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cosmetics: rename GetBitContext gb to gbc

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Originally committed as revision 11354 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2007-12-30 20:47:22 +00:00
parent 005ab694ae
commit 23c8cb89c9
1 changed files with 83 additions and 83 deletions
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166
libavcodec/ac3dec.c
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@ -188,7 +188,7 @@ typedef struct {
DECLARE_ALIGNED_16(float, window[256]); ///< window coefficients
/* Miscellaneous. */
GetBitContext gb; ///< bitstream reader
GetBitContext gbc; ///< bitstream reader
AVRandomState dith_state; ///< for dither generation
AVCodecContext *avctx; ///< parent context
} AC3DecodeContext;
@ -322,11 +322,11 @@ static int ac3_decode_init(AVCodecContext *avctx)
static int ac3_parse_header(AC3DecodeContext *ctx)
{
AC3HeaderInfo hdr;
GetBitContext *gb = &ctx->gb;
GetBitContext *gbc = &ctx->gbc;
float center_mix_level, surround_mix_level;
int err, i;
err = ff_ac3_parse_header(gb->buffer, &hdr);
err = ff_ac3_parse_header(gbc->buffer, &hdr);
if(err)
return err;
@ -351,46 +351,46 @@ static int ac3_parse_header(AC3DecodeContext *ctx)
ctx->output_mode |= AC3_OUTPUT_LFEON;
/* skip over portion of header which has already been read */
skip_bits(gb, 16); // skip the sync_word
skip_bits(gb, 16); // skip crc1
skip_bits(gb, 8); // skip fscod and frmsizecod
skip_bits(gb, 11); // skip bsid, bsmod, and acmod
skip_bits(gbc, 16); // skip the sync_word
skip_bits(gbc, 16); // skip crc1
skip_bits(gbc, 8); // skip fscod and frmsizecod
skip_bits(gbc, 11); // skip bsid, bsmod, and acmod
if(ctx->channel_mode == AC3_CHMODE_STEREO) {
skip_bits(gb, 2); // skip dsurmod
skip_bits(gbc, 2); // skip dsurmod
} else {
if((ctx->channel_mode & 1) && ctx->channel_mode != AC3_CHMODE_MONO)
skip_bits(gb, 2); // skip cmixlev
skip_bits(gbc, 2); // skip cmixlev
if(ctx->channel_mode & 4)
skip_bits(gb, 2); // skip surmixlev
skip_bits(gbc, 2); // skip surmixlev
}
skip_bits1(gb); // skip lfeon
skip_bits1(gbc); // skip lfeon
/* read the rest of the bsi. read twice for dual mono mode. */
i = !(ctx->channel_mode);
do {
skip_bits(gb, 5); // skip dialog normalization
if (get_bits1(gb))
skip_bits(gb, 8); //skip compression
if (get_bits1(gb))
skip_bits(gb, 8); //skip language code
if (get_bits1(gb))
skip_bits(gb, 7); //skip audio production information
skip_bits(gbc, 5); // skip dialog normalization
if (get_bits1(gbc))
skip_bits(gbc, 8); //skip compression
if (get_bits1(gbc))
skip_bits(gbc, 8); //skip language code
if (get_bits1(gbc))
skip_bits(gbc, 7); //skip audio production information
} while (i--);
skip_bits(gb, 2); //skip copyright bit and original bitstream bit
skip_bits(gbc, 2); //skip copyright bit and original bitstream bit
/* skip the timecodes (or extra bitstream information for Alternate Syntax)
TODO: read & use the xbsi1 downmix levels */
if (get_bits1(gb))
skip_bits(gb, 14); //skip timecode1 / xbsi1
if (get_bits1(gb))
skip_bits(gb, 14); //skip timecode2 / xbsi2
if (get_bits1(gbc))
skip_bits(gbc, 14); //skip timecode1 / xbsi1
if (get_bits1(gbc))
skip_bits(gbc, 14); //skip timecode2 / xbsi2
/* skip additional bitstream info */
if (get_bits1(gb)) {
i = get_bits(gb, 6);
if (get_bits1(gbc)) {
i = get_bits(gbc, 6);
do {
skip_bits(gb, 8);
skip_bits(gbc, 8);
} while(i--);
}
@ -419,7 +419,7 @@ static int ac3_parse_header(AC3DecodeContext *ctx)
* Decode the grouped exponents according to exponent strategy.
