This ensures that any processing between the MDCT and exponent extraction will
be using clipped coefficients.
---
libavcodec/ac3enc.c | 10 +++++++++-
libavcodec/ac3enc.h | 8 ++++++++
libavcodec/ac3enc_template.c | 16 +++++++++++++++-
3 files changed, 32 insertions(+), 2 deletions(-)
diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c
index 3426bd2..e5e2edc 100644
--- a/libavcodec/ac3enc.c
+++ b/libavcodec/ac3enc.c
@@ -1898,7 +1898,10 @@ int ff_ac3_encode_frame(AVCodecContext *avctx, unsigned char *frame,
s->apply_mdct(s);
- s->scale_coefficients(s);
+ if (s->fixed_point)
+ s->scale_coefficients(s);
+
+ s->clip_coefficients(s);
s->cpl_on = s->cpl_enabled;
compute_coupling_strategy(s);
@@ -1908,6 +1911,9 @@ int ff_ac3_encode_frame(AVCodecContext *avctx, unsigned char *frame,
s->compute_rematrixing_strategy(s);
+ if (!s->fixed_point)
+ s->scale_coefficients(s);
+
apply_rematrixing(s);
process_exponents(s);
@@ -2354,6 +2360,7 @@ av_cold int ff_ac3_encode_init(AVCodecContext *avctx)
s->allocate_sample_buffers = ff_ac3_fixed_allocate_sample_buffers;
s->deinterleave_input_samples = ff_ac3_fixed_deinterleave_input_samples;
s->apply_mdct = ff_ac3_fixed_apply_mdct;
+ s->clip_coefficients = ff_ac3_fixed_clip_coefficients;
s->apply_channel_coupling = ff_ac3_fixed_apply_channel_coupling;
s->compute_rematrixing_strategy = ff_ac3_fixed_compute_rematrixing_strategy;
} else if (CONFIG_AC3_ENCODER || CONFIG_EAC3_ENCODER) {
@@ -2364,6 +2371,7 @@ av_cold int ff_ac3_encode_init(AVCodecContext *avctx)
s->allocate_sample_buffers = ff_ac3_float_allocate_sample_buffers;
s->deinterleave_input_samples = ff_ac3_float_deinterleave_input_samples;
s->apply_mdct = ff_ac3_float_apply_mdct;
+ s->clip_coefficients = ff_ac3_float_clip_coefficients;
s->apply_channel_coupling = ff_ac3_float_apply_channel_coupling;
s->compute_rematrixing_strategy = ff_ac3_float_compute_rematrixing_strategy;
}
diff --git a/libavcodec/ac3enc.h b/libavcodec/ac3enc.h
index bf25298..ff8a389 100644
--- a/libavcodec/ac3enc.h
+++ b/libavcodec/ac3enc.h
@@ -50,12 +50,16 @@
#if CONFIG_AC3ENC_FLOAT
#define AC3_NAME(x) ff_ac3_float_ ## x
#define MAC_COEF(d,a,b) ((d)+=(a)*(b))
+#define COEF_MIN (-16777215.0/16777216.0)
+#define COEF_MAX ( 16777215.0/16777216.0)
typedef float SampleType;
typedef float CoefType;
typedef float CoefSumType;
#else
#define AC3_NAME(x) ff_ac3_fixed_ ## x
#define MAC_COEF(d,a,b) MAC64(d,a,b)
+#define COEF_MIN -16777215
+#define COEF_MAX 16777215
typedef int16_t SampleType;
typedef int32_t CoefType;
typedef int64_t CoefSumType;
@@ -235,6 +239,7 @@ typedef struct AC3EncodeContext {
void (*deinterleave_input_samples)(struct AC3EncodeContext *s,
const SampleType *samples);
void (*apply_mdct)(struct AC3EncodeContext *s);
+ void (*clip_coefficients)(struct AC3EncodeContext *s);
void (*apply_channel_coupling)(struct AC3EncodeContext *s);
void (*compute_rematrixing_strategy)(struct AC3EncodeContext *s);
@@ -289,6 +294,9 @@ void ff_ac3_float_deinterleave_input_samples(AC3EncodeContext *s,
void ff_ac3_fixed_apply_mdct(AC3EncodeContext *s);
void ff_ac3_float_apply_mdct(AC3EncodeContext *s);
+void ff_ac3_fixed_clip_coefficients(AC3EncodeContext *s);
+void ff_ac3_float_clip_coefficients(AC3EncodeContext *s);
+
void ff_ac3_fixed_apply_channel_coupling(AC3EncodeContext *s);
void ff_ac3_float_apply_channel_coupling(AC3EncodeContext *s);
diff --git a/libavcodec/ac3enc_template.c b/libavcodec/ac3enc_template.c
index f6248a8..2e4b01a 100644
--- a/libavcodec/ac3enc_template.c
+++ b/libavcodec/ac3enc_template.c
@@ -107,6 +107,20 @@ void AC3_NAME(apply_mdct)(AC3EncodeContext *s)
}
+void AC3_NAME(clip_coefficients)(AC3EncodeContext *s)
+{
+#if CONFIG_AC3ENC_FLOAT
+#define vector_clip_coef s->dsp.vector_clipf
+#else
+#define vector_clip_coef s->dsp.vector_clip_int32
+#endif
+ int chan_size = AC3_MAX_COEFS * AC3_MAX_BLOCKS;
+ vector_clip_coef(s->mdct_coef_buffer + chan_size,
+ s->mdct_coef_buffer + chan_size,
+ COEF_MIN, COEF_MAX, chan_size * s->channels);
+}
+
+
/**
* Calculate a single coupling coordinate.
*/
@@ -161,7 +175,7 @@ void AC3_NAME(apply_channel_coupling)(AC3EncodeContext *s)
}
/* coefficients must be clipped to +/- 1.0 in order to be encoded */
- s->dsp.vector_clipf(cpl_coef, cpl_coef, -1.0f, 1.0f, num_cpl_coefs);
+ s->dsp.vector_clipf(cpl_coef, cpl_coef, COEF_MIN, COEF_MAX, num_cpl_coefs);
/* scale coupling coefficients from float to 24-bit fixed-point */
s->ac3dsp.float_to_fixed24(&block->fixed_coef[CPL_CH][cpl_start],
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