MXPA97002871A - Digital vcr with derivation of current dereproduccion truc - Google Patents

Abstract

The present invention relates to a method for generating a representative MPEG compatible digital image signal for recording which facilitates reproduction at more than one speed, said method comprising the steps of: (a) receiving a stream of data comprising a MPEG compatible digital image representative signal: (b) decoding said data stream to extract intracoding data, (c) storing predetermined intracoded data of said extracted intracoded data to form an intracoded frame having resolution in the reduced space, (d) periodically selecting said intra-coded frame of said stored frame having resolution in the reduced space, (e) sequentially selecting said intra-coded frame selected periodically and said data stream to form an MPEG compatible character stream, and (f) recording said stream of MP compatible characters

Description

DIGITAL VCR WITH TRUCKED REPRODUCTION CURRENT DERIVATION 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 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 proposed "Grand Alliance" or GA signal. The DN recorder uses a compressed component video signal format that employs intra-field / frame DCT, with adaptive quantization and variable length coding. The digital VCR or DVCR of DN can digitally record NTSC or PAL television signals and has sufficient capacity to record data to record an advanced television signal. A specification of the GA signal is included in a project specification document entitled "Grand Alliance" HDTV System Specification, published in "1994 Proceeding" of the "48th Annual Broadcast Engineering Conference Proceedings", March 20-24 1994 The GA signal employs a compatible MPEG encoding method that uses an encoded image between the frame, named frame I, an advanced predicted frame, named frame P and a bidirectionally provided frame, named a frame B These three frame types are presented in groups known as GDI or Image Groups The number of frames in a GDI is defined by the user but can comprise, for example 15 frames Each GDI contains a frame I, which can border on two frames, which are followed by a frame P In a VCR, "Trucking" or analogue RT aspect for the consumer, such as a forward or backward image, fast or slow movement, are easily achieved. Given that each recorded band normally contains a television field, therefore, playback at speeds other than normal may result in the reproduction of heads or heads, the crossing of multiple bands and the recovery of recognizable segments of images. of images can have boundaries and provide a recognizable and useful image An advanced television or similar MPEG signal can 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 distributed in 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 frames P and B provided. However, when operating a DVCR at an abnormal playback speed, the transducer response heads However, since the predicted P and B frames require precedent data to facilitate decoding, the possibility of decoding is greatly diminished, as these DVCR bands no longer represent discrete registers of consecutive image fields. reconstruct any useful frames of the reproduced data pieces In addition to the fact that 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 reproduced in an RT mode, is capable of reconstructing the image without the use of information from adjacent or preceding frames. Specific data or "Trick Play" data must be semantically correct to allow decoding of MPEG. , a selection of "Playback T" speeds rucada ", 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 from previous frames, it is required that the specific data of the" Trucada "are derived from the frames The specific data of ia Trick Play "must be corrected syntactically and semantically to allow decoding, for example, by a compatible decoder of GA or MPEG. In addition, the Trick Play" or RT data must be inserted in the MPEG-like data stream to be recorded together with the MPEG-like signal of normal reproduction This compartment of the data capacity of engraving channels, can impose impediments in terms of RT data character regime that can be provided within the available tracking capability. The data character regime of RT, may be used or shared in a variety of manner between the resolution in space and / or time in the 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 at the expense of processing. additional data added to the cost of DVCR Therefore, the real-time consumer's DVCR "Trick Play" image quality may seem inferior to the RT image data derived by non-real-time image processing using processing Sophisticated digital image processing With non-real time RT image processing, for example, an edited program can be processed, possibly on a scene-by-scene basis, possibly at non-real time playback speeds, to allow the use of sophisticated digital image processing techniques Such non-reai time processing can inherently provide images of "Reproduction Tru each 'of superior quality that can be obtained with real-time processing. COMPENDIUM OF THE INVENTION A method to generate in real time a representative signal of compatible digital image of MPEG, to record in order to facilitate the reproduction in no more than a speed The method comprises the steps of receiving a data stream comprising a representative digital compatible image signal of MPEG, decoding the data stream for extracting intra-coded data, storing predetermined intra-coded data of the extracted intra-coded data to form coded frames having resolution in the reduced space, periodically selecting an intra-coded frame of the stored frames having resolution in the reduced space, selecting sequentially the selected intra-coded frame and the data stream to form a stream of characters; and recording the current of characters in real time BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a simplified block diagram of an inventive system for the real-time generation of a stream of 'trick-play' data having low resolution. 