/* * IMC compatible decoder * Copyright (c) 2002-2004 Maxim Poliakovski * Copyright (c) 2006 Benjamin Larsson * Copyright (c) 2006 Konstantin Shishkov * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file imc.c IMC - Intel Music Coder * A mdct based codec using a 256 points large transform * divied into 32 bands with some mix of scale factors. * Only mono is supported. * */ #include <math.h> #include <stddef.h> #include <stdio.h> #define ALT_BITSTREAM_READER #include "avcodec.h" #include "bitstream.h" #include "dsputil.h" #include "imcdata.h" #define IMC_BLOCK_SIZE 64 #define IMC_FRAME_ID 0x21 #define BANDS 32 #define COEFFS 256 typedef struct { float old_floor[BANDS]; float flcoeffs1[BANDS]; float flcoeffs2[BANDS]; float flcoeffs3[BANDS]; float flcoeffs4[BANDS]; float flcoeffs5[BANDS]; float flcoeffs6[BANDS]; float CWdecoded[COEFFS]; /** MDCT tables */ //@{ float mdct_sine_window[COEFFS]; float post_cos[COEFFS]; float post_sin[COEFFS]; float pre_coef1[COEFFS]; float pre_coef2[COEFFS]; float last_fft_im[COEFFS]; //@} int bandWidthT[BANDS]; ///< codewords per band int bitsBandT[BANDS]; ///< how many bits per codeword in band int CWlengthT[COEFFS]; ///< how many bits in each codeword int levlCoeffBuf[BANDS]; int bandFlagsBuf[BANDS]; ///< flags for each band int sumLenArr[BANDS]; ///< bits for all coeffs in band int skipFlagRaw[BANDS]; ///< skip flags are stored in raw form or not int skipFlagBits[BANDS]; ///< bits used to code skip flags int skipFlagCount[BANDS]; ///< skipped coeffients per band int skipFlags[COEFFS]; ///< skip coefficient decoding or not int codewords[COEFFS]; ///< raw codewords read from bitstream float sqrt_tab[30]; GetBitContext gb; VLC huffman_vlc[4][4]; int decoder_reset; float one_div_log2; DSPContext dsp; FFTContext fft; DECLARE_ALIGNED_16(FFTComplex, samples[COEFFS/2]); DECLARE_ALIGNED_16(float, out_samples[COEFFS]); } IMCContext; static av_cold int imc_decode_init(AVCodecContext * avctx) { int i, j; IMCContext *q = avctx->priv_data; double r1, r2; q->decoder_reset = 1; for(i = 0; i < BANDS; i++) q->old_floor[i] = 1.0; /* Build mdct window, a simple sine window normalized with sqrt(2) */ for(i = 0; i < COEFFS; i++) q->mdct_sine_window[i] = sin((i + 0.5) / 512.0 * M_PI) * sqrt(2.0); for(i = 0; i < COEFFS/2; i++){ q->post_cos[i] = cos(i / 256.0 * M_PI); q->post_sin[i] = sin(i / 256.0 * M_PI); r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI); r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI); if (i & 0x1) { q->pre_coef1[i] = (r1 + r2) * sqrt(2.0); q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0); } else { q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0); q->pre_coef2[i] = (r1 - r2) * sqrt(2.0); } q->last_fft_im[i] = 0; } /* Generate a square root table */ for(i = 0; i < 30; i++) { q->sqrt_tab[i] = sqrt(i); } /* initialize the VLC tables */ for(i = 0; i < 4 ; i++) { for(j = 0; j < 4; j++) { init_vlc (&q->huffman_vlc[i][j], 9, imc_huffman_sizes[i], imc_huffman_lens[i][j], 1, 1, imc_huffman_bits[i][j], 2, 2, 1); } } q->one_div_log2 = 1/log(2); ff_fft_init(&q->fft, 7, 1); dsputil_init(&q->dsp, avctx); return 0; } static void imc_calculate_coeffs(IMCContext* q, float* flcoeffs1, float* flcoeffs2, int* bandWidthT, float* flcoeffs3, float* flcoeffs5) { float workT1[BANDS]; float workT2[BANDS]; float workT3[BANDS]; float snr_limit = 1.e-30; float accum = 0.0; int i, cnt2; for(i = 0; i < BANDS; i++) { flcoeffs5[i] = workT2[i] = 0.0; if (bandWidthT[i]){ workT1[i] = flcoeffs1[i] * flcoeffs1[i]; flcoeffs3[i] = 2.0 * flcoeffs2[i]; } else { workT1[i] = 0.0; flcoeffs3[i] = -30000.0; } workT3[i] = bandWidthT[i] * workT1[i] * 0.01; if (workT3[i] <= snr_limit) workT3[i] = 0.0; } for(i = 0; i < BANDS; i++) { for(cnt2 = i; cnt2 < cyclTab[i]; cnt2++) flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i]; workT2[cnt2-1] = workT2[cnt2-1] + workT3[i]; } for(i = 1; i < BANDS; i++) { accum = (workT2[i-1] + accum) * imc_weights1[i-1]; flcoeffs5[i] += accum; } for(i = 0; i < BANDS; i++) workT2[i] = 0.0; for(i = 0; i < BANDS; i++) { for(cnt2 = i-1; cnt2 > cyclTab2[i]; cnt2--) flcoeffs5[cnt2] += workT3[i]; workT2[cnt2+1] += workT3[i]; } accum = 0.0; for(i = BANDS-2; i >= 0; i--) { accum = (workT2[i+1] + accum) * imc_weights2[i]; flcoeffs5[i] += accum; //there is missing code here, but it seems to never be triggered } } static void imc_read_level_coeffs(IMCContext* q, int stream_format_code, int* levlCoeffs) { int i; VLC *hufftab[4]; int start = 0; const uint8_t *cb_sel; int s; s = stream_format_code >> 1; hufftab[0] = &q->huffman_vlc[s][0]; hufftab[1] = &q->huffman_vlc[s][1]; hufftab[2] = &q->huffman_vlc[s][2]; hufftab[3] = &q->huffman_vlc[s][3]; cb_sel = imc_cb_select[s]; if(stream_format_code & 4) start = 1; if(start) levlCoeffs[0] = get_bits(&q->gb, 7); for(i = start; i < BANDS; i++){ levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table, hufftab[cb_sel[i]]->bits, 2); if(levlCoeffs[i] == 17) levlCoeffs[i] += get_bits(&q->gb, 4); } } static void imc_decode_level_coefficients(IMCContext* q, int* levlCoeffBuf, float* flcoeffs1, float* flcoeffs2) { int i, level; float tmp, tmp2; //maybe some frequency division thingy flcoeffs1[0] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125 flcoeffs2[0] = log(flcoeffs1[0])/log(2); tmp = flcoeffs1[0]; tmp2 = flcoeffs2[0]; for(i = 1; i < BANDS; i++) { level = levlCoeffBuf[i]; if (level == 16) { flcoeffs1[i] = 1.0; flcoeffs2[i] = 0.0; } else { if (level < 17) level -=7; else if (level <= 24) level -=32; else level -=16; tmp *= imc_exp_tab[15 + level]; tmp2 += 0.83048 * level; // 0.83048 = log2(10) * 0.25 flcoeffs1[i] = tmp; flcoeffs2[i] = tmp2; } } } static void imc_decode_level_coefficients2(IMCContext* q, int* levlCoeffBuf, float* old_floor, float* flcoeffs1, float* flcoeffs2) { int i; //FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors // and flcoeffs2 old scale factors // might be incomplete due to a missing table that is in the binary code for(i = 0; i < BANDS; i++) { flcoeffs1[i] = 0; if(levlCoeffBuf[i] < 16) { flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i]; flcoeffs2[i] = (levlCoeffBuf[i]-7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25 } else { flcoeffs1[i] = old_floor[i]; } } } /** * Perform bit allocation depending on bits available */ static int bit_allocation (IMCContext* q, int stream_format_code, int freebits, int flag) { int i, j; const float limit = -1.e20; float highest = 0.0; int indx; int t1 = 0; int t2 = 1; float summa = 0.0; int iacc = 0; int summer = 0; int rres, cwlen; float lowest = 1.e10; int low_indx = 0; float workT[32]; int flg; int found_indx = 0; for(i = 0; i < BANDS; i++) highest = FFMAX(highest, q->flcoeffs1[i]); for(i = 0; i < BANDS-1; i++) { q->flcoeffs4[i] = q->flcoeffs3[i] - log(q->flcoeffs5[i])/log(2); } q->flcoeffs4[BANDS - 1] = limit; highest = highest * 0.25; for(i = 0; i < BANDS; i++) { indx = -1; if ((band_tab[i+1] - band_tab[i]) == q->bandWidthT[i]) indx = 0; if ((band_tab[i+1] - band_tab[i]) > q->bandWidthT[i]) indx = 1; if (((band_tab[i+1] - band_tab[i])/2) >= q->bandWidthT[i]) indx = 2; if (indx == -1) return -1; q->flcoeffs4[i] = q->flcoeffs4[i] + xTab[(indx*2 + (q->flcoeffs1[i] < highest)) * 2 + flag]; } if (stream_format_code & 0x2) { q->flcoeffs4[0] = limit; q->flcoeffs4[1] = limit; q->flcoeffs4[2] = limit; q->flcoeffs4[3] = limit; } for(i = (stream_format_code & 0x2)?4:0; i < BANDS-1; i++) { iacc += q->bandWidthT[i]; summa += q->bandWidthT[i] * q->flcoeffs4[i]; } q->bandWidthT[BANDS-1] = 0; summa = (summa * 0.5 - freebits) / iacc; for(i = 0; i < BANDS/2; i++) { rres = summer - freebits; if((rres >= -8) && (rres <= 8)) break; summer = 0; iacc = 0; for(j = (stream_format_code & 0x2)?4:0; j < BANDS; j++) { cwlen = av_clip((int)((q->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6); q->bitsBandT[j] = cwlen; summer += q->bandWidthT[j] * cwlen; if (cwlen > 0) iacc += q->bandWidthT[j]; } flg = t2; t2 = 1; if (freebits < summer) t2 = -1; if (i == 0) flg = t2; if(flg != t2) t1++; summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa; } for(i = (stream_format_code & 0x2)?4:0; i < BANDS; i++) { for(j = band_tab[i]; j < band_tab[i+1]; j++) q->CWlengthT[j] = q->bitsBandT[i]; } if (freebits > summer) { for(i = 0; i < BANDS; i++) { workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415); } highest = 0.0; do{ if (highest <= -1.e20) break; found_indx = 0; highest = -1.e20; for(i = 0; i < BANDS; i++) { if (workT[i] > highest) { highest = workT[i]; found_indx = i; } } if (highest > -1.e20) { workT[found_indx] -= 2.0; if (++(q->bitsBandT[found_indx]) == 6) workT[found_indx] = -1.e20; for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (freebits > summer); j++){ q->CWlengthT[j]++; summer++; } } }while (freebits > summer); } if (freebits < summer) { for(i = 0; i < BANDS; i++) { workT[i] = q->bitsBandT[i] ? (q->bitsBandT[i] * -2 + q->flcoeffs4[i] + 1.585) : 1.e20; } if (stream_format_code & 0x2) { workT[0] = 1.e20; workT[1] = 1.e20; workT[2] = 1.e20; workT[3] = 1.e20; } while (freebits < summer){ lowest = 1.e10; low_indx = 0; for(i = 0; i < BANDS; i++) { if (workT[i] < lowest) { lowest = workT[i]; low_indx = i; } } //if(lowest >= 1.e10) break; workT[low_indx] = lowest + 2.0; if (!