Apparatus and method for injecting synchronized stream data in digital broadcasting environment

Abstract

An apparatus and method for injecting synchronized stream data into a Motion Picture Experts Group 2 (MPEG-2) video/audio transport stream for a digital data broadcasting service. The apparatus and method for injecting synchronized stream data calculate the injection time point of data access unit (DAU) that forms the synchronized stream data and injects DAU into the MPEG-2 video/audio transport stream based on the calculated injection time point so that the synchronized stream data could be presented smoothly in a receiver. The synchronized stream data injecting apparatus includes: an additional data storing unit, a synchronized stream data selection/establishment unit, a synchronized stream data analyzing unit, a transport stream analyzing unit, a synchronized stream data injection/management unit, a presentation time stamp re-stamping unit and a multiplexing unit.

What is claimed is: 
     
       1. An apparatus for injecting synchronized stream data for a digital data broadcasting service, comprising:
 an additional data storing means for storing, managing and outputting additional data used for the digital data broadcasting service; 
 a synchronized stream data selection/establishment means for selecting synchronized stream data to be multiplexed with a video/audio transport stream, which is inputted from the outside, among the additional data stored in the additional data storing means, and establishing parameter values necessary to multiplex the selected synchronized stream data and the video/audio transport stream; 
 a synchronized stream data analyzing means for analyzing the selected synchronized stream data periodically based on the parameter values established in the synchronized stream data selection/establishment means, and generating information related to the transport stream of the synchronized stream data; 
 a transport stream analyzing means for analyzing the video/audio transport stream periodically based on the parameter values established in the synchronized stream data selection/establishment means, and generating information related to the video/audio transport stream; 
 a synchronized stream data injection/management means for determining whether to inject a data access unit (DAU) that forms the synchronized stream data or not based on the information related to the synchronized stream data transport stream generated in the synchronized stream data analyzing means and the information related to the video/audio transport stream generated in the transport stream analyzing means, and controlling the output of the DAU that forms the synchronized stream data which are stored in the additional data storing means; 
 a presentation time stamp re-stamping means for re-stamping the presentation time stamp of the synchronized stream data which are outputted from the additional data storing means based on the parameter values established in the synchronized stream data selection/establishment means; and 
 a multiplexing means for multiplexing and outputting the video/audio transport stream and the synchronized stream data outputted from the presentation time stamp re-stamping means. 
 
     
     
       2. The apparatus as recited in  claim 1 , wherein the parameter values established in the synchronized stream data selection/establishment means include at least any one selected from a group having a new presentation time stamp of a first DAU of the synchronized stream data;
 an injection period, which is a time interval for analyzing the video/audio transport stream and synchronized stream data and injecting the synchronized stream data to the video/audio transport stream; and 
 the number of analyzed DAUs within the analyzed synchronized stream data during the above established injection period. 
 
     
     
       3. The apparatus as recited in  claim 1 , wherein if the number of analyzed DAUs is not established in the synchronized stream data selection/establishment means, the synchronized stream data selection/establishment means calculates the number of analyzed DAUs by multiplying the largest value (59.94 or 60) of the number of frequency of DAU generation to the established injection period, and if the injection period and the number of analyzed DAUs are not established in the synchronized stream data selection/establishment means, the injection period and the number of DAU to be injected are determined to be 50 msec and 3, respectively. 
     
     
       4. The apparatus as recited in  claim 1 , wherein if synchronized stream data synchronized with the video/audio transport stream are not stored in the additional data storing means, the synchronized stream data selection/establishment means receives the synchronized stream data from the outside and stores the synchronized stream data in the additional data storing means. 
     
     
       5. The apparatus as recited in  claim 1 , wherein the synchronized stream data analyzing means obtains many as DAUs as the analyzed DAU by analyzing the synchronized stream data selected in the synchronized stream data selection/establishment means based on an injection period and the number of analyzed DAUs established in the synchronized stream data selection/establishment means, and obtains the presentation time stamp of a corresponding DAU and the number of transport stream packets. 
     