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 streams of low-resolution "trick-play" data for inclusion in pre-recorded digital records Figure 4 shows a simplified block diagram illustrating an additional inventive method for generating "trick-play" data streams for inclusion in the records Pre-recorded digitals Figure 5 illustrates the derivation of macroblock CD coefficients Figure 6 shows a simplified partial block diagram 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 consumer digital video cassette recorder, 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 parts of the existing character stream and implying minor modifications to the character stream parameters. trickle "can be produced in real time by extracting pieces of intra-information independent of the original data stream. This intra-information can come from intra-frames, intra-modules, and / or intra-macroblocks. The source selected for data derivation from the Framework I, depends on the form of intra-renovation used in the original stream and for illustrative purposes, it is assumed that any renewal method is employed whether intra-frames or intra-modules In a first inventive method of real-time generation a "Trick Play" data stream is derived from resolution in the low space. The trick-play reproduction stream in the low space can, for example, have resolution according to the standard of CCIR 601, (720 x 480 pixels), regardless of the original HDTV current resolution Since the available effective character regime for trick-play streams is limited to nolly 2M characters / second, using low-space 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 stream having the same resolution, oc is generated Count of pixels, like the original HDTV material. However, since the scheme of useful trick play characters is limited by the engraving channel capacity of nolly 2 M. characters / second, there is a compromise between the resolution in space and time. Therefore, the effective provision of a "Trick Play" mode of resolution 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 real-time generation of "Trick Play" 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, low-resolution intra-coded frames are constructed from a transport stream similar to MPEG received. By detecting the information of MPEG headers of transport stream below the level of the module, one can extract, process and use intramodules, to create a single frame I in the memory 110. The extraction and processing stage 100 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 a resolution I frame of RT in memory 10, it is used in the generation of velocity-specific data streams 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 transport current of Advanced television 09 is demultiplexed in block 20 to obtain only the Packed Elementary Current or CEP current corresponding to the advanced television video information. The PEG stream is decoded in block 30 to extract the video stream payload. encoded MPEG Having extracted the MPEG encoded stream, it can detect and extract intrac The requested sequence block 40, exas the character stream for the presentation of a starting code characterized by twenty-five 0's followed by 1, followed by an MPEG video header indicating the 8-character address. is carried out in block 50 and module 60 is detected in module modules 60. Given that the intracoded "trick play" frame I will be constructed, it is only extracted between modules. Intramodules only contain intra-coded macrobioces and are characterized by an intra-module indicator in the module header Therefore, 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-module or intramodule renewal techniques are used and also that 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 is required below the level of the macroblock. processing step 100, is selected from the intra-coded macrobioques extracted in block 70, only intrainformation that is used to construct several trick-play data streams. In addition, 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 frame I d e reconstructed RT is of resolution in the lower space than the original MPEG current, only a subgroup of intra macroblocks detected is required. To determine which macroblocks or MB are to be maintained and which are to be discarded, a mathematical anointing can be used and A predefined lookup table The resulting lower space resolution frame results from the criss-crossing with various parts selected from the macroblocks A stage of the controller 90 is coupled to the processing step 10 and provides both the calculation required by the mathematical function or provides the search table to determine the selection of macroblocks The relation between the position of MB in the new frame I of low resolution, (mb (?, j),? = 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 eiyj 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 relation is given by i (row of low resolution) = [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 ax The low resolution RT frame I uses a subset of the macroblocks of the original frame being discarded the remaining unselected MBs Figure 5 illustrates a mastered signal of 420 illustrative comprising three intra-coded macroblocks MB1, MB2 and MB3, wherein each comprises blocks 0, 1, 2, 3, 4, and 5 The macroblock 2 is crossed to illustrate the lack of use in the construction of the or I of reduced resolution RT The CD coefficients of each illumination block and chrominance are described in Figure 5 with dark strips The CD coefficients are provided within each macroblock, with the CD coefficient of the first block of a MB being predicted from 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, it must be returned to calculate certain CD coefficients of the newly attached macroblock, as described by the "NES" arrows in Figure 5, and re-encode using DPCM. This recoding process is carried out as the macroblocks are written into the frame memory. , 110 If the HDTV video stream originated from an interleaved sweep source, an optional processing step can be included to remove the interspersed "flicker" displayed by the interca fields frozen sides that contain motion If the temporal resolution of the reconstructed trick-play stream is such that the same frame (two fields) is displayed for more than one frame period, then that interspersed "flicker" can be very noticeable in coded macrobiocs from capo, this "flickering" artifact can be eliminated by copying the two upper blocks of the macroblock, blocks 0 and 1, to the two lower blocks, blocks 2 and 3. This copying within the macroblock, effectively forms both fields thus removing the same any field movement Frame field 