MXPA97002872A - Derivation of truncated reproduction current for pregrab digital video recording - Google Patents

Abstract

The present invention relates to a digital video cassette recorder (210), consumer, can record a television signal in advance (09) having a signal format similar to MPEG. The predictive nature of the MPEG similar signal format requires that additional I frame data (51, 61, 71) be generated and recorded together with a normal playback speed data stream (10) to facilitate non-normal speed, or the diffusion of trumped-up reproduction. Additional frame I data streams (51, 61, 71) are generated specifically for each playback speed and written into recorded tapes to facilitate playback at predetermined speeds. Various methods of the invention are described for the derivation of streams of trick-play data of full resolution and reduced resolution. The generation of trick-play data stream of the invention is described for recording in real time by the consumer apparatus and generating normal and trick-play data stream of non-real time for users with pre-recorded digital media

Description

DERIVATION OF TRUCKED REPRODUCTION CURRENT FOR RECORDED DIGITAL VIDEO RECORDING This invention relates to the field of digital video recording and in particular, to the derivation, recording and reproduction of similar advanced MPEG television signals at non-normal speeds. BACKGROUND OF THE INVENTION A standardization committee has proposed a digital video cassette recorder employing a helical scan format. The proposed standard specifies digital signal recording of normal definition television signals, for example, NTSC or PAL and high definition television signals that have a compatible MPEG structure such as a "Grand Alliance" or GA signal proposed. The DN recorder uses a compressed component video signal format that employs intra-field / frame DCT, with adaptive quantization and variable length encoding.The digital VCR or DVCR of DN can digitally record NTSC or PAL television signals and has sufficient capacity for record data to record an advanced television signal A specification of the GA signal is included in a project specification document entitled "Grand Ailiance" HDTV System Specification, published in 1994 Proceeding "del" 48lh Annual Broadcast Engineering Conference Proceedings " March 20-24 1994. The GA signal employs a compatible MPEG encoding method that uses a coded image between the frame, named frame I, an advanced predicframe, named frame P and a bidirectionally intended frame, named a frame B. These Three types of frames are presenin groups known as GDI or Image Groups. The number of frames in a GDI is defined by the user but may include, for example, 15 frames. Each GDI contains a frame I, which may be adjacent to two frames, which are followed by a frame P. In a VCR, "Trucking" or analogue aspect of RT for the consumer, such as a forward or backward image. backward, fast or slow movement, are easily achieved, since each recorded band usually contains a television field. Therefore, the reproduction at speeds different from the normal ones, can give as a result the reproduction of head or heads, the crossing of multiple bands and recovery of recognizable segments of images. The segments of images can have boundaries and provide a recognizable and useful image. An advanced television or similar MPEG signal may comprise groups of GDI images. The GDI, for example, can comprise 15 frames and each frame can be registered by occupying multiple bands on the tape. For example, if 10 bands are distribuin each frame, then a GDI of 15 frames will comprise 150 bands. During the playback speed operation, data is retrieved from frame I, which allows the decoding and reconstruction of the planned frames P and B. However, when operating a DVCR at an abnormal reproduction rate, the response heads transduce sections or segments from the multiple bands. Unfortunately, these DVCR bands no longer represent discrete records of consecutive image fields. However, since the predicframes P and B require preceding data facilitate decoding, the possibility of reconstructing any useful frames of the reproduced pieces of data is greatly diminished. In addition, the MPEG data stream is particularly inexorable for missing or unintelligible data. Therefore, to provide "Trick Play" or non-normal speed response characteristics requires that specific data be recorded, which, when played back in an RT mode, is capable of reconstructing the image without the use of frame information. adjacent or preceding. The specific data or "Trick Play" data must be semantically correct to allow decoding of MPEG., a selection of speeds of "Trick Play", may require different derivation of RT data and may require places of bands recorded at RT specific speed. To be able to reconstruct without data of previous frames, it is required that the specific data of the "Trick Play" are derived from the frames I. The specific data of the "Trick Play" must be corrected syntactically and semantically to allow the decoding, for example, by a compatible GA or MPEG decoder. In addition, the "Trick Play" or RT data should be inserted into the MPEG-like data stream to be recorded along with the MPEG-like signal of normal playback.This compartment of the data capacity of engraving channels can impose impediments in terms of the RT data character regime that can be provided within the available tracking capability The RT data character regime can be used or shared in a variety of spatial and / or temporal resolution in ia Derived or reconstructed RT image The reproduced "Trick Play" image quality can be determined by the complexity of the RT data derivation For example, a DVCR consumer must derive RT data during recording, essentially in real time and only with additional data processing expense added to the cost of DVCR Therefore, the consumer's DVCR "Trump Play" image quality Real-time, it may seem inferior to the RT image data derived by non-real-time image processing using sophisticated digital image processing With non-real-time RT image processing, for example, a program can be processed edited, possibly on a scene-by-scene basis, possibly at non-real time playback speeds, to allow the use of sophisticated digital image processing techniques. Said non-real-time processing may inherently provide high-quality "Trick Play" images that can be obtained with real-time processing. COMPENDIUM OF THE INVENTION A method for deriving and recording a representative MPEG compatible