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cosmetics: rename some iterator variables to match what they represent

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Originally committed as revision 25973 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2010-12-14 14:52:00 +00:00
parent 777732756a
commit ce67b7cd38
1 changed files with 58 additions and 57 deletions
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115
libavcodec/ac3enc.c
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@ -344,36 +344,36 @@ static void compute_exp_strategy_ch(uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX
uint8_t exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
int ch, int is_lfe)
{
int i, j;
int blk, blk1;
int exp_diff;
/* estimate if the exponent variation & decide if they should be
reused in the next frame */
exp_strategy[0][ch] = EXP_NEW;
for (i = 1; i < AC3_MAX_BLOCKS; i++) {
exp_diff = calc_exp_diff(exp[i][ch], exp[i-1][ch], AC3_MAX_COEFS);
for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) {
exp_diff = calc_exp_diff(exp[blk][ch], exp[blk-1][ch], AC3_MAX_COEFS);
if (exp_diff > EXP_DIFF_THRESHOLD)
exp_strategy[i][ch] = EXP_NEW;
exp_strategy[blk][ch] = EXP_NEW;
else
exp_strategy[i][ch] = EXP_REUSE;
exp_strategy[blk][ch] = EXP_REUSE;
}
if (is_lfe)
return;
/* now select the encoding strategy type : if exponents are often
recoded, we use a coarse encoding */
i = 0;
while (i < AC3_MAX_BLOCKS) {
j = i + 1;
while (j < AC3_MAX_BLOCKS && exp_strategy[j][ch] == EXP_REUSE)
j++;
switch (j - i) {
case 1: exp_strategy[i][ch] = EXP_D45; break;
blk = 0;
while (blk < AC3_MAX_BLOCKS) {
blk1 = blk + 1;
while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1][ch] == EXP_REUSE)
blk1++;
switch (blk1 - blk) {
case 1: exp_strategy[blk][ch] = EXP_D45; break;
case 2:
case 3: exp_strategy[i][ch] = EXP_D25; break;
default: exp_strategy[i][ch] = EXP_D15; break;
case 3: exp_strategy[blk][ch] = EXP_D25; break;
default: exp_strategy[blk][ch] = EXP_D15; break;
}
i = j;
blk = blk1;
}
}
@ -545,21 +545,21 @@ static int bit_alloc(AC3EncodeContext *s,
uint8_t bap[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS],
int frame_bits, int coarse_snr_offset, int fine_snr_offset)
{
int i, ch;
int blk, ch;
int snr_offset;
snr_offset = (((coarse_snr_offset - 15) << 4) + fine_snr_offset) << 2;
for (i = 0; i < AC3_MAX_BLOCKS; i++) {
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
s->mant1_cnt = 0;
s->mant2_cnt = 0;
s->mant4_cnt = 0;
for (ch = 0; ch < s->channels; ch++) {
ff_ac3_bit_alloc_calc_bap(mask[i][ch], psd[i][ch], 0,
ff_ac3_bit_alloc_calc_bap(mask[blk][ch], psd[blk][ch], 0,
s->nb_coefs[ch], snr_offset,
s->bit_alloc.floor, ff_ac3_bap_tab,
bap[i][ch]);
frame_bits += compute_mantissa_size(s, bap[i][ch], s->nb_coefs[ch]);
bap[blk][ch]);
frame_bits += compute_mantissa_size(s, bap[blk][ch], s->nb_coefs[ch]);
}
}
return 16 * s->frame_size - frame_bits;
@ -580,7 +580,7 @@ static int compute_bit_allocation(AC3EncodeContext *s,
uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS],
int frame_bits)
{
int i, ch;
int blk, ch;
int coarse_snr_offset, fine_snr_offset;
uint8_t bap1[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
int16_t psd[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
@ -610,18 +610,18 @@ static int compute_bit_allocation(AC3EncodeContext *s,
frame_bits += frame_bits_inc[s->channel_mode];
/* audio blocks */
for (i = 0; i < AC3_MAX_BLOCKS; i++) {
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
frame_bits += s->fbw_channels * 2 + 2; /* blksw * c, dithflag * c, dynrnge, cplstre */
if (s->channel_mode == AC3_CHMODE_STEREO) {
frame_bits++; /* rematstr */
if (!i)
if (!blk)
frame_bits += 4;
}
frame_bits += 2 * s->fbw_channels; /* chexpstr[2] * c */
if (s->lfe_on)
frame_bits++; /* lfeexpstr */
for (ch = 0; ch < s->fbw_channels; ch++) {
if (exp_strategy[i][ch] != EXP_REUSE)
if (exp_strategy[blk][ch] != EXP_REUSE)
frame_bits += 6 + 2; /* chbwcod[6], gainrng[2] */
}
frame_bits++; /* baie */
