EP1078366A1 - Traitement de train binaire de reproduction - Google Patents

Traitement de train binaire de reproduction

Info

Publication number
EP1078366A1
EP1078366A1 EP98920220A EP98920220A EP1078366A1 EP 1078366 A1 EP1078366 A1 EP 1078366A1 EP 98920220 A EP98920220 A EP 98920220A EP 98920220 A EP98920220 A EP 98920220A EP 1078366 A1 EP1078366 A1 EP 1078366A1
Authority
EP
European Patent Office
Prior art keywords
encoded signal
memory
digitally encoded
data
transducer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP98920220A
Other languages
German (de)
English (en)
Inventor
Mark Alan Schultz
Donald Henry Willis
Jianlei Xie
Steven Anthony Barron
Barth Alan Canfield
John Alan Hague
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
THOMSON LICENSING
Original Assignee
Thomson Licensing SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thomson Licensing SAS filed Critical Thomson Licensing SAS
Publication of EP1078366A1 publication Critical patent/EP1078366A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
    • G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
    • G11B27/005—Reproducing at a different information rate from the information rate of recording
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
    • G11B19/20—Driving; Starting; Stopping; Control thereof
    • G11B19/26—Speed-changing arrangements; Reversing arrangements; Drive-transfer means therefor
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/10009—Improvement or modification of read or write signals
    • G11B20/10037—A/D conversion, D/A conversion, sampling, slicing and digital quantisation or adjusting parameters thereof
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/10527—Audio or video recording; Data buffering arrangements
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/12—Formatting, e.g. arrangement of data block or words on the record carriers
    • G11B20/1217—Formatting, e.g. arrangement of data block or words on the record carriers on discs
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
    • G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
    • G11B27/102—Programmed access in sequence to addressed parts of tracks of operating record carriers
    • G11B27/105—Programmed access in sequence to addressed parts of tracks of operating record carriers of operating discs
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
    • G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
    • G11B27/19—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier
    • G11B27/28—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording
    • G11B27/30—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording on the same track as the main recording
    • G11B27/3027—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording on the same track as the main recording used signal is digitally coded
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/42—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation
    • H04N19/423—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation characterised by memory arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
    • H04N19/61—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding in combination with predictive coding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/76—Television signal recording
    • H04N5/78—Television signal recording using magnetic recording
    • H04N5/782—Television signal recording using magnetic recording on tape
    • H04N5/783—Adaptations for reproducing at a rate different from the recording rate
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/24—Systems for the transmission of television signals using pulse code modulation
    • H04N7/52—Systems for transmission of a pulse code modulated video signal with one or more other pulse code modulated signals, e.g. an audio signal or a synchronizing signal
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/10527—Audio or video recording; Data buffering arrangements
    • G11B2020/1062—Data buffering arrangements, e.g. recording or playback buffers
    • G11B2020/1075—Data buffering arrangements, e.g. recording or playback buffers the usage of the buffer being restricted to a specific kind of data
    • G11B2020/10787—Data buffering arrangements, e.g. recording or playback buffers the usage of the buffer being restricted to a specific kind of data parameters, e.g. for decoding or encoding
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/12—Formatting, e.g. arrangement of data block or words on the record carriers
    • G11B20/1217—Formatting, e.g. arrangement of data block or words on the record carriers on discs
    • G11B2020/1218—Formatting, e.g. arrangement of data block or words on the record carriers on discs wherein the formatting concerns a specific area of the disc
    • G11B2020/1232—Formatting, e.g. arrangement of data block or words on the record carriers on discs wherein the formatting concerns a specific area of the disc sector, i.e. the minimal addressable physical data unit
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/12—Formatting, e.g. arrangement of data block or words on the record carriers
    • G11B2020/1264—Formatting, e.g. arrangement of data block or words on the record carriers wherein the formatting concerns a specific kind of data
    • G11B2020/1265—Control data, system data or management information, i.e. data used to access or process user data
    • G11B2020/1267—Address data
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B2220/00—Record carriers by type
    • G11B2220/20—Disc-shaped record carriers
    • G11B2220/25—Disc-shaped record carriers characterised in that the disc is based on a specific recording technology
    • G11B2220/2537—Optical discs
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B2220/00—Record carriers by type
    • G11B2220/20—Disc-shaped record carriers
    • G11B2220/25—Disc-shaped record carriers characterised in that the disc is based on a specific recording technology
    • G11B2220/2537—Optical discs
    • G11B2220/2562—DVDs [digital versatile discs]; Digital video discs; MMCDs; HDCDs
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/76—Television signal recording
    • H04N5/84—Television signal recording using optical recording
    • H04N5/85—Television signal recording using optical recording on discs or drums
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/79—Processing of colour television signals in connection with recording
    • H04N9/80—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback
    • H04N9/804—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback involving pulse code modulation of the colour picture signal components
    • H04N9/8042—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback involving pulse code modulation of the colour picture signal components involving data reduction
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/79—Processing of colour television signals in connection with recording
    • H04N9/80—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback
    • H04N9/804—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback involving pulse code modulation of the colour picture signal components
    • H04N9/806—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback involving pulse code modulation of the colour picture signal components with processing of the sound signal
    • H04N9/8063—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback involving pulse code modulation of the colour picture signal components with processing of the sound signal using time division multiplex of the PCM audio and PCM video signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/79—Processing of colour television signals in connection with recording
    • H04N9/80—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback
    • H04N9/82—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback the individual colour picture signal components being recorded simultaneously only
    • H04N9/8205—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback the individual colour picture signal components being recorded simultaneously only involving the multiplexing of an additional signal and the colour video signal
    • H04N9/8227—Transformation of the television signal for recording, e.g. modulation, frequency changing; Inverse transformation for playback the individual colour picture signal components being recorded simultaneously only involving the multiplexing of an additional signal and the colour video signal the additional signal being at least another television signal

Definitions

  • This invention relates to the reproduction of a digitally encoded signal from a medium and in particular to the identification and processing of replay data in a multiplex format. BACKGROUND OF THE INVENTION.
  • an MPEG 2 signal stream may comprise three types of pictures having varying degrees of content compression.
  • An intra-coded frame or I frame has the least compression of the three types and may b e decoded without reference to any other frame.
  • a predicted frame or P frame is compressed with reference to a preceding I or P frame and achieves greater degree of compression than an intra-coded frame .
  • the third type of MPEG frame termed a bi-directionally coded or B frame, may be compressed based on predictions from preceding and / or succeeding frames. Bi-directionally coded frames have the greatest degree of compression.
  • the three types of MPEG frames are arranged in groups of pictures or GOPs.
  • the GOP may for example contain 1 2 frames arranged as illustrated in FIGURE 1A.
  • each GOP may only be decoded following the decoding of the I frame.
  • the first predicted frame or P frame may be decoded and stored based on modification of the stored, preceding I frame.
  • Subsequent P frames may be predicted from the stored preceding P frame.
  • the prediction of P frames is indicated in FIGURE 1A by the curved, solid arrow he ad 2 lines.