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 macroblock that can not be accommodated in the newly constructed RT frame I due to the low rate of available characters for trick play streams To achieve this, each block is decoded of variable length to the point where the block will be padded 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 overall allowed regime for each trick-play stream and the resolution or temporary number of updates. of frame 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 the RT speeds, for example, to provide deferred resolution at each speed, the number of CA coefficients retained in the memory of the I 110 frame will also differ for each speed. Therefore, the memory of the frame I 110, can not be shared and separate memories may be required from frame I for each RT rate or character frame. The low resolution RT frame I of the invention, assembled in memory 110 of frame I, is coupled to three trick-play current generation stages; 5 times, block 145; 18 times, block 160 and 35 times, block 170. In illustrative figure 1, each trick-play stream may distribute the same pattern of characters and time resolution, which could represent a preferred configuration. However, each reconstructed RT frame I is not used for each RT rate. For example, if the rate of renewal of the frame i in the original stream 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 times of frame between frame updates, then for 5 times speed; (speed 5x). (3 repetitions of frame) / (15 frame renewals) = 1.0 therefore each frame I of RT will be used. Similarly for speeds of 18x and 35x, (18). (3) / (15) = 3.6 (35). (3) / (15) = 7.0 Therefore at the speed of 18 x, approximately every third or fourth frame If it is assumed that the period of intra-renewal in an advanced television stream of 0.5 seconds (M = 15 for a source of 30 fps), then a maintenance time of three frames for 5x speed is the highest possible RT temporal resolution For simplicity and consistency, you can use a maintenance time of three frames for the remaining RT speeds A higher time resolution of two frames or a single frame maintenance time can be used for higher RT velocities since lower temporal resolution at higher speeds can give a false sense of decreasing the actual trick play speed Assuming that the effective trick play pattern is constant, the The resolution of a higher temporal resolution may consequently require a quality of resolution in the lower space. The reconstructed RT frame i is read in the memory 110 and packed, according to the RT speed, by blocks 145, 160 and 170, which add the appropriate MPEG image headers and a layer of CEP The advanced television transport stream 09 is regulated by a compensator 15, which generates the signal 10 a transport stream for normal reproduction speed processing The transport stream of normal reproduction 10 is coupled to the MUX multiplexer 150 MUX 150 multiplexer 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 band format default The registered band format is selected to provide the registered RT character regime and to facilitate physical distribution. Specifies the speed-specific RT frame I packages within specific recorded bands The recorded-band format therefore facilitates playback at normal speed and predetermined trick-play speeds The frames of the RT frame I, signal 121 of 5x, signal 131 of 18x, and signal 141 of 35c, are coupled to the multiplexer 150 which inserts the packets of the frame i for each speed of RT in the normal reproduction transport stream Therefore, a transport current, similar to MPEG, valid, is formatted to record the processing by the recorder 210 and register on the tape 220 To minimize the rate of RT characters, instead of repeated RT frames I the frame repetitions or maintenance times, can be implemented by writing empty frames P between the frames i in the video stream A frame P empty results in the prediction of the frame encoder in the previous frame, ie the RT framework 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 frame I of RT the necessary number of times of separate frame is presented Each method of repetition of frame produces the same result However, the second method does not require extra processing of the current of RT 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 repetition method can 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 pixeies and a frame rate. 2.0 Mbps effective trick-play data The different trick-play speeds were evaluated and can be summarized by the following points: The speed data of each trick-play was generated by representing low-resolution compatible MPEG 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 remainder 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 the majority of the AC coefficients to remain in the macroblocks selected for normal test material. The resolution in the subjective, global space is just, 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 recommendation 601 of CCiR. However, if operation at a lower resolution is not provided, then the trick-play data should be derived having nominally the same resolution in the space, i.e., the same pixel count as the original source. Figure 2 illustrates an inventive illustrative system to generate real-time, full-resolution trick-play streams Three trick-play speeds of 5 times, 18 times and 35 times are illustrated The difference between the full-resolution scheme of Figure 2 and the low resolution scheme illustrated in Figure 1 is in block 105 for data extraction and processing, and current generation blocks 15, 165, and 175 The transport current decoding and 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 to extract only the intrainformation required to form trick-play streams and to perform any processing that is required to guarantee the syntactic and semantic corrections of the resulting RT frame I The functionality of the block 105 differs from that of block 100 in that the frame I regenerated must have the same resolution, or pixel count, as the original data stream. Therefore, all intra-macroblocks are used to reconstruct the new RT frame. Since no MBs are erased, no transformation coefficient is required of CD The main function of the processing block 105 is the removal of the AC coefficients of each macroblock, 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 regime, 