Method and an apparatus for stream conversion a method and an apparatus for data recording and data recording medium

• US 20040184764A1
• Filed: 05/10/2004
• Published: 09/23/2004
• Est. Priority Date: 11/30/2001
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.), Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation), Sony Corporation (Sony Group Corp.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.), Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation), Sony Corporation (Sony Group Corp.)
• Inventors: Kelly, Declan Patrick, Kato, Motoki, Van Gestel, Wilhelmus Jacobus, Nakamura, Masanobu, Yahata, Hiroshi, Kawasaki, Kojiro, Yagi, Tomotaka
• Granted Patent: US 7,386,223 B2
• Time in Patent Office: Days
• US Class Current: 386/46
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 2020/10537 Audio or video recording
• CPC Class Codes: G11B 2020/10592 specifically adapted for recording or reproducing multichannel signals
• CPC Class Codes: G11B 2020/10814 involving specific measures to prevent a buffer underrun
• CPC Class Codes: G11B 2220/216 Rewritable discs
• CPC Class Codes: G11B 2220/2516 Hard disks
• CPC Class Codes: G11B 2220/2562 DVDs [digital versatile discs]; Digital video discs; MMCDs; HDCDs
• CPC Class Codes: G11B 2220/2575 DVD-RAMs
• CPC Class Codes: G11B 2220/2583 wherein two standards are used on a single disc, e.g. one DVD section and one CD section
• CPC Class Codes: G11B 2220/455 said record carriers being in one device and being used as primary and secondary/backup media, e.g. HDD-DVD combo device, or as source and target media, e.g. PC and portable player
• CPC Class Codes: G11B 27/034 on discs G11B27/036, G11B27/038 take precedence
• CPC Class Codes: G11B 27/105 of operating discs
• CPC Class Codes: G11B 27/329 on a disc [VTOC]
• CPC Class Codes: H04N 21/4135 external recorder interface circuits between an apparatus for recording television signals and a television receiver H04N5/775
• CPC Class Codes: H04N 21/440218 by transcoding between formats or standards, e.g. from MPEG-2 to MPEG-4 conversion of standards in analogue television systems H04N7/01
• CPC Class Codes: H04N 5/775 between a recording apparatus and a television receiver
• CPC Class Codes: H04N 5/781 on disks or drums
• CPC Class Codes: H04N 5/85 on discs or drums
• CPC Class Codes: H04N 5/907 using static stores, e.g. storage tubes or semiconductor memories H04N5/91 takes precedence
• CPC Class Codes: H04N 9/8042 : involving data reduction
• CPC Class Codes: H04N 9/8205 : involving the multiplexing of an additional signal and the colour video signal

Abstract

In a recording medium storing MPEG stream, flag information (encode_condition) indicating that the stream is recorded in a format enabling easily the first stream (MPEG transport stream) to be converted into the second stream (MPEG program stream) is provided. Such a flag information is included in Tip packet which is a control packet, in the medium. Thus it can easily determine whether the data is recorded in this format without analysis of data stored in the recording medium.

Claims

1. A stream conversion apparatus for converting a first stream of multiplexed video data and audio data recorded to a recording medium to a second stream, the first stream having a structure for storing data segmented in first blocks, the second stream having a structure for storing data segmented in second blocks, the maximum data size of the first and second blocks being different, wherein the first stream format is a constrained format for conversion to the second stream,

with the constrained format,

a specific number of consecutive first blocks in the first stream are managed as a unit (Multiplexing Unit), the specific number is set so that a total amount of data stored in the unit does not exceed an amount of data stored to one second block, and all data stored in the same unit are the same video stream or the same audio stream,

an input start time to a system decoder of a destination second block to which the stream is converted is the same as the later one of a first candidate time and a second candidate time, the first candidate time being the input start time to the system decoder of a source unit being converted, the second candidate time being the time at which input to the system decoder of the second block immediately before the destination second block to which the source unit is converted ends,

the recording medium also records a flag indicating whether the recorded first stream is recorded in the constrained format,

the stream conversion system comprises:

a reading section operable to read the first stream from the recording medium;

a conversion section operable to convert the read first stream to a second stream; and

a recording section operable to record the converted second stream to the recording medium; and

the conversion section references the flag to determine if the format of the first stream is the constrained format, and when the first stream determined to be recorded using the constrained format, converts, by unit, the first blocks composing the unit to one second block without changing the multiplexing order of the first blocks, and selects the later one of the first and second candidate times as the time stamp information of the converted second block to set the decoder input start time of the second block.

