New VBR rate controller that doesn't allow more than one frame worth of excess
bit-rate
This commit is contained in:
Jean-Marc Valin
parent
328b8bd7fc
commit
bd5d54adb8
1 changed files with 79 additions and 9 deletions
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@ -92,7 +92,13 @@ struct CELTEncoder {
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int fold_decision;
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celt_word16 gain_prod;
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int VBR_rate; /* Target number of 16th bits per frame */
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/* VBR-related parameters */
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celt_int32 vbr_reservoir;
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celt_int32 vbr_drift;
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celt_int32 vbr_offset;
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celt_int32 vbr_count;
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celt_int32 vbr_rate; /* Target number of 16th bits per frame */
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celt_word16 * restrict preemph_memE;
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celt_sig * restrict preemph_memD;
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@ -133,6 +139,16 @@ CELTEncoder *celt_encoder_create(const CELTMode *mode, int channels, int *error)
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*error = CELT_INVALID_MODE;
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return NULL;
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}
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#ifdef DISABLE_STEREO
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if (channels > 1)
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{
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celt_warning("Stereo support was disable from this build");
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if (error)
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*error = CELT_BAD_ARG;
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return NULL;
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}
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#endif
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if (channels < 0 || channels > 2)
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{
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celt_warning("Only mono and stereo supported");
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@ -158,7 +174,7 @@ CELTEncoder *celt_encoder_create(const CELTMode *mode, int channels, int *error)
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st->overlap = mode->overlap;
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st->channels = channels;
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st->VBR_rate = 0;
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st->vbr_rate = 0;
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st->pitch_enabled = 1;
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st->pitch_permitted = 1;
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st->pitch_available = 1;
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@ -662,7 +678,7 @@ int celt_encode_float(CELTEncoder * restrict st, const celt_sig * pcm, celt_sig
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compute_band_energies(st->mode, freq, bandE, C);
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for (i=0;i<st->mode->nbEBands*C;i++)
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bandLogE[i] = amp2Log(bandE[i]);
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/* Band normalisation */
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normalise_bands(st->mode, freq, X, bandE, C);
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if (!shortBlocks && !folding_decision(st->mode, X, &st->tonal_average, &st->fold_decision, C))
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@ -754,25 +770,69 @@ int celt_encode_float(CELTEncoder * restrict st, const celt_sig * pcm, celt_sig
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coarse_needed = ((coarse_needed*3-1)>>3)+1;
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/* Variable bitrate */
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if (st->VBR_rate>0)
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if (st->vbr_rate>0)
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{
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celt_word16 alpha;
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celt_int32 delta, vbr_bound;
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/* The target rate in 16th bits per frame */
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int target=st->VBR_rate;
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celt_int32 target=st->vbr_rate;
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/* Shortblocks get a large boost in bitrate, but since they
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are uncommon long blocks are not greatly effected */
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if (shortBlocks)
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target*=2;
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else if (st->mode->nbShortMdcts > 1)
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target-=(target+14)/28;
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target-=(target+14)/28;
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/* The average energy is removed from the target and the actual
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energy added*/
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target=target-588+ec_enc_tell(&enc, BITRES);
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target=target+st->vbr_offset-588+ec_enc_tell(&enc, BITRES);
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/* In VBR mode the frame size must not be reduced so much that it would result in the coarse energy busting its budget */
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target=IMAX(coarse_needed,(target+64)/128);
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nbCompressedBytes=IMIN(nbCompressedBytes,target);
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/* Make the adaptation coef (alpha) higher at the beginning */
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if (st->vbr_count < 990)
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{
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st->vbr_count++;
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alpha = celt_rcp(SHL32(EXTEND32(st->vbr_count+10),16));
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/*printf ("%d %d\n", st->vbr_count+10, alpha);*/
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} else
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alpha = QCONST16(.001f,15);
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/* By how much did we "miss" the target on that frame */
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delta = (8<<BITRES)*(celt_int32)nbCompressedBytes - st->vbr_rate;
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/* How many bits have we used in excess of what we're allowed */
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st->vbr_reservoir += delta;
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/*printf ("%d\n", st->vbr_reservoir);*/
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/* Compute the offset we need to apply in order to reach the target */
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st->vbr_drift += MULT16_32_Q15(alpha,delta-st->vbr_offset-st->vbr_drift);
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st->vbr_offset = -st->vbr_drift;
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/*printf ("%d\n", st->vbr_drift);*/
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/* We could use any multiple of vbr_rate as bound (depending on the delay) */
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vbr_bound = st->vbr_rate;
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if (st->vbr_reservoir > vbr_bound)
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{
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/* Busted the reservoir -- reduce the rate */
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int adjust = 1+(st->vbr_reservoir-vbr_bound-1)/(8<<BITRES);
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nbCompressedBytes -= adjust;
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st->vbr_reservoir -= adjust*(8<<BITRES);
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st->vbr_offset -= 8<<BITRES;
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/*printf ("-%d\n", adjust);*/
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} else if (st->vbr_reservoir < 0)
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{
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/* We're under the min value -- increase rate */
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int adjust = 1-(st->vbr_reservoir-1)/(8<<BITRES);
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st->vbr_reservoir += adjust*(8<<BITRES);
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nbCompressedBytes += adjust;
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st->vbr_offset += 8<<BITRES;
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/*printf ("+%d\n", adjust);*/
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}
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/* This moves the raw bits to take into account the new compressed size */
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ec_byte_shrink(&buf, nbCompressedBytes);
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}
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@ -962,8 +1022,8 @@ int celt_encoder_ctl(CELTEncoder * restrict st, int request, ...)
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goto bad_arg;
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if (value>3072000)
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value = 3072000;
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st->VBR_rate = ((st->mode->Fs<<3)+(st->block_size>>1))/st->block_size;
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st->VBR_rate = ((value<<7)+(st->VBR_rate>>1))/st->VBR_rate;
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st->vbr_rate = ((st->mode->Fs<<3)+(st->block_size>>1))/st->block_size;
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st->vbr_rate = ((value<<7)+(st->vbr_rate>>1))/st->vbr_rate;
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}
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break;
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case CELT_RESET_STATE:
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@ -1066,6 +1126,16 @@ CELTDecoder *celt_decoder_create(const CELTMode *mode, int channels, int *error)
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*error = CELT_INVALID_MODE;
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return NULL;
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}
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#ifdef DISABLE_STEREO
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if (channels > 1)
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{
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celt_warning("Stereo support was disable from this build");
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if (error)
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*error = CELT_BAD_ARG;
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return NULL;
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}
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#endif
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if (channels < 0 || channels > 2)
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{
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celt_warning("Only mono and stereo supported");
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