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Level 3: Fix alpha miss-calculation that affected SNR

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hoo2
2026-02-16 00:10:05 +02:00
parent 781cb3047f
commit 6b1ebc3cfe
11 changed files with 268 additions and 396 deletions
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source/level_1/core/aac_coder.py
+7 -37
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@@ -485,46 +485,16 @@ def aac_coder_3(
sfc_L_dpcm = np.asarray(sfc_L, dtype=np.int64)[1:, ...]
sfc_R_dpcm = np.asarray(sfc_R, dtype=np.int64)[1:, ...]
# Codebook 11:
# maxAbsCodeVal = 16 is RESERVED for ESCAPE.
# We must stay strictly within [-15, +15] to avoid escape decoding.
# sf_cb = 11
# sf_max_abs = int(huff_LUT_list[sf_cb]["maxAbsCodeVal"]) - 1 # -> 15
#
# sfc_L_dpcm = np.clip(
# sfc_L_dpcm,
# -sf_max_abs,
# sf_max_abs,
# ).astype(np.int64, copy=False)
#
# sfc_R_dpcm = np.clip(
# sfc_R_dpcm,
# -sf_max_abs,
# sf_max_abs,
# ).astype(np.int64, copy=False)
sfc_L_stream, cb_sfc_L = aac_encode_huff(
sfc_L_dpcm.reshape(-1, order="F"),
huff_LUT_list,
# force_codebook=11,
)
sfc_R_stream, cb_sfc_R = aac_encode_huff(
sfc_R_dpcm.reshape(-1, order="F"),
huff_LUT_list,
# force_codebook=11,
)
# sfc_L_stream, cb_sfc_L = aac_encode_huff(sfc_L_dpcm.reshape(-1, order="F"), huff_LUT_list, force_codebook=11)
# sfc_R_stream, cb_sfc_R = aac_encode_huff(sfc_R_dpcm.reshape(-1, order="F"), huff_LUT_list, force_codebook=11)
sfc_L_stream, cb_sfc_L = aac_encode_huff(sfc_L_dpcm.reshape(-1, order="F"), huff_LUT_list)
sfc_R_stream, cb_sfc_R = aac_encode_huff(sfc_R_dpcm.reshape(-1, order="F"), huff_LUT_list)
if cb_sfc_L != 11 or cb_sfc_R != 11:
print (f"frame: {i}: cb_sfc_l={cb_sfc_L}, cb_sfc_r={cb_sfc_R}")
raise ValueError(f"Illegal codebook value for frame: {i}: cb_sfc_l={cb_sfc_L}, cb_sfc_r={cb_sfc_R}.")
mdct_L_stream, cb_L = aac_encode_huff(
np.asarray(S_L, dtype=np.int64).reshape(-1),
huff_LUT_list,
)
mdct_R_stream, cb_R = aac_encode_huff(
np.asarray(S_R, dtype=np.int64).reshape(-1),
huff_LUT_list,
)
mdct_L_stream, cb_L = aac_encode_huff(np.asarray(S_L, dtype=np.int64).reshape(-1), huff_LUT_list)
mdct_R_stream, cb_R = aac_encode_huff(np.asarray(S_R, dtype=np.int64).reshape(-1), huff_LUT_list)
# Typed dict construction helps static analyzers validate the schema.
frame_out: AACSeq3Frame = {