2. The stream conversion apparatus according to claim 1, wherein:

a plurality of consecutive units in the first stream are managed as a capsule in which a control block is inserted;

the first block located at the head of the unit includes first time stamp information (ATS[i]) indicating an input start time to a system decoder based on a first reference value;

the control block contains the first time stamp information (ATS_tip) based on the first reference value, and second time stamp information (PCR_tip) based on a second reference value different from the first reference value; and

the second time stamp information (calculated_PCR[i]) of the first block located at the head of each unit and input start time (SCR[i]) to the system decoder of each second block included in the second stream converted from the first stream are obtained from the following formulas,

SCR[1]=calculated_—

PCR[1]SCR[i]=max(SCR[i−

1]+T, calculated_—

PCR[i])calculated_—

PCR[i]=PCR_tip +(ATS[i]−

ATS_tip+C)

where i is an integer which is 2 or more, T is the minimum transfer time of a second block, and C is a correction factor for overflow of ATS[i].

3. The stream conversion apparatus according to claim 1, wherein when determining, by referencing the flag, that the format of the first stream is not the constrained format, the conversion section re-encodes the first stream to convert the first stream to the second stream.

4. A recording apparatus for multiplexing video information and audio information to record the information to a recording medium in a format enabling conversion from a first stream to a second stream, the first stream having a structure for storing data segmented in first blocks, the second stream having a structure for storing data segmented in second blocks, the maximum data size of the first and second blocks being different, wherein

with the format,

a specific number of consecutive first blocks in the first stream are managed as a unit (Multiplexing Unit), the specific number is set so that a total amount of data stored in the unit does not exceed an amount of data stored to one second block, and all data stored in the same unit are the same video stream or the same audio stream,

a plurality of consecutive units including video data by decode unit in the first stream are managed as a capsule in which a control block is inserted, the control block stores a flag indicating if the recording format of the first stream is the constrained format,

an input start time to a system decoder of a destination second block to which the stream is converted is the same as the later one of a first candidate time and a second candidate time, the first candidate time being the input start time to the system decoder of a source unit being converted, and the second candidate time being the time at which input to the system decoder of the second block immediately before the destination second block to which the source unit is converted ends,

the first stream is converted to the second stream by converting, by unit, the first blocks composing the unit to one second block without changing the multiplexing order of the first blocks, and selecting the later one of the first and second candidate times as the time stamp information of the converted second block to set the decoder input start time of the second block;

the recording apparatus comprises;

an encoding section operable to encode the video information and audio information to be recorded to the first stream according to the format;

a recording section operable to record the encoded first stream to the recording medium; and

a control section operable to control the encoding section and recording section,

the control section anticipates the second stream converted from the encoded first stream when encoding the first stream, and then encodes the first stream so that at least one of a buffer underflow and buffer overflow occurs in neither the encoded first stream or the anticipated second stream.

5. The recording apparatus according to claim 4, wherein:

a plurality of consecutive units in the first stream are managed as a capsule in which a control block is inserted;

the first block located at the head of the unit includes first time stamp information (ATS[i]) indicating an input start time to a system decoder based on a first reference value;

the control block contains the first time stamp information (ATS_tip) based on the first reference value, and second time stamp information (PCR_tip) based on a second reference value different from the first reference value; and

the second time stamp information (calculated_PCR[i]) of the first block located at the head of each unit and input start time (SCR[i]) to the system decoder of each second block included in the second stream converted from the first stream are obtained from the following formulas,

SCR[1]=calculated_—

PCR[1]SCR[i]=max(SCR[i−

1]+T, calculated_—

PCR[i])calculated_—

PCR[i]=PCR_tip +(ATS[i]−

ATS_tip+C)

where i is an integer which is 2 or more, T is the minimum transfer time of a second block, and C is a correction factor for overflow of ATS[i].

