mirror of https://github.com/FFmpeg/FFmpeg.git
Originally committed as revision 21570 to svn://svn.ffmpeg.org/ffmpeg/trunkrelease/0.6
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/*
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* Bink Audio decoder |
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* Copyright (c) 2007-2010 Peter Ross (pross@xvid.org) |
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* Copyright (c) 2009 Daniel Verkamp (daniel@drv.nu) |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/**
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* @file libavcodec/binkaudio.c |
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* Bink Audio decoder |
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* |
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* Technical details here: |
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* http://wiki.multimedia.cx/index.php?title=Bink_Audio
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*/ |
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#include "avcodec.h" |
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#define ALT_BITSTREAM_READER_LE |
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#include "get_bits.h" |
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#include "dsputil.h" |
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extern const uint16_t ff_wma_critical_freqs[25]; |
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#define MAX_CHANNELS 2 |
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#define BINK_BLOCK_MAX_SIZE (MAX_CHANNELS << 11) |
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typedef struct { |
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AVCodecContext *avctx; |
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GetBitContext gb; |
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DSPContext dsp; |
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int first; |
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int channels; |
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int frame_len; ///< transform size (samples)
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int overlap_len; ///< overlap size (samples)
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int block_size; |
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int num_bands; |
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unsigned int *bands; |
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float root; |
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DECLARE_ALIGNED_16(FFTSample, coeffs[BINK_BLOCK_MAX_SIZE]); |
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DECLARE_ALIGNED_16(short, previous[BINK_BLOCK_MAX_SIZE / 16]); ///< coeffs from previous audio block
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float *coeffs_ptr[MAX_CHANNELS]; ///< pointers to the coeffs arrays for float_to_int16_interleave
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union { |
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RDFTContext rdft; |
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DCTContext dct; |
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} trans; |
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} BinkAudioContext; |
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static av_cold int decode_init(AVCodecContext *avctx) |
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{ |
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BinkAudioContext *s = avctx->priv_data; |
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int sample_rate = avctx->sample_rate; |
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int sample_rate_half; |
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int i; |
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int frame_len_bits; |
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s->avctx = avctx; |
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dsputil_init(&s->dsp, avctx); |
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/* determine frame length */ |
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if (avctx->sample_rate < 22050) { |
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frame_len_bits = 9; |
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} else if (avctx->sample_rate < 44100) { |
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frame_len_bits = 10; |
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} else { |
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frame_len_bits = 11; |
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} |
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s->frame_len = 1 << frame_len_bits; |
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if (s->channels > MAX_CHANNELS) { |
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av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels); |
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return -1; |
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} |
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if (avctx->codec->id == CODEC_ID_BINKAUDIO_RDFT) { |
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// audio is already interleaved for the RDFT format variant
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sample_rate *= avctx->channels; |
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s->frame_len *= avctx->channels; |
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s->channels = 1; |
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if (avctx->channels == 2) |
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frame_len_bits++; |
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} else { |
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s->channels = avctx->channels; |
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} |
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s->overlap_len = s->frame_len / 16; |
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s->block_size = (s->frame_len - s->overlap_len) * s->channels; |
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sample_rate_half = (sample_rate + 1) / 2; |
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s->root = 2.0 / sqrt(s->frame_len); |
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/* calculate number of bands */ |
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for (s->num_bands = 1; s->num_bands < 25; s->num_bands++) |
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if (sample_rate_half <= ff_wma_critical_freqs[s->num_bands - 1]) |
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break; |
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s->bands = av_malloc((s->num_bands + 1) * sizeof(*s->bands)); |
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if (!s->bands) |
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return AVERROR(ENOMEM); |
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/* populate bands data */ |
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s->bands[0] = 1; |
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for (i = 1; i < s->num_bands; i++) |
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s->bands[i] = ff_wma_critical_freqs[i - 1] * (s->frame_len / 2) / sample_rate_half; |
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s->bands[s->num_bands] = s->frame_len / 2; |
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s->first = 1; |
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avctx->sample_fmt = SAMPLE_FMT_S16; |
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for (i = 0; i < s->channels; i++) |
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s->coeffs_ptr[i] = s->coeffs + i * s->frame_len; |
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if (avctx->codec->id == CODEC_ID_BINKAUDIO_RDFT) |
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ff_rdft_init(&s->trans.rdft, frame_len_bits, IRIDFT); |
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else |
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ff_dct_init(&s->trans.dct, frame_len_bits, 0); |
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return 0; |
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} |
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static float get_float(GetBitContext *gb) |
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{ |
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int power = get_bits(gb, 5); |
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float f = ldexpf(get_bits_long(gb, 23), power - 23); |
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if (get_bits1(gb)) |
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f = -f; |
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return f; |
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} |
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static const uint8_t rle_length_tab[16] = { |
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2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 32, 64 |
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}; |
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/**
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* Decode Bink Audio block |
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* @param[out] out Output buffer (must contain s->block_size elements) |
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*/ |
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static void decode_block(BinkAudioContext *s, short *out, int use_dct) |
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{ |
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int ch, i, j, k; |
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float q, quant[25]; |
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int width, coeff; |
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GetBitContext *gb = &s->gb; |
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if (use_dct) |
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skip_bits(gb, 2); |