digital image signal that facilitates the reproduction in more than one speed. The method comprises the steps of: receiving a representative digital image signal; temporarily processing the representative digital image signal to generate a representative digital image signal scanned progressively; spatially processing the representative digital image signal progressively scanned to produce a representative digital image signal of reduced resolution; temporarily sub-sampling the representative digital image signal of reduced resolution to form a specific signal for a trick-play speed; encoding the specific signal for a trick-play speed to produce a MPEG-compatible signal of trick-play-specific speed; encoding the representative signal of digital image to produce a compatible MPEG signal of normal reproduction; selecting between the MPEG compatible signal of trick-play specific speed and the MPEG compatible signal of normal reproduction to form a stream of formatted MPEG character record; and, record the stream of MPEG formatted record characters. BRIEF DESCRIPTION OF THE DRAWING Figure 1 is a simplified block diagram of an inventive system for the real-time generation of a "trick-play" data stream having low resolution. Figure 2 shows a simplified block diagram of an additional inventive system for the real-time generation of a "full-resolution trick-play" data stream Figure 3 shows a simplified block diagram illustrating an inventive method for generating low-resolution "trick-play" data streams for inclusion in pre-recorded digital registers Figure 4 shows a simplified block diagram illustrating an additional inventive method for generating "trick-play" data streams for inclusion in pre-recorded digital records. Figure 5 illustrates the derivation of coefficients of predicted macroblock CDs Figure 6 shows a block diagram Simplified Partial Illustrating an Additional Inventive Method for Non-Real Time Generation of Pre-Recorded Records Figure 7 shows a simplified partial block diagram illustrating another inventive method for non-real time generation of pre-recorded records DETAILED DESCRIPTION In a video recorder digital video cassette for consumers, the main considerations in the real-time generation of a trick-play stream are the complexity and cost of processing required and the need to maintain this cost at a reasonable level. For this reason, the processing used in the generation of a stream of real-time trick-play data can be limited by extracting pieces from the existing character stream and implementing minor modifications to the character comment parameters. The "trick-play" data streams can be produced in real time by extracting intra-informac pieces independent ion of the original data stream This intra-information can come from intra-frames, intra-modes, and / or intra-macrobioques The source selected for data derivation from frame I, depends on the form of intra-renewal used in the original current and for illustrative purposes, it is assumed that any method of renovation is used whether intra-frames or intra-moduios In a first inventive method of real-time generation, a "trick play" data stream of resolution is derived in the low space. The trick-play stream of resolution in the low space can, for example, have resolution in accordance with the standard of CCIR 601, (720 x 480 pixels), regardless of the resolution of the original HDTV stream Since the set of effective characters available for trick-play comments is limited to 2M characters / second, using low-resolution, this form results in fewer characters used per frame, and therefore, a relatively high temporal resolution can be achieved. However, this resolution in the low space can only be practical if an advanced decoder and television screen are capable of such resolution In a second inventive method, a trick-play comment is generated that has the same resolution, or count d e pixels, like the original HDTV material However, since the scheme of useful trick play characters is limited by the engraving channel capacity of nominally 2 M characters / second, there is a compromise between the resolution in space and temporal Therefore, the effective provision of a "Trick Play" resolution mode in the entire space requires that the temporal resolution be reduced to remain in proportion to the capacity of the RT data channel. The first inventive method for generating time "Trick Play" real-time resolution data in the low space is illustrated in Figure 1 In this illustrative block diagram, trick-play speeds of 5x, 18x and 35x are generated. For each RT speed, intra-coded frames are constructed , of low resolution, from a transport stream similar to MPEG received Detecting the information of MPEG headers of current of t Transportations below the level of the module can be extracted, processed and used intramodules to create a single frame I in the memory 110. The stage of extraction and processing 1.00 performs three tasks; extracting macroblocks for the construction of an RT framework I, recodes the CD transformation coefficients when DPCM coding is needed and discards unwanted CA transformation coefficients, when necessary. Having constructed and stored an I-frame of resolution RT in memory 10, it is used in the generation of velocity-specific data quotes for each trick-play speed. A modulated radio-frequency carrier that responds to a compatible signal of MPEG, is received by the receiver 05. The modulated vehicle can come from an antenna or a cable, not shown. The receiver 05 demodulates and processes the received carrier to produce an MPEG compatible advanced television transport stream 09. The advanced television transport stream 09 is demodiplexed in block 20 to obtain only the Packed Elementary Component or CEP stream corresponding to the advanced television video information. The PEG stream is decoded in block 30 to extract the payload of MPEG encoded video stream. Having extracted the encoded MPEG stream, the required intra-encoded information can be detected and extracted. The sequence detection block 40 examines the character stream for the presentation of a departure code characterized by twenty-five O's followed by 1, followed by an MPEG video header indicating the 8-character address. The image detection is carried out in block 50 and block modules 60 are detected in block module 60. Since the intra-coded "trick play" frame I is to be constructed, it is only extracted between modules. The intramodules only contain uncoded macroblocks and are