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libavcodec/binkaudio.c

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00001 /*
00002  * Bink Audio decoder
00003  * Copyright (c) 2007-2010 Peter Ross (pross@xvid.org)
00004  * Copyright (c) 2009 Daniel Verkamp (daniel@drv.nu)
00005  *
00006  * This file is part of FFmpeg.
00007  *
00008  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 "fft.h"
00036 
00037 extern const uint16_t ff_wma_critical_freqs[25];
00038 
00039 #define MAX_CHANNELS 2
00040 #define BINK_BLOCK_MAX_SIZE (MAX_CHANNELS << 11)
00041 
00042 typedef struct {
00043     AVCodecContext *avctx;
00044     GetBitContext gb;
00045     DSPContext dsp;
00046     int first;
00047     int channels;
00048     int frame_len;          
00049     int overlap_len;        
00050     int block_size;
00051     int num_bands;
00052     unsigned int *bands;
00053     float root;
00054     DECLARE_ALIGNED(16, FFTSample, coeffs)[BINK_BLOCK_MAX_SIZE];
00055     DECLARE_ALIGNED(16, short, previous)[BINK_BLOCK_MAX_SIZE / 16];  
00056     float *coeffs_ptr[MAX_CHANNELS]; 
00057     union {
00058         RDFTContext rdft;
00059         DCTContext dct;
00060     } trans;
00061 } BinkAudioContext;
00062 
00063 
00064 static av_cold int decode_init(AVCodecContext *avctx)
00065 {
00066     BinkAudioContext *s = avctx->priv_data;
00067     int sample_rate = avctx->sample_rate;
00068     int sample_rate_half;
00069     int i;
00070     int frame_len_bits;
00071 
00072     s->avctx = avctx;
00073     dsputil_init(&s->dsp, avctx);
00074 
00075     /* determine frame length */
00076     if (avctx->sample_rate < 22050) {
00077         frame_len_bits = 9;
00078     } else if (avctx->sample_rate < 44100) {
00079         frame_len_bits = 10;
00080     } else {
00081         frame_len_bits = 11;
00082     }
00083     s->frame_len = 1 << frame_len_bits;
00084 
00085     if (s->channels > MAX_CHANNELS) {
00086         av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels);
00087         return -1;
00088     }
00089 
00090     if (avctx->codec->id == CODEC_ID_BINKAUDIO_RDFT) {
00091         // audio is already interleaved for the RDFT format variant
00092         sample_rate  *= avctx->channels;
00093         s->frame_len *= avctx->channels;
00094         s->channels = 1;
00095         if (avctx->channels == 2)
00096             frame_len_bits++;
00097     } else {
00098         s->channels = avctx->channels;
00099     }
00100 
00101     s->overlap_len   = s->frame_len / 16;
00102     s->block_size    = (s->frame_len - s->overlap_len) * s->channels;
00103     sample_rate_half = (sample_rate + 1) / 2;
00104     s->root          = 2.0 / sqrt(s->frame_len);
00105 
00106     /* calculate number of bands */
00107     for (s->num_bands = 1; s->num_bands < 25; s->num_bands++)
00108         if (sample_rate_half <= ff_wma_critical_freqs[s->num_bands - 1])
00109             break;
00110 
00111     s->bands = av_malloc((s->num_bands + 1) * sizeof(*s->bands));
00112     if (!s->bands)
00113         return AVERROR(ENOMEM);
00114 
00115     /* populate bands data */
00116     s->bands[0] = 1;
00117     for (i = 1; i < s->num_bands; i++)
00118         s->bands[i] = ff_wma_critical_freqs[i - 1] * (s->frame_len / 2) / sample_rate_half;
00119     s->bands[s->num_bands] = s->frame_len / 2;
00120 
00121     s->first = 1;
00122     avctx->sample_fmt = SAMPLE_FMT_S16;
00123 
00124     for (i = 0; i < s->channels; i++)
00125         s->coeffs_ptr[i] = s->coeffs + i * s->frame_len;
00126 
00127     if (CONFIG_BINKAUDIO_RDFT_DECODER && avctx->codec->id == CODEC_ID_BINKAUDIO_RDFT)
00128         ff_rdft_init(&s->trans.rdft, frame_len_bits, DFT_C2R);
00129     else if (CONFIG_BINKAUDIO_DCT_DECODER)
00130         ff_dct_init(&s->trans.dct, frame_len_bits, DCT_III);
00131     else
00132         return -1;
00133 
00134     return 0;
00135 }
00136 
00137 static float get_float(GetBitContext *gb)
00138 {
00139     int power = get_bits(gb, 5);
00140     float f = ldexpf(get_bits_long(gb, 23), power - 23);
00141     if (get_bits1(gb))
00142         f = -f;
00143     return f;
00144 }
00145 
00146 static const uint8_t rle_length_tab[16] = {
00147     2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 32, 64
00148 };
00149 
00154 static void decode_block(BinkAudioContext *s, short *out, int use_dct)
00155 {
00156     int ch, i, j, k;
00157     float q, quant[25];
00158     int width, coeff;
00159     GetBitContext *gb = &s->gb;
00160 
00161     if (use_dct)
00162         skip_bits(gb, 2);
00163 
00164     for (ch = 0; ch < s->channels; ch++) {
00165         FFTSample *coeffs = s->coeffs_ptr[ch];
00166         q = 0.0f;
00167         coeffs[0] = get_float(gb) * s->root;
00168         coeffs[1] = get_float(gb) * s->root;
00169 
00170         for (i = 0; i < s->num_bands; i++) {
00171             /* constant is result of 0.066399999/log10(M_E) */
00172             int value = get_bits(gb, 8);
00173             quant[i] = expf(FFMIN(value, 95) * 0.15289164787221953823f) * s->root;
