 (this table being referred to hereinafter as the TCT). The TCT 66 is configured to detect a "load TCTO instruction in the output data of the de-interleave and error correction circuit 52 in accordance with the kind of the modes and instruction indicated by the output signal of the modelinstruction decoder 53. hold transparency control bits TW-0 through TCB-15, and output by selecting one of the TW-0 through TCB-15 being held, corresponding to a color number 26 indicated by the data read-out from the picture memory device 55.

The output signal of the TCT 66 is supplied to a video switch 33 as a control signal. In addition to the output signal of the TCT 66, the video format signal obtained from the subcode and output by the analog-tovideo converting circuit 65, and the video format signal output by the video format signal demodulating and processing circuit 30 are supplied to the video switch 33.

In the video switch 33, the video format signal obtained from the subcode is supplied to a stationary contact x of the changeover switch 68, and also supplied to its stationary contact y through a resistor Rj. No connection is made to a stationary contact z of the changeover switch 68. The changeover switch 68 is configured to selectively output one of the signals supplied to its stationary contacts X, y, A by moving its movable contact u to be in contact with one of the stationary contacts y X z in accordance with a control signal issued from the TCT 66. The video format signal output from the video format signal demodulating and processing circuit 30 is directly supplied to a stationary contact z of a changeover switch 69 and also supplied to its stationary contact v through a resistor R2. No connection is made to a stationary contact A of the changeover switch 69. The changeover switch 69. like the changeover switch 68, is configured to move its movable contact u to be in contact with one of its stationary contacts x, y, z in accordance with the control,signal. The movable contacts u, 11 of the changeover switches 68 and 69 are mutually connected. A resistor R3 is connected between a common junction i of the movable contacts u, 31 and ground. A mixed signal of the video format signal obtained from the subcode and the video format signal output from the video format signal demodulating and processing circuit 30 is derived at the common junction J. When the movable contacts u, u of the changeover switches 68 and 69 are in contact with the stationary contacts x, IL respectively, the mixing ratio of the video format signal obtained from the subcode becomes 100%, and the mixing ratio is reduced to 0% when the movable contacts u. u are in contact with the stationary contacts z. z. When, on the other.hand. the movable contacts u, u are in contact with the stationary contacts y, y. the mixing ratio is equal to M which is determined by the resistors Rl and R2, and the resistances of the resistors R1 and R2 are selected so that M has a value between 20% and 80%. The signal derived at the common junction i is supplied to a video output terminal 28 OUT3.

A position detector 70 is provided in the vicinity of the path of the movement of pickup 22 along the radial direction of the disc, and serves to detect when the beam spot emitted from the pickup 22 has reached a position corresponding to the vicinity of the boundary between the CD area and the video area of a composite disc. to produce a detection signal. By the generation of this detection signal. a state that the pickup 22 has reached to the video area can be detected. The position detector 70 can have a known structure including for example an optical sensor. The detection signal output by the position detector 70 is supplied to the system controller 32.

The system controller 32 comprises a microcomputer which consists of a processor, a ROM (read only memory), a RAN and so on. The system controller 32 is supplied with various signals and information such as the horizontal sync signal h, the vertical sync signal v, and the control data c, the P-channel and Q-channel bits in the subcode issued from the EFR demodulation circuit 42, disc designation information from the operating part 60 indicating whether the disc to be played is a compact disc or a composite disc, and mode designation information from the operating part 60, indicating 29 - whether the reproducing area is only the CD area or the video area, or both CD and video areas in the case of the playback of a composite disc. In this system controller 32. the processor executes processing of the signals inputted in accordance with programs previously stored in the ROM, and performs the control operation of each part of the video format signal demodulating and processing circuit 30, the selector switch 35, a drive circuit (not shown) for driving the spindle motor 21, the driving circuit 71 for driving the slider motor, and the display part 72.

Fig. llis a block diagram showing a specific circuit construction of the video format signal demodulating and processing circuit 30. As shown, the RF signal from the RF amplifier 26 is demodulated at a demodulation circuit 75. then supplied to a time base correction circuit 76 and to a separator circuit 77. In the separator circuit 77, the horizontal sync signal h, the vertical sync signal v and the control data c which are contained in the video format signal are extracted. The time base correction circuit 76 consists of, for example. a variable delay element of e.g. CCD (charge coupled device) type and configured to vary the delay amount of that element in accordance with a control signal from a time base control circuit 78. The time base control - 30 circuit 78 is configured to output as the control signal a signal corresponding to a phase difference between an oscillation signal and its divided signal of a crystal oscillator (VCO) 79 which oscillates, for example, in synchronism with the horizontal sync signal h extracted at the separator circuit 77, and the horizontal sync signal and the color burst signal of the video signal transmitted through the time base correction circuit 76. For more specific configuration, reference is directed for example to Japanese patent application laid-open number P56-102182.

