Method of incorporating a variable rate auxiliary data stream with a variable rate primary data stream

• US 5,734,432 A
• Filed: 07/15/1994
• Issued: 03/31/1998
• Est. Priority Date: 07/15/1994
• Status: Expired due to Term

• Current Assignee: Nokia of America Corporation (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Netravali, Arun Narayan, Petajan, Eric David
• Primary Examiner(s): RAO, ANAND SHASHIKANT
• Application Number:
  US08/276,069
• Time in Patent Office: 1,355 Days
• Field of Search: 348/419, 348/416, 348/415, 348/405, 348/407, 348/423, 348/432, 348/474, 348/473, 348/406, 348/461, 348/462, 370/110.4, 370/115
• US Class Current: 375/240.05
• CPC Class Codes: H04N 19/102 characterised by the element, parameter or selection affected or controlled by the adaptive coding
• CPC Class Codes: H04N 19/146 Data rate or code amount at the encoder output
• CPC Class Codes: H04N 19/147 according to rate distortion criteria rate-distortion as a criterion for motion estimation H04N19/567
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/184 the unit being bits, e.g. of the compressed video stream
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/23614 Multiplexing of additional data and video streams arrangements for simultaneous broadcast of plural pieces of information H04H20/28
• CPC Class Codes: H04N 21/4348 Demultiplexing of additional data and video streams

Abstract

A method of incorporating an auxiliary signal with an input video signal includes the step of encoding the input video signal to generate a variable bit rate encoded signal having a selected level of distortion. The video signal is applied to a buffer. The level of distortion is selected as a function of the fullness of the buffer. The video signal is read from the buffer and applied to a transmission channel at a predetermined video output rate. Portions of an auxiliary signal are applied to the channel at times when the buffer is in an underflow condition. The selected level of distortion has a flow which corresponds to a predetermined, non-zero level of perceptual distortion in the video signal.

Claims

1. A method comprising the steps of:

encoding an input video signal to generate a variable-bit-rate encoded signal having a selected level of distortion,

applying said video signal to a buffer, said level of distortion selected as a function of fullness of said buffer,

reading said video signal from said buffer and applying it to a transmission channel at a predetermined video output rate, and

regulating an auxiliary signal such that portions of said auxiliary signal are applied to said channel only at times when said buffer is in an underflow condition,

wherein said selected level of distortion has a floor which corresponds to a predetermined, non-zero level of perceptual distortion in said video signal and which is higher than that required for buffer fullness control, such that more frequent buffer underflow conditions and transmission of auxiliary signals result.

2. The method of claim 1 wherein said predetermined, non-zero level of perceptual distortion is such that underflow condition occurs often enough that said auxiliary signal can be applied to said channel at at least a predetermined auxiliary data rate.

3. The method of claim 1 wherein said step of encoding an input video signal comprises the step of:

generating a perceptual distortion metric indicative of a desired level of distortion for the encoded signal, said perceptual distortion metric being a function of the fullness of said buffer.

4. A method comprising the steps of:

encoding an input video signal to generate a variable-bit-rate encoded signal, said encoding including generating a perceptual distortion metric indicative of a desired level of distortion for the encoded signal and encoding said input video signal to achieve said desired level of distortion,

applying said video signal to a buffer, said perceptual distortion metric being a function of fullness of said buffer,

reading said video signal from said buffer and applying it to a transmission channel at a predetermined video output rate, and

regulating an auxiliary signal such that portions said auxiliary signal are applied to said channel only at times when said buffer is in an underflow condition, and

wherein said perceptual metric has a non-zero floor whose value is higher than that required for buffer fullness control, such that an application of said auxiliary signal to said channel occurs at a predetermined average bit rate and more frequent buffer underflow conditions and transmission of auxiliary signals result.

5. The method of claim 4 wherein said floor is a function of the level of distortion of said video signal at which a lower level of distortion will not be perceived by a human viewer.

6. The method of claim 4 wherein said floor is substantially at a level of distortion is not perceived by a human viewer.

7. A method of incorporating an auxiliary signal with a variable rate primary signal comprising the steps of:

encoding the primary signal at a particular level of quantization,

applying said encoded primary signal to a buffer,

transmitting said primary signal over a transmission channel at a predetermined output rate,

setting the level of quantization so that an underflow condition is achieved in said buffer, and

regulating the auxiliary signal such that portions of the variable auxiliary signal are transmitted over said transmission channel only during said underflow condition,

establishing a perceptual distortion metric which is responsive to a state of buffer fullness,

measuring a distortion level associated with the primary signal, and

establishing a non-zero floor for the distortion level and lowering the perceptual distortion metric so that both are higher than that required for buffer fullness control, such that more frequent buffer underflow conditions occur resulting in more frequent transmission of auxiliary signals.