     
       6. The apparatus as recited in  claim 1 , wherein the transport stream analyzing means analyzes the video/audio transport stream periodically based on an injection period established in the synchronized stream data selection/establishment means, and obtains the program clock references (PCRs) of a beginning part and a final part of an analyzing section of the video/audio transport stream analyzed during one injection period. 
     
     
       7. The apparatus as recited in  claim 1 , wherein in order to calculate PCR of the transport stream, the transport stream analyzing means directly obtains a PCR value from a transport stream including PCR within an analyzing section, obtains PCR from the transport stream packets including PCR among an inputted MPEG-2 transport streams by calculating the PCR for another transport stream packet using an output rate of the MPEG-2 transport stream, or by having a reference clock that increases at 27 MHz which is a per-second increase of PCR of the transport stream analyzing means, and obtains the PCR value by establishing the value of the reference clock with the same value as the obtained PCR and then obtaining the value of the reference clock at a moment when the PCR value is needed. 
     
     
       8. The apparatus as recited in  claim 1 , wherein the synchronized stream data injection/management means calculates the presentation time offset value by using the difference between the new presentation time stamp of a first DAU of the synchronized stream data established in the synchronized stream data selection/establishment means and the presentation time stamp of the first DAU of the synchronized stream data obtained in the synchronized stream data analyzing means, calculates a new presentation time stamp of DAU of the synchronized stream data by adding the presentation time offset value to the presentation time stamp of DAU of the synchronized stream data obtained periodically in the synchronized stream data analyzing means, compares the calculated new presentation time stamp with the PCR generated periodically based on an injection period, which is established in the synchronized stream data selection/establishment means, in the transport stream analyzing means, and if the new presentation time stamp of DAU is larger than the PCR in the final part of the video/audio transport stream currently analyzed and smaller than the summation of the PCR increase during one period and the PCR of the final part, determines to inject the corresponding DAU, and controls the additional data storing means to output the corresponding DAU. 
     
     
       9. The apparatus as recited in  claim 1 , wherein if a new presentation time stamp for an first DAU is stamped in the synchronized stream data selection/establishment means, the presentation time stamp re-stamping means receives synchronized stream data outputted from the additional data storing means, re-stamps the presentation time stamp of a DAU that forms the synchronized stream data by referring to the presentation time stamp newly stamped in the synchronized stream data selection/establishment means, and outputs the re-stamped presentation time stamp of the DAU to the multiplexing means, and wherein, to re-stamp the presentation time stamp of all DAUs that form the synchronized stream data, the presentation time stamp re-stamping means calculates a presentation time offset value by using the difference between the presentation time stamp of the first DAU of the synchronized stream data and the new presentation time stamp stamped in the synchronized stream data selection/establishment means, and re-stamps the presentation time stamp of all DAUs that form the synchronized stream data by adding the presentation time offset value to the presentation time stamp of all DAUs that form the synchronized stream data. 
     
     
       10. The apparatus as recited in  claim 1 , wherein the multiplexing means injects the DAU of the synchronized stream data outputted from the presentation time stamp re-staming means into the places of null packets in the video/audio transport stream within a section analyzed in the transport stream analyzing means, instead of the null packets. 
     
     
       11. The apparatus as recited in  claim 1 , wherein if the number of DAUs multiplexed in the video/audio transport stream analyzed in the transport stream analyzing means is more than two, the multiplexing means injects the DAUs into the video/audio transport stream in the order of quick presentation time stamp, and the locations for DAU to be injected into are moved from a part where PCR of the analyzed video/audio transport stream is small to a part where PCR of the analyzed video/audio transport stream is large. 
     