The video signal having been processed by the time base correction operation is used as one input of a selector switch 80, and also supplied to an AID converter 82 through an LPF (Low Pass Filter) 81. In the AID converter 82, the sampling of the video signal is performed at intervals of a predetermined period, and the thus obtained sampled values are in turn converted to digital data. The output data of the AID converter 82 is supplied to a video memory 83 consisting of a RAN (random access memory) and so on. A memory having a capacity for storing video information of at least one field long is u as the video memory 83. Address and mode controls of this video memory 83 are performed by a memory control circuit 84. The memory control circuit 84 is configured to perform control operations for sequentially reading data written in each address of the video memory 83 in accordance with a clock from a reference clock generating circuit 85, and for rewriting the contents of each address of the video memory 83 in response to a write enable signal w which is output from the system controller 32. The data read-out from the video memory 83 is converted to an analog signal in a D/A (digital to analog) converter 86, and supplied through an LPF 87 as the other input to the selector switch 80. The selector switch 80 is normally held at a position a to selectively output the video format signal directly supplied from the time base correction circuit 76, and switched to a position b in response to a changeover command from the system controller 32, to selectively output the video format signal having been processed through the video memory 83.

Operations of the processor in the system controller 32 in the above configuration will be specifically explained with reference to the flowchart of Fig. 12.

It is assumed that a composite disc is set in a playback position. When a start command is issued from the operating part 60 in this state,, the processor transmits a drive command to the motor driving circuit 71, so that the slider motor 24 is driven to move the 32 pickup 22 to an innermost.peripheral position (step S1). If it is detected that the pickup 22 has reached the innermost peripheral position by means of a detector switch of any usual configuration (not shown), the processor executes a focusing operation of the pickup 22, and reads index code information which is recorded in an audio lead-in area at an innermost peripheral area of the disc (step S2). Subsequently, the processor judges whether or not the disc being set is the composite disc or not, on the basis of the read information (step S3). If it is judged that the disc being set is a compact disc, then the executi6n directly proceeds to a CD playback mode (step S4) and a playback operation is continuously performed unless any command for the programmed music selecting operation for example has been issued. Since the playback operation in the CD playback mode itself is well known, the explanation thereof is omitted here.

If it is judged in step S3 that the disc being set is a composite disc, the processor immediately accelerates the slider motor 21 to a maximum rated speed of rotation for the video area (step SS). At the same time. the processor moves the pickup 22 toward the outer periphery of the disc at high speed by driving the slider motor 24 at high speed (step S6). After these operations, when it is detected that the pickup 22 has reached the video area by the detection signal from the position detector 70 (step S7), the processor starts the playback operation of the video area (step S8).

During the video area playback. the processor performs the control operation for writing the video information of at least one field (or one frame) obtained from the disc into the video memory 83. ghis video information to be written may be, for example. the first information in the video area, or designated by an address designation through the key operation of the operating part 60.

If it is detected that the playback of the video area has been completed, in step Sg, then the processor decelerates the spindle motor 21 to the maximum rated speed of rotation for the CD area (step S10). At the same time, the processor drives the slider motor 24 at high speed, to move the pickup, 22 to the innermost peripheral position of the disc at high speed (step S11). If it is detected (step S12) that the pickup 22 has reached the innermost peripheral position by the detection output signal of the above mentioned detector switch (not illustrated), the processor starts the playback operation of the CD area (step S13). At the same time. the selector switch 80 in the video format signal demodulating and 34 processing circuit 30 is changed over by the processor to the position b thereby selecting and outputting the video information which was written in the video memory 83 during video area playback. Thus, playback of a still picture is performed during CD area playback. When the completion of the CD area playback is detected by reading the information of audio lead-out (step S14), the processor initiatesthe driving of the slider motor 24 to move the pickup 22 to its home position (step S15) unless any operational command is present. Furthermore, the disc is ejected by a loading mechanism (not shown in the drawings), to complete the playback operating sequence.

In the operating sequence described above, playback of the information recorded in the CD area of the composite disc is performed in steps S10 through S14 after the playback of information recorded in the video area through steps S1 to S9.