  • bi-directionally coded or B frames may be decoded b y means of predictions from preceding and or succeeding frames, for example, stored I and P frames. Decoding of B frames by predictions from adjacent stored frames is depicted in FIGURE 1A by the curved, dotted arrow head lines.
  • FIGURE IB illustrates play back in the forward direction at normal speed and at a time prior to time tO, a rev ers e three times speed mode trick play mode is selected. The trick play mode is initiated at time tO where I-frame 1(25) is decoded and displayed.
  • the next frame required for decoding is I-frame 1( 13 ) , thus the transducer is repositioned, as indicated by arrow Jl to acquire frame 1(13). Having recovered and decoded I-frame 1( 13 ) , the transducer tracks, as indicated by arrow J2 to acquire and decode frame P(16). The process is repeated as indicated by arrows J 3, J4. Following the acquisition and decoding of frame P (22) the transducer is moved as depicted by arrow Jn to recover frame I (1). To smoothly portray scene motion requires the decoding and display of I, P, an d possibly B-frames. The jump and play process is repeated for preceding GOP, thereby progressing haltingly backwards through th e records whilst smoothly portraying the program material in a reverse sequence at the video output.
  • An apparatus reproduces a bitstream signal from a disk.
  • the bitstream is controlled to ensure that only requested bitstream data is coupled for MPEG decoding.
  • a transducer is repositioned to obtain requested bitstream data prior to completion of preceding MPEG picture decoding.
  • the bitstream data is read prior to buffer storage to select wanted data for storage and to reject unwanted data.
  • Buffer storage is reallocated for trick play operation and is random accessed to facilitate trick play picture selection.
  • MPEG picture decoding a n d storage are controlled to facilitate frame decoding within one field period. Decoded pictures are stored and read out substantially concurrently within a field period.
  • an apparatus reproduces a digitally encoded signal from a medium.
  • the apparatus comprises a transducer for transducing the digitally encoded signal and generating a bit stream therefrom.
  • a processor is coupled to receive the bit stream for controllably processing the bit stream.
  • a memory is coupled to the processor for storing the processed bit s tream information.
  • a controller is coupled to control the memory and th e processor for controlling identification of information within the bit stream, wherein the controller controls the processor to identify a specific sector type in the bit stream and responsive to the specific sector identification the controller controls the memory for storing th e identified specific sector.
  • a start code is acquired from a plurality of start codes in a data stream arranged in a plurality of sectors transduced during reproduction by a digital disk apparatus .
  • the method comprises the steps of searching the data stream to locate a specific sector type in the plurality of sectors.
  • the specific sector type is searched to locate a start code from the plurality of start codes .
  • the start code is tested to determine if it is incomplete.
  • Searching th e data stream to locate a second sector of the specific sector type in th e plurality of sectors.
  • Searching the second sector of the specific sector type to locate a second start code of the start code type from th e plurality of start codes. Determining if the second start code is th e residue of the incomplete start code. Combining the incomplete start 4 code value and the residue start code value to form a complete s tart code.
  • a further inventive apparatus for reproducing a digitally encoded signal from a medium comprises a transducer for transducing the digitally encoded signal and generating a bit stream therefrom.
  • a first memory is coupled to the transducer for storing the bit stream.
  • a second memory for storing data is controllably coupled from the first memory.
  • a controller is coupled to control the first and second memories for controlling identification of information within the bi t stream wherein the controller controls the first memory to output th e bit stream from a specific sector address therein, and the controller controls the second memory to store a first part of the bit s tre am output from the specific sector address.
  • a digitally encoded signal is reproduced from a medium.
  • the apparatus comprises a transducer for transducing the digitally encoded signal and generating a bit stream therefrom.
  • a memory is coupled to the transducer for storing the bit stream.
  • a processor is coupled to the memory for processing the stored bit stream to identify an MPEG start code contained therein.
  • the processor searches the stored bit stream to identify the MPEG start code in the stored bit stream and responsive to the MPEG start code identification the processor indicates th e identification and stores a sector address of the identified MPEG start code.
  • Storing the digitally encoded signal in a first memory Decoding the digitally encoded signal to produce a picture. Storing the picture in a second memory. Coupling the picture from the second memory for display. Controlling the storing in the second memory and the coupling for display to occur substantially concurrently.
  • one field of th e picture is stored in a first field of the second memory and a previous picture is coupled for display from a second field of said second memory .
  • one field of the picture is stored in a first field of said second memory and a previous picture 5 is coupled for display from a first field of the second memory.
  • the storing in said first field of said second memory and the coupling for display are controlled to occur sequentially within a field period.
  • an apparatus for reproducing a digitally encoded signal from a disk medium comprises a transducer which transduces the digitally encoded signal.
  • a memory is coupled to the transducer for storing the digitally encoded signal.
  • a decoder is responsive to the digitally encoded signal for decoding a picture therefrom.
  • a controller for the memory wherein a first operational mode the controller controls the memory to read th e stored digitally encoded signal from the memory responsive to a first sequence and in a second operational mode the controller controls th e memory to read the stored digitally encoded signal from the m emory in a second sequence.
  • an apparatus for reproduces a digitally encoded signal from a disk medium an d comprises a source of a bitstream representative of a digitally encoded signal.
  • a processor is coupled to the bitstream for processing the bitstream to extract at least a first and a second data type represented therein.
  • a memory is controllably coupled to th e processor for storing one of the first and a second data types.
  • a controller is coupled to control allocation of the memory, wherein a first reproducing mode the controller allocates the memory for storing the first data type, and in a second reproducing mode the controller allocates the memory for storing the second data type.
  • an apparatus for reproducing a digitally encoded signal from a disk medium comprises a transducer for transducing the digitally encoded signal.
  • a processor is coupled to receive the digitally encoded signal for processing and generating a picture therefrom.
  • a memory is coupled to the processor for storing the picture.
  • a controller is coupled to control the memory and the processor, wherein a first mode the picture is stored in th e memory and in a second mode the picture is sub-sampled and stored in the memory.
  • unnecessary processing of unwanted sector data is avoided.
  • a method for controlling data reproduced in sectors by a disk player employing optical read out comprises the steps of transducing groups of sectors 6 including sectors wanted for processing, and sectors unwanted for processing.
  • delay in a transduced bitstream path is substantially obviated from a process for controlling a transducer position.
  • a method comprises the steps of receiving a first and a second transducer address for controlling the transducer position responsive to a replayed address. Comparing the replayed address with the first transducer address to detect equality therebetween. In response to the detected equality moving the transducer to a new position determined by the second transducer address.
  • FIGURE 1A illustrates an MPEG 2 group of pictures.
  • FIGURE IB illustrates recorded groups of pictures, during replay and reverse trick play at three times speed.
  • FIGURE 2 is a block diagram of an exemplary digital disk player including inventive arrangements.
  • FIGURE 3 shows in greater detail part of FIGURE 2 an d depicting various inventive arrangements.
  • FIGURE 4 shows the digital disk player of FIGURE 2 including other advantageous arrangements to those of FIGURE 2.