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. Therefore, any limited inclusion of even few CA coefficients in each full-resolution macroblock will produce a significant reduction in temporal resolution, that is, the frame update time will be extended, with no more frame repetitions. Therefore, to facilitate constant temporal resolution in streams of full resolution trick representation, a system can only use the CD coefficients of each macroblock, all the AC coefficients being discarded. Furthermore, the discarding of the AC coefficients reduces the processing complexity since only the 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 they were generated original HDTV video images by interleaved scanning, then an optional processing step can be included to remove the interspersed "flicker" exhibited by frozen fields containing motion One such method has already been described. However, since this RT system If the illustrative resolution only converts CD coefficients, a simpler and more efficient method can be provided by setting the indicator of frame_pred_marco_dct in the section of? cod_max? f? cac? ón_extens? to "1" This indicator shows that all the MBs were encoded by the frame, therefore, a block coded by field previously, which could produce 'flicker', is decoded as a block encoded in the frame The result is that each field is coioca in the upper or lower portion of a block and any 'flicker' is removed This method of flicker removal also reduces the number of characters used in the macroblocks section-modes given that the indicator dct_t? po can no longer be present if the frame_pred_marco_dct_ is set to '1' The frame I of reconstructed RT is assembled in memory 115, and is coupled to three stages of generation of trick-play current, speed of 5 times described in bioque 155, velocity of 18 times in block 165 and velocity of 35 times in block 175. The illustrative system of Figure 2 assumes that in each stream of trick representation it has the same effective character regime and therefore, the same approximate temporal resolution, as previously discussed, does not use each frame I of RT reconstructed for each velocity. 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 temporal resolution constant or frame that hold time, can not be set for each trick-play stream Instead of the frame that retains 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 if the RT frame i accumulated in the compensator at the time there is a new RT frame I, ie one that has not been coded in the specific trick-play speed, the RT frame I is encoded and the number of characters used 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 regime, 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., 165 and 175 to form a compatible MPEG of transport streams in exactly the same way as detailed for the low resolution system The stream generation technique of trick representation 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 The performance should be summarized as follows An MPEG compatible transport stream of only one RT frame I, 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 Experienced maintenance times 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 RT frame I uses only CD coefficients. The global resolution of space resolution 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 RT encoded material. However, the reproduction images The resulting differences 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 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 rate RT data streams can be derived independently from each other and independently of the actual engraving event. Therefore, pre-recorded trick-play data can be derived in non-real time, possibly in non-normal or slower frame repetition rates. Since the concerns of the consumer's real-time method are no longer applied, the quality of trick-play broadcast achieved by the pre-recorded material can be significantly higher. A first method of the invention of data derivation of Pre-recorded RT, provides a resolution in the space of, for example, CCiR Rec. 601 that has a resolution of 720 x 480 pixels, without taking into account the original HDTV current resolution. A second method of the invention involves a trick-play stream of the same resolution, i.e. 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 original HDTV video material 09, the temporary processing block 30, performs temporary sub-sampling which produces a 30 Hz progressive signal 31. The operation of this stage may differ depending on whether the material of the The original source is progressive with a frame rate of 29.97 / 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 the temporal resolution of the original source material. With the source material interspersed, the frame rate remains the same but only one field of each frame is used. This process results in a progressive sequence of half the vertical resolution and the same frame rate. The frames scanned progressively, signal 31 is coupled to 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 720 x 480 pixel mailbox format. 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 they implement 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 a 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 it goes 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. The 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 real-time processing of pre-recorded environment is not necessary, the same MPEG encoding hardware can be used to encode the current of normal representation. and every 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 51, 61, and 71 are encoded as MPEG 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 reproduction speed, and speeds of current 121 of trick play of 5x, stream 131 of 18x and stream 141 of 35x, are coupled for registration formatting by the 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 reproduction 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 signal 200 of the synchronization block to locate frame data. Speed I RT I specified in specific places in the synchronization block ation 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 the Figure 3 The RT signals 51, 61 and 71 processed at specific speeds, are coupled to the memories 520, 530 and 540 which store the digital image signals processed 5 times, 18 times and 35 times respectively. The original