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for (ch = 0; ch < s->channels; ch++) { |
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FFTSample *coeffs = s->coeffs_ptr[ch]; |
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q = 0.0f; |
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coeffs[0] = get_float(gb) * s->root; |
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coeffs[1] = get_float(gb) * s->root; |
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for (i = 0; i < s->num_bands; i++) { |
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/* constant is result of 0.066399999/log10(M_E) */ |
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int value = get_bits(gb, 8); |
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quant[i] = expf(FFMIN(value, 95) * 0.15289164787221953823f) * s->root; |
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} |
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// find band (k)
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for (k = 0; s->bands[k] < 1; k++) { |
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q = quant[k]; |
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} |
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// parse coefficients
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i = 2; |
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while (i < s->frame_len) { |
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if (get_bits1(gb)) { |
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j = i + rle_length_tab[get_bits(gb, 4)] * 8; |
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} else { |
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j = i + 8; |
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} |
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j = FFMIN(j, s->frame_len); |
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width = get_bits(gb, 4); |
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if (width == 0) { |
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memset(coeffs + i, 0, (j - i) * sizeof(*coeffs)); |
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i = j; |
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while (s->bands[k] * 2 < i) |
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q = quant[k++]; |
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} else { |
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while (i < j) { |
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if (s->bands[k] * 2 == i) |
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q = quant[k++]; |
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coeff = get_bits(gb, width); |
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if (coeff) { |
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if (get_bits1(gb)) |
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coeffs[i] = -q * coeff; |
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else |
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coeffs[i] = q * coeff; |
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} else { |
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coeffs[i] = 0.0f; |
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} |
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i++; |
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} |
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} |
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} |
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if (use_dct) |
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ff_dct_calc (&s->trans.dct, coeffs); |
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else |
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ff_rdft_calc(&s->trans.rdft, coeffs); |
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} |
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s->dsp.float_to_int16_interleave(out, (const float **)s->coeffs_ptr, s->frame_len, s->channels); |
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if (!s->first) { |
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int count = s->overlap_len * s->channels; |
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int shift = av_log2(count); |
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for (i = 0; i < count; i++) { |
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out[i] = (s->previous[i] * (count - i) + out[i] * i) >> shift; |
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} |
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} |
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memcpy(s->previous, out + s->block_size, |
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s->overlap_len * s->channels * sizeof(*out)); |
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s->first = 0; |
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} |
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static av_cold int decode_end(AVCodecContext *avctx) |
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{ |
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BinkAudioContext * s = avctx->priv_data; |
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av_freep(&s->bands); |
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if (avctx->codec->id == CODEC_ID_BINKAUDIO_RDFT) |
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ff_rdft_end(&s->trans.rdft); |
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else |
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ff_dct_end(&s->trans.dct); |
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return 0; |
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} |
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static void get_bits_align32(GetBitContext *s) |
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{ |
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int n = (-get_bits_count(s)) & 31; |
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if (n) skip_bits(s, n); |
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} |
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static int decode_frame(AVCodecContext *avctx, |
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void *data, int *data_size, |
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AVPacket *avpkt) |
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{ |
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BinkAudioContext *s = avctx->priv_data; |
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const uint8_t *buf = avpkt->data; |
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int buf_size = avpkt->size; |
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short *samples = data; |
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short *samples_end = (short*)((uint8_t*)data + *data_size); |
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int reported_size; |
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GetBitContext *gb = &s->gb; |
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init_get_bits(gb, buf, buf_size * 8); |
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reported_size = get_bits_long(gb, 32); |
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while (get_bits_count(gb) / 8 < buf_size && |
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samples + s->block_size <= samples_end) { |
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decode_block(s, samples, avctx->codec->id == CODEC_ID_BINKAUDIO_DCT); |
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samples += s->block_size; |
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get_bits_align32(gb); |
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} |
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*data_size = (uint8_t*)samples - (uint8_t*)data; |
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if (reported_size != *data_size) { |
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av_log(avctx, AV_LOG_WARNING, "reported data size (%d) does not match output data size (%d)\n", |
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reported_size, *data_size); |
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} |
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return buf_size; |
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} |
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AVCodec binkaudio_rdft_decoder = { |
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"binkaudio_rdft", |
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CODEC_TYPE_AUDIO, |
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CODEC_ID_BINKAUDIO_RDFT, |
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sizeof(BinkAudioContext), |
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decode_init, |
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NULL, |
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decode_end, |
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decode_frame, |
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.long_name = NULL_IF_CONFIG_SMALL("Bink Audio (RDFT)") |
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}; |
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AVCodec binkaudio_dct_decoder = { |
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"binkaudio_dct", |
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CODEC_TYPE_AUDIO, |
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CODEC_ID_BINKAUDIO_DCT, |
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sizeof(BinkAudioContext), |
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decode_init, |
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NULL, |
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decode_end, |
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decode_frame, |
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.long_name = NULL_IF_CONFIG_SMALL("Bink Audio (DCT)") |
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}; |
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