US6169843B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recording and playback of audio-video transport streams
Assignee: Harmonic Inc
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Filing: 1997-09-19
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Granted: 2001-01-02
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Expires: 2017-09-19
Abstract
Abstract A method and apparatus for recording and playback of transport stream packets including multiplexed audio, video and other data streams. The transport streams may be generated in accordance with an MPEG-2 standard. In a record mode, an arrival timestamp is generated for each input transport packet to be recorded in a peripheral storage device. A given arrival timestamp indicates the arrival time of the corresponding transport packet in the recording system. Each of the transport packets are then stored with their corresponding arrival timestamps. The record mode may utilize a packet identifier (PID) decoder to perform packet filtering such that only incoming transport packets with selected PIDs are stored. In a playback mode, transport packets and corresponding arrival timestamps are retrieved from the storage device and the arrival timestamps are utilized to direct synchronous delivery of the transport packets to, for example, a decoder or a transport stream broadcast system. The playback mode may detect a timestamp discontinuity code in one or more of the arrival timestamps, and adjust the playback system time clock accordingly. The playback mode may also provide null packet interleaving in which a selectable number of null packets are inserted between each valid transport packet to thereby provide a selectable fixed-rate transport packet output. The recording and playback features may be implemented using a spooler card and a storage controller card incorporated into an otherwise conventional personal computer.
Inventors
- 👤 Michael P. Lenihan
- 👤 Sean C. Hart
- 👤 Mark Magee
- 👤 Brian Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:05
CPC Classifications
H; H04; H04N; H04N21/00; H04N21/40; H04N21/43; H04N21/435; H04N21/20; H04N21/23; H04N21/235; H04N21/236; H04N21/2368; H04N21/41; H04N21/4104; H04N21/4113; H04N21/4135; H04N21/4302; H04N21/4305; H04N21/433; H04N21/4334; H04N21/434; H04N21/4341; H04N21/4344; H04N21/80; H04N21/83; H04N21/845; H04N21/8455; H04N9/00; H04N9/79; H04N9/80; H04N9/804; H04N9/8042; H04N9/806; H04N9/8063
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
167 words
A method of playing back transport packets in a transport stream playback system comprising the steps of: retrieving from storage each of a plurality of formatted packets, including a transport packet with synchronization word, a corresponding formatted arrival timestamp, the arrival timestamp indicative of an arrival time of the corresponding transport packet in a recording system used to store the formatted packets; distinguishing between said arrival timestamps and said synchronization words based on a bit pattern format of said arrival timestamps which is unambiguously free of any bit pattern that matches said synchronization pattern; determining if one of the plurality of packets includes a timestamp discontinuity; altering a playback system time clock in accordance with an identified timestamp discontinuity; and delivering the transport packets in one or more transport streams in accordance with the corresponding arrival timestamps relative to an independent playback system time clock, wherein the independent playback system time clock is loaded with the arrival time stamp of the transport packet with a playback discontinuity.
Claim 2
Independent Claim
167 words
A method of playing back transport packets in a transport stream playback system comprising the steps of: retrieving from storage each of a plurality of formatted packets, including a transport packet with synchronization word, a corresponding formatted arrival timestamp, the arrival timestamp indicative of an arrival time of the corresponding transport packet in a recording system used to store the formatted packets; distinguishing between said arrival timestamps and said synchronization words based on a bit pattern format of said arrival timestamps which is unambiguously free of any bit pattern that matches said synchronization pattern; determining if one of the plurality of packets includes a timestamp discontinuity; altering a playback system time clock in accordance with an identified timestamp discontinuity; and delivering the transport packets in one or more transport streams in accordance with the corresponding arrival timestamps relative to an independent playback system time clock, wherein the independent playback system time clock is loaded with the arrival time stamp of the transport packet with a playback discontinuity.
Claim 3
Dependent Claim
39 words
The method of claim 1 wherein the step of determining if one of the plurality of packets includes a timestamp discontinuity further includes the step of identifying a predetermined code placed in the arrival timestamp of the corresponding packet.
Claim 4
Dependent Claim
50 words
The method of claim 1 wherein the step of altering a playback system time clock in accordance with an identified timestamp discontinuity further includes the step of resetting the playback system time clock to a value corresponding to an arrival timestamp of the packet for which the discontinuity was identified.
