Libav 0.7.1
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00001 /* 00002 * Bink Audio decoder 00003 * Copyright (c) 2007-2011 Peter Ross (pross@xvid.org) 00004 * Copyright (c) 2009 Daniel Verkamp (daniel@drv.nu) 00005 * 00006 * This file is part of Libav. 00007 * 00008 * Libav is free software; you can redistribute it and/or 00009 * modify it under the terms of the GNU Lesser General Public 00010 * License as published by the Free Software Foundation; either 00011 * version 2.1 of the License, or (at your option) any later version. 00012 * 00013 * Libav is distributed in the hope that it will be useful, 00014 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00016 * Lesser General Public License for more details. 00017 * 00018 * You should have received a copy of the GNU Lesser General Public 00019 * License along with Libav; if not, write to the Free Software 00020 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00021 */ 00022 00031 #include "avcodec.h" 00032 #define ALT_BITSTREAM_READER_LE 00033 #include "get_bits.h" 00034 #include "dsputil.h" 00035 #include "dct.h" 00036 #include "rdft.h" 00037 #include "fmtconvert.h" 00038 #include "libavutil/intfloat_readwrite.h" 00039 00040 extern const uint16_t ff_wma_critical_freqs[25]; 00041 00042 #define MAX_CHANNELS 2 00043 #define BINK_BLOCK_MAX_SIZE (MAX_CHANNELS << 11) 00044 00045 typedef struct { 00046 GetBitContext gb; 00047 DSPContext dsp; 00048 FmtConvertContext fmt_conv; 00049 int version_b; 00050 int first; 00051 int channels; 00052 int frame_len; 00053 int overlap_len; 00054 int block_size; 00055 int num_bands; 00056 unsigned int *bands; 00057 float root; 00058 DECLARE_ALIGNED(32, FFTSample, coeffs)[BINK_BLOCK_MAX_SIZE]; 00059 DECLARE_ALIGNED(16, short, previous)[BINK_BLOCK_MAX_SIZE / 16]; 00060 float *coeffs_ptr[MAX_CHANNELS]; 00061 union { 00062 RDFTContext rdft; 00063 DCTContext dct; 00064 } trans; 00065 } BinkAudioContext; 00066 00067 00068 static av_cold int decode_init(AVCodecContext *avctx) 00069 { 00070 BinkAudioContext *s = avctx->priv_data; 00071 int sample_rate = avctx->sample_rate; 00072 int sample_rate_half; 00073 int i; 00074 int frame_len_bits; 00075 00076 dsputil_init(&s->dsp, avctx); 00077 ff_fmt_convert_init(&s->fmt_conv, avctx); 00078 00079 /* determine frame length */ 00080 if (avctx->sample_rate < 22050) { 00081 frame_len_bits = 9; 00082 } else if (avctx->sample_rate < 44100) { 00083 frame_len_bits = 10; 00084 } else { 00085 frame_len_bits = 11; 00086 } 00087 00088 if (avctx->channels > MAX_CHANNELS) { 00089 av_log(avctx, AV_LOG_ERROR, "too many channels: %d\n", avctx->channels); 00090 return -1; 00091 } 00092 00093 s->version_b = avctx->codec_tag == MKTAG('B','I','K','b'); 00094 00095 if (avctx->codec->id == CODEC_ID_BINKAUDIO_RDFT) { 00096 // audio is already interleaved for the RDFT format variant 00097 sample_rate *= avctx->channels; 00098 s->channels = 1; 00099 if (!s->version_b) 00100 frame_len_bits += av_log2(avctx->channels); 00101 } else { 00102 s->channels = avctx->channels; 00103 } 00104 