characterized by an intra-module indicator in the module header. Thus, when an intra-module indicator is set to 1, the entire module is passed to stage 100 of "data extraction and processing." The intradetection process of block 70 assumes that both intra-domain and intra-module renewal techniques are employed and Also, if the intramodule indicator in the module header is set when appropriate, if the intramodule indicator is not fixed or if the intra-macroblock refresh is used, then an additional level of detection below the macrobiocheck level is required. of data and processing step 100, is selected from the intra-coded macroblocks extracted in block 70, only intrainformation which is used to construct several trick-play data streams.Further, block 100 performs any processing that may be necessary to ensure syntactic and semantic corrections for the MPEG compatibility of the resulting reconstructed RT frame I. Since the reconstructed RT frame i is of resolution in the lower space than the original MPEG current, only a subgroup of detected intra-macroblocks is required. To determine which macroblocks or MB are to be maintained and which are to be discarded, you can use either a mathematical unction and a predefined lookup table. The resolution frame in the resulting lower space results from the work with various parts selected from the macroblocks. A stage of the controller 90 is coupled to the processing step 10 and provides either the calculation required by the mathematical function or provides the lookup table to determine the selection of macroblocks. The relation between the position of MB in the new frame I of low resolution, (mb (i, j), i = 0, 1, 2, ... n-1, j = 0, 1, 2, ... m-1, where m and n are the new width and height of the frame I in MB respectively e and j refer to the row and column of MB) and the original full resolution frame ((MB (I, J), l = 0, 1, 2, ... N-1, J = 0, 1, 2, ... M-1, where M and N are the original width and height of the frame and I and J are the row and column of MB ), the relationship is given by: i (low resolution row) = [I. (nl) / (N-1)] j (low resolution column) = [J. (m-1) / (M-1) )] where the product of the square brackets [x] denotes the value of the nearest whole number to x.The low resolution RT frame I uses a subset of the macroblocks of the original frame with the remaining unselected MBs discarded. Figure 5 illustrates an illustrated 4: 2: 0 mastered signal comprising three intracoded macrobiocs MB1, MB2 and MB3, wherein each nde blocks 0, 1, 2, 3, 4, and 5 Macrobioche 2 is crossed to illustrate the lack of use in the construction of the frame of RT reduced resolution The CD coefficients of each block of illumination and chrominance are described in Figure 5 with dark strips The CD coefficients are foreseen within each macrobiocheque, with the CD coefficient of the first block of a MB being provided with the last CD coefficient of the immediately preceding MB of the module. The arrows in Figure 5, illustrate the Prediction sequence Therefore, if the preceding MB is not selected, for example, MB 2 of Figure 5, certain CD coefficients of the newly contiguous macrobiocide must be recalculated as described by the "NES" arrows of Figure 5 and they are recoded using DPCM. This recoding process is carried out as the macroblocks are written into the memory of frame I, 110. If the HDTV video sequence originating from an interleaved scan source is to include an optional processing step to remove the interspersed "flashing" displayed by the frozen interleaved fields containing motion If the temporal resolution of the reconstructed gimmicked stream is so that the same frame (two fields) is displayed for more than one frame period, then said intermittent 'flicker' can be very noticeable In the coded macroblocks of capo, this "flickering" artifact can be eliminated by copying the two upper blocks of the macrobioc, blocks 0 and 1, to the two lower blocks, blocks 2 and 3. This copying within the macrobiocide, effectively forms both fields, thus removing the same any movement from field to field of the frame. This recoding process is performed as the macroblocks are written to the frame memory I 110. An additional function performed by the processing step 100, is the removal of AC coefficients from each macrobioque that can not be accommodated in the frame. I RT newly built due to the low rate of characters available for trick play streams. To achieve this, each block is decoded of variable length to the point where the block will be filled with zeros, indicating the last coefficient of that block. The number of characters for each block is stored and accumulated in a compensator. Characters are counted, and when an account exceeds a predetermined number, the remaining A coefficients are disabled or deleted. The number of characters per MB of RT depends on the global regime allowed for each trick-play stream and the resolution or temporary number of frame updates per second. The block diagram of Figure 1 illustrates the formation of trick play data streams having the same set of placed characters. If the regime differs significantly between RT speeds, for example, to provide deferred resolution at each speed, the number of AC coefficients retained in the frame memory I 110 will also differ for each speed. Therefore, the memory of the frame I 110, can not be shared and separate memories of the frame I can be required for each RT rate or character scheme The low resolution RT frame I of the invention assembled in the memory 110 of the frame I, is coupled to three stages of generating generation of trick-play, 5 times, block 145, 18 times, block 160 and 3 times of bioque 170 In illustrative figure 1, each trick-play stream can distribute the same character regime and temporal resolution as it could represent a preferred configuration However, each reconstructed RT frame I is not used for each RT speed. For example, if the frame refresh rate I in the The original comment is once every fifteen frames (M = 15) and the time resolution used by each trick play stream is selected to be three, that is, the number of frame times between frame updates, then for 5 times speed , (speed 5x) (3 frames repeats) / (15 frame renewals) = 1 0 therefore each frame i of RT will be used Similarly for speeds of 18x and 35x, (18) (3) / (15) = 36 (35) (3) / (15) = 7 0 Therefore at the speed of 18 x, approximately every third or fourth frame I is used, and at a speed of 35x, every seventh frame I is used. If it is assumed