  • FIGURES 5C - 5D depict exemplary data in buffer memory.
  • FIGURE 6 is a flow chart illustrating an inventive arrangement for the recovery of start codes distributed across sector boundaries.
  • Figure 7 is a chart illustrating an inventive sequence for a reverse trick play mode of 3 times play speed (3X).
  • FIGURE 2 depicts an exemplary block diagram of a digital video disk player.
  • a deck is shown which may accept a digitally recorded disk 14 for rotation by a motor 12.
  • a digital signal is recorded on disk 14 as a spiral track containing pits with respective pit lengths determined by an 8/16 modulation coding responsive to respective signal data bits.
  • the record on disk 14 is read by pick u p 7 15 which gathers reflected illumination from a laser.
  • the reflected laser light is collected by a photo detector or opto pick-up device.
  • a n imaging device for example a lens or mirror, which form part of transducer pick-up 15, is servo controlled and driven by motor 1 1 to follow the recorded track.
  • Different parts of the recording may b e accessed by rapidly repositioning the imaging device.
  • Servo controlled motors 11 and 12 are driven by integrated circuit drive amplifier 20.
  • Pick up 15 is coupled to an opto preamplifier, block 30, which includes drive circuitry for the laser illuminator and a preamplifier which provides amplification and equalization for th e reflected signal output from the opto pick-up device.
  • the amplified and equalized replay signal from opto preamplifier 30 is connected to a channel processor block 40 where the replay signal is employed to synchronize a phase locked loop which is utilized to demodulate th e 8: 16 modulation employed for recording.
  • the MPEG encoded bitstream is encoded for error detection and correction by means of Reed Solomon product coding which is applied in blocks of 16 sectors, where each sector contains 2048 bytes of payload data.
  • Reed Solomon product coding which is applied in blocks of 16 sectors, where each sector contains 2048 bytes of payload data.
  • 8:16 demodulation the replay data stream is de-interleaved or unshuffled and error corrected by means of Reed Solomon product correction implemented in ECC buffer memories 45 and 46 of FIGURE 4.
  • Each buffer stores 16 sectors of th e replay data stream arranged as an array to facilitate de-interleaving and to enable the required row and column product processing.
  • the cascaded ECC buffer memories introduce a delay to reproduced serial bit stream of approximately (2 * 16 * 1.4) milliseconds, where 2 represents the pair of ECC buffers, 16 represents the sectors over which the correction is applied and 1.4 milliseconds represents a sector period at IX rotational speed.
  • the reproduced serial bit stream is delayed by a minimum of approximately 45 milliseconds.
  • the error corrected signal bitstream 41 is coupled via a link processor to a bit stream or mechanical / track buffer memory 60 A.
  • the track buffer comprises a DRAM memory type and is used to store an amount of replayed data such that data losses during transducer o r pickup 15 repositioning will not result in any visible deficiency w hen decoded. Thus the final output image stream will appear to b e continuous or seamless to the viewer.
  • Bitstream buffer memory 60 A is part of an exemplary 16 megabit DRAM memory.
  • a further 8 exemplary 16 megabit SDRAM memory block is partitioned to provide frame buffers 60C and 60D which provide storage for at least tw o decoded image frames, compressed video bit stream storage in buffer 60B prior to decoding, an audio bit stream buffer 60E and other storage in buffers 60F, G and H.
  • the channel processor 40 also includes timing control circuitry which control writing by link 505 to bitstream buffer 60 A. Data may be intermittently written to th e bitstream buffer as a consequence of changes in replay track addresses, for example, resulting from user defined replay video content such as a "Directors cut", parental guidance selection, or e ve n user selectable alternative shot angles.
  • disk 14 may be rotated at a n increased speed resulting in the transduced bitstream having a higher bit rate, and possibly intermittent delivery.
  • the recorded data stream is arranged in ECC blocks of 16 sectors. Each sector has a unique sector identification address which is protected with error correction bits that are processed by ECC block 47 of FIGURE 4. However, because the sector address is short and sector specific, any delay to sector address signal 42 resulting from error correction processing block 4 7 is insignificant.
  • Sector address signal 42 is coupled to provide positional information to servo control integrated circuit 50.
  • Integrated circuit 50 provides drive and control signals for servo motors 11 and 12.
  • Motor 12 rotates disk 14 and provides servo controlled rotation at a plurality of speeds.
  • the opto pickup o r transducer 15 is positioned and servo controlled by motor 1 1 responsive to sector address signal 42, and in addition, may b e controlled to rapidly reposition or jump to another sector address, o r location on the disk surface in response to a sector address request, transmitted by I 2 C control bus 514, and coupled via element 54 of FIGURE 4.
  • the digital video disk player is controlled by a central processing unit or CPU, element 510 of block 500, which accepts th e reproduced bitstream and error flags from channel IC 40, an d provides control instructions to servo IC 50.
  • CPU 5 1 0 accepts user control commands from user interface 90, and MPEG decoder control functions from the MPEG decoder element 530 of block 500.
  • a system buffer memory 80 is addressed by and provides 9 data to CPU 510.
  • buffer 80 may comprise both RAM a nd PROM memory locations.
  • the RAM may be used to store various d ata extracted from bitstream 41 by CPU 510, for example such data m a y include descrambling or decryption information, bitstream and frame buffer memory management data, and navigation data.
  • the PROM may, for example contain advantageous transducer jump algorithms which facilitate trick mode operation at a selection of speeds i n forward or reverse directions.
  • the MPEG encoded bitstream is coupled to link processor 505 in FIGURE 3, which may function as a hardware demultiplexer to separate MPEG encoded audio, video and control information from the DVD formatted bitstream.
  • link processor 505 in FIGURE 3 may function as a hardware demultiplexer to separate MPEG encoded audio, video and control information from the DVD formatted bitstream.
  • bitstream demultiplexing may be accomplished by software control of direct memory access or DMA of buffer 60A, from CPU 510 of FIGURE 3.
  • the encoded bitstream prior to or within track buffer 60 A is searched by microcontroller 510 to locate and read headers and to extract navigation data.
  • Advantageous bit stream searching will b e discussed with reference to FIGURE 6.
  • Microcontroller 510 is coupled the front end via I 2 C control bus signal 514 to control or request transducer repositioning to acquire the next sector required by a trick play sequence.
  • the transducer positioning may be controlled by an advantageous stored sequence, or jump play pattern which is indexed with reference to replayed sector addresses and GOP sector addresses read from navigation pack data contained in each video object unit or VOBU. Exemplary sector addresses and VOBU navigation pack are depicted in FIGURE 5A.
  • the sectors initially retrieved from the front end may be identified by exemplary microcontroller 510 as not those requested by the jump instruction.
  • microcontroller 510 advantageously overwrites this unwanted data in track buffer 60A and ensures that only the requested data is present in the buffer.
  • microcontroller 510 controls direct memory access of buffer 60 A which effectively separates MPEG data from other DVD formatted data stored in the buffer.
  • video DMA 515 separates compressed video bits which are coupled for storage in exemplary video bit buffer 60B.
