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https://github.com/FFmpeg/FFmpeg.git
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cosmetics: comment clean-up and misc cosmetics
Originally committed as revision 26019 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles
parent
5901cebecd
commit
2d82d9b1df
@ -144,7 +144,8 @@ static void adjust_frame_size(AC3EncodeContext *s)
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s->bits_written -= s->bit_rate;
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s->samples_written -= s->sample_rate;
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}
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s->frame_size = s->frame_size_min + 2 * (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
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s->frame_size = s->frame_size_min +
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2 * (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
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s->bits_written += s->frame_size * 8;
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s->samples_written += AC3_FRAME_SIZE;
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}
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@ -401,7 +402,7 @@ static void lshift_tab(int16_t *tab, int n, int lshift)
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int i;
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if (lshift > 0) {
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for(i = 0; i < n; i++)
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for (i = 0; i < n; i++)
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tab[i] <<= lshift;
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} else if (lshift < 0) {
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lshift = -lshift;
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@ -460,10 +461,8 @@ static void extract_exponents(AC3EncodeContext *s)
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{
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int blk, ch, i;
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/* extract exponents */
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for (ch = 0; ch < s->channels; ch++) {
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for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
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/* compute "exponents". We take into account the normalization there */
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AC3Block *block = &s->blocks[blk];
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for (i = 0; i < AC3_MAX_COEFS; i++) {
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int e;
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@ -576,7 +575,7 @@ static void compute_exp_strategy(AC3EncodeContext *s)
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* exponent in the same frequency bin of a following block.
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* exp[i] = min(exp[i], exp1[i]
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*/
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static void exponent_min(uint8_t exp[AC3_MAX_COEFS], uint8_t exp1[AC3_MAX_COEFS], int n)
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static void exponent_min(uint8_t *exp, uint8_t *exp1, int n)
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{
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int i;
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for (i = 0; i < n; i++) {
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@ -589,8 +588,7 @@ static void exponent_min(uint8_t exp[AC3_MAX_COEFS], uint8_t exp1[AC3_MAX_COEFS]
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/**
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* Update the exponents so that they are the ones the decoder will decode.
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*/
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static void encode_exponents_blk_ch(uint8_t encoded_exp[AC3_MAX_COEFS],
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uint8_t exp[AC3_MAX_COEFS],
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static void encode_exponents_blk_ch(uint8_t *encoded_exp, uint8_t *exp,
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int nb_exps, int exp_strategy,
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uint8_t *num_exp_groups)
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{
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@ -649,12 +647,12 @@ static void encode_exponents(AC3EncodeContext *s)
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AC3Block *block, *block1, *block2;
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for (ch = 0; ch < s->channels; ch++) {
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/* for the EXP_REUSE case we select the min of the exponents */
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blk = 0;
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block = &s->blocks[0];
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while (blk < AC3_MAX_BLOCKS) {
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blk1 = blk + 1;
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block1 = block + 1;
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/* for the EXP_REUSE case we select the min of the exponents */
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while (blk1 < AC3_MAX_BLOCKS && block1->exp_strategy[ch] == EXP_REUSE) {
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exponent_min(block->exp[ch], block1->exp[ch], s->nb_coefs[ch]);
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blk1++;
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@ -833,26 +831,26 @@ static void count_frame_bits(AC3EncodeContext *s)
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/**
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* Calculate the number of bits needed to encode a set of mantissas.
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*/
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static int compute_mantissa_size(AC3EncodeContext *s, uint8_t *m, int nb_coefs)
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static int compute_mantissa_size(AC3EncodeContext *s, uint8_t *bap, int nb_coefs)
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{
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int bits, mant, i;
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int bits, b, i;
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bits = 0;
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for (i = 0; i < nb_coefs; i++) {
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mant = m[i];
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switch (mant) {
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b = bap[i];
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switch (b) {
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case 0:
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/* nothing */
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/* bap=0 mantissas are not encoded */
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break;
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case 1:
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/* 3 mantissa in 5 bits */
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/* 3 mantissas in 5 bits */
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if (s->mant1_cnt == 0)
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bits += 5;
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if (++s->mant1_cnt == 3)
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s->mant1_cnt = 0;
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break;
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case 2:
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/* 3 mantissa in 7 bits */
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/* 3 mantissas in 7 bits */
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if (s->mant2_cnt == 0)
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bits += 7;
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if (++s->mant2_cnt == 3)
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@ -862,7 +860,7 @@ static int compute_mantissa_size(AC3EncodeContext *s, uint8_t *m, int nb_coefs)
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bits += 3;
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break;
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case 4:
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/* 2 mantissa in 7 bits */
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/* 2 mantissas in 7 bits */
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if (s->mant4_cnt == 0)
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bits += 7;
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if (++s->mant4_cnt == 2)
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@ -875,7 +873,7 @@ static int compute_mantissa_size(AC3EncodeContext *s, uint8_t *m, int nb_coefs)
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bits += 16;
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break;
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default:
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bits += mant - 1;
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bits += b - 1;
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break;
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}
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}
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@ -966,9 +964,8 @@ static int cbr_bit_allocation(AC3EncodeContext *s)
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bit_alloc(s, s->bap, snr_offset) > bits_left) {
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snr_offset -= 64;
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}
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if (snr_offset < 0) {
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if (snr_offset < 0)
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return AVERROR(EINVAL);
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}