@ -1082,7 +1082,8 @@ static int ac3_encode_frame(AVCodecContext *avctx,
{
AC3EncodeContext *s = avctx->priv_data;
const int16_t *samples = data;
int i, j, k, v, ch;
int v;
int blk, blk1, blk2, ch, i;
int16_t input_samples[AC3_WINDOW_SIZE];
int32_t mdct_coef[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
uint8_t exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
@ -1096,53 +1097,53 @@ static int ac3_encode_frame(AVCodecContext *avctx,
for (ch = 0; ch < s->channels; ch++) {
int ich = s->channel_map[ch];
/* fixed mdct to the six sub blocks & exponent computation */
for (i = 0; i < AC3_MAX_BLOCKS; i++) {
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
const int16_t *sptr;
int sinc;
/* compute input samples */
memcpy(input_samples, s->last_samples[ich], AC3_BLOCK_SIZE * sizeof(int16_t));
sinc = s->channels;
sptr = samples + (sinc * AC3_BLOCK_SIZE * i) + ich;
for (j = 0; j < AC3_BLOCK_SIZE; j++) {
sptr = samples + (sinc * AC3_BLOCK_SIZE * blk) + ich;
for (i = 0; i < AC3_BLOCK_SIZE; i++) {
v = *sptr;
input_samples[j + AC3_BLOCK_SIZE] = v;
s->last_samples[ich][j] = v;
input_samples[i + AC3_BLOCK_SIZE] = v;
s->last_samples[ich][i] = v;
sptr += sinc;
}
/* apply the MDCT window */
for (j = 0; j < AC3_BLOCK_SIZE; j++) {
input_samples[j] = MUL16(input_samples[j],
ff_ac3_window[j]) >> 15;
input_samples[AC3_WINDOW_SIZE-j-1] = MUL16(input_samples[AC3_WINDOW_SIZE-j-1],
ff_ac3_window[j]) >> 15;
for (i = 0; i < AC3_BLOCK_SIZE; i++) {
input_samples[i] = MUL16(input_samples[i],
ff_ac3_window[i]) >> 15;
input_samples[AC3_WINDOW_SIZE-i-1] = MUL16(input_samples[AC3_WINDOW_SIZE-i-1],
ff_ac3_window[i]) >> 15;
}
/* Normalize the samples to use the maximum available precision */
v = 14 - log2_tab(input_samples, AC3_WINDOW_SIZE);
if (v < 0)
v = 0;
exp_shift[i][ch] = v - 9;
exp_shift[blk][ch] = v - 9;
lshift_tab(input_samples, AC3_WINDOW_SIZE, v);
/* do the MDCT */
mdct512(mdct_coef[i][ch], input_samples);
mdct512(mdct_coef[blk][ch], input_samples);
/* compute "exponents". We take into account the normalization there */
for (j = 0; j < AC3_MAX_COEFS; j++) {
for (i = 0; i < AC3_MAX_COEFS; i++) {
int e;
v = abs(mdct_coef[i][ch][j]);
v = abs(mdct_coef[blk][ch][i]);
if (v == 0)
e = 24;
else {
e = 23 - av_log2(v) + exp_shift[i][ch];
e = 23 - av_log2(v) + exp_shift[blk][ch];
if (e >= 24) {
e = 24;
mdct_coef[i][ch][j] = 0;
mdct_coef[blk][ch][i] = 0;
}
}
exp[i][ch][j] = e;
exp[blk][ch][i] = e;
}
}
@ -1151,22 +1152,22 @@ static int ac3_encode_frame(AVCodecContext *avctx,
/* compute the exponents as the decoder will see them. The
EXP_REUSE case must be handled carefully : we select the
min of the exponents */
i = 0;
while (i < AC3_MAX_BLOCKS) {
j = i + 1;
while (j < AC3_MAX_BLOCKS && exp_strategy[j][ch] == EXP_REUSE) {
exponent_min(exp[i][ch], exp[j][ch], s->nb_coefs[ch]);
j++;
blk = 0;
while (blk < AC3_MAX_BLOCKS) {
blk1 = blk + 1;
while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1][ch] == EXP_REUSE) {
exponent_min(exp[blk][ch], exp[blk1][ch], s->nb_coefs[ch]);
blk1++;
}
frame_bits += encode_exponents_blk_ch(encoded_exp[i][ch],
exp[i][ch], s->nb_coefs[ch],
exp_strategy[i][ch]);
frame_bits += encode_exponents_blk_ch(encoded_exp[blk][ch],
exp[blk][ch], s->nb_coefs[ch],
exp_strategy[blk][ch]);
/* copy encoded exponents for reuse case */
for (k = i+1; k < j; k++) {
memcpy(encoded_exp[k][ch], encoded_exp[i][ch],
for (blk2 = blk+1; blk2 < blk1; blk2++) {
memcpy(encoded_exp[blk2][ch], encoded_exp[blk][ch],
s->nb_coefs[ch] * sizeof(uint8_t));
}
i = j;
blk = blk1;
}
}
@ -1183,9 +1184,9 @@ static int ac3_encode_frame(AVCodecContext *avctx,
/* everything is known... let's output the frame */
output_frame_header(s, frame);
for (i = 0; i < AC3_MAX_BLOCKS; i++) {
output_audio_block(s, exp_strategy[i], encoded_exp[i],
bap[i], mdct_coef[i], exp_shift[i], i);
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
output_audio_block(s, exp_strategy[blk], encoded_exp[blk],
bap[blk], mdct_coef[blk], exp_shift[blk], blk);
}
return output_frame_end(s);
}