6. A recording medium for recording video data and audio data multiplexed in a format enabling converting a first stream to a second stream, the first stream having a structure for storing data segmented in first blocks, the second stream having a structure for storing data segmented in second blocks, the maximum data size of the first and second blocks being different, wherein

with the format,

a specific number of consecutive first blocks in the first stream are managed as a unit (Multiplexing Unit), the specific number is set so that a total amount of data stored in the unit does not exceed an amount of data stored to one second block, and all data stored in the same unit are the same video stream or the same audio stream,

a plurality of consecutive units including video data by decode unit in the first stream are managed as a capsule in which a control block is inserted, the control block stores a flag indicating if the recording format of the first stream is the constrained format,

an input start time to a system decoder of a destination second block to which the stream is converted is the same as the later one of a first candidate time and a second candidate time, the first candidate time being the input start time to a system decoder of a source unit being converted, and the second candidate time being the time at which input to the system decoder of the second block immediately before the destination second block to which the source unit is converted ends,

the first stream is converted to the second stream by converting, by unit, the first blocks composing the unit to one second block without changing the multiplexing order of the first blocks, and selecting the later one of the first and second candidate times as the time stamp information of the converted second block to set the decoder input start time of the second block.

7. A stream conversion method for converting a first stream of multiplexed video data and audio data recorded to a recording medium to a second stream, the first stream having a structure for storing data segmented in first blocks, the second stream having a structure for storing data segmented in second blocks, the maximum data size of the first and second blocks being different, wherein

the first stream format is a constrained format for conversion to the second stream,

with the constrained format,

a specific number of consecutive first blocks in the first stream are managed as a unit (Multiplexing Unit), the specific number is set so that a total amount of data stored in the multiplexing unit does not exceed an amount of data stored to one second block, and all data stored in the same unit are the same video stream or the same audio stream,

an input start time to a system decoder of a destination second block to which the stream is converted is the same as the later one of a first candidate time and a second candidate time, the first candidate time being the input start time to the system decoder of a source unit being converted, the second candidate time being the time at which input to the system decoder of the second block immediately before the destination second block to which the source unit is converted ends,

the recording medium also records a flag indicating whether the recorded first stream is recorded in the constrained format,

the stream conversion method comprises

referencing the flag to determine the format of the first stream in order to convert the first stream to the second stream,

when the format of the first stream is the constrained format,

converting, by unit, the first blocks composing the unit to one second block without changing the multiplexing order of the first blocks, and

selecting the later one of the first and second candidate times as the time stamp information of the converted second block to set the decoder input start time of the second block.

9. A computer-readable program for executing the method as described in claim 7 or claim 8 on a computer.

8. A recording method for multiplexing video information and audio information to record the information to a recording medium in a format enabling conversion from a first stream to a second stream, the first stream having a structure for storing data segmented in first blocks, the second stream having a structure for storing data segmented in second blocks, the maximum data size of the first and second blocks being different, wherein

with the format,

a specific number of consecutive first blocks in the first stream are managed as a unit (Multiplexing Unit), the specific number is set so that a total amount of data stored in the unit does not exceed an amount of data stored to one second block, and all data stored in the same unit are the same video stream or the same audio stream,

a plurality of consecutive units including video data by decode unit in the first stream are managed as a capsule in which a control block is inserted, the control block stores a flag indicating if the recording format of the first stream is the constrained format,

an input start time to a system decoder of a destination second block to which the stream is converted is the same as the later one of a first candidate time and a second candidate time, the first candidate time being the input start time to the system decoder of the source unit being converted, and the second candidate time being the time at which input to the system decoder of the second block immediately before the destination second block to which the source unit is converted ends,

the first stream is converted to the second stream by converting, by unit, the first blocks composing the unit to one second block without changing the multiplexing order of the first blocks, and selecting the later one of the first and second candidate times as the time stamp information of the converted second block to set the decoder input start time of the second block,

the recording method comprises, when encoding the first stream, anticipating the second stream converted from the encoded first stream, and encoding the first stream so that at least one of buffer underflow or buffer overflow occurs in neither the encoded first stream or the anticipated second stream.