00105 s->frame_len = 1 << frame_len_bits; 00106 s->overlap_len = s->frame_len / 16; 00107 s->block_size = (s->frame_len - s->overlap_len) * s->channels; 00108 sample_rate_half = (sample_rate + 1) / 2; 00109 s->root = 2.0 / sqrt(s->frame_len); 00110 00111 /* calculate number of bands */ 00112 for (s->num_bands = 1; s->num_bands < 25; s->num_bands++) 00113 if (sample_rate_half <= ff_wma_critical_freqs[s->num_bands - 1]) 00114 break; 00115 00116 s->bands = av_malloc((s->num_bands + 1) * sizeof(*s->bands)); 00117 if (!s->bands) 00118 return AVERROR(ENOMEM); 00119 00120 /* populate bands data */ 00121 s->bands[0] = 2; 00122 for (i = 1; i < s->num_bands; i++) 00123 s->bands[i] = (ff_wma_critical_freqs[i - 1] * s->frame_len / sample_rate_half) & ~1; 00124 s->bands[s->num_bands] = s->frame_len; 00125 00126 s->first = 1; 00127 avctx->sample_fmt = AV_SAMPLE_FMT_S16; 00128 00129 for (i = 0; i < s->channels; i++) 00130 s->coeffs_ptr[i] = s->coeffs + i * s->frame_len; 00131 00132 if (CONFIG_BINKAUDIO_RDFT_DECODER && avctx->codec->id == CODEC_ID_BINKAUDIO_RDFT) 00133 ff_rdft_init(&s->trans.rdft, frame_len_bits, DFT_C2R); 00134 else if (CONFIG_BINKAUDIO_DCT_DECODER) 00135 ff_dct_init(&s->trans.dct, frame_len_bits, DCT_III); 00136 else 00137 return -1; 00138 00139 return 0; 00140 } 00141 00142 static float get_float(GetBitContext *gb) 00143 { 00144 int power = get_bits(gb, 5); 00145 float f = ldexpf(get_bits_long(gb, 23), power - 23); 00146 if (get_bits1(gb)) 00147 f = -f; 00148 return f; 00149 } 00150 00151 static const uint8_t rle_length_tab[16] = { 00152 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 32, 64 00153 }; 00154 00159 static void decode_block(BinkAudioContext *s, short *out, int use_dct) 00160 { 00161 int ch, i, j, k; 00162 float q, quant[25]; 00163 int width, coeff; 00164 GetBitContext *gb = &s->gb; 00165 00166 if (use_dct) 00167 skip_bits(gb, 2); 00168 00169 for (ch = 0; ch < s->channels; ch++) { 00170 FFTSample *coeffs = s->coeffs_ptr[ch]; 00171 if (s->version_b) { 00172 coeffs[0] = av_int2flt(get_bits(gb, 32)) * s->root; 00173 coeffs[1] = av_int2flt(get_bits(gb, 32)) * s->root; 00174 } else { 00175 coeffs[0] = get_float(gb) * s->root; 00176 coeffs[1] = get_float(gb) * s->root; 00177 } 00178 00179 for (i = 0; i < s->num_bands; i++) { 00180 /* constant is result of 0.066399999/log10(M_E) */ 00181 int value = get_bits(gb, 8); 00182 quant[i] = expf(FFMIN(value, 95) * 0.15289164787221953823f) * s->root; 00183 } 00184 00185 k = 0; 00186 q = quant[0]; 00187 00188 // parse coefficients 00189 i = 2; 00190 while (i < s->frame_len) { 00191 if (s->version_b) { 00192 j = i + 16; 00193 } else if (get_bits1(gb)) { 00194 j = i + rle_length_tab[get_bits(gb, 4)] * 8; 00195 } else { 00196 j = i + 8; 00197 } 00198 00199 j = FFMIN(j, s->frame_len); 00200 00201 width = get_bits(gb, 4); 00202 if (width == 0) { 00203 memset(coeffs + i, 0, (j - i) * sizeof(*coeffs)); 00204 i = j; 00205 while (s->bands[k] < i) 00206 q = quant[k++]; 00207 } else { 00208 while (i < j) { 00209 if (s->bands[k] == i) 00210 q = quant[k++]; 00211 coeff = get_bits(gb, width); 00212 if (coeff) { 00213 if (get_bits1(gb)) 00214 coeffs[i] = -q * coeff; 00215 else 00216 coeffs[i] = q * coeff; 00217 } else { 00218 coeffs[i] = 0.0f; 00219 } 00220 i++; 00221 } 00222 } 00223 } 00224 00225 if (CONFIG_BINKAUDIO_DCT_DECODER && use_dct) { 00226 coeffs[0] /= 0.5; 00227 s->trans.dct.dct_calc(&s->trans.dct, coeffs); 00228 s->dsp.vector_fmul_scalar(coeffs, coeffs, s->frame_len / 2, s->frame_len); 00229 } 00230 else if (CONFIG_BINKAUDIO_RDFT_DECODER) 00231 s->trans.rdft.rdft_calc(&s->trans.rdft, coeffs); 00232 } 00233 00234 s->fmt_conv.float_to_int16_interleave(out, (const float **)s->coeffs_ptr, 00235 s->frame_len, s->channels); 00236 00237 if (!s->first) { 00238 int count = s->overlap_len * s->channels; 00239 int shift = av_log2(count); 00240 for (i = 0; i < count; i++) { 00241 out[i] = (s->previous[i] * (count - i) + out[i] * i) >> shift; 00242 } 00243 } 00244 00245 memcpy(s->previous, out + s->block_size, 00246 s->overlap_len * s->channels * sizeof(*out)); 00247 00248 s->first = 0; 00249 } 00250 00251 static av_cold int decode_end(AVCodecContext *avctx) 00252 { 00253 BinkAudioContext * s = avctx->priv_data; 00254 av_freep(&s->bands); 00255 if (CONFIG_BINKAUDIO_RDFT_DECODER && avctx->codec->id == CODEC_ID_BINKAUDIO_RDFT) 00256 ff_rdft_end(&s->trans.rdft); 00257 else if (CONFIG_BINKAUDIO_DCT_DECODER) 00258 ff_dct_end(&s->trans.dct); 00259 return 0; 00260 } 00261 00262 static void get_bits_align32(GetBitContext *s) 00263 { 00264 int n = (-get_bits_count(s)) & 31; 00265 if (n) skip_bits(s, n); 00266 } 00267 00268 static int decode_frame(AVCodecContext *avctx, 00269 void *data, int *data_size, 00270 AVPacket *avpkt) 00271 { 00272 BinkAudioContext *s = avctx->priv_data; 00273 const uint8_t *buf = avpkt->data; 00274 int buf_size = avpkt->size; 00275 short *samples = data; 00276 short *samples_end = (short*)((uint8_t*)data + *data_size); 00277 int reported_size; 00278 GetBitContext *gb = &s->gb; 00279 00280 init_get_bits(gb, buf, buf_size * 8); 00281 00282 reported_size = get_bits_long(gb, 32); 00283 while (get_bits_count(gb) / 8 < buf_size && 00284 samples + s->block_size <= samples_end) { 00285 decode_block(s, samples, avctx->codec->id == CODEC_ID_BINKAUDIO_DCT); 00286 samples += s->block_size; 00287 get_bits_align32(gb); 00288 } 00289 00290 *data_size = FFMIN(reported_size, (uint8_t*)samples - (uint8_t*)data); 00291 return buf_size; 00292 } 00293 00294 AVCodec ff_binkaudio_rdft_decoder = { 00295 "binkaudio_rdft", 00296 AVMEDIA_TYPE_AUDIO, 00297 CODEC_ID_BINKAUDIO_RDFT, 00298 sizeof(BinkAudioContext), 00299 decode_init, 00300 NULL, 00301 decode_end, 00302 decode_frame, 00303 .long_name = NULL_IF_CONFIG_SMALL("Bink Audio (RDFT)") 00304 }; 00305 00306 AVCodec ff_binkaudio_dct_decoder = { 00307 "binkaudio_dct", 00308 AVMEDIA_TYPE_AUDIO, 00309 CODEC_ID_BINKAUDIO_DCT, 00310 sizeof(BinkAudioContext), 00311 decode_init, 00312 NULL, 00313 decode_end, 00314 decode_frame, 00315 .long_name = NULL_IF_CONFIG_SMALL("Bink Audio (DCT)") 00316 };