DRA多声道数字音频编码算法的改进

采用2遍扫描和金字塔编码技术对DRA(Digital Rise Audio)多声道数字音频编码算法进行了改进,新算法会依据网络的状况自适应调整传输码率,用可变的DRA码流适应可变的网络条件.当网络条件较好时,用户可欣赏高质量DRA音乐；当网络条件变差时,传输的DRA码流减少,但用户仍可以欣赏流畅的DRA音乐.用比特流容器配置的DRA格式音乐码流在移动智能终端上的播放测试结果表明,在网络状况较差的情况下DRA格式的音乐也能流畅播放.

Improvement to DRA Multichannel Audio Coding Standard

Developed two-pass bit allocation module for DRA standard to optimize bit allocation across all frames of a piece of music so as to improve compression efficiency. Introduced a pyramidal (multiresolution) coding scheme to DRA standard to enable a DRA internet server to deliver bit stream in a Laplacian pyramidal structure. This structure is essential for DRA streaming over a wireless network: when the network condition is good, the whole pyramid can be delivered to the receiver, allowing a user to enjoy music with the best sound quality; when the network condition becomes poor, only lower layers of the pyramid can be delivered at significantly reduced bit rate so that the user can still enjoy DRA encoded music, although at a lower sound quality. Extensive testing using mobile terminals indicates that these two improvements enables smooth streaming of DRA music over a variety of network conditions.