Method and device for packaging audio samples of a non-PCM encoded audio bitstream into a sequence of frames

Abstract

An audio bitstream is read from a digital video disc DVD for transfer, subsequent to parsing thereof, via an IEC 958 protocolled interface, for use in a multi-channel audio reproduction apparatus. For each respective audio channel MPEG audio samples are packaged recurrently in burst payloads, and these burst payloads are packaged as user data in IEC958 format frames. Pause bursts are used for signalling absence of audio for all associated channels with, each pause burst representing such audio absence during a perceptibly acceptable time interval only.

I claim: 
     
       1. A method of transferring a non-PCM encoded multichannel bitstream to digital audio reproduction apparatus via an interface which is adapted for transfer of PCM encoded bitstreams, the non-PCM encoded multichannel bitstream resulting from parsing a multichannel bitstream received from a digital video disc (DVD), comprising the steps of:
 (i) recurrently packaging audio samples of the non-PCM encoded multichannel bitstream in data burst payloads; 
 (ii) packing the data burst payloads as user data in successive frames having a predetermined format including pause bursts signifying the absence of audio in all channels, each pause burst having a duration in the range below 10 milliseconds; and 
 (iii) decoding and supplying the packaged data burst payloads of the respective channels to respective channel inputs of said audio reproduction apparatus. 
 
     
     
       2. A method as claimed in  claim 1 , wherein each pause burst has a repetition interval of 32 or a multiple of 32 of the periods of said audio samples. 
     
     
       3. A method as claimed in  claim 1 , wherein the presence of a pause burst is indicated by a burst header in the non-PCM encoded multichannel bitstream. 
     
     
       4. A method as claimed in  claim 1 , wherein each pause burst has a repetition period not over one-fifth that of any non-pause burst in the non-PCM encoded multichannel bitstream. 
     
     
       5. A method as claimed in  claim 1 , wherein the data bursts have a repetition period of 384 periods of the audio samples. 
     
     
       6. A method as claimed in  claim 1 , further comprising adding stuffing zeros to the data burst payloads in order to maintain a uniform size burst format, the bursts being multiplexed among the multiple channels in a recurrent manner, relevant data from other channels being superposed on stuffing zero positions in channels having stuffing zeros. 
     
     
       7. A coupling device for transferring a non-PCM encoded multichannel bitstream to digital audio reproduction apparatus via an interface which is adapted for transfer of PCM encoded bitstreams, the non-PCM encoded multichannel bitstream resulting from parsing a multichannel bitstream read from a digital video disc (DVD); comprising:
 means for recurrently packaging audio samples of the non-PCM encoded multichannel bitstream in data burst payloads; 
 means for packing the data burst payloads as user data in successive frames having a predetermined format including pause bursts signifying the absence of audio in all channels, each pause burst having a duration in the millisecond range below 10 milliseconds; and 
 means for decoding and supplying the packaged data burst payloads of the respective channels to respective channel inputs of said audio reproduction apparatus. 
 
     
     
       8. A method of transferring a non-PCM encoded multichannel bitstream to digital audio reproduction apparatus via an interface which is adapted for transfer of PCM encoded bitstreams, the non-PCM encoded multichannel bitstream resulting from parsing a multichannel bitstream read from a digital video disc (DVD), the parsed bitstream being received as a sequence of frames which accumulates, for each channel, a uniform number of data bits, comprising the steps of:
 storing each frame in an intermediate frame buffer; 
 detecting the presence of data pertaining to a particular output channel or the absence of such data as represented by one or more sequential pause bursts; 
 upon detecting the presence of said data in said detecting step, decoding and outputting decoded information for the particular channel; and 
 upon detecting one or more sequential pause bursts in the detecting step, controlling a soft mute block to conceal the absence of said data. 
 
     
     
       9. A coupling device for transferring a non-PCM encoded multichannel bitstream to digital audio reproduction apparatus via an interface which is adapted for transfer of PCM encoded bitstreams, the non-PCM encoded multichannel bitstream resulting from parsing a multichannel bitstream read from a digital video disc (DVD), comprising:
 means for receiving said parsed bitstream as a sequence of frames which each accommodate, for each channel, a uniform number of data bits; 
 an intermediate frame buffer for storing each frame; 
 detection means for detecting the presence of data pertaining to a particular output channel or the absence of such data as represented by one or more sequential pause bursts; 
 decoding means controlled by said detection means for decoding and outputting from a stored frame decoded information for said particular channel; and 
 means responsive to detection by said detection means of said one or more sequential pause bursts to control an audio soft mute block of said one or more sequential pause bursts to conceal the absence of data in said mute block. 
 