     
       12. A method for injecting synchronized stream data for a digital data broadcasting service, comprising the steps of:
 a) selecting synchronized stream data that are synchronized with a video/audio transport stream supplied from the outside among additional data used for the digital data broadcasting service, and establishing an injection period which is a time interval for analyzing the video/audio transport stream and the synchronized stream data and injecting the synchronized stream data, the number of analyzed DAUs which is the largest number of DAUs that can be injected into the video/audio transport stream during the above established injection period, and a new presentation time stamp of a first data access unit (DAU) of the synchronized stream data; 
 b) obtaining the presentation time stamp of a corresponding DAU and the number of transport stream packets by analyzing the selected synchronized stream data periodically based on the injection period and the number of analyzed DAU which are established in the step a), and obtaining as many as DAUs as the analyzed DAUs; 
 c) obtaining PCR information of the video/audio transport stream within an analyzing section by analyzing the video/audio transport stream periodically based on the injection period determined in the step a); 
 d) determining whether to inject the DAU of the synchronized stream data into the video/audio transport stream within the analyzing section or not based on the new presentation time stamp of the first DAU of the synchronized stream data, presentation time stamp of DAU of the synchronized stream data and the PCR information of the video/audio transport stream; 
 e) if the DAU of the synchronized stream data is to be injected into the video/audio transport stream within the analyzing section, re-stamping the presentation time stamp of DAU of the synchronized stream data by using the new presentation time stamp of the first DAU of the synchronized stream data; and 
 f) injecting the DAU of the synchronized stream data whose presentation time stamp is re-stamped newly into the video/audio transport stream and outputting the video/audio transport stream with the DAU. 
 
     
     
       13. The method as recited in  claim 12 , further comprising the step of:
 g) going back to the step b) if the analyzing section does not satisfy the condition for injecting the DAU. 
 
     
     
       14. The method as recited in  claim 12 , further comprising the step of:
 h) determining whether all of the DAUs of synchronized stream data are injected or not, and going back to the step b) if there remain any of the DAUs to be injected, otherwise, ending the method. 
 
     
     
       15. The method as recited in  claim 12 , wherein the step a) includes the steps of:
 a1) if the number of analyzed DAU is not established, calculating the number of analyzed DAU by multiplying the largest value (59.94 or 60) of the number of frequency of DAU generation to the injection period established above; and 
 a2) if the injection period and the number of analyzed DAU are not established, determining the injection period and the number of analyzed DAU to be 50 msec and 3, respectively. 
 
     
     
       16. The method as recited in  claim 12 , wherein the PCRs of the beginning part and the final part of the analyzing section of the video/audio transport stream analyzed during one injection period are obtained by analyzing the video/audio transport stream periodically based on the injection period. 
     
     
       17. The method as recited in  claim 12 , wherein said step d) includes the steps of:
 d1) calculating a new presentation time stamp one of the DAUs based on the new presentation time stamp of a first DAU of the synchronized stream data established in the step a) and the presentation time stamp of DAU of the synchronized stream data which are obtained periodically at the step b); 
 d2) comparing the new presentation time stamp of the DAU with the PCR information of the video/audio transport stream obtained in the step c); 
 d3) if the new substantial presentation time stamp of the DAU is larger than a base value PCR_base of the PCR of the video/audio transport stream and smaller than a summation value of increase of the base value PCR_base during one injection period and the base value PCR_base of the PCR of the video/audio transport stream, deciding a time to inject the DAU of the synchronized stream data into the video/audio transport stream. 
 
     
     
       18. The method as recited in  claim 17 , wherein the step d1) includes the steps of:
 d1-1) calculating a presentation time offset value by using the difference between the new presentation time stamp of the first DAU of the synchronized stream data established in the step a) and the presentation time stamp of the first DAU of the synchronized stream data obtained in the step b); and 
 d1-2) calculating the new presentation time stamp of the DAU of the synchronized stream data by adding the presentation time offset value to the presentation time stamp of DAU of the synchronized stream data. 
 
