Video transcoding of scalable multi-layer videos to single layer video

• US 20030202579A1
• Filed: 04/24/2002
• Published: 10/30/2003
• Est. Priority Date: 04/24/2002
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Wang, Chung-Neng, Vetro, Anthony, Sun, Huifang, Chiang, Tihao, Lin, Yao-Chung
• Granted Patent: US 7,391,807 B2
• Time in Patent Office: Days
• US Class Current: 375/240.03
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/154 Measured or subjectively estimated visual quality after decoding, e.g. measurement of distortion use of rate-distortion criteria H04N19/147
• CPC Class Codes: H04N 19/187 the unit being a scalable video layer
• CPC Class Codes: H04N 19/34 Scalability techniques involving progressive bit-plane based encoding of the enhancement layer, e.g. fine granular scalability [FGS]
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

A method transcodes a compressed multi-layer video bitstream that includes a base layer bitstream and an enhancement layer bitstream. The base and enhancement layers are first partially decoded, and then the partially decoded signals are combined with a motion compensated signal yielding a combined signal. The combined signal is quantized into an output signal according to a quantization parameter, and the output signal is variable length encoded as a single layer bitstream. In a preprocessing step, the enhancement layer can be truncated according to rate control constraint, and the same constraints can also be used during the quantization.

Claims

1. A method for transcoding a compressed multi-layer video bitstream including a base layer bitstream and an enhancement layer bitstream, comprising:

partially decoding the base layer bitstream;

partially decoding the enhancement layer bitstream;

combining the partially decod e d base layer bitstream and the partially decoded enhancement layer bitstream with a motion compensated signal yielding a combined signal;

quantizing the combined signal into an output signal according to a quantization parameter; and

variable length encoding the output signal as a single layer bitstream.

2. The method of claim 1 wherein the quantization parameter is determined according to constraints and data extracted from the compressed multi-layer video bitstream.

3. The method of claim 1 wherein the enhancement layer includes bit-plane data, and further comprising:

truncating the bit-plane data according to constraints before the partial decoding of the enhancement layer bitstream to reduce a complexity of the partial decoding.

4. The method of claim 2 wherein the constraints include rate control constraints.

5. The method of claim 4 wherein the rate control constraints are acquired from a network transporting the single layer bitsteam.

6. The method of claim 2 wherein the constraints include buffer constraints.

7. The method of claim 6 wherein the buffer constraints are acquired from a device receiving the single layer bitstream.

8. The method of claim 2 wherein the constraints include complexity constraints including system processing load.

9. A method for transcoding a compressed multi-layer video bitstream including a base layer bitstream and an enhancement layer bitstream, comprising:

means for partially decoding the base layer bitstream;

means for partially decoding the enhancement layer bitstream;

means for combining the partially decoded base layer bitstream and the partially decoded enhancement layer bitstream with a motion compensated signal yielding a combined signal;

means for quantizing the combined signal into an output signal according to a quantization parameter; and

means for variable length encoding the output signal as a single layer bitstream.

10. A network for transporting a video, comprising:

a fine granular scalable coder configured to encode the video as a compressed multi-layer bitstream including a base layer bitstream and an enhancement layer bitstream;

a server transcoding the compressed multi-layer bitstream to a single layer bitstream based on both the base layer bitstream and the enhancement layer bitstream; and

a terminal device receiving the single layer bitstream.