(--q->bitsBandT[low_indx])) workT[low_indx] = 1.e20; for(j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++){ if(q->CWlengthT[j] > 0){ q->CWlengthT[j]--; summer--; } } } } return 0; } static void imc_get_skip_coeff(IMCContext* q) { int i, j; memset(q->skipFlagBits, 0, sizeof(q->skipFlagBits)); memset(q->skipFlagCount, 0, sizeof(q->skipFlagCount)); for(i = 0; i < BANDS; i++) { if (!q->bandFlagsBuf[i] || !q->bandWidthT[i]) continue; if (!q->skipFlagRaw[i]) { q->skipFlagBits[i] = band_tab[i+1] - band_tab[i]; for(j = band_tab[i]; j < band_tab[i+1]; j++) { if ((q->skipFlags[j] = get_bits1(&q->gb))) q->skipFlagCount[i]++; } } else { for(j = band_tab[i]; j < (band_tab[i+1]-1); j += 2) { if(!get_bits1(&q->gb)){//0 q->skipFlagBits[i]++; q->skipFlags[j]=1; q->skipFlags[j+1]=1; q->skipFlagCount[i] += 2; }else{ if(get_bits1(&q->gb)){//11 q->skipFlagBits[i] +=2; q->skipFlags[j]=0; q->skipFlags[j+1]=1; q->skipFlagCount[i]++; }else{ q->skipFlagBits[i] +=3; q->skipFlags[j+1]=0; if(!get_bits1(&q->gb)){//100 q->skipFlags[j]=1; q->skipFlagCount[i]++; }else{//101 q->skipFlags[j]=0; } } } } if (j < band_tab[i+1]) { q->skipFlagBits[i]++; if ((q->skipFlags[j] = get_bits1(&q->gb))) q->skipFlagCount[i]++; } } } } /** * Increase highest' band coefficient sizes as some bits won't be used */ static void imc_adjust_bit_allocation (IMCContext* q, int summer) { float workT[32]; int corrected = 0; int i, j; float highest = 0; int found_indx=0; for(i = 0; i < BANDS; i++) { workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415); } while (corrected < summer) { if(highest <= -1.e20) break; highest = -1.e20; for(i = 0; i < BANDS; i++) { if (workT[i] > highest) { highest = workT[i]; found_indx = i; } } if (highest > -1.e20) { workT[found_indx] -= 2.0; if (++(q->bitsBandT[found_indx]) == 6) workT[found_indx] = -1.e20; for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) { if (!q->skipFlags[j] && (q->CWlengthT[j] < 6)) { q->CWlengthT[j]++; corrected++; } } } } } static void imc_imdct256(IMCContext *q) { int i; float re, im; /* prerotation */ for(i=0; i < COEFFS/2; i++){ q->samples[i].re = -(q->pre_coef1[i] * q->CWdecoded[COEFFS-1-i*2]) - (q->pre_coef2[i] * q->CWdecoded[i*2]); q->samples[i].im = (q->pre_coef2[i] * q->CWdecoded[COEFFS-1-i*2]) - (q->pre_coef1[i] * q->CWdecoded[i*2]); } /* FFT */ ff_fft_permute(&q->fft, q->samples); ff_fft_calc (&q->fft, q->samples); /* postrotation, window and reorder */ for(i = 0; i < COEFFS/2; i++){ re = (q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]); im = (-q->samples[i].im * q->post_cos[i]) - (q->samples[i].re * q->post_sin[i]); q->out_samples[i*2] = (q->mdct_sine_window[COEFFS-1-i*2] * q->last_fft_im[i]) + (q->mdct_sine_window[i*2] * re); q->out_samples[COEFFS-1-i*2] = (q->mdct_sine_window[i*2] * q->last_fft_im[i]) - (q->mdct_sine_window[COEFFS-1-i*2] * re); q->last_fft_im[i] = im; } } static int inverse_quant_coeff (IMCContext* q, int