     
     
       19. The method as recited in  claim 12 , wherein the step e) includes the steps of:
 e1) checking if a new presentation time stamp for the first DAU of the selected synchronized stream data is established; 
 e2) if a new presentation time stamp for the first DAU of the selected synchronized stream data is established, calculating a presentation time offset value by subtracting the presentation time stamp of the first DAU of the actual synchronized stream data from the new presentation time stamp, or otherwise, terminating the process of re-stamping the presentation time stamp; and 
 e3) adding the calculated presentation time offset value to the actual presentation time stamp of all DAUs of the inputted synchronized stream data. 
 
     
     
       20. The method as recited in  claim 19 , wherein the step e) further includes the step of:
 if a new presentation time stamp for the first DAU of the selected synchronized stream data is not established, returning to the step f). 
 
     
     
       21. An apparatus for injecting synchronized stream data for a digital data broadcasting service, comprising:
 an additional data storing unit that stores, manages, and outputs additional data used for the digital data broadcasting service;   a synchronized stream data selection/establishment unit that selects synchronized stream data to be multiplexed with a video/audio transport stream, which is inputted from the outside, among the additional data stored in the additional data storing unit, and establishes parameter values necessary to multiplex the selected synchronized stream data and the video/audio transport stream;   a synchronized stream data analyzing unit that analyzes the selected synchronized stream data periodically based on the parameter values established in the synchronized stream data selection/establishment unit, and generates information related to the transport stream of the synchronized stream data;   a transport stream analyzing unit that analyzes the video/audio transport stream periodically, and generates information related to the video/audio transport stream;   a synchronized stream data injection/management unit that determines whether to inject a data access unit (DAU) that forms the synchronized stream data or not based on the information related to the synchronized stream data transport stream generated in the synchronized stream data analyzing unit and the information related to the video/audio transport stream generated in the transport stream analyzing unit, and controls the output of the DAU that forms the synchronized stream data which are stored in the additional data storing unit;   a presentation time stamp re-stamping unit that re-stamps the presentation time stamp of the synchronized stream data which are outputted from the additional data storing unit based on the parameter values established in the synchronized stream data selection/establishment unit; and   a multiplexing unit that multiplexes and outputs the video/audio transport stream and the synchronized stream data outputted from the presentation time stamp re-stamping unit.   
     
     
       22. A method for injecting synchronized stream data for a digital data broadcasting service, comprising the steps of:
 a) selecting synchronized stream data that are synchronized with a video/audio transport stream supplied from the outside among additional data used for the digital data broadcasting service, and establishing an injection period which is a time interval for analyzing the video/audio transport stream and the synchronized stream data and injecting the synchronized stream data, the number of analyzed DAUs which is the largest number of DAUs that can be injected into the video/audio transport stream during the above established injection period, and a new presentation time stamp of a first data access unit (DAU) of the synchronized stream data;   b) obtaining the presentation time stamp of a corresponding DAU and the number of transport stream packets by analyzing the selected synchronized stream data periodically based on the injection period and the number of analyzed DAU which are established in the step a), and obtaining as many as DAUs as the analyzed DAUs;   c) obtaining PCR information of the video/audio transport stream within an analyzing section by analyzing the video/audio transport stream periodically;   d) determining whether to inject the DAU of the synchronized stream data into the video/audio transport stream within the analyzing section or not based on the new presentation time stamp of the first DAU of the synchronized stream data, presentation time stamp of DAU of the synchronized stream data and the PCR information of the video/audio transport stream;   e) if the DAU of the synchronized stream data is to be injected into the video/audio transport stream within the analyzing section, re-stamping the presentation time stamp of DAU of the synchronized stream data by using the new presentation time stamp of the first DAU of the synchronized stream data; and   f) injecting the DAU of the synchronized stream data whose presentation time stamp is re-stamped newly into the video/audio transport stream and outputting the video/audio transport stream with the DAU.   
     