HDTV signal 09, also it is stored in the memory 500 Production of the prerecorded medium or tape is facilitated by the sequential selection between the different digital signal sources stored to form an output signal that is encoded by MPEG by the encoder 100 and recorded on the medium. A multiplexer 150 is controlled to select between the different sources of digital signals to form an output signal to encode MPEG The MPEG encoded signal 200 has the different signal components arranged so that a register can be reproduced at normal and trick-play speeds. Therefore, the arrangement of the invention of Figure 6 facilitates the derivation of non-reactive time. independent of the sources of normal playback and trick play digital signals to encode them as MPEG compatible character streams Figure 7 is a partial block diagram illustrating another inventive setup of the trick play apparatus "of non-real time Figure 3 In Figure 7, the digital signals 09, 51, 61 and 71 processed from normal reproduction and trick play, are coupled to be encoded as compatible character streams by the encoder 100 With non-reai time signal processing and preparation of pre-recorded material, signals 09 , 51, 61 and 71, can be derived separately and individually collected 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 normali and 5x, 18x and 35x reproduction character streams, respectively. The memories 550, 560, 570 and 580 produce output signals 501, 521, 531 and 541 that are coupled to the multiplexer 150 that responds in a controlled manner to the recorder 210 to generate a registered MPEG compatible character stream that is formatted to provide playback at normal playback speed and speeds s of "trick play" predetermined. The illustrative system of low resolution RT in space, illustrated in Figure 3, and described above, produces quality of truncated reproduction of significantly higher quality than that obtained from trickle current reproduction currents derived real time. The results produced can be summarized in the following way. During recording, a low resolution MPEG compatible stream (720 x 480 pixels) of a single, independent I frame is written to the tape for each trick-play speed. The size of the image in the reai space is 720 x 384 pixels, to retain aspect ratio of 16: 9, presented in a "mailbox" 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 quality of the trick-play image 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, no sub-sampling is required in the space and therefore less processing is required than shown in Figure 3. Since the original or compressed, original material can be used, the frames that are intra-coded will be they can choose with accuracy to adapt the speed of the trick representation, instead of selecting the frames I of an encoded 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 as being collected from the MPEG encoder 100 which generates an MPEG 101 stream for normal playback speed operation. The signal 09 is also coupled for temporary sub-sampling in blocks 55, 65 and 75 respectively. For a 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 5Nth or 8Nth frame in order to provide a resolution in the acceptable space. Therefore, the frame maintenance times, or temporal resolution, are similar to those of the real-time full resolution system described above Having selected a frame that maintains or updates time, for example each frame 5Nth for each trick-play speed N times, signal 09 of the HDTV stream is temporarily sub-sampled for each RT rate. The 5-fold RT current 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, a 18-fold RT current is derived in bioque 65, which sub-samples temporarily by a factor of 1 / 5N, or 1/90 and generates the output signal 66. The RT current of 35 times is derived in block 75, which sub-samples temporarily by a factor of 1 / 5N or 1/175 and generates output signal 76. The three subsampled RT character stream signals, 56, 66, and 76, are coupled to encode MPRG in the encoder blocks 120, 130 and 140 respectively. Since the MPEG-compatible encoding is the same for each speed and because real-time processing is not necessary in a pre-recorded environment, the same MPEG encoding hardware can be used to encode the normali playback current and each trick play stream This community of use is indicated by the dotted line enclosing the blocks of the MPEG encoder 100, 120, 130 and 140. The temporarily sub-sampled character streams 56, 66 and 76 are encoded by MPEG as I. frames. Frame update is constant through each trick-play stream, it 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_industry 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 sync bioke format signal 200, suitable for record processing by the record reproduction system 210 and writing on the tape 220 As previously described, the speeds of predetermined RTs, allow the specific rate RT data to be placed, or recorded at specific locations within recorded bands. This multiplexer 150 formats the sync block signal 200 to distribute the speed-specific RT frame I data in the specific sync block locations that facilitate playback at the different Specific RT rates The inventive arrangements of Figures 6 and 7 can also be applied to the non-real time "trick play" generation array of Figure 4 As described, the arrays of Figures 6 and 7 7, can facilitate the independent derivation of digital signals of normal reproduction and trick-play for the subsequent MPEG encoding and format for the production of pre-recorded tapes or controlled video of the user requesting the service. The concern to retain complete resolution in space and temporary, results in a trick-play reproduction 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 maintenance time of the frame is constant. The described trick play stream provides 5x, 18x and 35x trick play speeds, which have full resolution in space, and an effective trick play rate of 2.0 Mbps. The performance can be summarized as follows: recording, an MPEG stream is written, from a single I frame, independent, on the tape for each trick-play speed. The resolution in the space is equal to the original material. The temporary resolution is fixed having a maintenance time of 5 frames. Each frame I uses all the coefficients of CD and some of CA. The 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 described methods of invention.