* reference: Section 7.1.3 Exponent Decoding
*/
static void decode_exponents(GetBitContext *gb, int exp_strategy, int ngrps,
static void decode_exponents(GetBitContext *gbc, int exp_strategy, int ngrps,
uint8_t absexp, int8_t *dexps)
{
int i, j, grp, group_size;
@ -429,7 +429,7 @@ static void decode_exponents(GetBitContext *gb, int exp_strategy, int ngrps,
/* unpack groups */
group_size = exp_strategy + (exp_strategy == EXP_D45);
for(grp=0,i=0; grp<ngrps; grp++) {
expacc = get_bits(gb, 7);
expacc = get_bits(gbc, 7);
dexp[i++] = exp_ungroup_tab[expacc][0];
dexp[i++] = exp_ungroup_tab[expacc][1];
dexp[i++] = exp_ungroup_tab[expacc][2];
@ -488,7 +488,7 @@ typedef struct {
*/
static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_groups *m)
{
GetBitContext *gb = &ctx->gb;
GetBitContext *gbc = &ctx->gbc;
int i, gcode, tbap, start, end;
uint8_t *exps;
uint8_t *bap;
@ -509,7 +509,7 @@ static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_gro
case 1:
if(m->b1ptr > 2) {
gcode = get_bits(gb, 5);
gcode = get_bits(gbc, 5);
m->b1_mant[0] = b1_mantissas[gcode][0];
m->b1_mant[1] = b1_mantissas[gcode][1];
m->b1_mant[2] = b1_mantissas[gcode][2];
@ -520,7 +520,7 @@ static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_gro
case 2:
if(m->b2ptr > 2) {
gcode = get_bits(gb, 7);
gcode = get_bits(gbc, 7);
m->b2_mant[0] = b2_mantissas[gcode][0];
m->b2_mant[1] = b2_mantissas[gcode][1];
m->b2_mant[2] = b2_mantissas[gcode][2];
@ -530,12 +530,12 @@ static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_gro
break;
case 3:
coeffs[i] = b3_mantissas[get_bits(gb, 3)];
coeffs[i] = b3_mantissas[get_bits(gbc, 3)];
break;
case 4:
if(m->b4ptr > 1) {
gcode = get_bits(gb, 7);
gcode = get_bits(gbc, 7);
m->b4_mant[0] = b4_mantissas[gcode][0];
m->b4_mant[1] = b4_mantissas[gcode][1];
m->b4ptr = 0;
@ -544,12 +544,12 @@ static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_gro
break;
case 5:
coeffs[i] = b5_mantissas[get_bits(gb, 4)];
coeffs[i] = b5_mantissas[get_bits(gbc, 4)];
break;
default:
/* asymmetric dequantization */
coeffs[i] = get_sbits(gb, quantization_tab[tbap]) * scale_factors[quantization_tab[tbap]-1];
coeffs[i] = get_sbits(gbc, quantization_tab[tbap]) * scale_factors[quantization_tab[tbap]-1];
break;
}
coeffs[i] *= scale_factors[exps[i]];
@ -769,19 +769,19 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
int fbw_channels = ctx->fbw_channels;
int channel_mode = ctx->channel_mode;
int i, bnd, seg, ch;
GetBitContext *gb = &ctx->gb;
GetBitContext *gbc = &ctx->gbc;
uint8_t bit_alloc_stages[AC3_MAX_CHANNELS];
memset(bit_alloc_stages, 0, AC3_MAX_CHANNELS);
/* block switch flags */
for (ch = 1; ch <= fbw_channels; ch++)
ctx->block_switch[ch] = get_bits1(gb);
ctx->block_switch[ch] = get_bits1(gbc);
/* dithering flags */
ctx->dither_all = 1;
for (ch = 1; ch <= fbw_channels; ch++) {
ctx->dither_flag[ch] = get_bits1(gb);
ctx->dither_flag[ch] = get_bits1(gbc);
if(!ctx->dither_flag[ch])
ctx->dither_all = 0;
}
@ -789,8 +789,8 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
/* dynamic range */
i = !(ctx->channel_mode);
do {
if(get_bits1(gb)) {
ctx->dynamic_range[i] = ((dynamic_range_tab[get_bits(gb, 8)]-1.0) *
if(get_bits1(gbc)) {
ctx->dynamic_range[i] = ((dynamic_range_tab[get_bits(gbc, 8)]-1.0) *
ctx->avctx->drc_scale)+1.0;
} else if(blk == 0) {
ctx->dynamic_range[i] = 1.0f;
@ -798,24 +798,24 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
} while(i--);
/* coupling strategy */
if (get_bits1(gb)) {
if (get_bits1(gbc)) {
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
ctx->cpl_in_use = get_bits1(gb);
ctx->cpl_in_use = get_bits1(gbc);
if (ctx->cpl_in_use) {
/* coupling in use */
int cpl_begin_freq, cpl_end_freq;
