Advanced television system

A method of receiving and decoding the audio portion of a television signal, the audio portion representing an input audio source, wherein the audio portion of the television signal has been transmitted in a format comprising a first set of bits that represents audio at a first quality and that can be decoded to provide an output at the first quality, and a second set of bits that represents enhancement information and that can be decoded and used in conjunction with the first set of bits to provide an audio output at a second quality greater than the first quality, the first set of bits and the second set of bits having been transmitted over a single bandlimited television channel, the method of receiving and decoding comprising the steps of:

• receiving the first set of bits and the second set of bits over the bandlimited television channel;
• decoding the first set of bits according to a first decoding procedure to provide information representative of audio at the first quality;
• decoding the second set of bits according to a second decoding procedure to provide the enhancement information;
• using at least some of the enhancement information and at least some of the information representative of audio at the first quality to provide the output at the second quality.

A system for receiving and decoding a television signal representing an input video source, wherein the television signal has been transmitted in a format comprising a first set of bits that represents images at a first quality and that can be decoded to provide an output at the first quality, and a second set of bits that represents enhancement information and that can be decoded and used in conjunction with the first set of bits to provide an output at a second quality greater than the first quality, the first set of bits and the second set of bits being transmitted over a single, bandlimited television channel, the system for receiving and decoding comprising:

• means for receiving the first set of bits and the second set of bits over the bandlimited television channel;
• means for decoding the first set of bits according to a first decoding procedure to provide information representative of images at the first quality;
• means for decoding the second set of bits according to a second decoding procedure to provide the enhancement information;
• means for using at least some of the enhancement information and at least some of the information representative of images at the first quality to provide the output at the second quality.

A system of receiving and decoding the audio portion of a television signal, the audio portion representing an input audio source, wherein the audio portion of the television signal has been transmitted in a format comprising a first set of bits that represents audio at a first quality and that can be decoded to provide an output at the first quality, and a second set of bits that represents enhancement information and that can be decoded and used in conjunction with the first set of bits to provide an audio output at a second quality greater than the first quality, the first set of bits and the second set of bits having been transmitted over a single, bandlimited television channel, the system of receiving and decoding comprising:

• means for receiving the first set of bits and the second set of bits over the bandlimited television channel;
• means for decoding the first set of bits according to a first decoding procedure to provide information representative of audio at the first quality;
• means for decoding the second set of bits according to a second decoding procedure to provide the enhancement information;
• means for using at least some of the enhancement information and at least some of the information representative of audio at the first quality to provide the output at the second quality.

A method of encoding a television signal representing an input video source, the television signal comprising an encoded signal and a set of enhancement bits to be transmitted over a single television channel, the television channel having a restricted bandwidth, the method comprising the steps of:

• using a first transmission standard to encode the input video source to produce the encoded signal, the encoded signal being of a lower quality than the quality of the input video source;
• using a second transmission standard to encode the enhancement bits to permit the decoder to enhance the signal decoded from the encoded signal, the number of the enhancement bits being less than or equal to the number of bits the channel is free to carry in addition to the encoded signal;
• the second transmission standard comprising the steps of
• decoding the encoded signal to produce an estimate of the signal that would be decoded in a receiver;
• processing the estimate with a prediction method to produce a predicted signal for the input video source;
• and
• comparing the predicted signal to the input video source and using the result of the comparison to vary the prediction method to reduce variation between the predicted signal and the input video source;
• and
• encoding information representative of the prediction method for use by the decoder.

A system for encoding a television signal representing an input video source, the television signal comprising an encoded signal and a set of enhancement bits to be transmitted over a single television channel, the television channel having a restricted bandwidth, the system comprising:

• means for using a first transmission standard to encode the input video source to produce the encoded signal, the encoded signal being of a lower quality than the quality of the input video source;
• means for using a second transmission standard to encode the enhancement bits to permit the decoder to enhance the signal decoded from the encoded signal, the number of the enhancement bits being less than or equal to the number of bits the television channel is free to carry in addition to the encoded signal;
• the second transmission standard comprising
• decoding the encoded signal to produce an estimate of the signal that would be decoded in a receiver;
• processing the estimate with a prediction method to produce a predicted signal with a quality intermediate that of the input video source and the encoded signal;
• and
• comparing the predicted signal to the input video source and using the result of the comparison to vary the prediction method to reduce variation between the predicted signal and the input video source;
• and
• encoding information representative of the prediction method for use by the decoder.