Adding resampling support
We use the MDCT as low-pass filter.
This commit is contained in:
Jean-Marc Valin
parent
c97b258c62
commit
913a1742b9
2 changed files with 103 additions and 23 deletions
118
libcelt/celt.c
118
libcelt/celt.c
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@ -63,6 +63,32 @@ static const unsigned char tapset_icdf[3]={2,1,0};
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#define COMBFILTER_MAXPERIOD 1024
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#define COMBFILTER_MINPERIOD 15
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static int resampling_factor(celt_int32 rate)
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{
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int ret;
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switch (rate)
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{
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case 48000:
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ret = 1;
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break;
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case 24000:
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ret = 2;
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break;
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case 16000:
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ret = 3;
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break;
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case 12000:
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ret = 4;
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break;
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case 8000:
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ret = 6;
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break;
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default:
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ret = 0;
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}
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return ret;
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}
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/** Encoder state
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@brief Encoder state
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*/
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@ -73,6 +99,7 @@ struct CELTEncoder {
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int force_intra;
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int complexity;
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int upsample;
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int start, end;
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celt_int32 vbr_rate_norm; /* Target number of 8th bits per frame */
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@ -127,12 +154,13 @@ int celt_encoder_get_size(const CELTMode *mode, int channels)
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return size;
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}
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CELTEncoder *celt_encoder_create(int channels, int *error)
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CELTEncoder *celt_encoder_create(int sampling_rate, int channels, int *error)
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{
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CELTMode *mode = celt_mode_create(48000, 960, NULL);
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return celt_encoder_init(
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CELTEncoder *st = celt_encoder_init(
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(CELTEncoder *)celt_alloc(celt_encoder_get_size(mode, channels)),
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channels, error);
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sampling_rate, channels, error);
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return st;
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}
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CELTEncoder *celt_encoder_create_custom(const CELTMode *mode, int channels, int *error)
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@ -142,9 +170,17 @@ CELTEncoder *celt_encoder_create_custom(const CELTMode *mode, int channels, int
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mode, channels, error);
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}
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CELTEncoder *celt_encoder_init(CELTEncoder *st, int channels, int *error)
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CELTEncoder *celt_encoder_init(CELTEncoder *st, int sampling_rate, int channels, int *error)
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{
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return celt_encoder_init_custom(st, celt_mode_create(48000, 960, NULL), channels, error);
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celt_encoder_init_custom(st, celt_mode_create(48000, 960, NULL), channels, error);
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st->upsample = resampling_factor(sampling_rate);
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if (st->upsample==0)
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{
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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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return st;
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}
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CELTEncoder *celt_encoder_init_custom(CELTEncoder *st, const CELTMode *mode, int channels, int *error)
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@ -169,6 +205,7 @@ CELTEncoder *celt_encoder_init_custom(CELTEncoder *st, const CELTMode *mode, int
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st->overlap = mode->overlap;
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st->channels = channels;
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st->upsample = 1;
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st->start = 0;
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st->end = st->mode->effEBands;
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st->constrained_vbr = 1;
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@ -385,10 +422,11 @@ static void compute_inv_mdcts(const CELTMode *mode, int shortBlocks, celt_sig *X
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} while (++c<C);
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}
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static void deemphasis(celt_sig *in[], celt_word16 *pcm, int N, int _C, const celt_word16 *coef, celt_sig *mem)
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static void deemphasis(celt_sig *in[], celt_word16 *pcm, int N, int _C, int downsample, const celt_word16 *coef, celt_sig *mem)
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{
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const int C = CHANNELS(_C);
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int c;
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int count=0;
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c=0; do {
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int j;
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celt_sig * restrict x;
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@ -402,9 +440,15 @@ static void deemphasis(celt_sig *in[], celt_word16 *pcm, int N, int _C, const ce
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m = MULT16_32_Q15(coef[0], tmp)
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- MULT16_32_Q15(coef[1], *x);
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tmp = SHL32(MULT16_32_Q15(coef[3], tmp), 2);
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*y = SCALEOUT(SIG2WORD16(tmp));
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x++;
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y+=C;
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/* Technically the store could be moved outside of the if because