/* determine which channels are coupled */
for (ch = 1; ch <= fbw_channels; ch++)
ctx->channel_in_cpl[ch] = get_bits1(gb);
ctx->channel_in_cpl[ch] = get_bits1(gbc);
/* phase flags in use */
if (channel_mode == AC3_CHMODE_STEREO)
ctx->phase_flags_in_use = get_bits1(gb);
ctx->phase_flags_in_use = get_bits1(gbc);
/* coupling frequency range and band structure */
cpl_begin_freq = get_bits(gb, 4);
cpl_end_freq = get_bits(gb, 4);
cpl_begin_freq = get_bits(gbc, 4);
cpl_end_freq = get_bits(gbc, 4);
if (3 + cpl_end_freq - cpl_begin_freq < 0) {
av_log(ctx->avctx, AV_LOG_ERROR, "3+cplendf = %d < cplbegf = %d\n", 3+cpl_end_freq, cpl_begin_freq);
return -1;
@ -824,7 +824,7 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
ctx->start_freq[CPL_CH] = cpl_begin_freq * 12 + 37;
ctx->end_freq[CPL_CH] = cpl_end_freq * 12 + 73;
for (bnd = 0; bnd < ctx->num_cpl_subbands - 1; bnd++) {
if (get_bits1(gb)) {
if (get_bits1(gbc)) {
ctx->cpl_band_struct[bnd] = 1;
ctx->num_cpl_bands--;
}
@ -842,13 +842,13 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
for (ch = 1; ch <= fbw_channels; ch++) {
if (ctx->channel_in_cpl[ch]) {
if (get_bits1(gb)) {
if (get_bits1(gbc)) {
int master_cpl_coord, cpl_coord_exp, cpl_coord_mant;
cpl_coords_exist = 1;
master_cpl_coord = 3 * get_bits(gb, 2);
master_cpl_coord = 3 * get_bits(gbc, 2);
for (bnd = 0; bnd < ctx->num_cpl_bands; bnd++) {
cpl_coord_exp = get_bits(gb, 4);
cpl_coord_mant = get_bits(gb, 4);
cpl_coord_exp = get_bits(gbc, 4);
cpl_coord_mant = get_bits(gbc, 4);
if (cpl_coord_exp == 15)
ctx->cpl_coords[ch][bnd] = cpl_coord_mant / 16.0f;
else
@ -861,7 +861,7 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
/* phase flags */
if (channel_mode == AC3_CHMODE_STEREO && ctx->phase_flags_in_use && cpl_coords_exist) {
for (bnd = 0; bnd < ctx->num_cpl_bands; bnd++) {
if (get_bits1(gb))
if (get_bits1(gbc))
ctx->cpl_coords[2][bnd] = -ctx->cpl_coords[2][bnd];
}
}
@ -869,13 +869,13 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
/* stereo rematrixing strategy and band structure */
if (channel_mode == AC3_CHMODE_STEREO) {
ctx->rematrixing_strategy = get_bits1(gb);
ctx->rematrixing_strategy = get_bits1(gbc);
if (ctx->rematrixing_strategy) {
ctx->num_rematrixing_bands = 4;
if(ctx->cpl_in_use && ctx->start_freq[CPL_CH] <= 61)
ctx->num_rematrixing_bands -= 1 + (ctx->start_freq[CPL_CH] == 37);
for(bnd=0; bnd<ctx->num_rematrixing_bands; bnd++)
ctx->rematrixing_flags[bnd] = get_bits1(gb);
ctx->rematrixing_flags[bnd] = get_bits1(gbc);
}
}
@ -884,9 +884,9 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
ctx->exp_strategy[ctx->lfe_ch] = EXP_REUSE;
for (ch = !ctx->cpl_in_use; ch <= ctx->channels; ch++) {
if(ch == ctx->lfe_ch)
ctx->exp_strategy[ch] = get_bits(gb, 1);
ctx->exp_strategy[ch] = get_bits(gbc, 1);
else
ctx->exp_strategy[ch] = get_bits(gb, 2);
ctx->exp_strategy[ch] = get_bits(gbc, 2);
if(ctx->exp_strategy[ch] != EXP_REUSE)
bit_alloc_stages[ch] = 3;
}
@ -899,7 +899,7 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
if (ctx->channel_in_cpl[ch])
ctx->end_freq[ch] = ctx->start_freq[CPL_CH];
else {
int bandwidth_code = get_bits(gb, 6);
int bandwidth_code = get_bits(gbc, 6);
if (bandwidth_code > 60) {
av_log(ctx->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60", bandwidth_code);
return -1;
@ -924,49 +924,49 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
num_groups = 2;
else
num_groups = (ctx->end_freq[ch] + group_size - 4) / group_size;
ctx->dexps[ch][0] = get_bits(gb, 4) << !ch;
decode_exponents(gb, ctx->exp_strategy[ch], num_groups, ctx->dexps[ch][0],
ctx->dexps[ch][0] = get_bits(gbc, 4) << !ch;
decode_exponents(gbc, ctx->exp_strategy[ch], num_groups, ctx->dexps[ch][0],
