aacsbr: Initialize e_a[1] to -1.

This triggers lAPrev (e_a[0]) on the first SBR frame to be -1. The spec is
somewhat ambiguous to what this value should be but this increases the accuracy
of al_sbr_e_44_1 and similar streams from 14 bits to 15 bits.

Originally committed as revision 22408 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Alex Converse 2010-03-09 20:16:14 +00:00
parent 2ed6f39944
commit 46751a65e3
1 changed files with 1 additions and 0 deletions

View File

@ -138,6 +138,7 @@ av_cold void ff_aac_sbr_init(void)
av_cold void ff_aac_sbr_ctx_init(SpectralBandReplication *sbr)
{
sbr->kx[0] = sbr->kx[1] = 32; //Typo in spec, kx' inits to 32
sbr->data[0].e_a[1] = sbr->data[1].e_a[1] = -1;
sbr->data[0].synthesis_filterbank_samples_offset = SBR_SYNTHESIS_BUF_SIZE - (1280 - 128);
sbr->data[1].synthesis_filterbank_samples_offset = SBR_SYNTHESIS_BUF_SIZE - (1280 - 128);
ff_mdct_init(&sbr->mdct, 7, 1, 1.0/64);