  • compressed audio bits are read from buffer 60A a n d 1 0 stored in audio buffer 60E.
  • Sub-picture data is also retrieved from track buffer 60A by DMA and stored in buffer 60F.
  • the compressed video bit stream in video bit buffer 60B is searched to locate picture or higher level start codes by start code detector 520.
  • a detected start code signal 512 is coupled to microcontroller 510 which then communicates with MPEG decoder
  • Compressed video bit buffer 60B may be considered to function as a FIFO or circular buffer where the stored bitstream is sequentially accessed for MPEG decoding, however, trick mode operation may b e advantageously facilitated by random access of buffer 60B, as will b e described.
  • the video bit stream is processed by a variable length decoder 531 which searches th e bitstream to locate slice and macro-block start codes.
  • Certain decoded pictures from each group of pictures are written to frame buffers 60C and 60D for subsequent use as predictors when deriving o r constructing other pictures, for example P and B pictures, of the GOP.
  • Frame buffers 60C and 60D have a storage capacity of at least two video frames.
  • Separated audio packets are stored in audio bit buffer 60E which is read out and coupled for audio decoding in block 1 10.
  • Following MPEG or AC3 audio decoding a digitized audio signal results which is coupled to an audio post processor 130 for digital to analog conversion and generation of various base band audio signal outputs .
  • a digital video output signal is transformed into raster scan format b y display buffer 580 from decoded blocks read from reference frame buffer 60C/D.
  • the output signal source may be a field memory advantageously reconfigured from memory unused during tick mode operation.
  • block to raster scan conversion within display buffer 580 may be advantageously controlled responsive to trick mode operation.
  • the display buffer is coupled to encoder 590 which provides digital to analog signal conversion and generates baseband video components and encoded video signals. 1 1 Operation of the exemplary video player illustrated in FIGURE 2 may be considered with reference to FIGURE IB which illustrates a forward play and reverse trick play sequence.
  • each group of pictures is decoded in a forward direction starting from an I-frame or picture.
  • reverse mode features may be provided by effectively jumping back to transduce an earlier, or preceding I picture and then decoding in a forw ard direction through that GOP.
  • the decoded pictures are stored in frame buffer memories for subsequent read out in reverse order.
  • sequences that include B pictures may utilize further advantageous features which will be described.
  • FIGURE IB it will be as sumed that at some time prior to time tO, for example at I-picture 1(1 ), th e exemplary video player assumed a forward play condition in response to a user command.
  • Each group of pictures is decoded in the forward direction as illustrated in FIGURE 1A by the arrow headed lines linking I, B and P frames.
  • a three times play speed reverse trick mode is selected, and initiated at time t O where I-picture 1(25) is decoded and displayed.
  • the next picture required for reverse trick play decoding is I-picture 1(13), thus the transducer is moved, as indicated by arrow Jl to acquire picture 1(13).
  • the signal recovery and decoding then follows a play sequence indicated in FIGURE IB by arrows Jl, to acquire 1(13), J2, to acquire P(16), J3, to P(19), J4 to P(22) ... Jn.
  • the intervening B pictures shown in FIGURE IB are transduced but m a y be discarded, for example, in the buffer by over writing or by decoder inhibit, as required specific to each trick play mode.
  • various advantageous methods for MPEG decoder, buffer memory control and allocation are employed.
  • FIGURE 5 A shows part of exemplary bit stream 41 including a video object unit containing audio video and sub-picture data sectors . 1 2 Each sector contains 2048 payload bytes with sector addresses shown shaded at the sector boundary.
  • video picture A is shown ending in sector 54 and is immediately followed by the s tart code for video picture B.
  • FIGURE 5C Determination or location of picture data / video sectors in units of sectors is illustrated in FIGURE 5C where a start code for exemplary picture A is shown in sector 2 with the start code of next picture B, occurring in sector 9. Equation 1 shows picture data location by sector count, since picture A starts i n sector 2 and ends in sector 9, picture A has a duration of 8 sectors . Unwanted data fragments are illustrated FIGURE 5C, where video d ata is depicted referenced to (video) sector numbers. However such video sector numbering may be directly related to the sector number o r address in the reproduced bit stream.
  • FIGURE 5C a video bit stream is shown with an exemplary picture A depicted with a picture start code initiated at byte 1000 of video sector 2.
  • a picture start code initiated at byte 1000 of video sector 2.
  • th e preceding 999 bytes of sector 2 correspond to data from a preceding picture.
  • Byte accurate processing may require more complexity of memory control than that required for sector level accuracy.
  • byte accurate processing is employed only complete picture data are stored in the video bit buffer, thus fragments are eliminated and hang up of MPEG decoder 530 is avoided.
  • FIGURE 5C Byte accurate picture determination is shown in FIGURE 5C for exemplary picture A, where a picture start code starts at byte 1000 of video sector 2 and picture B start code starts at by te 500 of sector 9.
  • the size of picture A may be calculated, by u s e of equation 2, as 13,835 bytes.
  • byte accurate picture addresses allow microprocessor 510 to point to a specific byte in exemplary video bit buffer 60B from which variable length decoder VLD 531 , of FIGURE 3, is to start decoding.
  • each video object block unit or VOBU includes navigation data that identifies the end sector address of the first I picture an d the last sector addresses of two following reference or P pictures of 5 the first GOP of the VOBU.
  • the navigation data includes sector addresses of I-pictures in preceding and succeeding VOBUs, hence an I-picture only trick mode may be readily provided .
  • problems resulting from picture fragments may be avoided if the end byte of the wanted picture can be identified.
  • Microprocessor 510/A for example type ST20, is advantageously configured as a hardware search engine which searches through th e data stored in the track buffer to locate the ending byte of the I - picture within the ending sector stored in the buffer 60A.
  • b y identifying an I-picture it alone may be loaded into video bit buffer
  • the exemplary microprocessor 5 1 0/ A may be employed to find start codes in an I-picture only mode since the ending sector is known from the navigation data. However, for P, B or multiple I-pictures, the exemplary microprocessor may not
  • the location and determination of start codes prior to decoding may be facilitated by an arrangement which utilizes the link
  • link interface 505 advantageously provides early pre-processing or parsing for picture and or audio headers which may be signaled to microprocessor 5 10.
  • pictures and audio required by a specific trick mode may be stored in exemplary track buffer 60A with unwanted pictures an d or other data deleted in the buffer by overwriting.
  • start codes are located by use of start code detector 520 which searches the bit stream in either the
  • start code detection is facilitated by a start code detector which searches the bit s tream exclusively for MPEG start codes prior to, or within track buffer 60 A.
  • start code detector which searches the bit s tream exclusively for MPEG start codes prior to, or within track buffer 60 A.
  • trick play picture requirements may be anticipated and memory manipulation specific to trick play operation may be performed.
  • the same advantageous parsing may be applied to the video packet stream prior to the video bit buffer during trick mode operation.
  • trick play specific selection between pictures to b e buffered for decoding, and those unwanted pictures to be discarded before storage.
  • Such picture selection for example discarding B- frames, may approximately double the number of I and P pictures stored in exemplary video bit buffer 60B during trick play operation.