Claim 5
Dependent Claim
59 words
The method of claim 1 wherein the step of altering a playback system time clock in accordance with an identified timestamp discontinuity further includes the step of resetting the playback system time clock to a value corresponding to an arrival timestamp of a packet arriving in the playback system subsequent to the packet for which the discontinuity was identified.
Claim 6
Dependent Claim
36 words
The method of claim 1 wherein the step of delivering transport packets further includes the additional step of delivering a predetermined number of null packets between delivery of each of the transport packets retrieved from storage.
Claim 7
Independent Claim
184 words
An apparatus for use in playing back transport packets in a transport stream playback system, the apparatus comprising: a controller for retrieving each of a plurality of formatted packets, including a transport packet having a synchronization word, and corresponding formatted arrival timestamps from a system storage device, each arrival timestamp indicative of an arrival time of the corresponding transport packet in a recording system used to store that formatted packet, for distinguishing between said arrival timestamps and said synchronization words based on a bit pattern format of said arrival timestamps which is unambiguously free of any bit pattern that matches said synchronization pattern, for determining if one of the plurality of packets includes a timestamp discontinuity, and for altering a playback system time clock in accordance with an identified timestamp discontinuity; and a spooler operative to deliver the retrieved transport packets in one or more transport streams in accordance with the retrieved arrival timestamps relative to an independent playback system time clock, wherein the independent playback system time clock is loaded with the arrival time stamp of the transport packet with a playback discontinuity.
Claim 8
Independent Claim
184 words
An apparatus for use in playing back transport packets in a transport stream playback system, the apparatus comprising: a controller for retrieving each of a plurality of formatted packets, including a transport packet having a synchronization word, and corresponding formatted arrival timestamps from a system storage device, each arrival timestamp indicative of an arrival time of the corresponding transport packet in a recording system used to store that formatted packet, for distinguishing between said arrival timestamps and said synchronization words based on a bit pattern format of said arrival timestamps which is unambiguously free of any bit pattern that matches said synchronization pattern, for determining if one of the plurality of packets includes a timestamp discontinuity, and for altering a playback system time clock in accordance with an identified timestamp discontinuity; and a spooler operative to deliver the retrieved transport packets in one or more transport streams in accordance with the retrieved arrival timestamps relative to an independent playback system time clock, wherein the independent playback system time clock is loaded with the arrival time stamp of the transport packet with a playback discontinuity.
Claim 9
Dependent Claim
34 words
The apparatus of claim 6 wherein the controller determines if one of the plurality of packets includes a timestamp discontinuity by identifying a predetermined code placed in the arrival timestamp of the corresponding packet.
Claim 10
Dependent Claim
38 words
The apparatus of claim 6 wherein the controller alters the playback system time clock by resetting the playback system time clock to a value corresponding to an arrival timestamp of the packet for which the discontinuity was identified.
Claim 11
Dependent Claim
47 words
The apparatus of claim 6 wherein the controller alters the playback system time clock by resetting the playback system time clock to a value corresponding to an arrival timestamp of a packet arriving in the playback system subsequent to the packet for which the discontinuity was identified.
Claim 12
Dependent Claim
26 words
The apparatus of claim 6 wherein the spooler delivers a predetermined number of null packets between delivery of each of the transport packets retrieved from storage.
Claim 13
Independent Claim
187 words
A method of playing back transport packets in a transport stream playback system comprising the steps of: retrieving from storage each of a plurality of formatted packets, including a transport packet and a corresponding formatted arrival timestamp, the arrival timestamp indicative of an arrival time of the corresponding transport packet in a recording system used to store the formatted packets, for each formatted packet, determining that the formatted packets includes a timestamp discontinuity if a predetermined portion of the formatted packet other than the transport packet itself equals a particular, fixed, predetermined value, the determination being made for each of plural, sequentially retrieved, formatted packets using the same particular, fixed predetermined value, altering playback of each transport packets in the formatted packets determined to include a timestamp discontinuity, and delivering the transport packets in accordance with the corresponding arrival timestamp relative to an independent playback system time clock and in accordance with alterations in playback made for transport packets determined to include the timestamp discontinuity, wherein the independent playback system time clock is loaded with the arrival time stamp of the transport packet with a playback discontinuity.
