diff options
| author | Daniil Cherednik <dan.cherednik@gmail.com> | 2025-08-20 21:29:42 +0200 |
|---|---|---|
| committer | michaelni <michael@niedermayer.cc> | 2025-08-29 12:29:52 +0000 |
| commit | 0828a3b6366042a2d65188c89a1f5bf0ae52ec75 (patch) | |
| tree | c3605f55da214cdbf9855533c7ad8d48761982c1 | |
| parent | e3f01682d77679397593656b741d98503ceb6d4b (diff) | |
| download | ffmpeg-0828a3b6366042a2d65188c89a1f5bf0ae52ec75.tar.gz | |
avcodec/atrac3: fix inconsistent band num calculation
'decode_spectrum' reads 5 bits from bitstream to get
number of encoded subbands – so 31 means all 32
subbands are encoded. This value also is used to
determinate the number of used band in the hybrid
filterbank.
'subband_tab' array contains 33 values of MDCT spec
line positions started from 0 line and used to map
subband number in to the range of mdct lines.
Since the subband_num returned by decode_spectrum
actually is number – 1 and subband_tab started from 0
we need to add 1 to make num_bands calculation correct.
| -rw-r--r-- | libavcodec/atrac3.c | 2 | ||||
| -rw-r--r-- | tests/fate/atrac.mak | 4 |
2 files changed, 3 insertions, 3 deletions
diff --git a/libavcodec/atrac3.c b/libavcodec/atrac3.c index fe156fa482..d91bdc79ac 100644 --- a/libavcodec/atrac3.c +++ b/libavcodec/atrac3.c @@ -616,7 +616,7 @@ static int decode_channel_sound_unit(ATRAC3Context *q, GetBitContext *gb, /* calculate number of used MLT/QMF bands according to the amount of coded spectral lines */ - num_bands = (subband_tab[num_subbands] - 1) >> 8; + num_bands = (subband_tab[num_subbands + 1] - 1) >> 8; if (last_tonal >= 0) num_bands = FFMAX((last_tonal + 256) >> 8, num_bands); diff --git a/tests/fate/atrac.mak b/tests/fate/atrac.mak index 098063e298..847eed5b61 100644 --- a/tests/fate/atrac.mak +++ b/tests/fate/atrac.mak @@ -11,11 +11,11 @@ FATE_ATRAC1-$(call PCM, AEA, ATRAC1, ARESAMPLE_FILTER) += $(FATE_ATRAC1) FATE_ATRAC3 += fate-atrac3-1 fate-atrac3-1: CMD = pcm -i $(TARGET_SAMPLES)/atrac3/mc_sich_at3_066_small.wav -fate-atrac3-1: REF = $(SAMPLES)/atrac3/mc_sich_at3_066_small.pcm +fate-atrac3-1: REF = $(SAMPLES)/atrac3/mc_sich_at3_066_small_with_band_fix.pcm FATE_ATRAC3 += fate-atrac3-2 fate-atrac3-2: CMD = pcm -i $(TARGET_SAMPLES)/atrac3/mc_sich_at3_105_small.wav -fate-atrac3-2: REF = $(SAMPLES)/atrac3/mc_sich_at3_105_small.pcm +fate-atrac3-2: REF = $(SAMPLES)/atrac3/mc_sich_at3_105_small_with_band_fix.pcm FATE_ATRAC3 += fate-atrac3-3 fate-atrac3-3: CMD = pcm -i $(TARGET_SAMPLES)/atrac3/mc_sich_at3_132_small.wav |