&ctx->dexps[ch][ctx->start_freq[ch]+!!ch]);
if(ch != CPL_CH && ch != ctx->lfe_ch)
skip_bits(gb, 2); /* skip gainrng */
skip_bits(gbc, 2); /* skip gainrng */
}
}
/* bit allocation information */
if (get_bits1(gb)) {
ctx->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gb, 2)] >> ctx->bit_alloc_params.sr_shift;
ctx->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gb, 2)] >> ctx->bit_alloc_params.sr_shift;
ctx->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gb, 2)];
ctx->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gb, 2)];
ctx->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gb, 3)];
if (get_bits1(gbc)) {
ctx->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> ctx->bit_alloc_params.sr_shift;
ctx->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> ctx->bit_alloc_params.sr_shift;
ctx->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gbc, 2)];
ctx->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)];
ctx->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gbc, 3)];
for(ch=!ctx->cpl_in_use; ch<=ctx->channels; ch++) {
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
}
}
/* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
if (get_bits1(gb)) {
if (get_bits1(gbc)) {
int csnr;
csnr = (get_bits(gb, 6) - 15) << 4;
csnr = (get_bits(gbc, 6) - 15) << 4;
for (ch = !ctx->cpl_in_use; ch <= ctx->channels; ch++) { /* snr offset and fast gain */
ctx->snr_offset[ch] = (csnr + get_bits(gb, 4)) << 2;
ctx->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gb, 3)];
ctx->snr_offset[ch] = (csnr + get_bits(gbc, 4)) << 2;
ctx->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
}
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
}
/* coupling leak information */
if (ctx->cpl_in_use && get_bits1(gb)) {
ctx->bit_alloc_params.cpl_fast_leak = get_bits(gb, 3);
ctx->bit_alloc_params.cpl_slow_leak = get_bits(gb, 3);
if (ctx->cpl_in_use && get_bits1(gbc)) {
ctx->bit_alloc_params.cpl_fast_leak = get_bits(gbc, 3);
ctx->bit_alloc_params.cpl_slow_leak = get_bits(gbc, 3);
bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
}
/* delta bit allocation information */
if (get_bits1(gb)) {
if (get_bits1(gbc)) {
/* delta bit allocation exists (strategy) */
for (ch = !ctx->cpl_in_use; ch <= fbw_channels; ch++) {
ctx->dba_mode[ch] = get_bits(gb, 2);
ctx->dba_mode[ch] = get_bits(gbc, 2);
if (ctx->dba_mode[ch] == DBA_RESERVED) {
av_log(ctx->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
return -1;
@ -976,11 +976,11 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
/* channel delta offset, len and bit allocation */
for (ch = !ctx->cpl_in_use; ch <= fbw_channels; ch++) {
if (ctx->dba_mode[ch] == DBA_NEW) {
ctx->dba_nsegs[ch] = get_bits(gb, 3);
ctx->dba_nsegs[ch] = get_bits(gbc, 3);
for (seg = 0; seg <= ctx->dba_nsegs[ch]; seg++) {
ctx->dba_offsets[ch][seg] = get_bits(gb, 5);
ctx->dba_lengths[ch][seg] = get_bits(gb, 4);
ctx->dba_values[ch][seg] = get_bits(gb, 3);
ctx->dba_offsets[ch][seg] = get_bits(gbc, 5);
ctx->dba_lengths[ch][seg] = get_bits(gbc, 4);
ctx->dba_values[ch][seg] = get_bits(gbc, 3);
}
}
}
@ -1019,10 +1019,10 @@ static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
}
/* unused dummy data */
if (get_bits1(gb)) {
int skipl = get_bits(gb, 9);
if (get_bits1(gbc)) {
int skipl = get_bits(gbc, 9);
while(skipl--)
skip_bits(gb, 8);
skip_bits(gbc, 8);
}
/* unpack the transform coefficients
@ -1079,7 +1079,7 @@ static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size,
int i, blk, ch, err;
/* initialize the GetBitContext with the start of valid AC-3 Frame */
init_get_bits(&ctx->gb, buf, buf_size * 8);
init_get_bits(&ctx->gbc, buf, buf_size * 8);
/* parse the syncinfo */
err = ac3_parse_header(ctx);