Apparatus and method for selecting one of a first encoding algorithm and a second encoding algorithm

A method for selecting one of a first encoding algorithm comprising a first characteristic and a second encoding algorithm comprising a second characteristic for encoding a portion of an audio signal to acquire an encoded version of the portion of the audio signal, comprising:

• estimating a first quality measure for the portion of the audio signal, the first quality measure being associated with the first encoding algorithm, without actually encoding and decoding the portion of the audio signal using the first encoding algorithm;
• estimating a second quality measure for the portion of the audio signal, the second quality measure being associated with the second encoding algorithm, without actually encoding and decoding the portion of the audio signal using the second coding algorithm;
• selecting the first encoding algorithm or the second encoding algorithm based on a comparison between the first quality measure and the second quality measure,
• wherein the first and second quality measures are SNRs (signal to noise ratio) or segmental SNRs of the corresponding portion of a weighted version of the audio signal;
• determining an estimated quantizer distortion which a quantizer used in the first coding algorithm would introduce when quantizing the portion of the audio signal and determining the quality measure based on an energy of a portion of a weighted version of the audio signal and the estimated quantizer distortion;
• and
• estimating a global gain for the portion of the audio signal such that the portion of the audio signal would produce a given target bitrate when encoded with a quantizer and an entropy coder used in the first coding algorithm, and determining the estimated quantizer distortion based on a power of the estimated global gain, wherein the quantizer is a uniform scalar quantizer, wherein the estimated quantizer distortion is determined using the formula D=G*G/12, wherein D is the estimated quantizer distortion and G is the estimated global gain.

A non-transitory storage medium comprising a program code for performing, when running on a computer, a method for selecting one of a first encoding algorithm comprising a first characteristic and a second encoding algorithm comprising a second characteristic for encoding a portion of an audio signal to acquire an encoded version of the portion of the audio signal, comprising:

• estimating a first quality measure for the portion of the audio signal, the first quality measure being associated with the first encoding algorithm, without actually encoding and decoding the portion of the audio signal using the first encoding algorithm;
• estimating a second quality measure for the portion of the audio signal, the second quality measure being associated with the second encoding algorithm, without actually encoding and decoding the portion of the audio signal using the second coding algorithm;
• selecting the first encoding algorithm or the second encoding algorithm based on a comparison between the first quality measure and the second quality measure,
• wherein the first and second quality measures are SNRs (signal to noise ratio) or segmental SNRs of the corresponding portion of a weighted version of the audio signal;
• determining an estimated quantizer distortion which a quantizer used in the first coding algorithm would introduce when quantizing the portion of the audio signal and determining the quality measure based on an energy of a portion of a weighted version of the audio signal and the estimated quantizer distortion;
• and
• estimating a global gain for the portion of the audio signal such that the portion of the audio signal would produce a given target bitrate when encoded with a quantizer and an entropy coder used in the first coding algorithm, and determining the estimated quantizer distortion based on a power of the estimated global gain, wherein the quantizer is a uniform scalar quantizer, wherein the estimated quantizer distortion is determined using the formula D=G*G/12, wherein D is the estimated quantizer distortion and G is the estimated global gain.