that the intra-renewal period in an advanced television stream of 0.5 seconds (M = 15 for 30 fps source) then, a maintenance time of three frames for 5x speed is the highest possible RT temporal resolution. For simplicity and consistency, a maintenance time of three frames can be used for the remaining RT speeds. A higher temporal resolution of two frames or a single frame maintenance time can be used for higher RT speeds since the lower temporal resolution at higher speeds can give a false sense of decreasing the actual trick-play speed. Assuming that the effective trick-play character set is constant, the provision of a higher temporal resolution could consequently require a resolution quality in the lower space. The reconstructed RT frame I is read in memory 110 and packed, according to the speed of RT, by blocks 145, 160 and 170, which add the appropriate MPEG image headers and a CEP layer. The advanced television transport stream 09 is regulated by a compensator 15, which generates the signal 10, a transport stream for normal playback speed processing. The normal reproduction transport stream 10 is coupled to the MUX multiplexer 150. The MUX multiplexer 150 is controlled by responding to the servo signals of the recorder 210 to generate a stream of output characters having a sequence, which, when recorded , produces a predetermined band format. The registered band format is selected to provide the registered RT character regime and to facilitate the specific physical distribution of specific speed RT frame I packages within specific recorded bands. The recorded band format therefore facilitates playback at normal speed and at predetermined trick play speeds. The frames of RT frame 1, signal 5x 5x, signal 13x 18x, and signal 141 of 35c are coupled to multiplexer 150 which inserts the frame packages I for each RT speed in the normal playback transport stream . Therefore, a valid transport stream, similar to MPEG, is formatted to record the processing by the recorder 210 and register on the tape 220. To minimize the character regime of RT, instead of frames I of RT Repeats, frame repetitions or maintenance times, can be implemented by writing empty frames P between frames I in the video stream. An empty P frame results in the prediction of the prior frame encoder, that is, the RT frame I. Alternatively, frame repeats can be implemented by setting the DSM-trick-mode-indicator in the CEP layer and calculating the MRT / MTD Decoding Time Mark and Presentation Time values so that each I frame of RT is present the necessary number of times in a separate frame. Each frame repeat method produces the same result. However, the second method does not require extra processing of the RT comment in reading and, therefore, does not add extra cost to the unit. However, the second method requires that the optional DSM-trick-mode-indicator be supported in advanced television decoders. With this second method, the extra processing is implemented in the advanced television decoder. Any frame repeat method may be implemented during the generation of specific velocity current in blocks 145, 160 and 170. The trick play current generation techniques of the invention, described above, were employed to produce trick-play speeds of 5x, 18x, and 35x with a resolution in the space of 720 x 480 pixels and an effective trick-play data rate of 2.0 Mbps. The different trick play speeds were evaluated and can be summarized by the following points: Speed data of each trick-play were generated by representing low resolution MPEG compatible transport streams (720 x 480 pixels). Each RT stream contains only intra-coded frames thus allowing the same trick-play stream to be used for both RT Fast Forward and Fast Backward modes.To retain an aspect ratio of 16: 9, the image size in real space is sampled at 720 x 384 pixels, the rest of the area being above and below the black part of the RT image. The temporal resolution is such that a constant maintenance time of three frames is used resulting in an effective regimen of 10 frames per second. Each frame I of the trick play streams comprises a selection of macroblocks sampled from the original stream. The character regime of 2.0 M. characters / sec. and the maintenance time of three frames allows that the majority of the AC coefficients remain in the macroblocks selected for standard testing material. The resolution in the subjective, global space is fair, depending on the amount of movement and image complexity in the original material. An image frame of 10 fps, provides good temporal resolution. The trick play data stream can be decoded to produce recognizable trick play video images and, therefore, is acceptable for tape search use. The low-resolution real-time trick-play mode of the invention, previously discussed, produces images in space recognizable at a relatively high temporal resolution. However, as already mentioned, this mode can be used if an advanced television receiver / decoder unit can be operated at lower resolution, for example, such as that produced by CCIR recommendation 601. However, if operation is not provided at a lower resolution, then the trick-play data must be derived having nominally the same resolution in space, i.e., the same pixel count as the original source. Figure 2 illustrates an inventive illustrative system for generating time-trick representation streams rea!, full resolution Three trick play speeds of 5 times, 18 times and 335 times are illustrated. The difference between the full resolution scheme of Figure 2 and the low resolution scheme illustrated in Figure 1 is in the block 105 for extracting and processing data, and the generation blocks of stream 15, 165, and 175 The decoding of transport stream and the intradetection described in blocks 20, 30, 40, 50, 60 and 70, operate and operate as described for the low resolution system of RT, the purpose of block 105 of the data extraction and processing stage, is extract only intrainformation required to form trick-play entries and to perform any processing that is required to guarantee the syntactic and semantic corrections of the resulting RT frame I The functionality of block 105 differs from that of block 100 in that the frame I regenerated it must have the same resolution, or pixel count, as the original data comment. Therefore, all intramacroblocks are used to reconstruct the new RT framework I. Since the MBs are not deleted, no CD transformation coefficient is required. The main function of the processing block 105 is