  • the storage capacity track buffer 60 A and video bit buffer 60B are increased during a trick play mode by only selecting for storage data that is to be u sed subsequently. For example, in an exemplary trick play mode B frames may not be decoded, hence need not be stored in the track o r video bit buffers. Thus only needed pictures are stored, an d unwanted picture or other data is discarded. To facilitate this advantageous selection between wanted and unwanted pictures requires that the bit stream or video packet stream be pre-processed, parsed or searched to locate a sequence_header, group_of_picture_header or picture_header prior to storage.
  • parsing or pre-processing of the compressed bit stream allows th e determination of MPEG parameters such as, time_code, closed_gop, 1 5 and broken_link data for each group of pictures or GOP.
  • the picture_start_code may b e located thus permitting processing of the picture_header which i n turn allows the determination of, for example, th e temporal_reference, picture_coding_type (I, P and B).
  • Such advantageous MPEG parsing is difficult, as has been described, due to
  • FIGURE 5B illustrates a bitstream prior to track buffer 60A where video picture A ends in sector 54 and is immediately followed by the start code for video picture B. However, the remainder of video picture B start code occurs in sector 65, with intervening sectors 55 - 64 containing sub-picture and audio data .
  • FIGURE 5C illustrates a demultiplexed video sector bitstream prior to video bit buffer 60B where a start code for exemplary picture A is shown in sector 2 with the start code of next picture B, occurring i n sector 9.
  • a distributed start code occurs for picture C which is initiated at byte 2046 of sector 12 and continues in sector 13. Hence, part of the start code is in one video sector with the remainder in the next video sector.
  • FIGURE 6 To enable a bitstream with distributed start codes to b e parsed an inventive exemplary method is shown in FIGURE 6.
  • the exemplary method identifies and saves sector types and addresses , and in addition identifies and saves wanted start codes.
  • Distributed or partial start codes are identified and saved by the use of a n inventive partial start code flag which indicates the occurrence. The remainder of the start code occurring in the next video sector is identified and recovered to complete start code.
  • the inventive method of FIGURE 6 depicts searching and MPEG parsing applied to bit stream 41 prior to track buffering.
  • the bit stream is searched for wanted sectors, for example a video sector, which is then searched for distributed start codes.
  • a distributed start code may be separated b y other non-video sectors containing for example audio, sub-pictures, navigation data etc.
  • bit stream is searched and th e subsequent video sector identified and processed, while th e intervening non-video sectors, not currently required, for example during a specific trick mode, are not processed and may be discarded 1 6 prior to storage or over written in exemplary track buffer 60A.
  • the packet data is searched to locate the next start code.
  • the partial start code flag is set, the remainder of the partial start code is searched for, an d with its occurrence this remainder is combined with that of th e preceding video sector to complete the start code.
  • the exemplary chart in FIGURE 6 illustrates the inventive method employed for bit stream searching to identify wanted sector addresses, picture types and addresses, and for detecting and reassembling distributed start codes.
  • the method starts at step 1 0 where an error corrected bitstream is searched to locate specific wanted sectors from a plurality of sectors including, navigation, audio video sector sub-picture data sectors.
  • a video sector is detected a t step 100 where a NO result forms a loop which continues th e bitstream search.
  • an audio sector may be detected at step 105 and its sector address stored accordingly. If step 100 tests YES, a video sector is detected and the sector address is stored at step 101 .
  • a detected video sector initiates a further test at step 200 to detect a start code within the video sector.
  • Step 200 depicts picture start code, however, various start codes may be present, for example sequence- headers, GOP headers or picture-headers all exist within the video sector hence any may suffer distribution across a sector boundary.
  • a NO at step 200 forms a loop which continues to search for a start code within the video sector.
  • a YES at step 200 indicates detection of a start code which initiates a further test to detect a partial start code at step 250.
  • the determination between partial and complete start codes depicted at steps 200 and 250 may be considered to occur both concurrently and serially since any start code becomes partial o r incomplete when interrupted by an occurrence of a sector boundary and sector address, as illustrated in FIGURES 5B and 5C.
  • a NO at step 250 forms a loop to wait for a partial start code occurrence.
  • the NO at step 250 also indicates detection of a complete start code which is tested at step 255 to determine if it is a wanted type.
  • Wanted start codes test YES at step 255 which results in th e storage of the type and byte location within the sector address at step 260.
  • Detection of a partial start results in a YES at step 250 which causes the sequence to restart searching the bitstream to locate th e 1 7 next video sector by looping back to step 100.
  • the YES at step 25 0 also initiates a test at step 300 to determine if a partial start code flag is set.
  • the partial start code flag is not set until a first distributed o r partial start code is detected.
  • NO at step 300 sets the partial
  • start code flag at step 350 stores the value of t h e partial start code at step 400.
  • a YES at test 300 indicates detection of the remainder or residue of the distributed start code and results in resetting the partial start code flag at step 500. The YES at step 300 also results in storage of the detected start code remainder at s tep
  • step 550 the values of the partial start code from step 400 and its remainder from step 450 are combined to reform the distributed start code.
  • the reformed start code type, byte and sector address are stored.
  • DVD format bit stream may be parsed to determine for example, specific MPEG coded picture types, prior to buffer storage.
  • start code detector 520 and variable length detector 531 to b e advantageously directed to randomly access pictures as required, for example, during trick mode operation. Operation in reverse at play speed and or slow motion playback requires the reproduction of B- frames. Such reverse mode operation may be advantageously
  • buffer memory size and control may be simplified
  • buffer memory capacity unu sed by these functions or features may be reallocated during trick mode operation to provide additional picture storage.
  • certain trick modes for example a fast play mode, there may be a beneficial requirement for the accompanying audio to be reproduced at high speed, and pitch corrected to assist in scene location.
  • a limited on screen display may be required to indicate trick play speed and direction.
  • unused buffer memory capacity m a y be dynamically reconfigured to advantageously facilitate trick mode buffering for compressed pictures, decoded frame predictors, and video display fields.
  • SDRAM buffer memory 60E - H is functionally reallocated between operation in forward and trick play modes.
  • the memory capacity allocated during forward play mode to audio 60E, sub-picture 60G may be used during trick play to provide additional compressed picture storage, to augment video bit buffer 60B and to provide an additional predictor frame for decoding.
  • buffer memory may be reallocated for example, for certain trick play modes storage of extra compressed pictures may not b e required, thus unused or non-required buffer memory capacity is reconfigured to provide an output display buffer memory, depicted a s 60H in FIGURE 3.
  • the output display buffer memory may store either a frame or field of video data for display.
  • This dynamically allocated memory facilitates output picture derivation and is not used as a predictor, thus simplifying memory management during trick mode operation.
  • the reallocation of memory may be initiated by u ser selection, however the dynamic allocation may be determined b y advantageous stored trick play sequence requirement and or use of 1 9 advantageous picture anticipation derived from bit stream pars ed identification of compressed picture type, as has been described.
  • frame buffer memory capacity may be effectively be doubled during trick play operation by horizontally sub-sampling the decoded picture data prior to buffer storage.
