From 4600e77583fc29738fd5c2aa6cb5ceb30596cc7d Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@amazon.com>
Date: Tue, 11 Jul 2023 19:03:13 -0400
Subject: [PATCH] Implement allocation of the DRED bits
Should work for both CBR and VBR. In the CBR case, we can make
CELT VBR and use DRED to fill the rest.
---
src/opus_encoder.c | 33 +++++++++++++++++++++++++++++----
1 file changed, 29 insertions(+), 4 deletions(-)
diff --git a/src/opus_encoder.c b/src/opus_encoder.c
index 8b365d219..3933ab277 100644
--- a/src/opus_encoder.c
+++ b/src/opus_encoder.c
@@ -1958,7 +1958,6 @@ opus_int32 opus_encode_native(OpusEncoder *st, const opus_val16 *pcm, int frame_
if (st->mode != MODE_SILK_ONLY)
{
opus_val32 celt_pred=2;
- celt_encoder_ctl(celt_enc, OPUS_SET_VBR(0));
/* We may still decide to disable prediction later */
if (st->silk_mode.reducedDependency)
celt_pred = 0;
@@ -2056,8 +2055,21 @@ opus_int32 opus_encode_native(OpusEncoder *st, const opus_val16 *pcm, int frame_
ec_enc_done(&enc);
nb_compr_bytes = ret;
} else {
- nb_compr_bytes = (max_data_bytes-1)-redundancy_bytes;
- ec_enc_shrink(&enc, nb_compr_bytes);
+ nb_compr_bytes = (max_data_bytes-1)-redundancy_bytes;
+#ifdef ENABLE_NEURAL_FEC
+ if (st->dred_duration > 0)
+ {
+ int max_celt_bytes;
+ opus_int32 dred_bytes = dred_bitrate_bps/(frame_rate*8);
+ /* Allow CELT to steal up to 25% of the remaining bits. */
+ max_celt_bytes = nb_compr_bytes - dred_bytes*3/4;
+ /* But try to give CELT at least 4 bytes */
+ max_celt_bytes = IMAX(ec_tell(&enc)/8 + 4, max_celt_bytes);
+ /* Subject to the original max. */
+ nb_compr_bytes = IMIN(nb_compr_bytes, max_celt_bytes);
+ }
+#endif
+ ec_enc_shrink(&enc, nb_compr_bytes);
}
#ifndef DISABLE_FLOAT_API
@@ -2092,6 +2104,7 @@ opus_int32 opus_encode_native(OpusEncoder *st, const opus_val16 *pcm, int frame_
if (st->mode != MODE_SILK_ONLY)
{
+ celt_encoder_ctl(celt_enc, OPUS_SET_VBR(st->use_vbr));
if (st->mode == MODE_HYBRID)
{
if( st->use_vbr ) {
@@ -2106,6 +2119,19 @@ opus_int32 opus_encode_native(OpusEncoder *st, const opus_val16 *pcm, int frame_
celt_encoder_ctl(celt_enc, OPUS_SET_BITRATE(st->bitrate_bps));
}
}
+#ifdef ENABLE_NEURAL_FEC
+ /* When Using DRED CBR, we can actually make the CELT part VBR and have DRED pick up the slack. */
+ if (!st->use_vbr && st->dred_duration > 0)
+ {
+ opus_int32 celt_bitrate = st->bitrate_bps;
+ celt_encoder_ctl(celt_enc, OPUS_SET_VBR(1));
+ celt_encoder_ctl(celt_enc, OPUS_SET_VBR_CONSTRAINT(0));
+ if (st->mode == MODE_HYBRID) {
+ celt_bitrate -= st->silk_mode.bitRate;
+ }
+ celt_encoder_ctl(celt_enc, OPUS_SET_BITRATE(celt_bitrate));
+ }
+#endif
if (st->mode != st->prev_mode && st->prev_mode > 0)
{
unsigned char dummy[2];
@@ -2118,7 +2144,6 @@ opus_int32 opus_encode_native(OpusEncoder *st, const opus_val16 *pcm, int frame_
/* If false, we already busted the budget and we'll end up with a "PLC frame" */
if (ec_tell(&enc) <= 8*nb_compr_bytes)
{
- celt_encoder_ctl(celt_enc, OPUS_SET_VBR(st->use_vbr));
ret = celt_encode_with_ec(celt_enc, pcm_buf, frame_size, NULL, nb_compr_bytes, &enc);
if (ret < 0)
{
--
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