In either encoder, its impossible for the coefficients to go past 25 bits
right after the MDCT. Our MDCT is numerically stable.
For the floating point encoder, in case a NaN is contained, lrintf() will
raise a floating point exception during the conversion.
Patch attached.
>From a64b83f243fee2a5224164db9a4a2a381259baa9 Mon Sep 17 00:00:00 2001
From: Lynne <d...@lynne.ee>
Date: Sat, 9 Jan 2021 09:05:18 +0100
Subject: [PATCH 2/6] ac3enc: do not clip coefficients after transforms
In either encoder, its impossible for the coefficients to go past 25 bits
right after the MDCT. Our MDCT is numerically stable.
For the floating point encoder, in case a NaN is contained, lrintf() will
raise a floating point exception during the conversion.
---
libavcodec/ac3enc_template.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/libavcodec/ac3enc_template.c b/libavcodec/ac3enc_template.c
index de6eba71d8..4f1e181e0b 100644
--- a/libavcodec/ac3enc_template.c
+++ b/libavcodec/ac3enc_template.c
@@ -383,9 +383,6 @@ int AC3_NAME(encode_frame)(AVCodecContext *avctx, AVPacket *avpkt,
apply_mdct(s);
- clip_coefficients(&s->adsp, s->blocks[0].mdct_coef[1],
- AC3_MAX_COEFS * s->num_blocks * s->channels);
-
s->cpl_on = s->cpl_enabled;
ff_ac3_compute_coupling_strategy(s);
--
2.30.0.rc2
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