KR960027868A

KR960027868A - How to convert bit rate of MPEG audio

Info

Publication number: KR960027868A
Application number: KR1019940034368A
Authority: KR
Inventors: 이성진; 홍성욱
Original assignee: 구자홍; Lg 전자주식회사
Priority date: 1994-12-15
Filing date: 1994-12-15
Publication date: 1996-07-22

Abstract

본 발명은 MPEG(Moving Picture Experts Group)에 따른 오디오 데이타의 부호/복호화 방법에 관한 것으로, 특히 MPEG 오디오 정보중에서 부가데이타 필드를 이용하여 비트율을 가변하는데 적당하도록 한 MPEG 오디오의 비트율 변환방법에 관한 것이다.The present invention relates to a method of encoding / decoding audio data according to a Moving Picture Experts Group (MPEG), and more particularly, to a method of converting a bit rate of MPEG audio, which is suitable for varying a bit rate using an additional data field in MPEG audio information. .

상기와 같은 본 발명의 MPEG 오디오의 비트율 변환방법은 MPEG에 따른 오디오 데이타의 부호/복호화에 있어서, 각 서브밴드의 할당 비트수를 결정하는 기준이 되는 SMR(Siganal-to-Mask Ratio)에 관한 정보를 오디오 비트 스트림상의 부가 데이타 필드영역에 코딩하여 전송하는 단계와, 수신된 MPEG 오디오 비트 스트림상의 부가 데이타 필드영역을 Read하여 SMR 정보가 코딩되었는가를 판다하는 단계와, SMR 정보 및 비트 할당 정보를 Read하여 수신자가 원하는 비트율에 따른 가용비트수를 계산하는 단계와, 수신자가 원하는 비트율에 따라 비트 할당 정보를 리포맷팅하는 단계와, 리포맷팅된 비트 할당 정보에 의해 오디오 데이타를 재부호화하여 MPEG 테이블에 의해 디코딩하여 PCM 데이타를 출력단계를 포함하여 이루어진다.As described above, the MPEG audio bit rate conversion method includes information on SMR (Siganal-to-Mask Ratio), which is a reference for determining the number of allocated bits of each subband in encoding / decoding of audio data according to MPEG. Coding the SMR information into an additional data field area on the audio bit stream, reading the additional data field area on the received MPEG audio bit stream to determine whether the SMR information is coded, and reading the SMR information and the bit allocation information. Calculating the number of available bits according to the desired bit rate of the receiver, reformatting the bit allocation information according to the desired bit rate of the receiver, recoding the audio data by the reformatted bit allocation information, and Decoding is performed including the output step of the PCM data.

Description

How to convert bit rate of MPEG audio

본 내용은 요부공개 건이므로 전문내용을 수록하지 않았음Since this is an open matter, no full text was included.

제4도는 본 발명의 MPEG 오디오 디코더의 구성블럭도.4 is a block diagram of an MPEG audio decoder of the present invention.

Claims

In encoding / decoding of audio data according to MPEG, information about a signal-to-mask ratio (SMR), which is a reference for determining the number of allocated bits of each subband, is coded and transmitted to an additional data field area on an audio bit stream. Reading the additional data field area on the received MPEG audio bit stream to determine whether the SMR information is coded; and reading the SMR information and the bit allocation information to calculate the number of available bits according to the desired bit rate of the receiver. Reformatting the bit allocation information according to the bit rate desired by the receiver, recoding the audio data according to the reformatted bit allocation information, decoding the MPEG data by an MPEG table, and outputting the PCM data. MPEG audio bit rate conversion method.

The method of claim 1, wherein the reformatting of the bit allocation information comprises: a first step of obtaining MNR by initializing SMR of each subband to zero and increasing a quantization level of a subband having a minimum MNR by one; A third step of reconstructing the MNR of each subband including the second band and the subband obtained in the second step to determine a subband having a minimum MNR, and the second and third steps at a bit rate desired by the receiver; And a fourth step of repeating until the number of available bits matches the number of available bits calculated accordingly.

The number of available bits is bit rate / Fs (sampling frequency) x 1152 (number of discrete signal samplings)-(number of bits in the header information area + number of bits of CRC + number of additional data bits + bit allocation information). Bit rate of an area).

※ Note: The disclosure is based on the initial application.