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while (snr_offset + 64 <= 1023 &&
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bit_alloc(s, s->bap1, snr_offset + 64) <= bits_left) {
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@ -1007,10 +1004,8 @@ static int cbr_bit_allocation(AC3EncodeContext *s)
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*/
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static int compute_bit_allocation(AC3EncodeContext *s)
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{
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/* count frame bits other than exponents and mantissas */
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count_frame_bits(s);
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/* calculate psd and masking curve before doing bit allocation */
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bit_alloc_masking(s);
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return cbr_bit_allocation(s);
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@ -1033,7 +1028,7 @@ static inline int sym_quant(int c, int e, int levels)
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v = (v + 1) >> 1;
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v = (levels >> 1) - v;
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}
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assert (v >= 0 && v < levels);
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assert(v >= 0 && v < levels);
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return v;
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}
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@ -1217,11 +1212,18 @@ static void output_audio_block(AC3EncodeContext *s,
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int ch, i, baie, rbnd;
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AC3Block *block = &s->blocks[block_num];
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/* block switching */
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for (ch = 0; ch < s->fbw_channels; ch++)
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put_bits(&s->pb, 1, 0); /* no block switching */
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put_bits(&s->pb, 1, 0);
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/* dither flags */
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for (ch = 0; ch < s->fbw_channels; ch++)
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put_bits(&s->pb, 1, 1); /* no dither */
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put_bits(&s->pb, 1, 0); /* no dynamic range */
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put_bits(&s->pb, 1, 1);
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/* dynamic range codes */
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put_bits(&s->pb, 1, 0);
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/* channel coupling */
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if (!block_num) {
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put_bits(&s->pb, 1, 1); /* coupling strategy present */
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put_bits(&s->pb, 1, 0); /* no coupling strategy */
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@ -1229,6 +1231,7 @@ static void output_audio_block(AC3EncodeContext *s,
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put_bits(&s->pb, 1, 0); /* no new coupling strategy */
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}
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/* stereo rematrixing */
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if (s->channel_mode == AC3_CHMODE_STEREO) {
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if (!block_num) {
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/* first block must define rematrixing (rematstr) */
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@ -1246,7 +1249,6 @@ static void output_audio_block(AC3EncodeContext *s,
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/* exponent strategy */
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for (ch = 0; ch < s->fbw_channels; ch++)
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put_bits(&s->pb, 2, block->exp_strategy[ch]);
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if (s->lfe_on)
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put_bits(&s->pb, 1, block->exp_strategy[s->lfe_channel]);
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@ -1261,15 +1263,16 @@ static void output_audio_block(AC3EncodeContext *s,
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if (block->exp_strategy[ch] == EXP_REUSE)
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continue;
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/* first exponent */
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/* DC exponent */
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put_bits(&s->pb, 4, block->grouped_exp[ch][0]);
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/* next ones are delta-encoded and grouped */
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/* exponent groups */
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for (i = 1; i <= block->num_exp_groups[ch]; i++)
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put_bits(&s->pb, 7, block->grouped_exp[ch][i]);
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/* gain range info */
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if (ch != s->lfe_channel)
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put_bits(&s->pb, 2, 0); /* no gain range info */
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put_bits(&s->pb, 2, 0);
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}
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/* bit allocation info */
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@ -1296,10 +1299,9 @@ static void output_audio_block(AC3EncodeContext *s,
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put_bits(&s->pb, 1, 0); /* no delta bit allocation */
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put_bits(&s->pb, 1, 0); /* no data to skip */
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/* mantissa encoding */
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/* mantissas */
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for (ch = 0; ch < s->channels; ch++) {
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int b, q;
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for (i = 0; i < s->nb_coefs[ch]; i++) {
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q = block->qmant[ch][i];
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b = s->bap[block_num][ch][i];
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@ -1361,28 +1363,27 @@ static void output_frame_end(AC3EncodeContext *s)
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int frame_size, frame_size_58, pad_bytes, crc1, crc2, crc_inv;
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uint8_t *frame;
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frame_size = s->frame_size; /* frame size in words */
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/* align to 8 bits */
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frame_size = s->frame_size;
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frame_size_58 = ((frame_size >> 2) + (frame_size >> 4)) << 1;
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/* pad the remainder of the frame with zeros */
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flush_put_bits(&s->pb);
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/* add zero bytes to reach the frame size */
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frame = s->pb.buf;
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pad_bytes = s->frame_size - (put_bits_ptr(&s->pb) - frame) - 2;
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assert(pad_bytes >= 0);
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if (pad_bytes > 0)
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memset(put_bits_ptr(&s->pb), 0, pad_bytes);
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/* Now we must compute both crcs : this is not so easy for crc1
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because it is at the beginning of the data... */
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frame_size_58 = ((frame_size >> 2) + (frame_size >> 4)) << 1;
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/* compute crc1 */
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/* this is not so easy because it is at the beginning of the data... */
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crc1 = av_bswap16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0,
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frame + 4, frame_size_58 - 4));
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/* XXX: could precompute crc_inv */
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crc_inv = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
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crc1 = mul_poly(crc_inv, crc1, CRC16_POLY);
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AV_WB16(frame + 2, crc1);
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/* compute crc2 */
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crc2 = av_bswap16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0,
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frame + frame_size_58,
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frame_size - frame_size_58 - 2));
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@ -1402,9 +1403,8 @@ static void output_frame(AC3EncodeContext *s,
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output_frame_header(s);
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for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
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for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
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output_audio_block(s, blk);
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}
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output_frame_end(s);
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}
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