     
       23. An apparatus configured to inject synchronized stream data into a transport stream, the apparatus comprising:
 a data storing unit configured to store synchronized stream data;   a synchronized stream data selection/establishment unit configured to select synchronized stream data corresponding to the transport stream;   a synchronized stream data analyzing unit configured to analyze the selected synchronized stream data and generate information related to the synchronized stream data;   a transport stream analyzing unit configured to analyze the transport stream and generate information related to the transport stream;   a synchronized stream data injection/management unit configured to determine whether to inject the selected synchronized stream data based on the information related to the synchronized stream data and the information related to the transport stream, and control the data storing unit to output the corresponding synchronized stream data based on the determination;   a presentation time stamp re-stamping unit configured to re-stamp the synchronized stream data outputted from the data storing unit with a new presentation time stamp; and   a multiplexing unit configured to multiplex the transport stream and the synchronized stream data.   
     
     
       24. The apparatus as recited in claim 23, wherein the synchronized stream data is encapsulated in a MPEG-2 transport stream form. 
     
     
       25. The apparatus as recited in claim 23, wherein if the additional data storing unit does not store the synchronized stream data corresponding to the transport stream, the synchronized stream data selection/establishment unit is further configured to receive the synchronized stream data from outside and store the received synchronized stream data in the data storing unit. 
     
     
       26. The apparatus as recited in claim 23, wherein the synchronized stream data selection/establishment unit is further configured to establish parameter values. 
     
     
       27. The apparatus as recited in claim 26, wherein the parameter values comprise:
 a new presentation time stamp of a first data access unit (DAU) of the selected synchronized stream data:   an injection period, wherein the injection period is a time interval for injecting the synchronized stream data into the transport stream; and   a maximum number of DAUs of the synchronized stream data that can be injected in one injection period.   
     
     
       28. The apparatus as recited in claim 27, wherein the synchronized stream data analyzing unit is further configured to obtain as many DAUs as the maximum number of the DAUs by analyzing the selected synchronized stream data based on the parameter values. 
     
     
       29. The apparatus as recited in claim 27, wherein the transport stream analyzing unit is further configured to periodically analyze the transport stream based on the parameter values. 
     
     
       30. The apparatus as recited in claim 23, wherein the information related to the synchronized stream data comprises:
 a presentation time stamp of a corresponding DAU; and   a number of transport stream packets.   
     
     
       31. The apparatus as recited in claim 30, wherein the synchronized stream data injection/management unit is further configured to calculate a presentation time offset by using a difference between the new presentation time stamp of a first data access unit (DAU) of the selected synchronized stream data and a presentation time stamp of a corresponding DAU generated from the synchronized stream data analyzing unit. 
     
     
       32. The apparatus as recited in claim 31, wherein the synchronized stream data injection/management unit is further configured to calculate a new presentation time stamp of DAU of the synchronized stream data by adding the presentation time offset to the presentation time stamp of a corresponding DAU. 
     
     
       33. The apparatus as recited in claim 32, wherein the synchronized stream data injection/management unit is further configured to compare the new presentation time stamp of DAU with the presentation time stamp of a corresponding DAU generated in the transport analyzing unit. 
     
     
       34. The apparatus as recited in claim 33, wherein if the new presentation time stamp of DAU is larger than the PCR in the final part of the video/audio transport stream currently analyzed and smaller than the summation of the PCR increase during one period and the PCR of the final part, the synchronized stream data injection/management unit is further configured to determine to inject the corresponding DAU, and control the data storing unit to output the corresponding DAU. 
     
     
       35. The apparatus as recited in claim 23, wherein the information related to the transport stream is a program clock reference (PCR) of the transport stream. 
     
     
       36. The apparatus as recited in claim 35, wherein the transport stream analyzing unit is further configured to obtain the PCR directly from the transport stream including PCR within an analyzing section, and calculate PCR for another transport stream packet based on an output rate of the transport stream. 
     
     
       37. The apparatus as recited in claim 35, wherein the transport stream analyzing unit is further configured to obtain the PCR by putting a reference clock that increases as 27 MHz, wherein the 27 MHz is a per-second increase of PCR of the transport stream analyzing unit. 
     
     
       38. The apparatus as recited in claim 35, wherein the transport stream analyzing unit is further configured to obtain the PCR by establishing a value of the reference clock with the same value as the obtained PCR and obtain the value of the reference clock at a moment when the PCR value is needed. 
     