  • Horizontal sub-sampling for example implemented by exemplary block 62 averages horizontally adjacent pixel pair values responsive to a trick mode control command from controller 510.
  • signal SI represents full bandwidth data coupled to sub-sampler 62 with the subsampled output data represented b y signal S2.
  • the sub-sampled picture contains approximately half the original number of pixels, and hence requires half the memory capacity allowing a picture, or video frame, to be stored in th e capacity of a field.
  • additional frame buffer storage is available as required by a trick play algorithm.
  • the inventive use of sub-sampling beneficially reduces data and address bus control by a memory manager during trick mode memory access. For example only half the data is communicated for half the time hence simplifying memory control and management.
  • the horizontally sub-sampled picture is read from memory, for example 60C, D or inventively reallocated buffer H to be restored by sub-sampler 62.
  • signal S3 represents sub-sampled reference picture data read from memory for pixel count restoration.
  • Sub-sampler 62 may address each sub-sampled memory location twice, however this action doubles data and address bus utilization which was beneficially reduced during the storage process.
  • th e sub- sampled picture is restored by duplicating each pixel value a nd output as signal S4 for coupling directly MPEG decoder 530 to prior to MPEG decoding.
  • this method doubles buffer capacity, a nd reduces both data and address bus utilization, horizontal spatial resolution is reduced.
  • FIGURE 4 shows the same functions an d element numbering as those depicted in FIGURE 2, however, FIGURE 4 includes additional inventive arrangements which will be explained.
  • the exemplary digital video disk player shown in FIGURES 2 , 3 and 4 may be considered to comprise two parts namely a front e n d and a back end.
  • the front end controls the disk and transducer with the back end providing MPEG decoding and overall control.
  • Such functional partitioning may represent an obvious solution for consistent, steady state, MPEG decoding.
  • partitioning of processing and control at the back end th e microcontroller may become overloaded, for example, during trick mode operation and in particular when playing in the reverse direction.
  • microcontroller 510 is required to manage the incoming bitstream 41 received from the front end a n d identify wanted from unwanted data.
  • bitstream 41 is controllably coupled between the front and back ends.
  • opto-pickup o r transducer 15 may be repositioned, as has been described.
  • Sector addresses derived in the back end are sent via an I 2 C control bus 5 1 4 to the front end servo system 50 to reposition transducer 15.
  • the opto-pickup or transducer 15 is servo controlled responsive to a sector address which is truncated to remove the least significant digit. This address truncation allows acquisition of sectors in groups or blocks of 16 sectors.
  • This grouping is required to facilitate error correction (ECC) by means of Reed Solomon product coding and payload data interleaving applied over 16 sectors during recording.
  • ECC error correction
  • the transducer moves relative to the rotating disk with either radial or tangential motion to acquire the track containing the ECC block of sectors within which the w anted sector address or addresses reside.
  • th e transducer refocusses and sectors are transduced as the disk rotates towards the ECC sector block containing the requested or w anted sectors address.
  • This bit stream is depicted in FIGURE 4 a s signal 44, and contains both wanted and unwanted data which is coupled for error correction at ECC blocks 45 and 46.
  • the error corrected bitstream is output from ECC processing as signal 41 which is coupled to the back end where microcontroller 510 identifies wanted from unwanted data.
  • FIGURE 4 An inventive arrangement is shown in FIGURE 4, where data signal 44 output from an 8: 16 code demodulator and is coupled via a control element 45 A, for example a transmission gate, or logic function, to Reed Solomon error correction blocks 45 and 46.
  • Control element 45A is controlled by element 43 which functions to compare the recovered, current replay sector address, error corrected in block 47 and output as address signal 42, with a sector address 53 A, derived from the back end, which represents the next wanted data, for example picture type. The comparison may be facilitated by a comparitor or logical function.
  • the demodulated data output is enabled by signal 43A for coupling to error correction buffer blocks ECC 45 and 46.
  • the requested sector address represents the initial data sector of a wanted picture type.
  • signal 43A which represents substantial equality between wanted and replay sector addresses , may be considered to represent a latch function where the logical state is maintained until the wanted address is changed i.e. until a further transducer jump is requested.
  • the receipt of a new sector 2 2 address changes the state of signal 43A, which inhibits reproduced data until the new wanted address occurs in the replay signal and i s detected by comparitor 43.
  • signal 44 remains enabled for error correction
  • ECC blocks 45 and 46 are enabled a n d output signal 41 is sustained, or in simple terms, the disk continues to play until a different transducer position is requested.
  • the detected replay occurrence of the wanted sector may b e performed by comparison with truncated sector addresses to ensure that error correction buffers 45 and 46 are filled with the number of sectors required for RS correction.
  • the s ame detected replay occurrence may be employed using signal 45B to control or enable operation of error correction buffer memory 45 an d 46.
  • only the reques ted sector is enabled via output control element 46A.
  • Selection b y element 46 A is different from the control provided by elements 45 A and 45B which, because of the interleaved, or shuffled data format enable the ECC block containing the requested sector.
  • Detection of th e wanted replay sector may be performed by comparison of the actual replay sector address and the requested or wanted address.
  • the resultant output signal 41 is delayed by at least one ECC block time period.
  • error corrected output data corresponds to groups of sectors transduced in advance of the wanted data (address) identified a s present at the ECC buffer input.
  • the buffer delay may be compensated for in the control coupling of signal 43A to element 46A, for example by use of a delaying method depicted as t.
  • Control element 46A is depicted as a series switch element capable of enabling or disabling bitstream supply to the back end.
  • signal 43 A may be applied to selectively enable de-interleaving bitsream 41 for transmission to processing block 500.
  • signal 43 A suitably timed to compensate processing and buffer delays, may be applied to selectively enable de-interleaving bitsream 41 for transmission to processing block 500.
  • transduced signal 31 is demodulated at block 40 to remove the 8: 16 modulation, and produce output signals 44 and 44A.
  • Signal 44 is coupled for de-interleaving and error 2 3 correction, with signal 44 A being separately error corrected to produce replay sector addresses.
  • De-interleaving and error correction is performed in ECC buffer memories 45, and 46 of FIGURE 4. Each buffer stores 16 sectors of the replay data stream arranged as a n
  • the cascaded ECC buffer memories introduce a delay to reproduced serial bit stream which, at IX rotational speed, may be approximated to with the following calculation (2 * 16 * 1.4) milliseconds, where 2 represents ECC buffers
  • Bitstream 44A is processed at ECC block 47 to error correct
  • error correction block 47 introduces a n insignificant delay to the replay sector address signal 42.
  • bitstream 41 is received at the back e n d
  • Video packets are stored in exemplary buffer 60B for decoding by MPEG decoder 530.
  • decoder 530 sends signal 5 1 3 to controller 510 to indicate completion of each picture decoded, which in turn results in the acquisition of the next picture to b e
  • transducer 15 mu s t be repositioned to the sector address containing the wanted picture.
  • FIGURE 5A shows part of bitstream 41, coupled to buffer 60A, including a video object unit composed of multiple sectors each containing video, audio, sub-picture and navigation data.
