This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "AMR-WB decoder". The branch, master has been updated via 1c399e4d298648f1ad8a70f50507c41fa7b21a62 (commit) from 42461e43223b4da99bbfa00a08e844fa8d6acd85 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit 1c399e4d298648f1ad8a70f50507c41fa7b21a62 Author: Marcelo Povoa <marspeoplester@gmail.com> Date: Thu Jul 29 02:51:15 2010 -0300 Finish writing the ISF vector extrapolation (6k60 HB) Fix white noise excitation randomness diff --git a/libavcodec/amrwbdata.h b/libavcodec/amrwbdata.h index acfb443..ce5fb63 100644 --- a/libavcodec/amrwbdata.h +++ b/libavcodec/amrwbdata.h @@ -28,8 +28,7 @@ #define LP_ORDER_16k 20 ///< lpc filter order at 16kHz #define UPS_FIR_SIZE 12 ///< upsampling filter size #define UPS_MEM_SIZE 2 * UPS_FIR_SIZE -//#define SAMPLE_MEM 24 ///< number of stored past samples given by - ///< max(LP_ORDER, UPS_FIR_SIZE * 2) + #define MIN_ISF_SPACING (128 / 32768.0) ///< minimum isf gap #define PRED_FACTOR (1.0 / 3.0) #define MIN_ENERGY -14.0 ///< initial innnovation energy (dB) @@ -39,7 +38,6 @@ #define AMRWB_SUBFRAME_SIZE 64 ///< samples per subframe at 12.8 kHz #define AMRWB_SFR_SIZE_OUT 80 ///< samples per subframe at 16 kHz #define AMRWB_SAMPLE_BOUND 32768.0 ///< threshold for synthesis overflow - #define AMRWB_P_DELAY_MAX 231 ///< maximum pitch delay value #define AMRWB_P_DELAY_MIN 34 diff --git a/libavcodec/amrwbdec.c b/libavcodec/amrwbdec.c index 83303ed..6833f23 100644 --- a/libavcodec/amrwbdec.c +++ b/libavcodec/amrwbdec.c @@ -1033,7 +1033,7 @@ static void scaled_hb_excitation(AMRWBContext *ctx, float *hb_exc, /* Generate a white-noise excitation */ for (i = 0; i < AMRWB_SUBFRAME_SIZE; i++) - hb_exc[i] = 32768.0 - (uint16_t) av_lfg_get(&ctx->prng) / 65536.0; + hb_exc[i] = 32768.0 - (uint16_t) av_lfg_get(&ctx->prng); ff_scale_vector_to_given_sum_of_squares(hb_exc, hb_exc, energy, AMRWB_SUBFRAME_SIZE); @@ -1042,6 +1042,9 @@ static void scaled_hb_excitation(AMRWBContext *ctx, float *hb_exc, hb_exc[i] *= hb_gain; } +/** + * Calculate auto-correlation for the ISF difference vector + */ static float auto_correlation(float *diff_isf, float mean, int lag) { int i; @@ -1054,10 +1057,19 @@ static float auto_correlation(float *diff_isf, float mean, int lag) return sum; } +/** + * Extrapolate a ISF vector to the 16kHz range (20th order LP) + * used at mode 6k60 LP filter for the high-freq band + * + * @param out [out] buffer for extrapolated isf + * @param isf [in] input isf vector + */ static void extrapolate_isf(float *out, float *isf) { float diff_isf[LP_ORDER - 2], diff_mean; + float *diff_hi = diff_isf - LP_ORDER + 1; // diff array for extrapolated indices float corr_lag[3]; + float est, scale; int i, i_max_corr; memcpy(out, isf, LP_ORDER - 1); @@ -1083,7 +1095,32 @@ static void extrapolate_isf(float *out, float *isf) for (i = LP_ORDER - 1; i < LP_ORDER_16k - 1; i++) out[i] = isf[i - 1] + isf[i - 1 - i_max_corr] - isf[i - 2 - i_max_corr]; - return; + + /* Calculate an estimate for ISF(18) and scale ISF based on the error */ + est = 79.65 + (out[2] - out[3] - out[4]) / 6.0; + scale = (FFMIN(est, 76.0) - out[LP_ORDER - 2]) / + (out[LP_ORDER_16k - 2] - out[LP_ORDER - 2]); + // XXX: should divide numerator by 2.0? + + for (i = LP_ORDER - 1; i < LP_ORDER_16k - 1; i++) + diff_hi[i] = scale * (out[i] - out[i - 1]); + + /* Stability insurance */ + for (i = LP_ORDER; i < LP_ORDER_16k - 1; i++) + if (diff_hi[i] + diff_hi[i - 1] < 5.0) { + if (diff_hi[i] > diff_hi[i - 1]) { + diff_hi[i - 1] = 5.0 - diff_hi[i]; + } else + diff_hi[i] = 5.0 - diff_hi[i - 1]; + } + + for (i = LP_ORDER - 1; i < LP_ORDER_16k - 1; i++) + out[i] = out[i - 1] + diff_hi[i]; + + /* XXX: Don't know why this 26214 coefficient, maybe it is not Q8 */ + /* Scale the ISF vector for 16000 Hz */ + for (i = 0; i < LP_ORDER_16k - 1; i++) + out[i] *= 26214 / (float) (1 << 8); } /** ----------------------------------------------------------------------- Summary of changes: libavcodec/amrwbdata.h | 4 +--- libavcodec/amrwbdec.c | 41 +++++++++++++++++++++++++++++++++++++++-- 2 files changed, 40 insertions(+), 5 deletions(-) hooks/post-receive -- AMR-WB decoder