     
     
       10. A method of packaging audio samples of a non-PCM encoded audio bitstream into a sequence of IEC958 format frames, the method comprising acts of:
 recurrently packaging audio samples of a plurality of audio channels of a non-PCM encoded audio bitstream into burst payloads;   packaging by a processor the burst payloads into IEC958 format frames, resulting in a sequence of IEC958 format frames, the packaging including:
 generating pause bursts indicating absence of audio data in one of the audio channels, the pause bursts representing such audio absence for a predetermined time interval; and 
 inserting the pause bursts into the sequence of IEC958 format frames; and 
   outputting the sequence of IEC958 format frames including the generated pause bursts.   
     
     
       11. The method of claim 10, wherein the audio samples are MPEG audio samples, and the pause bursts have a repetition time interval that is equal to at most one MPEG LFE sample recurrency time interval. 
     
     
       12. The method of claim 11, wherein the pause bursts have a repetition time interval equal to 32 audio sample periods or an integer multiple of 32 audio sample periods. 
     
     
       13. The method of claim 12, wherein the presence of the pause burst is indicated in a header of the burst. 
     
     
       14. The method of claim 12, wherein the pause burst has a repetition time that is at least five times shorter than the repetition time of any non-pause burst. 
     
     
       15. The method of claim 12, wherein the bursts include MPEG-1 layer data bursts with a repetition time interval of 384 audio sample periods. 
     
     
       16. The method of claim 12, wherein the bursts include MPEG-1 layer 2 or 3, or MPEG-2 without extension bursts with a repetition time interval of 1152 audio sample periods. 
     
     
       17. The method of claim 12, wherein the bursts include MPEG-2 extension bursts with a repetition time interval of 1152 audio sample periods. 
     
     
       18. The method of claim 12, wherein the bursts include MPEG2 layer 1 low sample rate bursts with a repetition time interval of 384 audio sample periods. 
     
     
       19. The method of claim 12, wherein the bursts include MPEG2 layer 2 or 3 low sample rate bursts with a repetition time interval of 1152 audio sample periods. 
     
     
       20. The method of claim 12, comprising acts of:
 adding stuffing zeroes for maintaining a uniform size among all the bursts;   multiplexing the bursts among the channels in a recurrent manner; and   superposing relevant data when stuffing a burst format at a uniform size among all bursts.   
     
     
       21. The method of claim 10, wherein the presence of the pause burst is indicated in a header of the burst. 
     
     
       22. The method of claim 10, wherein the pause burst has a repetition time that is at least five times shorter than the repetition time of any non-pause burst. 
     
     
       23. The method of claim 10, wherein the bursts include MPEG-1 layer data bursts with a repetition time interval of 384 audio sample periods. 
     
     
       24. The method of 23, wherein the presence of the pause burst is indicated in a header of the burst. 
     
     
       25. The method of claim 23, wherein the pause burst as a repetition time that is at least five times shorter than the repetition time of non-pause burst. 
     
     
       26. The method of claim 10, wherein the bursts include MPEG-1 layer 2 or 3, or MPEG-2 without extension bursts with a repetition time interval of 1152 audio sample periods. 
     
     
       27. The method of claim 10, wherein the bursts include MPEG-2 extension bursts with a repetition time interval of 1152 audio sample periods. 
     
     
       28. The method of claim 10, wherein the bursts include MPEG2 layer 1 low sample rate bursts with a repetition time interval of 384 audio sample periods. 
     
     
       29. The method of claim 10, wherein the bursts include MPEG2 layer 2 or 3 low sample rate bursts with a repetition time interval of 1152 audio sample periods. 
     
     
       30. The method of claim 10, comprising acts of:
 adding stuffing zeroes for maintaining a uniform size among all the bursts;   multiplexing the bursts among the channels in a recurrent manner; and   superposing relevant data when stuffing a burst format at a uniform size among all bursts.   
     
     
       31. The method of claim 10, wherein the non-PCM encoded bitstream is an AC-3 bitstream. 
     
     
       32. The method of claim 31, wherein the non-PCM encoded audio bursts have a repetition time interval of 1536 audio sample periods. 
     
     
       33. The method of claim 32, wherein the repetition time interval of the pause bursts equals 3 IEC958 frames. 
     
     
       34. The method of claim 31, wherein the repetition time interval of the pause bursts equals 3 IEC958 frames. 
     
     
       35. The method of claim 31, wherein the non-PCM encoded bitstream is an MPEG audio bitstream. 
     
     
       36. The method of claim 35, wherein the non-PCM encoded audio bursts have a repetition time interval of 1152 audio sample periods. 
     
