github-mirrors/FFmpeg
1
0
Fork 0
mirror of https://mirror.skon.top/https://github.com/FFmpeg/FFmpeg synced 2026-04-20 21:00:41 +08:00
Code Issues Packages Projects Releases Wiki Activity

aacsbr_template: fix SBR USAC coupling

Browse Source 
This issue hid under the radar since the codebooks between coupling
modes very often result in identical bit counts regardless of the encoded
data, leading to no frame-level bitstream desyncs except in rare cases.

AAC Mps212 data is parsed immediately after the SBR data, where a loss
of sync in SBR will result in Mps212 being wildly different.
This commit is contained in:
Lynne
2026-01-22 19:58:31 +01:00
parent a93cb79da2
commit 8349565d52
1 changed files with 5 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
libavcodec/aacsbr_template.c
View File

@@ -1287,6 +1287,8 @@ int ff_aac_sbr_decode_usac_data(AACDecContext *ac, ChannelElement *che,
if ((sbr->data[0].bs_add_harmonic_flag = get_bits1(gb)))
get_bits1_vector(gb, sbr->data[0].bs_add_harmonic, sbr->n[1]);
} else if (get_bits1(gb)) { /* bs_coupling == 1 */
sbr->bs_coupling = 1;
/* if (harmonicSBR) ... */
if (read_sbr_grid(ac, sbr, gb, &sbr->data[0]))
@@ -1317,7 +1319,10 @@ int ff_aac_sbr_decode_usac_data(AACDecContext *ac, ChannelElement *che,
if ((sbr->data[1].bs_add_harmonic_flag = get_bits1(gb)))
get_bits1_vector(gb, sbr->data[1].bs_add_harmonic, sbr->n[1]);
} else { /* bs_coupling == 0 */
sbr->bs_coupling = 0;
/* if (harmonicSBR) ... */
if (read_sbr_grid(ac, sbr, gb, &sbr->data[0]))
return -1;
if (read_sbr_grid(ac, sbr, gb, &sbr->data[1]))