static int ra144_encode_frame(AVCodecContext *avctx, uint8_t *frame, int buf_size, void *data) { static const uint8_t sizes[LPC_ORDER] = {64, 32, 32, 16, 16, 8, 8, 8, 8, 4}; static const uint8_t bit_sizes[LPC_ORDER] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2}; RA144Context *ractx; PutBitContext pb; int32_t lpc_data[NBLOCKS * BLOCKSIZE]; int32_t lpc_coefs[LPC_ORDER][MAX_LPC_ORDER]; int shift[LPC_ORDER]; int16_t block_coefs[NBLOCKS][LPC_ORDER]; int lpc_refl[LPC_ORDER]; /**< reflection coefficients of the frame */ unsigned int refl_rms[NBLOCKS]; /**< RMS of the reflection coefficients */ int energy = 0; int i, idx; if (buf_size < FRAMESIZE) { av_log(avctx, AV_LOG_ERROR, "output buffer too small\n"); return 0; } ractx = avctx->priv_data; /** * Since the LPC coefficients are calculated on a frame centered over the * fourth subframe, to encode a given frame, data from the next frame is * needed. In each call to this function, the previous frame (whose data are * saved in the encoder context) is encoded, and data from the current frame * are saved in the encoder context to be used in the next function call. */ for (i = 0; i < (2 * BLOCKSIZE + BLOCKSIZE / 2); i++) { lpc_data[i] = ractx->curr_block[BLOCKSIZE + BLOCKSIZE / 2 + i]; energy += (lpc_data[i] * lpc_data[i]) >> 4; } for (i = 2 * BLOCKSIZE + BLOCKSIZE / 2; i < NBLOCKS * BLOCKSIZE; i++) { lpc_data[i] = *((int16_t *)data + i - 2 * BLOCKSIZE - BLOCKSIZE / 2) >> 2; energy += (lpc_data[i] * lpc_data[i]) >> 4; } energy = ff_energy_tab[quantize(ff_t_sqrt(energy >> 5) >> 10, ff_energy_tab, 32)]; ff_lpc_calc_coefs(&ractx->lpc_ctx, lpc_data, NBLOCKS * BLOCKSIZE, LPC_ORDER, LPC_ORDER, 16, lpc_coefs, shift, FF_LPC_TYPE_LEVINSON, 0, ORDER_METHOD_EST, 12, 0); for (i = 0; i < LPC_ORDER; i++) block_coefs[NBLOCKS - 1][i] = -(lpc_coefs[LPC_ORDER - 1][i] << (12 - shift[LPC_ORDER - 1])); /** * TODO: apply perceptual weighting of the input speech through bandwidth * expansion of the LPC filter. */ if (ff_eval_refl(lpc_refl, block_coefs[NBLOCKS - 1], avctx)) { /** * The filter is unstable: use the coefficients of the previous frame. */ ff_int_to_int16(block_coefs[NBLOCKS - 1], ractx->lpc_coef[1]); ff_eval_refl(lpc_refl, block_coefs[NBLOCKS - 1], avctx); } init_put_bits(&pb, frame, buf_size); for (i = 0; i < LPC_ORDER; i++) { idx = quantize(lpc_refl[i], ff_lpc_refl_cb[i], sizes[i]); put_bits(&pb, bit_sizes[i], idx); lpc_refl[i] = ff_lpc_refl_cb[i][idx]; } ractx->lpc_refl_rms[0] = ff_rms(lpc_refl); ff_eval_coefs(ractx->lpc_coef[0], lpc_refl); refl_rms[0] = ff_interp(ractx, block_coefs[0], 1, 1, ractx->old_energy); refl_rms[1] = ff_interp(ractx, block_coefs[1], 2, energy <= ractx->old_energy, ff_t_sqrt(energy * ractx->old_energy) >> 12); refl_rms[2] = ff_interp(ractx, block_coefs[2], 3, 0, energy); refl_rms[3] = ff_rescale_rms(ractx->lpc_refl_rms[0], energy); ff_int_to_int16(block_coefs[NBLOCKS - 1], ractx->lpc_coef[0]); put_bits(&pb, 5, quantize(energy, ff_energy_tab, 32)); for (i = 0; i < NBLOCKS; i++) ra144_encode_subblock(ractx, ractx->curr_block + i * BLOCKSIZE, block_coefs[i], refl_rms[i], &pb); flush_put_bits(&pb); ractx->old_energy = energy; ractx->lpc_refl_rms[1] = ractx->lpc_refl_rms[0]; FFSWAP(unsigned int *, ractx->lpc_coef[0], ractx->lpc_coef[1]); for (i = 0; i < NBLOCKS * BLOCKSIZE; i++) ractx->curr_block[i] = *((int16_t *)data + i) >> 2; return FRAMESIZE; }