the removal of the CA coefficients of each macrobioche, which, as a consequence of a scheme of trick-play characters, can be distributed in the new RT framework I. The low RT channel character scheme, nominally 2 M characters / sec., Forces a transaction between the number of the used AC coefficients, ie resolution in space, and the temporal resolution, or update rate of frame of the trick-play stream. This transaction of the space against the storm is also present in the derivation of the low resolution current. However, in a full resolution frame, that is, the same pixel count, the DC coefficients alone probably represent more characters than all the coefficients, both CA and CD assembled in a low resolution RT frame. Thus, any limited inclusion of still few CA coefficients in each full-resolution macrobioque, will produce a significant reduction in the temporal resolution, that is, the frame update time will be extended, with no more frame repeats. Therefore, to facilitate constant temporal resolution in streams of full-resolution trick representation, a system can use only the CD coefficients of each macrobioche, all the CA coefficients being discarded. In addition, the discarding of the AC coefficients reduces the processing complexity since only variable length decoding of the DPCM value of the CD coefficient is required. Figure 2 illustrates an illustrative system in which each trick play speed has the same character regime, and therefore, the same frame memory I can be shared among the three RT speeds. As previously discussed, if original HDTV video images were generated by interleaved scanning, then an optional processing step may be included to remove the interspersed "flicker" exhibited by frozen fields containing motion. One such method has already been described. However, since this illustrative high resolution RT system only transforms CD coefficients, a simpler and more efficient method can be provided by setting the frame_pred_marker_dct flag in the extended_coding_coordinated image section to "1". This indicator shows that all the MBs were coded by the frame, therefore, a previously coded block, which could produce flicker, is decoded as a block coded in the frame. The result is that each field is placed in the upper or lower portion of a block and any 'blinking' is removed. This flicker removal method also reduces the number of characters used in the macroblock-mode section since the indicator dct_t? Po can no longer be present if the frame_pred_marco_dct_ is set to '1'. The reconstructed RT frame I is assembled in memory 115, and coupled to three stages of trick play generation, 5 times speed described in block 155, 18 times speed in block 165 and speed of 335 times in block 175. The illustrative system of Figure 2 assumes that in each trick-play stream it has the same effective character regime and therefore the same approximate time resolution, as discussed previously, each frame I is not used. RT reconstructed for each speed. However, the use of frame I of RT may be further limited for the following reason. Although each frame I of RT has the same number of coefficients, for example, only CD, each frame I of RT can not have the same number of characters since the CD coefficients are encoded with variable length. Therefore, a constant temporal resolution or frame that retains time, can not be fixed for each trick-play stream. Instead of the frame retaining time varies slightly after time with the number of characters required to encode or form each frame i of RT. For each trick-play speed, the respective "stream generation" steps, 155, 165 and 175, wait until enough characters have accumulated in the compensator 105 to encode a frame I of RT. Then yes the frame I of RT accumulated in the compensator at the moment in which there is a frame I of new RT, that is to say one that has not been coded in the speed of specific trick representation, the frame I of RT is coded and the number of used characters will be subtracted from those available If each frame I was of the same size and each speed of trick representation was distributed to the same effective character scheme, this scheme could be equivalent to that described for the low resolution system and the period of renewal of the frame could be constant for all speeds. The reconstructed RT frames I are read from memory 115 and packaged by current generators 155, 165 and 175 to form a compatible MPEG of transport streams in exactly the same way as detailed for the low resolution system. The generation technique of truncated representation signals of resolution in the entire space, of the invention, written before, was evaluated at an effective trick-play representation rate of 20 Mbps, for trick-play speeds of 5x, 18x and 35x Performance should be summarized as follows A MPEG compatible transport stream of only one RT frame, independent , each trick-play speed can be recorded. The temporal resolution varies with the scene complexity and is lower, having frame maintenance times longer than the low-resolution trick play system in the previously described space. The average and the variation in Maintenance times experienced for the normal source material are shown in the following table: Note: Because an identical effective trick play pattern is used for all speeds, the temporal resolution will always be similar (if not identical) for each speed. Each frame I of RT uses only CD coefficients. The overall quality of resolution in space is only fair since only CD coefficients are used. The quality of temporal resolution can vary between poor and fair, depending on the level of complexity within the material encoded by RT. However, the resulting trick-play images can be recognized and accepted for the use of tape search. The main differences between current derivation of real-time trick-play data and pre-recorded trick play result from cost concerns and lack of complexity imposed on a consumer recorder / player. The consumer unit must derive and record the trick-play data stream while recording normal playback data, ie the trick-play data stream is derived in real time With pre-recorded material, the trick-play data streams can be derived directly from a source of original images instead of a compressed MPEG encoded stream The specific velocity RT data streams can be derived independently from each other and independently of the actual recorded event Therefore, pre-recorded trick play data, can be derived in non-reai time possibly in non-normal or slower frame