  • the end of sector A may be advantageously determined in, or prior to, track buffer 60A by the occurrence of the next sector address, or following
  • interrupt prioritization of microcontroller 510 interrupts are reordered between operational modes. For example, in a forward play mode memory addressing and control requirements are different to those required for operation in trick modes, and in particular during operation a t play speed in reverse. During trick mode operation certain features , and consequently their memory and MPEG decoder control are no t required. For example, audio decoding, and sub-picture processing are not required during trick mode operation hence address, data and control bus interrupt priorities may be assigned a lower priority with a higher priority assigned to picture access from the track and video bit buffers. The timely acquisition of requested sectors is particularly important during trick mode operation.
  • FIGURE 4 shows arrow B positioned to indicate an approximate time relationship between replayed bit stream 41, or track buffer 60A, and the issuance to th e servo of inventive next/end sector addresses.
  • arrow B is shown occurring shortly after the navigation pack, shown shaded, has been read from the bitstream.
  • arrow NEXT is shown to illustrate the occurrence, approximately seven sectors later, of signal 513 (decode completed).
  • next/end sector addresses are generated b y microcontroller 510 following navigation pack acquisition and o r advantageous picture / sector address determination and table construction.
  • the employment of next/end sector addresses recognizes that the wanted sector address may be temporally separated from the transducer instruction to jump.
  • the nex t/end 2 5 sector addresses are effectively pre-loaded in the transducer servo system with the transducer jump executed in response to th e reproduction of the first unwanted sector address. Since the sector addresses are not subject to the lengthy ECC delay of bitstream 41 , the transducer is moved before the last wanted sector emerges from ECC blocks 45 and 46.
  • control data is transmitted by an I 2 C control b u s
  • the next wanted replay sector address is generated by microcontroller 510 which processes address data originating from a stored trick play, speed specific sequence, replayed and stored navigation data, or from advantageously determined replayed picture data.
  • the next address is read from the I 2 C bus an d stored in element 53.
  • the I 2 C data also includes an inventive end/las t sector address, or first unwanted sector address.
  • the end/last sector address may be obtained from recovered and stored navigation data, however this provides only a limited number of predetermined picture addresses, thus for trick modes the advantageously determined end of picture sector addresses are employed.
  • the end/last sector address is read from the I 2 C bus and stored in element 52.
  • the last sector address may modified either prior to b u s transmission or upon receipt, to prevent wanted sector loss, by for example, the addition of one unit count to sector address thu s ensuring addressing and detection of the first unwanted sector.
  • the last sector address, or modified address 52A is coupled for comparison with the replay sector address signal 42 in an exemplary comparitor 51.
  • the replay sector address 42 equals address 52A
  • the first unwanted sector is about to be transduced and comparitor 51 generates control signal 51 A.
  • Control signal 5 1 A enables coupling from element 53, for example by loading or shifting the stored address data to the servo, or as depicted by exemplary selector switch 54 which couples the next sector address to the servo system and initiates repositioning of transducer 15.
  • the transducer is moved to the track containing the next wanted picture and data output signal 41 is advantageously enabled by element 43 when the wanted picture is reproduced.
  • the transducer continues to follow the track reproducing wanted sectors which are processed by the back end.
  • a new pair of next and end sector addresses are generated and transmitted via the I 2 C bus.
  • n e w address are received and stored as before in elements 52 and 53.
  • exemplary selector 54 is reset or opened preventing premature initiation a nd acquisition of the new sector address.
  • the inventive transducer control sequence described above initiates transducer movement by comparison between essentially undelayed replay sector addresses and pre-loaded wanted sector addresses, thus delay in the acquisition of the new replay bitstream is obviated, facilitating enhanced trick mode operation.
  • MPEG picture decoding order is determined, as is well known, by the encoded picture hierarchy, hence forward mode operation the decoding sequence is followed.
  • trick play operation may b e advantageously facilitated by controlling MPEG picture decoding order based on picture sequences required by a predetermined trick play algorithm and knowledge of where the pictures start and stop in th e video bit buffer.
  • knowledge of picture location in the video bit buffer 60B for example as calculated in FIGURE 5C, or as determined by bitstream search of FIGURE 6, permits memory start pointers in the start code detector 520 and variable length detector 531 to b e advantageously directed to randomly access pictures as required, for example, during trick mode operation.
  • An exemplary video bit buffer is shown FIGURE 5D containing picture fragments as described previously.
  • a start code detector memory pointer is depicted a s arrow SCD which searches through the exemplary video bit buffer to locate MPEG start codes.
  • the start code detector memory pointer SCD1 indicates detection of a start code from the next, but unwanted picture.
  • unwanted pictures and undesirable decoder hang ups are avoided, as is indicated by arrow SCD2 of FIGURE 5D.
  • unwanted data from previous pictures is cleared input and output FIFOs, first in first out registers of start code detector (SCD) 520 and variable length decoder (VLD) 531.
  • Signals 521/532 depicted in FIGURE 3 clear or 2 7 reset respective FIFOs to purge data remaining from previous decode operations. Such clearance or flushing of the FIFOs ensures that th e SCD and VLD start the next decode operation with new data from exemplary bit buffer 60B thus eliminating a further source of decoder mis-operation resulting from residual prior data.
  • a decoder control capability which facilitates audio video synchronization or lip-syncing by skipping picture decoding is advantageous increased in control range and utilized during trick mode operation to allow a number of pictures, selectable between 2 and at least 6 to be skipped or not decoded.
  • Such picture manipulation advantageous facilitates trick play operation at six times play speed by skipping over B-pictures within each GOP.
  • MPEG decoding may be advantageously optimized, for example, by an essentially concurrent operation of decoding I or P pictures and writing the decoded result for either display and or memory storage within a field period. An ability to decode B type pictures without use of buffer memory is assumed.
  • Such B type picture decoding is known as B frames-on-the-fly (BOF).
  • trick play operation may be advantageously enhanced b y writing a decoded field to memory and concurrently reading a display 2 8 field from an interlaced location within the same memory.
  • the display field may be from a temporally separate picture.
  • Such virtually simultaneous read write operation may be accomplished within a display field period.
  • the decoded field must not overwrite or interfere with the display field readout. This interlaced read write operation is not required for B pictures due to the ability to decode without buffer storage.
  • a bitstream or track buffer 60A is employed to store th e compressed MPEG video bitstream recovered from the medium .
  • Track buffer 60 A or compressed video bit buffer 60B may be used to facilitate multiple accessing of individual MPEG pictures.
  • the decoded trick play output signal must comply with TV signal standards to enable display by a normal TV receiver.
  • Figure 7 is a chart illustrating an inventive arrangement for a reverse trick play mode of 3-times play speed (3X) in a video player. This exemplary chart has columns which represent MPEG coded I pictures and P pictures which comprise groups of pictures or GOPs A, B, C and D. Each GOP has contains twelve pictures which are not derived from a film source.
  • FIGURE 7 illustrates a sequence of 3 7 encoded pictures, with the picture number indicated in parentheses .