stream_format_code) { int i, j; int middle_value, cw_len, max_size; const float* quantizer; for(i = 0; i < BANDS; i++) { for(j = band_tab[i]; j < band_tab[i+1]; j++) { q->CWdecoded[j] = 0; cw_len = q->CWlengthT[j]; if (cw_len <= 0 || q->skipFlags[j]) continue; max_size = 1 << cw_len; middle_value = max_size >> 1; if (q->codewords[j] >= max_size || q->codewords[j] < 0) return -1; if (cw_len >= 4){ quantizer = imc_quantizer2[(stream_format_code & 2) >> 1]; if (q->codewords[j] >= middle_value) q->CWdecoded[j] = quantizer[q->codewords[j] - 8] * q->flcoeffs6[i]; else q->CWdecoded[j] = -quantizer[max_size - q->codewords[j] - 8 - 1] * q->flcoeffs6[i]; }else{ quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (q->bandFlagsBuf[i] << 1)]; if (q->codewords[j] >= middle_value) q->CWdecoded[j] = quantizer[q->codewords[j] - 1] * q->flcoeffs6[i]; else q->CWdecoded[j] = -quantizer[max_size - 2 - q->codewords[j]] * q->flcoeffs6[i]; } } } return 0; } static int imc_get_coeffs (IMCContext* q) { int i, j, cw_len, cw; for(i = 0; i < BANDS; i++) { if(!q->sumLenArr[i]) continue; if (q->bandFlagsBuf[i] || q->bandWidthT[i]) { for(j = band_tab[i]; j < band_tab[i+1]; j++) { cw_len = q->CWlengthT[j]; cw = 0; if (get_bits_count(&q->gb) + cw_len > 512){ //av_log(NULL,0,"Band %i coeff %i cw_len %i\n",i,j,cw_len); return -1; } if(cw_len && (!q->bandFlagsBuf[i] || !q->skipFlags[j])) cw = get_bits(&q->gb, cw_len); q->codewords[j] = cw; } } } return 0; } static int imc_decode_frame(AVCodecContext * avctx, void *data, int *data_size, const uint8_t * buf, int buf_size) { IMCContext *q = avctx->priv_data; int stream_format_code; int imc_hdr, i, j; int flag; int bits, summer; int counter, bitscount; uint16_t buf16[IMC_BLOCK_SIZE / 2]; if (buf_size < IMC_BLOCK_SIZE) { av_log(avctx, AV_LOG_ERROR, "imc frame too small!\n"); return -1; } for(i = 0; i < IMC_BLOCK_SIZE / 2; i++) buf16[i] = bswap_16(((const uint16_t*)buf)[i]); init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8); /* Check the frame header */ imc_hdr = get_bits(&q->gb, 9); if (imc_hdr != IMC_FRAME_ID) { av_log(avctx, AV_LOG_ERROR, "imc frame header check failed!\n"); av_log(avctx, AV_LOG_ERROR, "got %x instead of 0x21.\n", imc_hdr); return -1; } stream_format_code = get_bits(&q->gb, 3); if(stream_format_code & 1){ av_log(avctx, AV_LOG_ERROR, "Stream code format %X is not supported\n", stream_format_code); return -1; } // av_log(avctx, AV_LOG_DEBUG, "stream_format_code = %d\n", stream_format_code); if (stream_format_code & 0x04) q->decoder_reset = 1; if(q->decoder_reset) { memset(q->out_samples, 0, sizeof(q->out_samples)); for(i = 0; i < BANDS; i++)q->old_floor[i] = 1.0; for(i = 0; i < COEFFS; i++)q->CWdecoded[i] = 0; q->decoder_reset = 0; } flag = get_bits1(&q->gb); imc_read_level_coeffs(q, stream_format_code, q->levlCoeffBuf); if (stream_format_code & 0x4) imc_decode_level_coefficients(q, q->levlCoeffBuf, q->flcoeffs1, q->flcoeffs2); else imc_decode_level_coefficients2(q, q->levlCoeffBuf, q->old_floor, q->flcoeffs1, q->flcoeffs2); memcpy(q->old_floor, q->flcoeffs1, 