When the "load CLUT color 0 through color 711 instructions and the "load CLUT color 8 through color 1511 instructions are decoded by the modelinstruction decoder 53 during video area playback, data of designated 16 colors among 4096 colors are held in the CLUT 58.

Subsequently,, by the decoding of the "write font foreground/background" instruction etc., image data of 16 channels are in turn stored in the RAM 56a through 56p in the picture memory device 55. When one of the image data of 16 channels is designated by data corresponding to the key operation in the operating part 60. image data of the designated channel is sequentially output from the picture memory device 55, and in turn supplied to the CLUT 58 By this operation, color data of a color number indicated by the image data is then output from the CLUT 58. A video format signal based on this color data is output from the analog-to-video converting circuit 65, and supplied to the video switch 33.

If the "load TCT" instruction is decoded in this state. the transparency control bits TCB-0 through TCB-15 respectively corresponding to each color number are then held in the TCT 66. Among the WB-0 through TCB-15 being held. one corresponding to the color number indicated by the data readout from the picture memory device 55 is selectively output from the TCT 66. and the mixing ratio in the video switch 33 is designated by the output of the TCT 66. Thus. the mixing ratio between the video format signal output from the analog-to-video converting circuit 65 and the video format signal output from the video format signal demodulating and processing circuit 30 is controlled for each pixel. Consequently, a combination of pictures such as illustrated in Fig. 13 is made possible.

Specifically, the mixing ratio is set to 100 % for a 36 portion corresponding to each pixel outside a region D of a picture A based on the video format signal output from the video format signal demodulating and processing circuit 30, and set to 0 % for a portion corresponding to each pixel within the region D. On the other hand, the mixing ratio is set to 0 % for a portion corresponding to each pixel outside a region D' of a picture B based on the video format signal output from the analog-tovideo converting circuit 65, and set to 100 % for a portion corresponding to each pixel within the r egion D' of the picture B. Then a picture C can be formed by combining the portion of the picture A outside the region D and the portion of the picture B within the region W.

In this way, it is possible to compose a picture in which a caption, a musical score. or an explanation of a scene, etc., obtained from the subcode is inserted into a moving picture obtained by the video format signal recorded in the video area or a still picture obtained by the video memory 83.

When the video format signal of the NTSC format is demodulated, the signal format discrimination signal has the low level, to turn off the switch 15. As a result.

the horizontal sync signal h is continuously supplied to the counter 11. The count value of the counter 11 is sequentially varied by the pulses constituting the 37 - horizontal sync signal -h,-so that the image data written in one of RAMs 56a through 56p in the picture memory device 55 corresponding to the designated channel is sequentially read-out. Consequently. as shown in Figure 14 an image by the subcode is displayed in a display area PS of the subcode image within the display area PN Of the image by the NTSC format video format signal. Specifically, image data for one scanning line among image data written in address groups Al A7,--- respectively corresponding to each scanning line in the display area PS is once sequentially read-out, and the image by the subcode is displayed in the display area PS.

When the PAL format video format signal is demodulated, the signal format discrimination signal has the high level. so that the switch 15 turns on. When the count value of the modulo-6 counter 16 is varied as shown in Fig. 15B by the horizontal sync signal h shown in Fig. 15A and the count value of the modulo-6 counter 16 becomes equal to w511, a low level signal is issued from the modulo-6 counter 16. The low level signal issued from the modulo-6 counter 16 is supplied to the AND gate 14 through the switch 15 in the "on" position. As a result, the supply of the horizontal sync signal h to the counter 11 is inhibited. The horizontal sync signal h supplied to the counter 11 is as shown in Fig. 15D. As a result. the 38 count value of the counter 11 periodically becomes equal to the count value of 1H before during a 1H period, at a periodic rate of SR.

Consequently, the image data written in the address groupsAl - A7,... respectively corresponding to each scanning line in the display area PS of the subcode image which is set in the display area Pp of the image by the PAL format video format signal, is sequentially read- out for a 5H period. Then,the image data which has been read-out 1H before is repeatedly read-out for the 1H period, so that the interpolation is performed by the image data which has b6en read-out repeatedly. As a result, the image by the subcode displayed on the display area P.

is expanded at a rate of 615. In this way. ty.e relative size of the subcode image in the vertical direction is made substantially the same as the relative size in the case where the code image is combined in the image by the NTSC format video format signal.

Although the interpolation is performed by the image data of 1H before in the above described embodiment, it is also possible to execute the interpolation by using an average value between the image data of 1H before and the image data of 1H after.