     
       37. The method of claim 36, wherein the repetition time interval of the pause bursts equals 32 IEC958 frames. 
     
     
       38. The method of claim 35, wherein the repetition time interval of the pause bursts equals 32 IEC958 frames. 
     
     
       39. The method of claim 31, comprising acts of:
 adding stuffing zeroes for maintaining a uniform size among all the bursts;   multiplexing the bursts among the channels in a recurrent manner; and   superposing relevant data when stuffing a burst format at a uniform size among all bursts.   
     
     
       40. A device for packaging audio samples of a non-PCM encoded audio bitstream into a sequence of IEC958 format frames, the device comprising:
 packaging means for recurrently packaging data words of a multitude of audio channels of a non-PCM encoded audio bitstream into burst payloads, and for packaging the burst payloads into IEC958 format frames, resulting in a sequence of IEC958 format frames;   pause burst generating means for generating pause bursts and inserting those pause bursts into the sequence of IEC958 format frames, such pause bursts each indicating absence of audio data in one of the audio channels, each pause burst representing the absence of audio during a predetermined time interval; and   output means for outputting the sequence of IEC958 format frames including the inserted pause bursts.   
     
     
       41. A method of receiving a sequence of IEC958 format frames and outputting audio data for reproduction by an audio channel, the method comprising acts of:
 receiving a bit stream for a plurality of audio channels as a sequence of IEC958 format frames, each frame accommodating a uniform number of data bits for each respective audio channel;
 detecting by a processor presence or absence of audio data for each output channel, the absence of audio date being indicated by a series of one or more pause bursts; 
   upon detecting the absence of audio data for a given output channel, the processor outputting a concealing block for the given output channel for concealing the absence of audio data for the given output channel; and   alternatively, upon detecting the presence of audio data for the given output channel, the processor outputting the audio data for the given output channel.   
     
     
       42. A device for receiving a parsed non-PCM encoded bitstream and outputting audio data for reproduction by an audio channel, the device comprising:
 reception means for receiving a non-PCM encoded bitstream for a plurality of audio channels as a sequence of frames, each frame accommodating for each applicable channel a uniform number of data bits;
 detection means for detecting a presence or absence of audio data in the frames pertaining to a particular audio output channel; 
   decoding means for decoding and outputting decoded audio information for the particular audio channel, depending on the detection of audio data;   concealing means for generating and outputting a concealing block for the particular audio channel, for concealing the absence of audio data, depending on the detection of the absence of audio data for the particular audio channnel.   
     
     
       43. A method of packaging data words of a non-PCM encoded multichannel bitstream into a sequence of successive frames having a predetermined format, the method comprising acts of:
 recurrently packaging data words of a non-PCM encoded multichannel bitstream into data burst payloads;   packaging by a processor the data burst payloads as well as pause bursts into successive frames having a predetermined format the pause bursts signifying the absence of audio samples for a duration; and   outputting the successive frames having the predetermined format including the data burst payloads and the pause bursts.   
     
     
       44. A coupling device for transferring a non-PCM encoded multichannel bitstream to an audio reproduction apparatus, the device comprising:
 means for recurrently packaging data words of the non-PCM encoded multichannel bitstream into data burst payloads;   means for packaging the data burst payloads as well a pause bursts into successive frames that have a predetermined format, the pause bursts signifying the absence of audio samples for a duration; and   means for outputting the successive frames that have the predetermined format including the inserted pause bursts.   
     
     
       45. A processor for packaging audio samples of a non-PCM encoded multichannel bitstream into a sequence of successive frames having a predetermined format, the processor comprising:
 a portion for recurrently packaging audio samples of a non-PCM encoded multichannel bitstream into data burst payloads;   a portion for packaging the data burst payloads as well as pause bursts into successive frames having a predetermined format, the pause bursts signifying the absence of audio samples, each pause burst representing a pause having a duration in the millisecond range below 1000 milliseconds; and   a portion for outputting the successive frames having the predetermined format including the data burst payloads and the pause bursts.   
     
     
       46. A nontransitory storage device storing an audio signal comprising:
 a plurality of successive frames having a predetermined format and including:   audio samples of a non-PCM encoded multichannel bitstream recurrently packaged into data burst payloads; and   pause bursts signifying the absence of audio samples for one or more of the channels of the bitstream and having a duration in the millisecond range below 1000 milliseconds.   
     
     
       47. A method of packaging audio samples of a non-PCM encoded audio bitstream into a sequence of format frames, the method comprising acts of:
 recurrently packaging audio samples of a plurality of audio channels of a non-PCM encoded audio bitstream into burst payloads;   packaging by a processor the burst payloads into format frames according to a digital audio standard, resulting in a sequence of format frames, the packaging including:
 generating pause bursts indicating absence of audio data in one or more of the audio channels for a predetermined time interval; and 
 inserting the pause bursts into the sequence of format frames; and 
   outputting the sequence of format frames including the inserted pause bursts.   
     