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 preoccupations dealt with previously, it is possible to achieve the quality of the best possible reproduction, both in real time and in prerecorded material, through the use of tricky reproduction data of resolution. lower. 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 rate of approximately 2.0 Mbps is required. If the number of "Trick Play" speeds provided is small, 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 (17)

1. CLAIMS 1. A method for generating a representative MPEG compatible digital image signal for recording which facilitates reproduction at more than one speed, said method comprising the steps of: a) receiving a data stream comprising a signal (09) representative of MPEG compatible digital image; b) decoding said data stream (09) to extract encoding data (71); c) storing predetermined intra-coded data (103) of said extracted intra-coded data (71) to form an intra-coded frame having resolution in the reduced space (111); d) periodically selecting said intra-coded frame of said stored frame having resolution in the reduced space (111); e) sequentially selecting said intra-coded frame selected periodically (121, 131, 141) and said data stream (10) to form a compatible character stream of MPEG (200); and, f) recording (210) said MPEG compatible character stream (200). The method of claim 1, comprising an additional step of; selecting from said extracted intra-coded data (71) predetermined intra-coded data by reading a look-up table. 3. The method of claim 1, comprising an additional step of; selecting from said extracted intra-coded data (71) predetermined intra-coded data by performing a predetermined calculation. 4. The method of claim 1, further comprising a step of: selecting said intra-coded frame (111) at a rate related to a predetermined trick-play speed. The method of claim 4, wherein said additional step further comprises a step of: storing said intra-encoded frame of determined speed, of trick play, to form an intra-encoded frame of specific speed, of trick play (121, 131, 141 ). The method of claim 1, wherein said step d) further comprises a step of: selecting said intra-coded frame selected periodically (111) at a rate related to a predetermined time resolution. The method of claim 1, wherein step e) further comprises a step of controlling (FMT CTRL) said sequential selection of said periodically selected frame (121, 131, 141) to facilitate the reproduction of said compatible character stream of MPEG (200) at a reproduction speed different from the normal playback speed. The method of claim 1, wherein said sequential selection responsively responds to a format control signal (FMT CTRL) which includes a control signal (FIG. 211) of a recorder (210) recording said compatible MPEG character stream (200) 9 The method of claim 1, wherein said predetermined intra-coded data comprise predetermined intra-coded macroblocks (MB1, MB2). The method of claim 9, wherein said intra-coded macroblocks comprise illumination and chrominance bioques (0, 1, 2, 3, 4, 5) The method of claim 9, comprising a further step of copying blocks 0 and 1 to blocks 2 and 3 within of the macroblocks that are encoded in fields 12 The method of claim 10, wherein said step c) further includes a step of recoding the CD coefficients previ These are for the first blocks of said predetermined macroblock (MB3) of a immediately preceding predetermined macroblock (MB1) 13. The method of claim 5, comprising an additional step of: repeating said intracoded frame of specific trick-play speed by inserting a frame P empty to replace said intra-encoded frame of specific trick-play speed (121, 131, 141). The method of claim 5, comprising a further step of: setting a DSM_indicator_project_Display in a packed Elemental Current layer of said compatible MPEG signal to repeat said intra-encoded frame of a trick-play specific rate (121, 131, 141). The method of claim 1, wherein said intra-coded frame having resolution in the reduced space (71) comprises 720 x 480 pixels. 16. The method of claim 9, wherein said intra-coded macroblocks (MB1, MB3) comprise discrete cosine transform coefficients of CD and selected CA discrete cosine transform coefficients. The method of claim 16, wherein said selected CA discrete cosine transform coefficients are selected according to a predetermined number of characters distributed per macroblock.