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@ -61,6 +61,11 @@ typedef struct MpegAudioContext { |
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unsigned char scale_code[MPA_MAX_CHANNELS][SBLIMIT]; |
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int sblimit; /* number of used subbands */ |
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const unsigned char *alloc_table; |
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int16_t filter_bank[512]; |
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int scale_factor_table[64]; |
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unsigned char scale_diff_table[128]; |
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float scale_factor_inv_table[64]; |
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unsigned short total_quant_bits[17]; /* total number of bits per allocation group */ |
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} MpegAudioContext; |
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static av_cold int MPA_encode_init(AVCodecContext *avctx) |
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@ -136,19 +141,19 @@ static av_cold int MPA_encode_init(AVCodecContext *avctx) |
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#if WFRAC_BITS != 16 |
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v = (v + (1 << (16 - WFRAC_BITS - 1))) >> (16 - WFRAC_BITS); |
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#endif |
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filter_bank[i] = v; |
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s->filter_bank[i] = v; |
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if ((i & 63) != 0) |
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v = -v; |
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if (i != 0) |
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filter_bank[512 - i] = v; |
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s->filter_bank[512 - i] = v; |
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} |
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for(i=0;i<64;i++) { |
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v = (int)(pow(2.0, (3 - i) / 3.0) * (1 << 20)); |
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if (v <= 0) |
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v = 1; |
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scale_factor_table[i] = v; |
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scale_factor_inv_table[i] = pow(2.0, -(3 - i) / 3.0) / (float)(1 << 20); |
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s->scale_factor_table[i] = v; |
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s->scale_factor_inv_table[i] = pow(2.0, -(3 - i) / 3.0) / (float)(1 << 20); |
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} |
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for(i=0;i<128;i++) { |
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v = i - 64; |
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@ -162,7 +167,7 @@ static av_cold int MPA_encode_init(AVCodecContext *avctx) |
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v = 3; |
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else |
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v = 4; |
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scale_diff_table[i] = v; |
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s->scale_diff_table[i] = v; |
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} |
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for(i=0;i<17;i++) { |
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@ -171,7 +176,7 @@ static av_cold int MPA_encode_init(AVCodecContext *avctx) |
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v = -v; |
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else |
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v = v * 3; |
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total_quant_bits[i] = 12 * v; |
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s->total_quant_bits[i] = 12 * v; |
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} |
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return 0; |
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@ -318,7 +323,7 @@ static void filter(MpegAudioContext *s, int ch, const short *samples, int incr) |
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/* filter */ |
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p = s->samples_buf[ch] + offset; |
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q = filter_bank; |
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q = s->filter_bank; |
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/* maxsum = 23169 */ |
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for(i=0;i<64;i++) { |
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sum = p[0*64] * q[0*64]; |
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@ -352,7 +357,8 @@ static void filter(MpegAudioContext *s, int ch, const short *samples, int incr) |
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s->samples_offset[ch] = offset; |
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} |
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static void compute_scale_factors(unsigned char scale_code[SBLIMIT], |
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static void compute_scale_factors(MpegAudioContext *s, |
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unsigned char scale_code[SBLIMIT], |
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unsigned char scale_factors[SBLIMIT][3], |
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int sb_samples[3][12][SBLIMIT], |
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int sblimit) |
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@ -379,7 +385,7 @@ static void compute_scale_factors(unsigned char scale_code[SBLIMIT], |
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use at most 2 compares to find the index */ |
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index = (21 - n) * 3 - 3; |
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if (index >= 0) { |
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while (vmax <= scale_factor_table[index+1]) |
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while (vmax <= s->scale_factor_table[index+1]) |
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index++; |
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} else { |
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index = 0; /* very unlikely case of overflow */ |
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@ -389,7 +395,7 @@ static void compute_scale_factors(unsigned char scale_code[SBLIMIT], |
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} |
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av_dlog(NULL, "%2d:%d in=%x %x %d\n", |
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j, i, vmax, scale_factor_table[index], index); |
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j, i, vmax, s->scale_factor_table[index], index); |
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/* store the scale factor */ |
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assert(index >=0 && index <= 63); |
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sf[i] = index; |
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@ -397,8 +403,8 @@ static void compute_scale_factors(unsigned char scale_code[SBLIMIT], |
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/* compute the transmission factor : look if the scale factors
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are close enough to each other */ |
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d1 = scale_diff_table[sf[0] - sf[1] + 64]; |
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d2 = scale_diff_table[sf[1] - sf[2] + 64]; |
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d1 = s->scale_diff_table[sf[0] - sf[1] + 64]; |
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d2 = s->scale_diff_table[sf[1] - sf[2] + 64]; |
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/* handle the 25 cases */ |
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switch(d1 * 5 + d2) { |
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@ -548,12 +554,12 @@ static void compute_bit_allocation(MpegAudioContext *s, |
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if (subband_status[max_ch][max_sb] == SB_NOTALLOCATED) { |
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/* nothing was coded for this band: add the necessary bits */ |
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incr = 2 + nb_scale_factors[s->scale_code[max_ch][max_sb]] * 6; |
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incr += total_quant_bits[alloc[1]]; |
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incr += s->total_quant_bits[alloc[1]]; |
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} else { |
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/* increments bit allocation */ |
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b = bit_alloc[max_ch][max_sb]; |
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incr = total_quant_bits[alloc[b + 1]] - |
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total_quant_bits[alloc[b]]; |
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incr = s->total_quant_bits[alloc[b + 1]] - |
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s->total_quant_bits[alloc[b]]; |
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} |
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if (current_frame_size + incr <= max_frame_size) { |
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@ -665,7 +671,7 @@ static void encode_frame(MpegAudioContext *s, |
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float a; |
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sample = s->sb_samples[ch][k][l + m][i]; |
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/* divide by scale factor */ |
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a = (float)sample * scale_factor_inv_table[s->scale_factors[ch][i][k]]; |
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a = (float)sample * s->scale_factor_inv_table[s->scale_factors[ch][i][k]]; |
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q[m] = (int)((a + 1.0) * steps * 0.5); |
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if (q[m] >= steps) |
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q[m] = steps - 1; |
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@ -711,7 +717,7 @@ static int MPA_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, |
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} |
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for(i=0;i<s->nb_channels;i++) { |
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compute_scale_factors(s->scale_code[i], s->scale_factors[i], |
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compute_scale_factors(s, s->scale_code[i], s->scale_factors[i], |
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s->sb_samples[i], s->sblimit); |
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} |
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for(i=0;i<s->nb_channels;i++) { |
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