Claim 14
Independent Claim
187 words
A method of playing back transport packets in a transport stream playback system comprising the steps of: retrieving from storage each of a plurality of formatted packets, including a transport packet and a corresponding formatted arrival timestamp, the arrival timestamp indicative of an arrival time of the corresponding transport packet in a recording system used to store the formatted packets, for each formatted packet, determining that the formatted packets includes a timestamp discontinuity if a predetermined portion of the formatted packet other than the transport packet itself equals a particular, fixed, predetermined value, the determination being made for each of plural, sequentially retrieved, formatted packets using the same particular, fixed predetermined value, altering playback of each transport packets in the formatted packets determined to include a timestamp discontinuity, and delivering the transport packets in accordance with the corresponding arrival timestamp relative to an independent playback system time clock and in accordance with alterations in playback made for transport packets determined to include the timestamp discontinuity, wherein the independent playback system time clock is loaded with the arrival time stamp of the transport packet with a playback discontinuity.
Claim 15
Dependent Claim
16 words
The method of claim 11 wherein transport packets determined to have the timestamp discontinuity are discarded.
Claim 16
Dependent Claim
44 words
The method of claim 11 wherein each arrival time stamp contained in each formatted packet is formatted into a pattern of bits that is ambiguously free of a bit pattern that matches a synchronization word of the corresponding transport packet of the formatted packet.
Claim 17
Independent Claim
198 words
A apparatus for use in playing back transport packets in a transport stream playback system, the apparatus comprising: a controller configured for retrieving from storage each of a plurality of formatted packets, including a transport packet and a corresponding formatted arrival timestamp, the arrival timestamp indicative of an arrival time of the corresponding transport packet in a recording system used to store the formatted packets, for each formatted packet, determining that the formatted packets includes a timestamp discontinuity if a predetermined portion of the formatted packet other than the transport packet itself equals a particular, fixed, predetermined value, the determination being made for each of plural, sequentially retrieved formatted packets using the same particular, fixed predetermined value, and for altering playback of each transport packets in the formatted packets determined to include a timestamp discontinuity, and a spooler configured for delivering the transport packets in accordance with the corresponding arrival timestamp relative to an independent playback system time clock and in accordance with alterations in playback made for transport packets determined to include the timestamp discontinuity, wherein the independent playback system time clock is loaded with the arrival time stamp of the transport packet with a playback discontinuity.
Claim 18
Independent Claim
198 words
A apparatus for use in playing back transport packets in a transport stream playback system, the apparatus comprising: a controller configured for retrieving from storage each of a plurality of formatted packets, including a transport packet and a corresponding formatted arrival timestamp, the arrival timestamp indicative of an arrival time of the corresponding transport packet in a recording system used to store the formatted packets, for each formatted packet, determining that the formatted packets includes a timestamp discontinuity if a predetermined portion of the formatted packet other than the transport packet itself equals a particular, fixed, predetermined value, the determination being made for each of plural, sequentially retrieved formatted packets using the same particular, fixed predetermined value, and for altering playback of each transport packets in the formatted packets determined to include a timestamp discontinuity, and a spooler configured for delivering the transport packets in accordance with the corresponding arrival timestamp relative to an independent playback system time clock and in accordance with alterations in playback made for transport packets determined to include the timestamp discontinuity, wherein the independent playback system time clock is loaded with the arrival time stamp of the transport packet with a playback discontinuity.
Claim 19
Dependent Claim
16 words
The apparatus of claim 14 wherein transport packets determined to have the timestamp discontinuity are discarded.
Claim 20
Dependent Claim
44 words
The apparatus of claim 14 wherein each arrival time stamp contained in each formatted packet is formatted into a pattern of bits that is ambiguously free of a bit pattern that matches a synchronization word of the corresponding transport packet of the formatted packet.
References Cited (Backward Citations)
US5396497A
Cited
US5467342A
Cited
US5420866A
Cited
US5566174A
Cited
US5555244A
Cited
US5534944A
Cited
US5835668A
Cited
US5596420A
Cited
US5537408A
Cited
US5517250A
Cited
US5561791A
Cited
US5521907A
Cited
US5790543A
Cited
US5640388A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-01-02 | 2004-07-03 | 2005-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-01-02 | 2008-07-03 | 2009-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-01-02 | 2012-07-03 | 2013-01-02 | $7700.00 | Window Closed / Lapsed |