repetition regimes Since the concerns of the consumer's real-time method do not apply more than the quality of trick-play diffusion achieved by the pre-recorded material, it can be significantly A first method of the invention of the derivation of data from Pre-recorded RTs provide a resolution in the space of, for example, CCIR Rec 601 which has a resolution of 720 x 480 pixels without taking into account the resolution of the original HDTV stream. A second method of the invention involves a streamlined playback stream of the same resolution ie pixel count as the original HDTV material Figure 3 illustrates an illustrative block diagram showing a method of the invention for generating pre-recorded trick play data streams Without taking into account the format of the video material of the original HDTV 09 the temporary processing block 30, performs temporary sub-sampling which produces a progressive signal 31 of 30 Hz. The operation of this stage may differ depending on whether the material of the original source is progressive with a frame rate of 2997 / 30 Hz. With source material progressively scanned, the frame rate can be reduced by dropping the sequence every second frame. Falling from alternate frames a progressive sequence results in having half of the temporal resolution of the original source material. With the interleaved source material, the frame rate remains the same but only one field of each frame is used. This process results in a progressive sequence of half of the vertical resolution and the same frame rate. The frames scanned progressively, the signal 31 is coupled to the block 40, which generates a lower resolution signal having, for example, the resolution delivered by CCIR Rec. 601 Each frame scanned progressively is resampled at 720 x 480 pixels to retain the aspect ratio of 16: 9, and the upper and lower edges are filled with black to produce a 'letterbox' format of 720 x 480 pixels. The HDTV signal is now represented by the signal 41, having a resolution in the lower space of 720 x 480 pixels, progressively scanned with a frame rate of 30 Hz. The signal 41 is coupled to the blocks 50, 60, 70 which impiementan the temporal subsampling that depends on the speed. Each trick-play stream is constructed to have the same temporal resolution or frame that holds the time of 2 frames, that is, each frame will be repeated once. Therefore, at the trick-play speed of N times, the frame rate is reduced from 30 Hz to 30 / 2N Hz. Therefore, the resulting registered frame rates are as follows, 5x becomes 30/10 Hz, 18x becomes 30/36 Hz and 35x becomes 30/70 Hz. Since each frame is presented twice and the display rate is 30 Hz, the effective speed of the scene content remains correct at each speed. Temporary sub-sampling blocks 50, 60, 70, general output character streams 51, 61 and 71, respectively, which are coupled to the respective MPEG encoders 120, 130, and 140, to character streams compatible with the format of MPEG Since MPEG compatible coding is the same for each speed, and since in real-time processing of pre-recorded environment it is not necessary, the same MPEG encoding hardware can be used to encode the normal display stream and every trick-play stream. This community of use is indicated by the dotted line that encloses the MPEG encoder blocks 100, 120, 130, and 140. The temporarily sub-sampled character streams 51, 61, and 71 are encoded by MPEG as frames I. Each frame I it is repeated once using the DSM_truco_representac? ón_? nd ?dor, located in the CEP layer as previously described. The resulting compatible MPEG streams representing stream 101, NP of normal playback speed, and stream speeds 121 of the trick play of 5x, stream 131 of 18x and stream 141 of 35x, are coupled for registration format by multiplexer 150. The multiplexer 150 effectively selects between the different MPEG streams to generate a format signal of the synchronization block 200, suitable for recording the processing by the record playback system 210 and writing the tape 220. As described above , the use of the predetermined RT speeds allows the specific rate RT data to be placed, or recorded, at specific locations of the synchronization block within the recorded bands. This multiplexer 150 formats the signal 200 of the synchronization block to locate data of the specific speed RT frame I at specific locations of the synchronization block within the recorded bands. These specific locations facilitate reproduction at several specific speeds of RT. Figure 6 is a partial block diagram illustrating a further arrangement of the invention of the non-real time "trick play" apparatus of Figure 3. The RT 51, 61 and 71 signals processed at specific speeds are coupled to memories 520, 530 and 540 that store the digital image signals processed 5 times, 18 times and 35 times, respectively. The original HDTV signal 09 is also stored in the memory 500. The production of the pre-recorded media or tape is facilitated by the sequential selection between the different stored digital signal sources to form an output signal that is encoded by MPEG by the encoder 100 and it is recorded in the middle. A multiplexer 150 is controlled to select among the different sources of digital signals to form an output signal for MPEG encoding. The MPEG encoded signal 200 has the different signal components arranged so that a register can be reproduced at normal and trick-play rates. Therefore, the arrangement of the invention of Figure 6 facilitates the derivation of non-real time and independent of the sources of digital signals of normal reproduction and trick play to code them as MPEG compatible character streams. A further arrangement of the invention is shown in block 600 which shows an alternate use for the stream of MPEG encoded data of normal and multiplexed trick play, produced by MUX 150. The alternate system of the block 600 replaces the MPEG 200 encoded data stream, the recorder 210, FMT CTL format control signal, decoder 07 and screen 300. In block 600, a coded data stream The MPEG 202 communicates with a transmitter 400 to couple the encoder 07 and screen 300. A user who sees the screen 300 can choose to advance the material being viewed and initiate a REM CTRL remote control command that communicates with the user. multiplexer 150. The multiplexer 150 responds to the users of the remote command and selects, for example, the current 521 characters at a speed of 5 times, for couplers by the MPEG coding and subsequent transmission, decoding and display.

