static int ra144_decode_frame(AVCodecContext * avctx, void *vdata, int *data_size, const uint8_t *buf, int buf_size) { static const uint8_t sizes[10] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2}; unsigned int refl_rms[4]; // RMS of the reflection coefficients uint16_t block_coefs[4][30]; // LPC coefficients of each sub-block unsigned int lpc_refl[10]; // LPC reflection coefficients of the frame int i, c; int16_t *data = vdata; unsigned int energy; RA144Context *ractx = avctx->priv_data; GetBitContext gb; if(buf_size < 20) { av_log(avctx, AV_LOG_ERROR, "Frame too small (%d bytes). Truncated file?\n", buf_size); *data_size = 0; return buf_size; } init_get_bits(&gb, buf, 20 * 8); for (i=0; i<10; i++) lpc_refl[i] = lpc_refl_cb[i][get_bits(&gb, sizes[i])]; eval_coefs(ractx->lpc_coef[0], lpc_refl); ractx->lpc_refl_rms[0] = rms(lpc_refl); energy = energy_tab[get_bits(&gb, 5)]; refl_rms[0] = interp(ractx, block_coefs[0], 0, 1, ractx->old_energy); refl_rms[1] = interp(ractx, block_coefs[1], 1, energy <= ractx->old_energy, t_sqrt(energy*ractx->old_energy) >> 12); refl_rms[2] = interp(ractx, block_coefs[2], 2, 0, energy); refl_rms[3] = rescale_rms(ractx->lpc_refl_rms[0], energy); int_to_int16(block_coefs[3], ractx->lpc_coef[0]); for (c=0; c<4; c++) { do_output_subblock(ractx, block_coefs[c], refl_rms[c], &gb); for (i=0; i<BLOCKSIZE; i++) *data++ = av_clip_int16(ractx->curr_sblock[i + 10] << 2); } 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]); *data_size = 2*160; return 20; }