ref: 55507f19668afe68fbb5d9f4bbbae1fde36df9ce
parent: 15a30e282586f9c88784975944daf9e6c44aa72a
author: Jean-Marc Valin <jmvalin@jmvalin.ca>
date: Fri Jun 2 19:01:20 EDT 2017
Properly compute redundancy_bytes
--- a/src/opus_encoder.c
+++ b/src/opus_encoder.c
@@ -1042,6 +1042,34 @@
return ret;
}
+static int compute_redundancy_bytes(opus_int32 max_data_bytes, opus_int32 bitrate_bps, int frame_rate, int channels)
+{+ int redundancy_bytes_cap;
+ int redundancy_bytes;
+ opus_int32 redundancy_rate;
+ int base_bits;
+ opus_int32 available_bits;
+ base_bits = (40*channels+20);
+
+ /* Equivalent rate for 5 ms frames. */
+ redundancy_rate = bitrate_bps + base_bits*(200 - frame_rate);
+ /* For VBR, further increase the bitrate if we can afford it. It's pretty short
+ and we'll avoid artefacts. */
+ redundancy_rate = 3*redundancy_rate/2;
+ redundancy_bytes = redundancy_rate/1600;
+
+ /* Compute the max rate we can use given CBR or VBR with cap. */
+ available_bits = max_data_bytes*8 - 2*base_bits;
+ redundancy_bytes_cap = (available_bits*240/(240+48000/frame_rate) + base_bits)/8;
+ redundancy_bytes = IMIN(redundancy_bytes, redundancy_bytes_cap);
+ /* It we can't get enough bits for redundancy to be worth it, rely on the decoder PLC. */
+ if (redundancy_bytes > 4 + 8*channels)
+ redundancy_bytes = IMIN(257, redundancy_bytes);
+ else
+ redundancy_bytes = 0;
+ return redundancy_bytes;
+}
+
opus_int32 opus_encode_native(OpusEncoder *st, const opus_val16 *pcm, int frame_size,
unsigned char *data, opus_int32 out_data_bytes, int lsb_depth,
const void *analysis_pcm, opus_int32 analysis_size, int c1, int c2,
@@ -1580,11 +1608,9 @@
if (redundancy)
{- /* Fair share of the max size allowed */
- redundancy_bytes = IMIN(257, max_data_bytes*(opus_int32)(st->Fs/200)/(frame_size+st->Fs/200));
- /* For VBR, target the actual bitrate (subject to the limit above) */
- if (st->use_vbr)
- redundancy_bytes = IMIN(redundancy_bytes, st->bitrate_bps/1600);
+ redundancy_bytes = compute_redundancy_bytes(max_data_bytes, st->bitrate_bps, frame_rate, st->stream_channels);
+ if (redundancy_bytes == 0)
+ redundancy = 0;
}
/* printf("%d %d %d %d\n", st->bitrate_bps, st->stream_channels, st->mode, curr_bandwidth); */@@ -1830,7 +1856,8 @@
/* FIXME: How do we allocate the redundancy for CBR? */
if (st->silk_mode.opusCanSwitch)
{- redundancy = 1;
+ redundancy_bytes = compute_redundancy_bytes(max_data_bytes, st->bitrate_bps, frame_rate, st->stream_channels);
+ redundancy = (redundancy_bytes != 0);
celt_to_silk = 0;
st->silk_bw_switch = 1;
}
@@ -1942,13 +1969,12 @@
/* Reserve the 8 bits needed for the redundancy length,
and at least a few bits for CELT if possible */
max_redundancy = (max_data_bytes-1)-((ec_tell(&enc)+8+3+7)>>3);
- max_redundancy = IMIN(max_redundancy, redundancy_bytes);
}
else
max_redundancy = (max_data_bytes-1)-((ec_tell(&enc)+7)>>3);
/* Target the same bit-rate for redundancy as for the rest,
up to a max of 257 bytes */
- redundancy_bytes = IMIN(max_redundancy, st->bitrate_bps/1600);
+ redundancy_bytes = IMIN(max_redundancy, redundancy_bytes);
redundancy_bytes = IMIN(257, IMAX(2, redundancy_bytes));
if (st->mode == MODE_HYBRID)
ec_enc_uint(&enc, redundancy_bytes-2, 256);