00174         }
00175 
00176         // find band (k)
00177         for (k = 0; s->bands[k] < 1; k++) {
00178             q = quant[k];
00179         }
00180 
00181         // parse coefficients
00182         i = 2;
00183         while (i < s->frame_len) {
00184             if (get_bits1(gb)) {
00185                 j = i + rle_length_tab[get_bits(gb, 4)] * 8;
00186             } else {
00187                 j = i + 8;
00188             }
00189 
00190             j = FFMIN(j, s->frame_len);
00191 
00192             width = get_bits(gb, 4);
00193             if (width == 0) {
00194                 memset(coeffs + i, 0, (j - i) * sizeof(*coeffs));
00195                 i = j;
00196                 while (s->bands[k] * 2 < i)
00197                     q = quant[k++];
00198             } else {
00199                 while (i < j) {
00200                     if (s->bands[k] * 2 == i)
00201                         q = quant[k++];
00202                     coeff = get_bits(gb, width);
00203                     if (coeff) {
00204                         if (get_bits1(gb))
00205                             coeffs[i] = -q * coeff;
00206                         else
00207                             coeffs[i] =  q * coeff;
00208                     } else {
00209                         coeffs[i] = 0.0f;
00210                     }
00211                     i++;
00212                 }
00213             }
00214         }
00215 
00216         if (CONFIG_BINKAUDIO_DCT_DECODER && use_dct) {
00217             coeffs[0] /= 0.5;
00218             ff_dct_calc (&s->trans.dct,  coeffs);
00219             s->dsp.vector_fmul_scalar(coeffs, coeffs, s->frame_len / 2, s->frame_len);
00220         }
00221         else if (CONFIG_BINKAUDIO_RDFT_DECODER)
00222             ff_rdft_calc(&s->trans.rdft, coeffs);
00223     }
00224 
00225     if (s->dsp.float_to_int16_interleave == ff_float_to_int16_interleave_c) {
00226         for (i = 0; i < s->channels; i++)
00227             for (j = 0; j < s->frame_len; j++)
00228                 s->coeffs_ptr[i][j] = 385.0 + s->coeffs_ptr[i][j]*(1.0/32767.0);
00229     }
00230     s->dsp.float_to_int16_interleave(out, (const float **)s->coeffs_ptr, s->frame_len, s->channels);
00231 
00232     if (!s->first) {
00233         int count = s->overlap_len * s->channels;
00234         int shift = av_log2(count);
00235         for (i = 0; i < count; i++) {
00236             out[i] = (s->previous[i] * (count - i) + out[i] * i) >> shift;
00237         }
00238     }
00239 
00240     memcpy(s->previous, out + s->block_size,
00241            s->overlap_len * s->channels * sizeof(*out));
00242 
00243     s->first = 0;
00244 }
00245 
00246 static av_cold int decode_end(AVCodecContext *avctx)
00247 {
00248     BinkAudioContext * s = avctx->priv_data;
00249     av_freep(&s->bands);
00250     if (CONFIG_BINKAUDIO_RDFT_DECODER && avctx->codec->id == CODEC_ID_BINKAUDIO_RDFT)
00251         ff_rdft_end(&s->trans.rdft);
00252     else if (CONFIG_BINKAUDIO_DCT_DECODER)
00253         ff_dct_end(&s->trans.dct);
00254     return 0;
00255 }
00256 
00257 static void get_bits_align32(GetBitContext *s)
00258 {
00259     int n = (-get_bits_count(s)) & 31;
00260     if (n) skip_bits(s, n);
00261 }
00262 
00263 static int decode_frame(AVCodecContext *avctx,
00264                         void *data, int *data_size,
00265                         AVPacket *avpkt)
00266 {
00267     BinkAudioContext *s = avctx->priv_data;
00268     const uint8_t *buf  = avpkt->data;
00269     int buf_size        = avpkt->size;
00270     short *samples      = data;
00271     short *samples_end  = (short*)((uint8_t*)data + *data_size);
00272     int reported_size;
00273     GetBitContext *gb = &s->gb;
00274 
00275     init_get_bits(gb, buf, buf_size * 8);
00276 
00277     reported_size = get_bits_long(gb, 32);
00278     while (get_bits_count(gb) / 8 < buf_size &&
00279            samples + s->block_size <= samples_end) {
00280         decode_block(s, samples, avctx->codec->id == CODEC_ID_BINKAUDIO_DCT);
00281         samples += s->block_size;
00282         get_bits_align32(gb);
00283     }
00284 
00285     *data_size = FFMIN(reported_size, (uint8_t*)samples - (uint8_t*)data);
00286     return buf_size;
00287 }
00288 
00289 AVCodec binkaudio_rdft_decoder = {
00290     "binkaudio_rdft",
00291     AVMEDIA_TYPE_AUDIO,
00292     CODEC_ID_BINKAUDIO_RDFT,
00293     sizeof(BinkAudioContext),
00294     decode_init,
00295     NULL,
00296     decode_end,
00297     decode_frame,
00298     .long_name = NULL_IF_CONFIG_SMALL("Bink Audio (RDFT)")
00299 };
00300 
00301 AVCodec binkaudio_dct_decoder = {
00302     "binkaudio_dct",
00303     AVMEDIA_TYPE_AUDIO,
00304     CODEC_ID_BINKAUDIO_DCT,
00305     sizeof(BinkAudioContext),
00306     decode_init,
00307     NULL,
00308     decode_end,
00309     decode_frame,
00310     .long_name = NULL_IF_CONFIG_SMALL("Bink Audio (DCT)")
00311 };

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