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the stores we don't want will just be overwritten */
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if (++count==downsample)
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{
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*y = SCALEOUT(SIG2WORD16(tmp));
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y+=C;
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count=0;
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}
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}
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mem[c] = m;
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} while (++c<C);
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@ -841,6 +885,7 @@ int celt_encode_with_ec_float(CELTEncoder * restrict st, const celt_sig * pcm, i
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if (nbCompressedBytes<2 || pcm==NULL)
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return CELT_BAD_ARG;
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frame_size *= st->upsample;
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for (LM=0;LM<4;LM++)
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if (st->mode->shortMdctSize<<LM==frame_size)
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break;
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@ -919,19 +964,29 @@ int celt_encode_with_ec_float(CELTEncoder * restrict st, const celt_sig * pcm, i
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silence = 1;
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c=0; do {
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int count = 0;
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const celt_word16 * restrict pcmp = pcm+c;
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celt_sig * restrict inp = in+c*(N+st->overlap)+st->overlap;
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for (i=0;i<N;i++)
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{
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celt_sig x, tmp;
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x = SCALEIN(*pcmp);
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if (++count==st->upsample)
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{
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count=0;
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pcmp+=C;
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} else {
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x = 0;
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}
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/* Apply pre-emphasis */
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celt_sig tmp = MULT16_16(st->mode->preemph[2], SCALEIN(*pcmp));
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tmp = MULT16_16(st->mode->preemph[2], x);
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*inp = tmp + st->preemph_memE[c];
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st->preemph_memE[c] = MULT16_32_Q15(st->mode->preemph[1], *inp)
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- MULT16_32_Q15(st->mode->preemph[0], tmp);
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silence = silence && *inp == 0;
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inp++;
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pcmp+=C;
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}
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CELT_COPY(pre[c], prefilter_mem+c*COMBFILTER_MAXPERIOD, COMBFILTER_MAXPERIOD);
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CELT_COPY(pre[c]+COMBFILTER_MAXPERIOD, in+c*(N+st->overlap)+st->overlap, N);
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@ -1082,6 +1137,17 @@ int celt_encode_with_ec_float(CELTEncoder * restrict st, const celt_sig * pcm, i
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/* Compute MDCTs */
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compute_mdcts(st->mode, shortBlocks, in, freq, C, LM);
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if (st->upsample != 1)
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{
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c=0; do
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{
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int bound = N/st->upsample;
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for (i=0;i<bound;i++)
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freq[c*N+i] *= st->upsample;
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for (;i<N;i++)
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freq[c*N+i] = 0;
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} while (++c<C);
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}
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ALLOC(X, C*N, celt_norm); /**< Interleaved normalised MDCTs */
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compute_band_energies(st->mode, freq, bandE, effEnd, C, M);
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@ -1412,7 +1478,7 @@ int celt_encode_with_ec_float(CELTEncoder * restrict st, const celt_sig * pcm, i
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} while (++c<C);
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#endif /* ENABLE_POSTFILTER */
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deemphasis(out_mem, (celt_word16*)pcm, N, C, st->mode->preemph, st->preemph_memD);
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deemphasis(out_mem, (celt_word16*)pcm, N, C, st->upsample, st->mode->preemph, st->preemph_memD);
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st->prefilter_period_old = st->prefilter_period;
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st->prefilter_gain_old = st->prefilter_gain;
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st->prefilter_tapset_old = st->prefilter_tapset;
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@ -1651,6 +1717,7 @@ struct CELTDecoder {
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int overlap;
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int channels;
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int downsample;
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int start, end;
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/* Everything beyond this point gets cleared on a reset */
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@ -1685,12 +1752,12 @@ int celt_decoder_get_size(const CELTMode *mode, int channels)
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return size;
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}
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CELTDecoder *celt_decoder_create(int channels, int *error)
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CELTDecoder *celt_decoder_create(int sampling_rate, int channels, int *error)
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{
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const CELTMode *mode = celt_mode_create(48000, 960, NULL);
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return celt_decoder_init(
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(CELTDecoder *)celt_alloc(celt_decoder_get_size(mode, channels)),
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channels, error);
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sampling_rate, channels, error);
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}
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CELTDecoder *celt_decoder_create_custom(const CELTMode *mode, int channels, int *error)
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@ -1700,9 +1767,17 @@ CELTDecoder *celt_decoder_create_custom(const CELTMode *mode, int channels, int
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mode, channels, error);
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}
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CELTDecoder *celt_decoder_init(CELTDecoder *st, int channels, int *error)
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CELTDecoder *celt_decoder_init(CELTDecoder *st, int sampling_rate, int channels, int *error)