     
       48. A device for packaging audio samples of a non-PCM encoded audio bitstream into a sequence of IEC958 format frames, the device comprising:
 packaging means for recurrently packaging audio samples of a multitude of audio channels of a non-PCM encoded audio bitstream into burst payloads, and for packaging the burst payloads into format frames according to a digital audio standard, resulting in a sequence of IEC958 format frames;   pause burst generating means for generating pause bursts and inserting those pause bursts into the sequence of format frames, such pause bursts indicating absence of audio data in at least one of the audio channels during a predetermined time interval; and   output means for outputting the sequence of IEC958 format frames including the inserted pause bursts.   
     
     
       49. A method of receiving a sequence of format frames and outputting audio data for reproduction by an audio channel, the method comprising acts of:
 receiving a bit stream for a plurality of audio channels as a sequence of format frames according to an audio standard each frame accommodating a uniform number of data bits for each respective audio channel;   detecting by a processor presence or absence of audio data for each output channel, the absence of audio data being indicated by a series of one or more pause bursts;   upon detecting the absence of audio data, the processor outputting a concealing block for the channel for concealing the absence of audio data for the channel; and   alternatively, upon detecting the presence of audio data, the processor outputting the audio data for the particular channel in question.   
     
     
       50. A device for receiving a non-PCM encoded bitstream and outputting multichannel audio data for subsequent reproduction, the device comprising:
 reception means for receiving a non-PCM encoded bitstream for a plurality of audio channels as a sequence of frames, each frame accommodating data bits;   detection means for detecting a presence or absence of audio data in the frames;   decoding means for decoding and outputting decoded audio information depending on the detection of audio data;   concealing means for concealing the absence of audio data depending on the detection of the absence of audio data.   
     
     
       51. The device of claim 50, wherein the absence of audio is detected by detecting presence of one or more pause frames. 
     
     
       52. The device of claim 51, wherein the concealing means mutes the audio output. 
     
     
       53. The device of claim 52, wherein the mute is a soft mute. 
     
     
       54. The device of claim 50, wherein the concealing means mutes the audio output. 
     
     
       55. The device of claim 54, wherein the mute is a soft mute. 
     
     
       56. The device of claim 50, wherein a pause burst comprises a burst preamble and a 32 bit payload. 
     
     
       57. The device of claim 56, wherein the bust preamble consists of four control words. 
     
     
       58. The device of claim 57, wherein information in a third control word of the four control words indicates that a packet type is of a pause-type. 
     
     
       59. A device for receiving a non-PCM encoded bitstream and outputting multichannel audio data for subsequent reproduction, the device comprising:
 a receiver configured to receive a non-PCM encoded bitstream for a plurality of audio channels as a sequence of frames, each frame accommodating data bits;   a detector configured to detect a presence or absence of audio data in the frames;   a decoder configured to decode audio information and output decoded audio information depending on the detection of audio data and to conceal the absence of audio data depending on the detection of the absence of audio data.   
     
     
       60. The device of claim 59, wherein the absence of audio is detected by detecting presence of one or more pause frames. 
     
     
       61. The device of claim 60, wherein the concealing means mutes the audio output. 
     
     
       62. The device of claim 61, wherein the mute is a soft mute. 
     
     
       63. The device of claim 59, wherein the concealing means mutes the audio output. 
     
     
       64. The device of claim 63, wherein the mute is a soft mute. 
     
     
       65. The device of claim 59, wherein a pause burst comprises a burst preamble and a 32 bit payload. 
     
     
       66. The device of claim 65, wherein a the burst preamble consists of four control words. 
     
     
       67. The device of claim 66, wherein information in a third control word of the four control words indicates that a packet type is of a pause-type. 
     
     
       68. A device for packaging audio samples of a non-PCM encoded audio bitstream into a sequence of frames designed for transmission of PCM encoded audio streams, the device comprising:
 a processor configured to
 control a process of recurrently packaging audio samples of a non-PCM encoded audio bitstream into burst payloads, 
 control a process of packaging the burst payloads into a sequence of IEC958 format frames; 
 control a process of generating one or more pause bursts and inserting the one or more pause bursts into the sequence of IEC958 format frames, the one or more pause bursts indicating absence of audio data in one of the audio channels; and 
 control a process of outputting the sequence of IEC958 format frames including the inserted one or more pause bursts. 
   
     
     
       69. The device of claim 68, wherein a pause burst comprises a burst preamble and a 32 bit payload. 
     
     
       70. The device of claim 69, wherein the burst preamble consists of four control words. 
     
     
       71. The device of claim 70, wherein information in a third control word of the four control words indicates that a packet type is of a pause-type.