  • the extreme right column is labeled "output field #", and represents a time axis incremented in field periods.
  • the first field, output field # 1 marks the start of trick play reproduction.
  • Each row of the chart shows the inventive processing occurring within that respective field period.
  • the frame buffers are numbered 1 and 2.
  • An upper-case “D” signifies decoding the picture / frame indicated at the top of the specific column.
  • the process of decoding a picture and storing the result is depicted b y "D>1", where the number indicates the destination frame buffer number, i.e. 1.
  • a lower-case “d” indicates the display of a field from 2 9 the frame specific to the column.
  • the output field may be selected to preserve the output signal interlace sequence. To provide a continuous output field sequence clearly requires that each chart ro w contains one field display instruction "d".
  • the sequence illustrated in FIGURE 7 starts at output field # 1 , where I-picture 1(37) is decoded and stored in frame buffer 1 , 60C.
  • one field for example, the top field of I-frame (37) is displayed.
  • MPEG picture 1(25 ) is retrieved from bitstream buffer 60B, decoded and stored in frame buffer 2, 60D.
  • another field for example the bottom field of 1(37) read from frame buffer 1, 60 C and displayed.
  • pictures 1(25) and P(28) of GOP C are stored in frame buffers 1 (60C), and 2 (60D) respectively .
  • these frames represent temporally earlier events and are required to enable the decoding of the frames which occurred subsequently, for example frames P(31) and P(34).
  • Intra-coded picture 1(25), resident in memory 2 (60D) was utilized to decode frame P(28), and is not currently required.
  • frame memory 2 is over written with frame 1(37), re-read and decoded from video buffer 60B.
  • the appropriate field of frame 1(37) is accessed from frame buffer 2 for display.
  • Output field #5 is derived by reading a field of picture 3 0 1(37) from frame buffer 2. Simultaneously picture P(31) is decoded with reference to picture P(28), from frame memory 1, and th e decoded result is stored in buffer 2.
  • the first five output fields of this exemplary three times reverse direction replay comprise a still, or frozen image of I-picture (37).
  • the end of output field #5, with pictures 1(28) and P(31 ) stored in frame buffers 1 and 2 respectively trick play output signal generation is commenced.
  • predicted picture P(34) is read from bitstream buffer 60A or video bit buffer 60B, decoded and a n appropriate field displayed without storing. Thus field #6 initiates the display of 3 times speed reverse motion.
  • picture P(34) is retrieved again, decoded and the other field selected for display.
  • Picture P(31) previously decoded and stored in frame buffer 2 is read and provides output fields #8 and #9 respectively.
  • output fields #10 and #11 are read from frame buffer 1 which contains predicted picture P(28).
  • predicted picture P(16) is obtained from bitstream buffer 60B, decoded and sequentially stored in frame buffer 1. Since both frame buffers contain the anchor frames of the next preceding GOP B, output fields #12 and #13 are derived in the same manner as output fields #6 and #7. Predicted picture P(25) is read from bitstream buffer 60B, decoded and the appropriate field displayed without storing.
  • GOP B containing pictures 1( 13), P(16), P(19) and P(22), is processed as described for GOP C.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • Television Signal Processing For Recording (AREA)
  • Signal Processing For Digital Recording And Reproducing (AREA)
  • Indexing, Searching, Synchronizing, And The Amount Of Synchronization Travel Of Record Carriers (AREA)

Abstract

La présente invention concerne un appareil reproduisant un signal de train binaire à partir d'un disque et le train binaire est contrôlé afin d'assurer que seules les données du train binaire demandé sont branchées pour le décodage MPEG. Un transducteur est repositionné afin d'obtenir les données du train binaire requis avant que le décodage MPEG de l'image ne soit complété. Les données du train binaire sont lues préalablement à la mémoire tampon en vue de choisir les données utiles à être mémorisées et d'éliminer les données inutiles. La mémoire tampon est réaffectée en vue d'une opération de mode de lecture rapide et prévue en accès sélectif afin de faciliter la sélection d'images par mode de lecture rapide. Le décodage MPEG et la mémorisation d'images sont contrôlés en vue de faciliter le décodage des trames à l'intérieur d'une période de champ. Les images décodées sont mise en mémoire et lues sensiblement concomitamment au cours d'une période de champ d'images
EP98920220A 1998-05-06 1998-05-06 Traitement de train binaire de reproduction Ceased EP1078366A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1998/009099 WO1999057724A1 (fr) 1998-05-06 1998-05-06 Traitement de train binaire de reproduction

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EP1078366A1 true EP1078366A1 (fr) 2001-02-28

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EP98920220A Ceased EP1078366A1 (fr) 1998-05-06 1998-05-06 Traitement de train binaire de reproduction

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EP (1) EP1078366A1 (fr)
JP (1) JP3899233B2 (fr)
KR (1) KR100556717B1 (fr)
CN (4) CN100452220C (fr)
AU (1) AU7284298A (fr)
HK (5) HK1089283A1 (fr)
PL (2) PL192033B1 (fr)
WO (1) WO1999057724A1 (fr)

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EP1058263A1 (fr) * 1999-05-29 2000-12-06 Deutsche Thomson-Brandt Gmbh Procédé et appareil de reproduction d'un train de données numériques en sens inverse
CN100361521C (zh) * 1999-11-10 2008-01-09 汤姆森特许公司 在可记录媒体上识别和跳越视频信号的片段的方法和设备
EP1245027B1 (fr) * 1999-12-17 2004-09-15 Thomson Licensing S.A. Utilisation d'une memoire sdram comme memoire pour le tamponnage de correction et de piste sur circuit integre frontal de dispositif d'enregistrement ou de reproduction
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US7916866B2 (en) * 2006-05-19 2011-03-29 Mediatek, Inc. Apparatus for descrambling a data retrieved from an optical storage medium, and method therefor
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JP5428565B2 (ja) * 2009-06-19 2014-02-26 ソニー株式会社 情報再生装置、および情報再生方法、並びにプログラム
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Publication number Publication date
CN100447883C (zh) 2008-12-31
CN1301387A (zh) 2001-06-27
PL192033B1 (pl) 2006-08-31
WO1999057724A1 (fr) 1999-11-11
HK1089281A1 (en) 2006-11-24
AU7284298A (en) 1999-11-23
HK1089283A1 (en) 2006-11-24
KR20010106109A (ko) 2001-11-29
CN1783304A (zh) 2006-06-07
KR100556717B1 (ko) 2006-03-10
HK1089284A1 (en) 2006-11-24
CN1783301A (zh) 2006-06-07
PL343845A1 (en) 2001-09-10
JP3899233B2 (ja) 2007-03-28
CN100452220C (zh) 2009-01-14
CN1274145C (zh) 2006-09-06
PL195450B1 (pl) 2007-09-28
CN100447882C (zh) 2008-12-31
JP2002513983A (ja) 2002-05-14
HK1089280A1 (en) 2006-11-24
CN1783303A (zh) 2006-06-07
HK1035957A1 (en) 2001-12-14

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