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{
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return celt_decoder_init_custom(st, celt_mode_create(48000, 960, NULL), channels, error);
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celt_decoder_init_custom(st, celt_mode_create(48000, 960, NULL), channels, error);
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st->downsample = resampling_factor(sampling_rate);
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if (st->downsample==0)
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{
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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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return st;
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}
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CELTDecoder *celt_decoder_init_custom(CELTDecoder *st, const CELTMode *mode, int channels, int *error)
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@ -1727,6 +1802,7 @@ CELTDecoder *celt_decoder_init_custom(CELTDecoder *st, const CELTMode *mode, int
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st->overlap = mode->overlap;
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st->channels = channels;
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st->downsample = 1;
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st->start = 0;
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st->end = st->mode->effEBands;
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@ -1955,7 +2031,7 @@ static void celt_decode_lost(CELTDecoder * restrict st, celt_word16 * restrict p
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out_mem[c][MAX_PERIOD+i] = e[i];
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} while (++c<C);
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deemphasis(out_syn, pcm, N, C, st->mode->preemph, st->preemph_memD);
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deemphasis(out_syn, pcm, N, C, st->downsample, st->mode->preemph, st->preemph_memD);
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st->loss_count++;
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@ -2015,6 +2091,7 @@ int celt_decode_with_ec_float(CELTDecoder * restrict st, const unsigned char *da
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if (pcm==NULL)
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return CELT_BAD_ARG;
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frame_size *= st->downsample;
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for (LM=0;LM<4;LM++)
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if (st->mode->shortMdctSize<<LM==frame_size)
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break;
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@ -2220,10 +2297,13 @@ int celt_decode_with_ec_float(CELTDecoder * restrict st, const unsigned char *da
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for (i=0;i<M*st->mode->eBands[st->start];i++)
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freq[c*N+i] = 0;
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while (++c<C);
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c=0; do
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c=0; do {
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int bound = M*st->mode->eBands[effEnd];
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if (st->downsample!=1)
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bound = IMIN(bound, N/st->downsample);
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for (i=M*st->mode->eBands[effEnd];i<N;i++)
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freq[c*N+i] = 0;
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while (++c<C);
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} while (++c<C);
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out_syn[0] = out_mem[0]+MAX_PERIOD-N;
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if (C==2)
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@ -2280,7 +2360,7 @@ int celt_decode_with_ec_float(CELTDecoder * restrict st, const unsigned char *da
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}
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st->rng = dec->rng;
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deemphasis(out_syn, pcm, N, C, st->mode->preemph, st->preemph_memD);
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deemphasis(out_syn, pcm, N, C, st->downsample, st->mode->preemph, st->preemph_memD);
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st->loss_count = 0;
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RESTORE_STACK;
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if (ec_dec_tell(dec,0) > 8*len || ec_dec_get_error(dec))
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@ -167,7 +167,7 @@ EXPORT int celt_encoder_get_size(const CELTMode *mode, int channels);
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@param error Returns an error code
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@return Newly created encoder state.
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*/
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EXPORT CELTEncoder *celt_encoder_create(int channels, int *error);
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EXPORT CELTEncoder *celt_encoder_create(int sampling_rate, int channels, int *error);
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/** Creates a new encoder state. Each stream needs its own encoder
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state (can't be shared across simultaneous streams).
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@ -180,7 +180,7 @@ EXPORT CELTEncoder *celt_encoder_create(int channels, int *error);
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*/
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EXPORT CELTEncoder *celt_encoder_create_custom(const CELTMode *mode, int channels, int *error);
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EXPORT CELTEncoder *celt_encoder_init(CELTEncoder *st, int channels, int *error);
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EXPORT CELTEncoder *celt_encoder_init(CELTEncoder *st, int sampling_rate, int channels, int *error);
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EXPORT CELTEncoder *celt_encoder_init_custom(CELTEncoder *st, const CELTMode *mode, int channels, int *error);
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@ -245,7 +245,7 @@ EXPORT int celt_decoder_get_size(const CELTMode *mode, int channels);
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@param error Returns an error code
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@return Newly created decoder state.
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*/
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EXPORT CELTDecoder *celt_decoder_create(int channels, int *error);
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EXPORT CELTDecoder *celt_decoder_create(int sampling_rate, int channels, int *error);
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/** Creates a new decoder state. Each stream needs its own decoder state (can't
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be shared across simultaneous streams).
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@ -257,7 +257,7 @@ EXPORT CELTDecoder *celt_decoder_create(int channels, int *error);
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*/
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EXPORT CELTDecoder *celt_decoder_create_custom(const CELTMode *mode, int channels, int *error);
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EXPORT CELTDecoder *celt_decoder_init(CELTDecoder *st, int channels, int *error);
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EXPORT CELTDecoder *celt_decoder_init(CELTDecoder *st, int sampling_rate, int channels, int *error);
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EXPORT CELTDecoder *celt_decoder_init_custom(CELTDecoder *st, const CELTMode *mode, int channels, int *error);
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