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aacdec_usac: always zero out alpha_q values for stereo streams

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The issue is that if a frame has no complex stereo prediction,
the alpha values must all be assumed to be zero if the next frame
has complex prediction and uses delta coding.
This commit is contained in:
Lynne
2024-06-12 03:31:58 +02:00
parent d79fbad366
commit bdd3c6ca50
1 changed files with 5 additions and 4 deletions
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9
libavcodec/aac/aacdec_usac.c
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@@ -690,10 +690,6 @@ static int decode_usac_stereo_cplx(AACDecContext *ac, AACUsacStereo *us,
if (!indep_flag)
delta_code_time = get_bits1(gb);
/* Alpha values must be zeroed out if pred_used is 0. */
memset(us->alpha_q_re, 0, sizeof(us->alpha_q_re));
memset(us->alpha_q_im, 0, sizeof(us->alpha_q_im));
/* TODO: shouldn't be needed */
for (int g = 0; g < num_window_groups; g++) {
for (int sfb = 0; sfb < cpe->max_sfb_ste; sfb += SFB_PER_PRED_BAND) {
@@ -828,6 +824,11 @@ static int decode_usac_stereo_info(AACDecContext *ac, AACUSACConfig *usac,
us->common_window = 0;
us->common_tw = 0;
/* Alpha values must always be zeroed out for the current frame,
* as they are propagated to the next frame and may be used. */
memset(us->alpha_q_re, 0, sizeof(us->alpha_q_re));
memset(us->alpha_q_im, 0, sizeof(us->alpha_q_im));
if (!(!ue1->core_mode && !ue2->core_mode))
return 0;