     
       39. The apparatus as recited in claim 23, wherein if a new presentation time stamp for a first DAU is stamped in the synchronized stream data selection/establishment unit, the presentation time stamp re-stamping unit is further configured to:
 receive the synchronized stream data outputted from the data storing unit;   re-stamp the presentation time stamp of a DAU by referring to the presentation time stamp newly stamped in the synchronized stream data selection/establishment unit; and   output the re-stamped presentation time stamp of the DAU to the multiplexing unit.   
     
     
       40. The apparatus as recited in claim 39, wherein the presentation time stamp re-stamping unit is further configured to:
 calculate a presentation time offset value by using the difference between the presentation time stamp of the first DAU of the synchronized stream data and the new presentation time stamp stamped in the synchronized stream data selection/establishment unit; and   re-stamp the presentation time stamp of all DAUs by adding the presentation time offset value to the presentation time stamp of all DAUs.   
     
     
       41. The apparatus as recited in claim 23, wherein the multiplexing unit is further configured to inject DAUs of the synchronized stream data outputted from the presentation time stamp re-stamping unit into the places of null packets in the transport stream within a section analyzed in the transport stream analyzing unit, instead of the null packets. 
     
     
       42. The apparatus as recited in claim 23, wherein if a number of DAUs of the synchronized stream data multiplexed in the transport stream analyzed in the transport stream analyzing unit is more than two, the multiplexing unit is further configured to inject the DAUs into the transport stream in the order of quick presentation time stamp, and the locations for DAU to be injected into are moved from a part where PCR of the analyzed transport stream is small to a part where PCR of the analyzed transport stream is large. 
     
     
       43. A method for injecting synchronized stream data into a transport stream, the method comprising:
 selecting synchronized stream data corresponding to the transport stream;   analyzing the selected synchronized stream data and generating information related to the synchronized stream data;   analyzing the transport stream and generating information related to the transport stream;   determining whether to inject the selected synchronized stream data based on the information related to the synchronized stream data and the information related to the transport stream:   outputting the corresponding synchronized stream data based on the determination;   re-stamping the synchronized stream data outputted with a new presentation time stamp; and   multiplexing the transport stream and the synchronized stream data.   
     
     
       44. The method as recited in claim 43, wherein the synchronized stream data is encapsulated in a MPEG-2 transport stream form. 
     
     
       45. The method as recited in claim 43, wherein the method further comprises a step of establishing parameter values. 
     
     
       46. The method as recited in claim 45, wherein the parameter values comprise:
 the new presentation time stamp of a first data access unit (DAU) of the selected synchronized stream data;   an injection period, wherein the injection period is a time interval for injecting the synchronized stream data into the transport stream; and   a maximum number of DAUs of the synchronized stream data that can be injected in one injection period.   
     
     
       47. The method as recited in claim 46, wherein the method further comprises a step of obtaining as many DAUs as the maximum number of the DAUs by analyzing the selected synchronized stream data based on the parameter values. 
     
     
       48. The method as recited in claim 46, wherein the step of analyzing the transport stream further comprises a step of periodically analyzing the transport stream based on the parameter values. 
     
     
       49. The method as recited in claim 43, wherein the information related to the synchronized stream data comprises:
 a presentation time stamp of a corresponding DAU; and   a number of transport stream packets.   
     
     
       50. The method as recited in claim 49, wherein the method further comprises a step of calculating a presentation time offset by using a difference between the new presentation time stamp of a first data access unit (DAU) of the selected synchronized stream data and a presentation time stamp of a corresponding DAU generated from the synchronized stream data analyzing unit. 
     
     
       51. The method as recited in claim 50, wherein the method further comprises a step of calculating a new presentation time stamp of DAU of the synchronized stream data by adding the presentation time offset to the presentation time stamp of a corresponding DAU. 
     
