diff options
Diffstat (limited to 'src/opus_encoder.c')
| -rw-r--r-- | src/opus_encoder.c | 93 |
1 files changed, 87 insertions, 6 deletions
diff --git a/src/opus_encoder.c b/src/opus_encoder.c index c1cb2cf6..9259fab0 100644 --- a/src/opus_encoder.c +++ b/src/opus_encoder.c @@ -219,6 +219,44 @@ int opus_encoder_init(OpusEncoder* st, opus_int32 Fs, int channels, int applicat return OPUS_OK; } +static int pad_frame(unsigned char *data, int len, int new_len) +{ + if (len == new_len) + return 0; + if (len > new_len) + return 1; + + if ((data[0]&0x3)==0) + { + int i; + int padding, nb_255s; + + padding = new_len - len; + if (padding >= 2) + { + nb_255s = (padding-2)/255; + + for (i=len-1;i>=1;i--) + data[i+nb_255s+2] = data[i]; + data[0] |= 0x3; + data[1] = 0x41; + for (i=0;i<nb_255s;i++) + data[i+2] = 255; + data[nb_255s+2] = padding-255*nb_255s-2; + for (i=len+3+nb_255s;i<new_len;i++) + data[i] = 0; + } else { + for (i=len-1;i>=1;i--) + data[i+1] = data[i]; + data[0] |= 0x3; + data[1] = 1; + } + return 0; + } else { + return 1; + } +} + static unsigned char gen_toc(int mode, int framerate, int bandwidth, int channels) { int period; @@ -449,6 +487,15 @@ int opus_encode_float(OpusEncoder *st, const opus_val16 *pcm, int frame_size, st->bitrate_bps = user_bitrate_to_bitrate(st, frame_size, max_data_bytes); + if (!st->use_vbr) + { + int cbrBytes, frame_rate; + frame_rate = st->Fs/frame_size; + cbrBytes = IMIN( (st->bitrate_bps + 4*frame_rate)/(8*frame_rate) , max_data_bytes); + st->bitrate_bps = cbrBytes * (8*frame_rate); + max_data_bytes = cbrBytes; + } + /* Equivalent 20-ms rate for mode/channel/bandwidth decisions */ equiv_rate = st->bitrate_bps - 60*(st->Fs/frame_size - 50); @@ -614,6 +661,21 @@ int opus_encode_float(OpusEncoder *st, const opus_val16 *pcm, int frame_size, if (st->user_bandwidth != OPUS_AUTO) st->bandwidth = st->user_bandwidth; + /* This enforces safe rates for CBR SILK */ + if (!st->use_vbr && st->mode != MODE_CELT_ONLY) + { + int frame_rate; + opus_int32 max_rate; + frame_rate = st->Fs/frame_size; + max_rate = frame_rate*max_data_bytes; + if (max_rate < 15000) + st->bandwidth = IMIN(st->bandwidth, OPUS_BANDWIDTH_WIDEBAND); + if (max_rate < 12000) + st->bandwidth = IMIN(st->bandwidth, OPUS_BANDWIDTH_MEDIUMBAND); + if (max_rate < 9000) + st->bandwidth = OPUS_BANDWIDTH_NARROWBAND; + } + /* Prevents Opus from wasting bits on frequencies that are above the Nyquist rate of the input signal */ if (st->Fs <= 24000 && st->bandwidth > OPUS_BANDWIDTH_SUPERWIDEBAND) @@ -625,6 +687,9 @@ int opus_encode_float(OpusEncoder *st, const opus_val16 *pcm, int frame_size, if (st->Fs <= 8000 && st->bandwidth > OPUS_BANDWIDTH_NARROWBAND) st->bandwidth = OPUS_BANDWIDTH_NARROWBAND; + /* If max_data_bytes represents less than 8 kb/s, switch to CELT-only mode */ + if (max_data_bytes < 8000*frame_size / (st->Fs * 8)) + st->mode = MODE_CELT_ONLY; /* Can't support higher than wideband for >20 ms frames */ if (frame_size > st->Fs/50 && (st->mode == MODE_CELT_ONLY || st->bandwidth > OPUS_BANDWIDTH_WIDEBAND)) @@ -688,9 +753,6 @@ int opus_encode_float(OpusEncoder *st, const opus_val16 *pcm, int frame_size, if (st->mode == MODE_HYBRID && st->bandwidth <= OPUS_BANDWIDTH_WIDEBAND) st->mode = MODE_SILK_ONLY; - /* If max_data_bytes represents less than 8 kb/s, switch to CELT-only mode */ - if (max_data_bytes < 8000*frame_size / (st->Fs * 8)) - st->mode = MODE_CELT_ONLY; /* printf("%d %d %d %d\n", st->bitrate_bps, st->stream_channels, st->mode, st->bandwidth); */ bytes_target = IMIN(max_data_bytes, st->bitrate_bps * frame_size / (st->Fs * 8)) - 1; @@ -756,9 +818,6 @@ int opus_encode_float(OpusEncoder *st, const opus_val16 *pcm, int frame_size, st->silk_mode.bitRate = ( st->bitrate_bps - 8*st->Fs/frame_size ) * 4/5; } } - /* SILK is not allow to use more than 50% of max_data_bytes */ - if (max_data_bytes < st->silk_mode.bitRate*frame_size / (st->Fs * 4)) - st->silk_mode.bitRate = max_data_bytes*st->Fs*4/frame_size; st->silk_mode.payloadSize_ms = 1000 * frame_size / st->Fs; st->silk_mode.nChannelsAPI = st->channels; @@ -779,8 +838,24 @@ int opus_encode_float(OpusEncoder *st, const opus_val16 *pcm, int frame_size, } st->silk_mode.maxInternalSampleRate = 16000; + st->silk_mode.useCBR = !st->use_vbr; + /* Call SILK encoder for the low band */ nBytes = IMIN(1275, max_data_bytes-1); + + st->silk_mode.maxBits = nBytes*8; + /* Only allow up to 90% of the bits for hybrid mode*/ + if (st->mode == MODE_HYBRID) + st->silk_mode.maxBits = (opus_int32)st->silk_mode.maxBits*9/10; + if (st->silk_mode.useCBR) + { + st->silk_mode.maxBits = (st->silk_mode.bitRate * frame_size / (st->Fs * 8))*8; + /* Reduce the initial target to make it easier to reach the CBR rate */ + st->silk_mode.bitRate = 1; + } + if (redundancy) + st->silk_mode.maxBits -= st->silk_mode.maxBits/(1 + frame_size/(st->Fs/200)); + if (prefill) { int zero=0; @@ -1029,6 +1104,12 @@ int opus_encode_float(OpusEncoder *st, const opus_val16 *pcm, int frame_size, st->prev_framesize = frame_size; st->first = 0; + if (!redundancy && st->mode==MODE_SILK_ONLY && !st->use_vbr && ret >= 2) + { + nb_compr_bytes = st->bitrate_bps * frame_size / (st->Fs * 8); + pad_frame(data, ret+1, nb_compr_bytes); + return nb_compr_bytes; + } RESTORE_STACK; return ret+1+redundancy_bytes; } |