- Log ----------------------------------------------------------------- commit a7b84565a34cc81ceb2d60bc871a95eaafea6474 Author: Naufal <naufal11@gmail.com> Date: Mon Jul 26 20:41:09 2010 +0530 Add formant postfilter diff --git a/libavcodec/g723_1.c b/libavcodec/g723_1.c index 68653e5..f15860f 100755 --- a/libavcodec/g723_1.c +++ b/libavcodec/g723_1.c @@ -23,6 +23,10 @@ typedef struct g723_1_context { int16_t interp_gain; int16_t sid_gain; int16_t cur_gain; + + int16_t reflection_coef; + int16_t pf_fir_mem[LPC_ORDER]; ///< Formant FIR postfilter memory + int pf_iir_mem[LPC_ORDER]; ///< Formant IIR postfilter memory } G723_1_Context; static av_cold int g723_1_decode_init(AVCodecContext *avctx) @@ -686,6 +690,93 @@ static void residual_interp(int16_t *buf, int16_t *out, int16_t lag, } } +/* + * @param filter_coef filter coefficients vector + * @param src input signal vector + * @param dest output filtered vector + */ +static void iir_filter(int16_t filter_coef[][LPC_ORDER], int16_t *src, + int *dest) +{ + int i, j; + + for (i = 0; i < SUBFRAME_LEN; i++) { + int64_t filter = 0; + + for (j = 1; j <= LPC_ORDER; j++) { + filter -= filter_coef[0][j - 1] * src[i - j] - + filter_coef[1][j - 1] * (dest[i - j] >> 16); + } + + dest[i] = av_clipl_int32((src[i] << 16) + (filter << 3) + (1 << 15)); + } +} + +/* + * @param buf synthesized speech vector + * @param lpc quantized lpc coefficients + */ +static int formant_postfilter(G723_1_Context *p, int16_t *buf, int16_t *lpc) +{ + int16_t filter_coef[2][LPC_ORDER]; + int filter_signal[LPC_ORDER+SUBFRAME_LEN]; + int16_t temp_vector[SUBFRAME_LEN]; + int auto_corr[2]; + int16_t temp; + int scale, energy; + int i; + + // Compute FIR and IIR filter coefficients + for (i=0; i<LPC_ORDER; i++) { + filter_coef[0][i] = (-lpc[i] * postfilter_tbl[0][i] + (1<<14)) >> 15; + filter_coef[1][i] = (-lpc[i] * postfilter_tbl[1][i] + (1<<14)) >> 15; + } + + // Normalize + memcpy(temp_vector, buf, SUBFRAME_LEN * sizeof(int16_t)); + scale = scale_vector(temp_vector, SUBFRAME_LEN); + + // Compute auto correlation coefficients + auto_corr[0] = dot_product(temp_vector, temp_vector + 1, SUBFRAME_LEN - 1); + auto_corr[1] = dot_product(temp_vector, temp_vector, SUBFRAME_LEN); + + // Compute normalized signal energy + temp = 2 * scale + 4; + if (temp < 0) + energy = av_clipl_int32((int64_t)auto_corr[1] << -temp); + else + energy = auto_corr[1] >> temp; + + // Compute reflection coefficient + temp = auto_corr[1] >> 16; + if (temp) { + temp = (auto_corr[0]>>2) / temp; + } + + p->reflection_coef = ((p->reflection_coef << 2) - p->reflection_coef + + temp + 2) >> 2; + + memcpy(buf - LPC_ORDER, p->pf_fir_mem, LPC_ORDER * sizeof(int16_t)); + memcpy(filter_signal, p->pf_iir_mem, LPC_ORDER * sizeof(int)); + + iir_filter(filter_coef, buf, filter_signal + LPC_ORDER); + + memcpy(p->pf_fir_mem, buf + SUBFRAME_LEN - LPC_ORDER, LPC_ORDER * + sizeof(int16_t)); + memcpy(p->pf_iir_mem, filter_signal + SUBFRAME_LEN, LPC_ORDER * + sizeof(int)); + + // Compensation filter + temp = (p->reflection_coef * 0xffffc000 >> 15) & 0xfffc; + for (i = 0; i < SUBFRAME_LEN; i++) { + buf[i] = av_clipl_int32(filter_signal[LPC_ORDER + i] + + (((filter_signal[LPC_ORDER + i - 1] >> 16) * + temp) << 1)) >> 16; + } + + return energy; +} + static int g723_1_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { @@ -700,6 +791,7 @@ static int g723_1_decode_frame(AVCodecContext *avctx, void *data, int16_t excitation[FRAME_LEN + PITCH_MAX]; int16_t acb_vector[SUBFRAME_LEN]; int16_t *vector_ptr; + int energy; int bad_frame = 0, i, j; if (!buf_size || buf_size < frame_size[buf[0] & 3]) { @@ -794,6 +886,8 @@ static int g723_1_decode_frame(AVCodecContext *avctx, void *data, // Store the last 10 values of the output vector memcpy(p->filter_mem, vector_ptr + SUBFRAME_LEN - LPC_ORDER, LPC_ORDER * sizeof(int16_t)); + energy = formant_postfilter(p, vector_ptr, + &lpc[i * (LPC_ORDER + 1) + 1]); vector_ptr += SUBFRAME_LEN; } diff --git a/libavcodec/g723_1_data.h b/libavcodec/g723_1_data.h index 411e23c..ec93acf 100644 --- a/libavcodec/g723_1_data.h +++ b/libavcodec/g723_1_data.h @@ -1206,3 +1206,13 @@ static const int16_t adaptive_cb_gain170[170 * 20] = { 6538, -1712, -4280, -4804, -3613, -2609, -2707, -2868, -4534, -2487, -3932, -4166, -2113, -3341, -3540, -3070 }; + +/* + * 0.65^i (FIR) and 0.75^i (IIR) scaled by 2^15 + */ +static const int16_t postfilter_tbl[2][LPC_ORDER] = { + // Zero part + {21299, 13844, 8999, 5849, 3802, 2471, 1606, 1044, 679, 441}, + // Pole part + {24576, 18432, 13824, 10368, 7776, 5832, 4374, 3281, 2460, 1845} +}; ----------------------------------------------------------------------- Summary of changes: libavcodec/g723_1.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++ libavcodec/g723_1_data.h | 10 +++++ 2 files changed, 104 insertions(+), 0 deletions(-) -- http://github.com/naufal/ffmpeg-soc