Subject: Dynamic range compression (DRC) in AAC From: "Pinaki S. Chanda" <cpinaki@xxxxxxxx> Date: Thu, 31 May 2007 11:04:11 -0000 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>This is a multipart mime message --Next_1180609451---0-202.54.124.178-23450 Content-type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Dear group,=0A I am not sure if this is a right place to post thi= s question. I hope some group members would be interested in the topic.=0A= =0AThis is regarding the excl_chn_mask[] bits in the dynamic-range_info() o= f the AAC bit stream. Assume the excl_chn_mask[] bit is set for a channel i= n the AAC bit stream. =0A=0ADoes that mean? =0A=0A1. we are not interested= to change the DRC values (no. of bands, gain etc) for this channel using t= he recently transmitted DRC parameters but the DRC processing (spectral lin= e multiplication) must go on this channel with the previously transmitted v= alues.=0A=0Aor =0A=0A2. we would like to stop DRC processing for this chann= el from now on till we get the DRC parameters for this channel in a later f= rame.=0A=0Aor =0A=0AWe would like to stop DRC processing (spectral line mul= tiplication) on this frame for this channel but continue DRC processing fro= m next frame using the previous value.=0A=0AWhich one is correct ? =0A=0AT= hanks and regards,=0APinaki=0A=0A=0A=0A --Next_1180609451---0-202.54.124.178-23450 Content-type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline <P>=0ADear group,<BR>=0A I am not sure i= f this is a right place to post this question. I hope some group members wo= uld be interested in the topic.<BR>=0A<BR>=0AThis is regarding the excl_chn= _mask[] bits in the dynamic-range_info() of the AAC bit stream. Assume the = excl_chn_mask[] bit is set for a channel in the AAC bit stream. <BR>=0A<BR>= =0ADoes that mean? <BR>=0A<BR>=0A1. we are not interested to change t= he DRC values (no. of bands, gain etc) for this channel using the recently = transmitted DRC parameters but the DRC processing (spectral line multiplica= tion) must go on this channel with the previously transmitted values.<BR>= =0A<BR>=0Aor <BR>=0A<BR>=0A2. we would like to stop DRC processing for this= channel from now on till we get the DRC parameters for this channel in a l= ater frame.<BR>=0A<BR>=0Aor <BR>=0A<BR>=0AWe would like to stop DRC process= ing (spectral line multiplication) on this frame for this channel but conti= nue DRC processing from next frame using the previous value.<BR>=0A<B= R>=0AWhich one is correct ? <BR>=0A<BR>=0AThanks and regards,<BR>=0APinaki<= BR>=0A<BR>=0A<BR>=0A<BR>=0A=0A</P>=0A<br><br>=0A --Next_1180609451---0-202.54.124.178-23450--