Method and apparatus for audio and video synchronizing in MPEG playback systems

Claim 3

The apparatus of claim 1, wherein said first audio presentation time stamp detector outputs a buffer full handshake signal to said first audio data FIFO when a second audio presentation time stamp is detected in the encoded audio data stream prior to receiving a load signal from said second audio presentation time stamp detector such that at most only one audio presentation time stamp is stored in said second audio data buffer.

Claim 4

The apparatus of claim 2, wherein said system decoder further comprises: a parser for separating the encoded data stream into an encoded audio data stream comprising audio data packets and audio presentation time stamps and an encoded video data stream comprising video data packets and video presentation time stamps; and a memory having addressable storage, coupled to said parser, for addressing addressable storage to selectively store and read the encoded audio data, the encoded video data, or decoded video data to and from addressable storage.

Claim 5

The apparatus according to claim 3, wherein said video decoder further comprises: a decoder, coupled to the memory, for decoding the encoded video data and generating decoded video data; and a synchronizer, coupled to said decoder and said memory, for comparing a video presentation time stamp with the system time clock and when the comparison exceeds a predetermined threshold, substantially synchronizing the generation of the decoded video data by the decoder with the addressing of addressable storage by the memory.

Claim 6

The apparatus of claim 4 wherein the synchronizer determines that the video time value exceeds a system time clock value by the predetermined threshold, and a sequence of addressing addressable storage containing decoded video data by the memory is modified by repeating a sequence of addresses to substantially synchronize the generation of the decoded video data by the decoder with the addressing of addressable storage by the memory.

Claim 9

The method of claim 6, further comprising the step of outputting, from the first audio presentation time stamp detector, a buffer full handshake signal to the first audio data FIFO when a second audio presentation time stamp is detected in the encoded audio data stream prior to receiving a load signal from said second audio presentation time stamp detector such that at most only one audio presentation time stamp is stored in the second audio data buffer.

Claim 10

The method of claim 6, wherein said step of receiving and separating comprises the steps of: separating the encoded data stream into an encoded audio data stream and an encoded video data, stream, which audio data stream comprises audio data packets and audio presentation time stamps and which encoded video data stream comprises video data packets and video presentation time stamps; and addressing addressable storage to selectively store and read the encoded audio data, the encoded video data, or decoded video data to and from addressable storage.

Claim 11

The method according to claim 8, wherein said step of decoding/decompressing the video data further comprises the steps of: decoding the encoded video data and generating decoded video data; and comparing a video presentation time stamp with the system time clock and when the comparison exceeds a predetermined threshold, substantially synchronizing the generation of the decoded video data with the addressing of addressable storage.

Claim 12

The method of claim 9 wherein said comparing step further comprises the steps of: determining that the video time value exceeds a system time clock value by the predetermined threshold, and modifying a sequence of addressing addressable storage containing decoded video data by repeating a sequence of addresses to substantially synchronize the generation of the decoded video data with the addressing of addressable storage.

Claim 13

A multimedia system for reading, decoding, and decompressing encoded audio/video data into video data for display on a plurality of display types and into audio data for reproduction on a plurality of sound reproduction devices, the multimedia system comprising: a system decoder receiving the encoded data stream comprising at least audio data packets, video data packets, audio presentation time stamps and video presentation time stamps, and separating said encoded data stream into an encoded audio data stream and an encoded video data stream, which encoded audio data stream comprises at least audio data packets and said audio presentation time stamps and which encoded video data stream comprises at least said video data packets and said video presentation time stamps; a first audio data buffer, coupled to said system decoder, for receiving and storing audio data packets and audio presentation time stamps from said encoded audio data stream; a first audio presentation time stamp detector, coupled to said system decoder, for detecting the presence of an audio presentation time stamp in the encoded audio data stream; a latch, coupled to said first audio presentation time stamp detector, for storing a detected audio presentation time stamp from the encoded audio data stream; a system time clock counter, coupled to said first audio presentation time stamp detector, for receiving said audio presentation time stamp as a start count when a load signal is received, and incrementing said start count according to a predetermined clock frequency and outputting a system time clock; a video decoder, coupled to said system decoder and said system time clock counter, for receiving said system time clock and said encoded video data stream and decoding/decompressing said encoded video data stream in synchronization with said system time clock; an audio decoder, for receiving said audio data packets from the encoded audio data stream and decoding/decompressing said audio data packets, wherein said audio decoder further comprises a second audio data buffer for receiving the encoded audio data stream from said first audio data buffer and storing audio data packets and audio presentation time stamps; and a second audio presentation time stamp detector, coupled to said audio decoder, for detecting the presence of an audio presentation time stamp in the encoded audio data stream and outputting a load signal to said system time clock counter in said combined system and video decoder when audio data packets corresponding to said audio presentation time stamp are decoded.