     
       52. The method as recited in claim 51, wherein the method further comprises of a step of comparing the new presentation time stamp of DAU with the presentation time stamp of a corresponding DAU generated in the transport analyzing unit. 
     
     
       53. The method as recited in claim 52, wherein the corresponding synchronized stream data is outputted if the new presentation time stamp of DAU is larger than the PCR in the final part of the video/audio transport stream currently analyzed and smaller than the summation of the PCR increase during one period and the PCR of the final part. 
     
     
       54. The method as recited in claim 43, wherein the information related to the transport stream is a program clock reference (PCR) of the transport stream. 
     
     
       55. The method as recited in claim 43, wherein the step of analyzing the transport stream further comprises a step of obtaining a PCR directly from the transport stream including PCR within an analyzing section, and calculating PCR for another transport stream packet based on an output rate of the transport stream. 
     
     
       56. The method as recited in claim 43, wherein the step of analyzing the transport stream further comprises a step of obtaining the PCR by putting a reference clock that increases as 27 MHz, wherein the 27 MHz is a per-second increase of PCR of the transport stream analyzing unit. 
     
     
       57. The method as recited in claim 43, wherein the step of analyzing the transport stream further comprises a step of obtaining the PCR by establishing a value of the reference clock with the same value as the obtained PCR and obtaining the value of the reference clock at a moment when the PCR value is needed. 
     
     
       58. The method as recited in claim 43, wherein if a new presentation time stamp for a first DAU is stamped in the synchronized stream data selection/establishment unit, the step of re-stamping comprises a step of:
 receiving the outputted synchronized stream data;   re-stamping the presentation time stamp of a DAU by referring to the newly stamped presentation time stamp; and   outputting the re-stamped presentation time stamp of the DAU.   
     
     
       59. The method as recited in claim 58, wherein the step of re-stamping further comprises of a step of:
 calculating a presentation time offset value by using the difference between the presentation time stamp of the first DAU of the synchronized stream data and the new presentation time stamp stamped; and   re-stamping the presentation time stamp of all DAUs by adding the presentation time offset value to the presentation time stamp of all DAUs.   
     
     
       60. The method as recited in claim 43, wherein the step of multiplexing comprises a step of injecting DAUs of the outputted synchronized stream data into the places of null packets in the transport stream within a section analyzed, instead of the null packets. 
     
     
       61. The method as recited in claim 43, wherein if a number of DAUs of the synchronized stream data multiplexed in the transport stream analyzed is more than two, the step of multiplexing further comprises a step of injecting the DAUs into the transport stream in the order of quick presentation time stamp, and the locations for DAU to be injected into are moved from a part where PCR of the analyzed transport stream is small to a part where PCR of the analyzed transport stream is large. 
     
     
       62. An apparatus configured to inject synchronized stream data into a transport stream, the apparatus comprising:
 a synchronized stream data selection/establishment unit configured to select synchronized stream data corresponding to the transport stream;   a synchronized stream data analyzing unit configured to analyze the selected synchronized stream data and generate information related to the synchronized stream data;   a transport stream analyzing unit configured to analyze the transport stream and generate information related to the transport stream;   a synchronized stream data injection/management unit configured to determine whether to inject the selected synchronized stream data based on the information related to the synchronized stream data and the information related to the transport stream, and control the data storing unit to output the corresponding synchronized stream data based on the determination; and   a presentation time stamp re-stamping unit configured to re-stamp the synchronized stream data outputted from the data storing unit with a new presentation time stamp.   
     
     
       63. A method for injecting synchronized stream data into a transport stream, the method comprising:
 selecting synchronized stream data corresponding to the transport stream;   analyzing the selected synchronized stream data and generating information related to the synchronized stream data;   analyzing the transport stream and generating information related to the transport stream;   determining whether to inject the selected synchronized stream data based on the information related to the synchronized stream data and the information related to the transport stream;   outputting the corresponding synchronized stream data based on the determination; and   re-stamping the synchronized stream data outputted with a new presentation time stamp.