Similarly, the user may choose to view in the reverse direction in, for example, 5 times speed. This selection can make it easier to read the playback speed memory 520 of 5 times in reverse. Therefore, the arrangement of the block 600 provides controlled user selection between MPEG encoded data streams of normal and trick-play. Figure 7 is a partial block diagram illustrating another arrangement of the invention of the non-real-time trick play apparatus of Figure 3. In Figure 7, the reproduced digital signals 09, 51, 61 and 71 normal and trick-play, are coupled to be encoded as compatible character streams by the encoder 100. With non-real time signal processing and pre-recorded material preparation, the signals 09, 51, 61 and 71 can be derived separately and coupled individually for MPEG encoding by a single encoder 100. The individually encoded MPEG character streams 101, 121, 131 and 141 are stored in memories 550, 560, 570 and 580 representing streams of normal playback characters and 5x, 18x and 35x, respectively The storage memories 550, 560, 570 and 580 may be provided by disk in solid state, or magnetic medium and generate output signals 501, 521 , 531 and 541 which are coupled to the muitiplexer 150. The multiplexer 150 responds in a controlled manner to the recorder 210 to generate a registered MPEG compatible character stream formatted so as to provide playback at normal playback speed and at the speeds of "trick play" Predefined An additional arrangement of the invention is illustrated in the bioque 600, which shows an alternate use for the multiplexed trick-play and normal-play MPEG encoded data produced by MUX 150 The alternate system of the 600 block replaces the current of MPEG 200 encoded data, the grader 210, FMT CTL format control signal, decoder 07 and display 300 In block 600, an MPEG 202 encoded data stream communicates with a transmitter 400 for coupling the encoder 07 and screen 300 A user who sees the screen 300 can choose to advance the material that is being viewed and start a REM CTRL remote control command which communicates with the multiplexer 150 multiplexer 150 responds to the users of the remote command and selects, for example, the current 521 characters at 5 times speed, for connectors by MPEG encoding and subsequent transmission, decoding and display Similarly, the user can choose to view in the reverse direction at, for example, 5 times speed. This selection can facilitate reading the 5 times reverse playback rate 520. Therefore, the arrangement of the block 600 provides controlled user selection between of MPEG-encoded data for normal and trick-play The illustrative system of low-resolution RT in space, illustrated in Figure 3, and described above, produces trick-play quality of significantly higher quality than that obtained from streams of trick play real time derivatives. The results produced can be summarized as follows. During recording, a low resolution MPEG compatible stream (720 x 480 pixels) of a single, independent I frame is written for each trick-play speed. The size of the image in real space is 720 x 384 pixels, to retain aspect ratio of 16: 9, presented in a "letterbox" format. The temporal resolution is effectively 15 frames / second for each trick-play speed and produces quality from good to excellent that remains constant for each speed. The resolution in space produced by a data regime of 2.0 Mbps and resolution of 720 x 480 pixels is good to very good, depending on the complexity of the original material. In general, the image quality of trick play displayed with this scheme is very high. The low resolution, pre-recorded trick play system, shown in Figure 3 and described above, produces good quality space images at a relatively high temporal resolution. However, said low resolution method can be used by providing that the advanced television decoder / receiver unit can support the lower resolution display format. Figure 4 is an illustrative block diagram of a full resolution, pre-recorded trick play current generating system of the invention, which provides trick-play speeds of 5x, 18x and 35x. As previously discussed, the derivation of pre-recorded trick play data stream can be generated from the original, uncompressed, original material. Figure 4 illustrates the generation of normal playback and trick-play character streams, however, these can be generated independently of one another, directly from the original HDTV material. Since this system provides full resolution, sub-sampling in space is not required and therefore less processing is required than that shown in Figure 3. Since the original or compressed, original material can be used, the frames that are intra-coded can be chosen with exactitude to adapt the speed of the trick representation, instead to select frames I of a coded stream. In addition, a constant temporary renewal regime can be maintained, which is more pleasant for the user. The original HDTV video signal 09 is shown coupled to the MPEG encoder 100 which generates an MPEG 101 stream for normal playback speed operation. The signal 09 is also coupled for temporal sub-sampling in blocks 55, 65 and 75 respectively. trick-play speed of times N, to encode, only each font frame source Nth can be used However, depending on a desired transaction between the resolution in space and the temporal, the actual frames used for coding may be closer to each frame 5Nth or 8Nth in order to provide a resolution in the acceptable space Therefore, frame maintenance times, or temporal resolution, are similar to those of the real-time complete resolution system described above Having selected a framework which maintains or updates time, for example each frame 5Nth for each trick-play speed of N times, signal 09 of the HDTV stream, it is temporarily subsampled for each RT speed. The RT stream of 5 times, is derived in block 5 which temporarily subsamples by a factor of 1 / 5N or 1/25, that is, 1 frame in 25, is selected to generate the output signal 56 Similarly, the RT current of 18 times, is derived in block 65, which temporarily sub-samples by a factor of 1 / 5N, or 1/90 and generates the output signal 66 The RT current of 35 iveces, is derived in block 75, which sub-samples temporarily by a factor of 1 / 5N or 1/175 and generates the output signal 76 The three subsamplered character signals of RT, 56 , 66, and 76, are coupled to encode MPRG in encoder blocks 120, 130 and 140 respectively Since the MPEG-compatible coding is the same for each speed and because real-time processing is not necessary in an environment of pre-recorded, you can use the same MPEG encoding hardware for code the normali playback current and each trick-play stream. This community of use is indicated by the dotted line enclosing the MPEG encoder blocks 100, 120, 130 and 140. The temporarily sub-sampled character streams 56, 66 and 76 are encoded by MPEG as frames i. Since the frame update time is constant through each trick-play stream, is also the number of characters distributed for each frame I. Frame maintenance times or repeats of frame i can be implemented using the DSM_project_project_drum as previously described. The resulting MPEG transport streams representing the normal playback speed stream NP, and the trick play stream speeds 121, 5x, stream 131 18x, and stream 141, 35x, are coupled to record by formatting by the multiplexer 150 The multiplexer 15 effectively selects between the different MPEG streams to generate a synchronization block format signal 200, suitable for record processing by the record reproduction system 210 and writing on the tape 220. As previously described, predetermined RT speeds, allow specific speed RT data to be placed, or recorded at specific locations within recorded bands. This multiplexer 150 formats the synchronization block signal 200 to distribute the data of the specific speed RT frame I at the specific synchronization block locations that facilitate playback at the different specific RT rates. The arrangements of the invention of Figures 6 and 7 can also be applied to the generation arrangement of "non-real-time trick-play" of Figure 4. As described, the arrangements of Figures 6 and 7 can facilitate the real time and independent derivation of normal playback and trick play digital signals, and MPEG compatibie character streams Storage and retrieval memories 550, 560, 570, and 580 of Figure 7 generate compatible MPEG output signals 501, 521, 531, and 541, which are illustrated as being collected via the multiplexer MUX 150. The MPEG 200 output stream generated by MUX 150, in a modality of the alternate invention, may be coupled to a transmission system for distribution of The user's screen The MUX 150 multiplexer can be controlled to select between memory-derived compatible MPEG output signals that respond to user commands. For example, a user When you see a program at normal speed, you will receive and decode the character stream signal 501. The user may wish to fast forward or fast forward the program by remotely selecting to view, for example, the MPEG stream of five speed characters. The user's remote command for 5x playback causes the multiplexer 150 to select the MPEG 521 character stream that is output to the user. The concern of retaining full resolution in space and time, results in a trick-play quality that is very similar to that achieved by the full-resolution real-time method. However, this pre-recorded method has an advantage that the frame maintenance time is constant. The described trick play stream generation technique provides trick play speeds of 5x, 18x, and 35x, which have full resolution in space, and an effective iridescent playback rate of 2.0 Mbps. Performance can be summarized from as follows: During recording, an MPEG stream of a single I frame, independent, is written to the tape for each trick-play speed. The resolution in space is equal to that of the original material. The temporary resolution is fixed having a maintenance time of 5 frames. Each frame i uses all the CD coefficients and some of CA Global quality in space is fair. Recovered trick-play images can be recognized and are acceptable for tape search purposes.