Claim 14

A multimedia system for reading, decoding, and decompressing encoded audio/video data into video data for display on a plurality of display types and into audio data for reproduction on a plurality of sound reproduction devices, the multimedia system comprising: a system decoder receiving the encoded data stream comprising at least audio data packets, video data packets, audio presentation time stamps and video presentation time stamps, and separating said encoded data stream into an encoded audio data stream and an encoded video data stream, which encoded audio data stream comprises at least audio data packets and said audio presentation time stamps and which encoded video data stream comprises at least said video data packets and said video presentation time stamps; a first audio data buffer, coupled to said system decoder, for receiving and storing audio data packets and audio presentation time stamps from said encoded audio data stream; a first audio presentation time stamp detector, coupled to said system decoder, for detecting the presence of an audio presentation time stamp in the encoded audio data stream; a latch, coupled to said first audio presentation time stamp detector, for storing a detected audio presentation time stamp from the encoded audio data stream; a system time clock counter, coupled to said first audio presentation time stamp detector, for receiving said audio presentation time stamp as a start count when a load signal is received, and incrementing said start count according to a predetermined clock frequency and outputting a system time clock; a video decoder, coupled to said system decoder and said system time clock counter, for receiving said system time clock and said encoded video data stream and decoding/decompressing said encoded video data stream in synchronization with said system time clock; an audio decoder, for receiving said audio data packets from the encoded audio data stream and decoding/decompressing said audio data packets, wherein said audio decoder further comprises a second audio data buffer for receiving the encoded audio data stream from said first audio data buffer and storing audio data packets and audio presentation time stamps; and a second audio presentation time stamp detector, coupled to said audio decoder, for detecting the presence of an audio presentation time stamp in the encoded audio data stream and outputting a load signal to said system time clock counter in said combined system and video decoder when audio data packets corresponding to said audio presentation time stamp are decoded.

Claim 15

The multimedia system of claim 11, wherein said first audio presentation time stamp detector outputs a buffer full handshake signal to said first audio data FIFO when a second audio presentation time stamp is detected in the encoded audio data stream prior to receiving a load signal from said second audio presentation time stamp detector such that at most only one audio presentation time stamps is stored in said second audio data buffer.

Claim 16

The multimedia system of claim 11, wherein said system decoder further comprises: a parser for separating the encoded data stream into an encoded audio data stream comprising audio data packets and audio presentation time stamps and an encoded video data stream comprising video data packets and video presentation time stamps; and a memory having addressable storage, coupled to said parser, for addressing addressable storage to selectively store and read the encoded audio data, the encoded video data, or decoded video data to and from addressable storage.

Claim 17

The multimedia system according to claim 13, wherein said video decoder further comprises: a decoder, coupled to the memory, for decoding the encoded video data and generating decoded video data; and a synchronizer, coupled to said decoder and said memory, for comparing a video presentation time stamp with the system time clock and when the comparison exceeds a predetermined threshold, substantially synchronizing the generation of the decoded video data by the decoder with the addressing of addressable, storage by the memory.

Claim 18

The multimedia system of claim 14 wherein the synchronizer determines that the video time value exceeds a system time clock value by the predetermined threshold, and a sequence of addressing addressable storage containing decoded video data by the memory is modified by repeating a sequence of addresses to substantially synchronize the generation of the decoded video data by the decoder with the addressing of addressable storage by the memory.

Claim 19

The multimedia system of claim 11 further comprising a graphics controller, coupled to the video decoder and a video monitor, for displaying the decoded video data as an image on the video monitor.

Claim 20

The multimedia system of claim 11 further comprising a graphics controller, coupled to the video decoder and a digital display, for displaying the decoded video data as an image on the digital display.

Claim 21

The multimedia system of claim 11 further comprising a television signal encoder, coupled to the video decoder and a television display, for generating television data from the decoded video data and displaying the television data as an image on the television display.

Claim 22

The multimedia system of claim 11 further comprising a digital to analog converter, coupled to the audio decoder for generating an analog audio signal from decoded audio data.

Claim 23

The multimedia system of claim 19 further comprising an audio amplifier, coupled to the digital to analog converter, for amplifying the magnitude of the analog audio signal.

Claim 26

The apparatus according to claim 21, wherein said video decoder further comprises: a decoder, coupled to the memory, for decoding the encoded video data and generating decoded video data; and a synchronizer, coupled to said decoder and said memory, for comparing a video presentation time stamp with the system time clock and when the comparison exceeds a predetermined threshold, substantially synchronizing the generation of the decoded video data by the decoder with the addressing of addressable storage by the memory.

Claim 27

The apparatus of claim 22 wherein the synchronizer determines that the video time value exceeds a system time clock value by the predetermined threshold, and a sequence of addressing addressable storage containing decoded video data by the memory is modified by repeating a sequence of addresses to substantially synchronize the generation of the decoded video data by the decoder with the addressing of addressable storage by the memory.