Method and apparatus for searching in a layered hierarchical bit stream followed by replay, said bit stream including a base layer and at least one enhancement layer

Patent metadata

Field	Value
Publication number	US-9355644-B2
Application number	US-201113703417-A
Country	US
Kind code	B2
Filing date	Jun 1, 2011
Priority date	Jun 11, 2010
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

A two-layer hierarchical audio bit stream can have a frame-based structure for the base layer bit stream and can be decoded independently from a higher layer and the decoding can start following every sync header. In the extension layer bit stream the frame structure may not be reflected on bit stream level. To facilitate seek operations with such highly compressed extension-layer data, the header of the extension layer bit stream comprises an FAT table with seek target positions. Because there are fewer entry points in the enhancement layer than sync headers in the base layer, a re-synchronization and some base layer frames are required to start decoding of the enhancement layer and to generate the full audio quality. Three seeking ways of seeking are described, of which each one offers a different compromise between seeking accuracy, re-synchronization latency and audio quality.

First claim

The invention claimed is:

1. A method for searching in a layered hierarchical audio or video bit stream followed by replay, said layered bit stream including a base layer which can be decoded separately starting from base layer entry points, and including at least one enhancement layer which cannot be replayed without re-synchronized data from said base layer, said method comprising: from an enhancement layer entry point located directly prior to a desired base layer entry point, starting, by an enhancement layer partial decoder, a partial decoding of the related enhancement layer data, followed by re-synchronization of the related enhancement layer data, by an enhancement layer resynchronization stage, and, partially in parallel, starting a muted base layer decoding by a base layer decoder; and combining, upon said re-synchronization being carried out, from the following base layer entry point, which needs not be an enhancement layer entry point, by a combiner, the decoded base layer data and the decoded enhancement layer data; and outputting a transformed full-quality audio or video signal.

2. An apparatus for searching in a layered hierarchical audio or video hit stream followed by replay, said layered bit stream including a base layer which can be decoded separately starting from base layer entry points, and including at least one enhancement layer which cannot be replayed without re-synchronized data from said base layer, said apparatus comprising an enhancement layer partial decoder that from an enhancement layer entry point located directly prior to a desired base layer entry point, starts a partial decoding of the related enhancement layer data; an enhancement layer re-synchronization stage that re-synchronizes the related enhancement layer data; a base layer decoder that, partially in parallel, starts a muted base layer decoding; and a combiner that, upon said re-synchronization being carried out, starting from the following base layer entry point, which needs not be an enhancement layer entry point, combines the decoded base layer data and the decoded enhancement layer data, and outputs a transformed full-quality audio or video signal.

Assignees

• Jax Peter
• Kordon Sven
• Thomson Licensing

Inventors

• Jax Peter
• Kordon Sven

Classifications

• H04N21/4621

  Controlling the complexity of the content stream or additional data, e.g. lowering the resolution or bit-rate of the video stream for a mobile client with a small screen (arrangements for using the results of monitoring on user's side in broadcast systems H04H60/65; flow control in packet networks H04L47/10) · CPC title

• H04N19/44

  Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder · CPC title

• G10L19/24 Primary

  Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding · CPC title

• G10L19/167

  Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes · CPC title

• H04N21/4398

  involving reformatting operations of audio signals (details of audio signal transcoding G10L19/173) · CPC title