The following table summarizes the quality of trick play achieved by the different methods of the invention described.

GENERATION OF CURRENT CURRENT GENERATION REPRODUCTION PLAYBACK TRUCK OF TIME TRIED OF TIME NO REAL REAL QUALITY MODES IN SPACE: QUALITY IN SPACE: REPRODUCTION from poor to fair, only from poor to just, only TRICKED from using CD coefficients. they use CD coefficients and COMPLETE RESOLUTION TEMPORARY QUALITY: some of CA. from poor to acceptable, TEMPORARY QUALITY: retention times from poor to acceptable, frames of 5-8, variable retention times frames of 5, constant QUALITY MODES IN SPACE: QUALITY IN SPACE: REPRODUCTION from poor to good, depends on poor to very good, TRUCKED of the material, work by depends on the material RESOLUTION LOW used parts of Mbs. TEMPORARY QUALITY: TEMPORARY QUALITY: very good, good time, retention time, retention of frames 2, frames 3, constant. constant In view of the preoccupied concerns, the highest-quality trick play can be selected, both in real-time and pre-recorded terms, by using trick-play data of lower resolution. However, the advanced television receiver / decoder must support the use of a low resolution mode. If full-resolution trick play modes are used, the quality provided can be increased by manipulating several parameters. For example, raising the effective character rate for each trick-play speed will allow an increase in resolution. However, a minimum character ratio of approximately 2.0 Mbps is required. If the number of speeds of "Trick Play" provided is reduced, for example two in each direction, then the effective character rate can be increased for each remaining speed. The effective temporal resolution, or number of frame repeats, results from the transaction between the temporal and spatial resolution. Therefore, each parameter can be optimized depending on the desired application.

Claims (6)

1. CLAIMS 1. A method for deriving and recording a signal representative of MPEG compatible digital image which facilitates the reproduction at more than one speed, said method comprising the steps of: a) receiving a signal (09) representative of digital image; b) temporarily processing (30) said representative digital image signal to generate a representative digital progressively scanned signal (31); c) spatially processing (40) said progressively scanned digital image representative signal (31) to produce a representative digital image signal of reduced resolution (41); d) temporarily sub-sampling (50, 60. 70) said representative digital image signal of reduced resolution (41) to form a specific signal for a trick-play speed (51, 61, 71); e) encoding (120,130,140) said trick-play speed-specific signal to produce a trick-play specific velocity-compatible MPEG compatible signal (121, 131, 141); f) encoding (100) said image representative signal (09) to produce a normal reproduction MPEG compatible signal (101); g) selecting between said MPEG compatible velocity-specific reproduced signal (121, 131, 141) and said normal reproducing MPEG compatible signal (101) to form a register formatted MPEG character stream (200); and h) recording (210) said register formatted MPEG character stream (200).
2. 2. The method of claim 1, wherein said trick-play specific velocity-compatible MPEG compatible signal (121, 131, 141) comprises frames I.
3. 3. The method of claim 1, wherein said compatible MPEG signal of specific trick-play speed (121, 131, 141) is controlled (FMT CTRL) to be presented in said record formatted MPEG character stream (200 = so that when recording (210) said MPEG compatible signal of specific velocity
4. 4. The method of claim 1, comprising an additional step of erasing alternate frames when said image representative signal is scanned progressively having a frame rate of 60 hertz.
5. 5. The method of claim 1, comprising an additional step of erasing alternating fields when said representative digital image signal is scanned inter-layered. having a field regime of 60 hertz.
6. 6. The method of claim 1, wherein said time processing (30) generates a representative signal of reduced resolution digital image (41) comprises 720 x 480 pixels. 8. The method of claim 2, comprising a further step of: setting a DSM_truco_reproeduccíón_indicador in a layer of Packed Elementary Current of said MPEG compatible trick play signal (121, 131, 141) to repeat said frame i. The method of claim 1, wherein a rate of said temporary sub-sampling responds to said trick-play speed. The method of claim 1, wherein said selection step responds to a format control signal (FMT CTRL) comprising trick-play speed data and servo-recorder data.