32 * sizeof(float)); counter = 0; for (i=0 ; i<BANDS ; i++) { if (q->levlCoeffBuf[i] == 16) { q->bandWidthT[i] = 0; counter++; } else q->bandWidthT[i] = band_tab[i+1] - band_tab[i]; } memset(q->bandFlagsBuf, 0, BANDS * sizeof(int)); for(i = 0; i < BANDS-1; i++) { if (q->bandWidthT[i]) q->bandFlagsBuf[i] = get_bits1(&q->gb); } imc_calculate_coeffs(q, q->flcoeffs1, q->flcoeffs2, q->bandWidthT, q->flcoeffs3, q->flcoeffs5); bitscount = 0; /* first 4 bands will be assigned 5 bits per coefficient */ if (stream_format_code & 0x2) { bitscount += 15; q->bitsBandT[0] = 5; q->CWlengthT[0] = 5; q->CWlengthT[1] = 5; q->CWlengthT[2] = 5; for(i = 1; i < 4; i++){ bits = (q->levlCoeffBuf[i] == 16) ? 0 : 5; q->bitsBandT[i] = bits; for(j = band_tab[i]; j < band_tab[i+1]; j++) { q->CWlengthT[j] = bits; bitscount += bits; } } } if(bit_allocation (q, stream_format_code, 512 - bitscount - get_bits_count(&q->gb), flag) < 0) { av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n"); q->decoder_reset = 1; return -1; } for(i = 0; i < BANDS; i++) { q->sumLenArr[i] = 0; q->skipFlagRaw[i] = 0; for(j = band_tab[i]; j < band_tab[i+1]; j++) q->sumLenArr[i] += q->CWlengthT[j]; if (q->bandFlagsBuf[i]) if( (((band_tab[i+1] - band_tab[i]) * 1.5) > q->sumLenArr[i]) && (q->sumLenArr[i] > 0)) q->skipFlagRaw[i] = 1; } imc_get_skip_coeff(q); for(i = 0; i < BANDS; i++) { q->flcoeffs6[i] = q->flcoeffs1[i]; /* band has flag set and at least one coded coefficient */ if (q->bandFlagsBuf[i] && (band_tab[i+1] - band_tab[i]) != q->skipFlagCount[i]){ q->flcoeffs6[i] *= q->sqrt_tab[band_tab[i+1] - band_tab[i]] / q->sqrt_tab[(band_tab[i+1] - band_tab[i] - q->skipFlagCount[i])]; } } /* calculate bits left, bits needed and adjust bit allocation */ bits = summer = 0; for(i = 0; i < BANDS; i++) { if (q->bandFlagsBuf[i]) { for(j = band_tab[i]; j < band_tab[i+1]; j++) { if(q->skipFlags[j]) { summer += q->CWlengthT[j]; q->CWlengthT[j] = 0; } } bits += q->skipFlagBits[i]; summer -= q->skipFlagBits[i]; } } imc_adjust_bit_allocation(q, summer); for(i = 0; i < BANDS; i++) { q->sumLenArr[i] = 0; for(j = band_tab[i]; j < band_tab[i+1]; j++) if (!q->skipFlags[j]) q->sumLenArr[i] += q->CWlengthT[j]; } memset(q->codewords, 0, sizeof(q->codewords)); if(imc_get_coeffs(q) < 0) { av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n"); q->decoder_reset = 1; return 0; } if(inverse_quant_coeff(q, stream_format_code) < 0) { av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n"); q->decoder_reset = 1; return 0; } memset(q->skipFlags, 0, sizeof(q->skipFlags)); imc_imdct256(q); q->dsp.float_to_int16(data, q->out_samples, COEFFS); *data_size = COEFFS * sizeof(int16_t); return IMC_BLOCK_SIZE; } static av_cold int imc_decode_close(AVCodecContext * avctx) { IMCContext *q = avctx->priv_data; ff_fft_end(&q->fft); return 0; } AVCodec imc_decoder = { .name = "imc", .type = CODEC_TYPE_AUDIO, .id = CODEC_ID_IMC, .priv_data_size = sizeof(IMCContext), .init = imc_decode_init, .close = imc_decode_close, .decode = imc_decode_frame, };