Furthermore. in the embodiment described above the composite disc generally called "CDVII has been explained as an example of the recording medium on which the subcode carrying picture information is recorded. However. it is needless to say that the present invention is applicable to cases using, as the recording medium for recording the subcode carrying picture information, other recording media such as the disc called WD, i.e. a disc on which the FM modulated video format signal, the FR modulated audio signal and the CD formatdigital audio signal are recorded by using a frequency multiplexing operation.

As specifically described in the foregoing. the recording medium playing apparatus according to the present invention is configured such that a first counting means whose count value changes with the horizontal sync signal of the video format signal in the read-out signal and a second counting means whose count value varies with clocks having a frequency higher than the horizontal sync signal are provided, and depending on the signal format of the video format signal-the supply of the horizontal sync signal is periodically inhibited for a time interval corresponding to the difference in number of horizontal scanning lines between the two types of video format signals at apredetermined periodic rate. After the graphic code is extracted from the coded information signal contained in the read-out signal and in turn written in the memory, the graphic code is readout in the order of addresses represented by the outputs of the first and second counting means. A picture signal corresponding to the read-out graphic code is generated and mixed to the video format signal.

Therefore, in the recording medium playing apparatus according to the present invention, the count value of the first counting means is periodically made unchanged for the time interval corresponding to the difference of the number of horizontal scanning lines at the predetermined periodic rate, depending on the signal format of the video format signal. As a result, the same graphic code is repeatedly read-out, and the interpolation is performed by the read-out gre-hic code.

Thus, the subcode image is expanded in the vertical direction at a expansion factor corresponding to the difference of the number of horizontal scanning lines, and the change in the relative size of the subcode image in the vertical direction depending on the signal format of the video format signal is surely prevented.

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Claims (6)

Claims

1. An apparatus for playing a recording medium on which. in addition to one of two video format signals having different numbers of horizontal scanning lines and a coded information signal, graphic codes including picture information are recorded as a subcode of said coded information signal, said apparatus comprising:

reading means for retrieving signals recorded on said recording medium; demodulating means for demodulating a video format signal component contained in a read-out signal obtained by said reading means, and issuing a video format signal; signal format discriminating means for discriminating the signal format of said video format signal issued from said demodulating means and generating a format discrimination signal representing the discriminated signal format; sync separating means for separating a horizontal sync signal from said video format signal issued from said demodulating means; clock generating means for generating a clock signal having a frequency higher than the frequency of said horizontal sync signal; first counting means whose count value varies with said horizontal sync signal; 42 second counting means whose count value varies with said clock signal; inhibiting means responsive to said format discrimination signal, for periodically inhibiting the supply of said horizontal sync signal to said first counting means for a time period corresponding to a difference between the numbers of horizontal scanning lines of said two video format signals at a predetermined periodic rate; extracting means for extracting said graphic codes from said coded information signal contained in said read-out signal; a memory; memory control means for sequentially writing said graphic codes issued from said extracting means into.said memory and subsequently sequentially reading out said graphic codes in the order of address indicated by outputs of said first and second counting means; picture signal deriving means for deriving a picture signal corresponding to said graphic codes output by means of raid memory control means; and mixing means for mixing said picture signal with said video format signal issued from said demodulating means.

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2. Apparatus as claimed in claim 1, wherein the output of the first counting means indicates more significant bits and the.output of the second counting means less significant bits of the reading address. 5

3. Apparatus as claimed in claim 1 or 2 wherein said clock generating means generates a clock signal having-a frequency which is an integral multiple of that of the horizontal sync signal.

4. Apparatus as claimed in claim 1, 2 or 3 wherein said signal format discriminating means is capable of discriminating the PAL and NTSC formats and is arranged to periodically inhibit said supply of said horizontal sync signal when the signal format is the PAL format.

5. Apparatus as claimed in claim 4 wherein said inhibiting means comprises a modulo-6 counter arranged to count horizontal sync signals and to inhibit the supply of every sixth horizontal sync signal to the first counting means.

6. Apparatus for playing a recording medium, substantially as hereinbefore described with reference to Figs. 9 to 16 of the accompanying drawings.

Published 1991 at Ihe Patent Office. State House. 66171 High Holborn. L4)r&MnWC1R41P. Further copies may be obtained from Sales Branch. Unit 6. Nine Mile Point Cwmfelinfach. Cross Keys. Newport NPI 7HZ. Printed by Multiplex techniques lid, St Mary Cray, Kent.