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mirror of https://github.com/FFmpeg/FFmpeg.git synced 2024-12-23 12:43:46 +02:00

cosmetics: Move H.263-related functions around to avoid forward declarations.

Originally committed as revision 20978 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Diego Biurrun 2009-12-30 14:34:14 +00:00
parent 8380edd947
commit 1436f31709

View File

@ -56,10 +56,6 @@
#define H263_MBTYPE_B_VLC_BITS 6
#define CBPC_B_VLC_BITS 3
static int h263_decode_motion(MpegEncContext * s, int pred, int fcode);
static int h263p_decode_umotion(MpegEncContext * s, int pred);
static int h263_decode_block(MpegEncContext * s, DCTELEM * block,
int n, int coded);
static inline int mpeg4_decode_dc(MpegEncContext * s, int n, int *dir_ptr);
static inline int mpeg4_decode_block(MpegEncContext * s, DCTELEM * block,
int n, int coded, int intra, int rvlc);
@ -68,10 +64,6 @@ static void mpeg4_decode_sprite_trajectory(MpegEncContext * s, GetBitContext *gb
static inline int ff_mpeg4_pred_dc(MpegEncContext * s, int n, int level, int *dir_ptr, int encoding);
#if CONFIG_ENCODERS
static void h263_encode_block(MpegEncContext *s, DCTELEM *block, int n);
static void h263p_encode_umotion(MpegEncContext *s, int val);
static int h263_pred_dc(MpegEncContext *s, int n, int16_t **dc_val_ptr);
static void mpeg4_encode_visual_object_header(MpegEncContext *s);
static void mpeg4_encode_vol_header(MpegEncContext *s, int vo_number,
int vol_number);
@ -1244,6 +1236,213 @@ void mpeg4_encode_mb(MpegEncContext * s,
}
}
/**
* encodes a 8x8 block.
* @param block the 8x8 block
* @param n block index (0-3 are luma, 4-5 are chroma)
*/
static void h263_encode_block(MpegEncContext * s, DCTELEM * block, int n)
{
int level, run, last, i, j, last_index, last_non_zero, sign, slevel, code;
RLTable *rl;
rl = &rl_inter;
if (s->mb_intra && !s->h263_aic) {
/* DC coef */
level = block[0];
/* 255 cannot be represented, so we clamp */
if (level > 254) {
level = 254;
block[0] = 254;
}
/* 0 cannot be represented also */
else if (level < 1) {
level = 1;
block[0] = 1;
}
if (level == 128) //FIXME check rv10
put_bits(&s->pb, 8, 0xff);
else
put_bits(&s->pb, 8, level);
i = 1;
} else {
i = 0;
if (s->h263_aic && s->mb_intra)
rl = &rl_intra_aic;
if(s->alt_inter_vlc && !s->mb_intra){
int aic_vlc_bits=0;
int inter_vlc_bits=0;
int wrong_pos=-1;
int aic_code;
last_index = s->block_last_index[n];
last_non_zero = i - 1;
for (; i <= last_index; i++) {
j = s->intra_scantable.permutated[i];
level = block[j];
if (level) {
run = i - last_non_zero - 1;
last = (i == last_index);
if(level<0) level= -level;
code = get_rl_index(rl, last, run, level);
aic_code = get_rl_index(&rl_intra_aic, last, run, level);
inter_vlc_bits += rl->table_vlc[code][1]+1;
aic_vlc_bits += rl_intra_aic.table_vlc[aic_code][1]+1;
if (code == rl->n) {
inter_vlc_bits += 1+6+8-1;
}
if (aic_code == rl_intra_aic.n) {
aic_vlc_bits += 1+6+8-1;
wrong_pos += run + 1;
}else
wrong_pos += wrong_run[aic_code];
last_non_zero = i;
}
}
i = 0;
if(aic_vlc_bits < inter_vlc_bits && wrong_pos > 63)
rl = &rl_intra_aic;
}
}
/* AC coefs */
last_index = s->block_last_index[n];
last_non_zero = i - 1;
for (; i <= last_index; i++) {
j = s->intra_scantable.permutated[i];
level = block[j];
if (level) {
run = i - last_non_zero - 1;
last = (i == last_index);
sign = 0;
slevel = level;
if (level < 0) {
sign = 1;
level = -level;
}
code = get_rl_index(rl, last, run, level);
put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
if (code == rl->n) {
if(s->h263_flv <= 1){
put_bits(&s->pb, 1, last);
put_bits(&s->pb, 6, run);
assert(slevel != 0);
if(level < 128)
put_sbits(&s->pb, 8, slevel);
else{
put_bits(&s->pb, 8, 128);
put_sbits(&s->pb, 5, slevel);
put_sbits(&s->pb, 6, slevel>>5);
}
}else{
if(level < 64) { // 7-bit level
put_bits(&s->pb, 1, 0);
put_bits(&s->pb, 1, last);
put_bits(&s->pb, 6, run);
put_sbits(&s->pb, 7, slevel);
} else {
/* 11-bit level */
put_bits(&s->pb, 1, 1);
put_bits(&s->pb, 1, last);
put_bits(&s->pb, 6, run);
put_sbits(&s->pb, 11, slevel);
}
}
} else {
put_bits(&s->pb, 1, sign);
}
last_non_zero = i;
}
}
}
/* Encode MV differences on H.263+ with Unrestricted MV mode */
static void h263p_encode_umotion(MpegEncContext * s, int val)
{
short sval = 0;
short i = 0;
short n_bits = 0;
short temp_val;
int code = 0;
int tcode;
if ( val == 0)
put_bits(&s->pb, 1, 1);
else if (val == 1)
put_bits(&s->pb, 3, 0);
else if (val == -1)
put_bits(&s->pb, 3, 2);
else {
sval = ((val < 0) ? (short)(-val):(short)val);
temp_val = sval;
while (temp_val != 0) {
temp_val = temp_val >> 1;
n_bits++;
}
i = n_bits - 1;
while (i > 0) {
tcode = (sval & (1 << (i-1))) >> (i-1);
tcode = (tcode << 1) | 1;
code = (code << 2) | tcode;
i--;
}
code = ((code << 1) | (val < 0)) << 1;
put_bits(&s->pb, (2*n_bits)+1, code);
}
}
static int h263_pred_dc(MpegEncContext * s, int n, int16_t **dc_val_ptr)
{
int x, y, wrap, a, c, pred_dc;
int16_t *dc_val;
/* find prediction */
if (n < 4) {
x = 2 * s->mb_x + (n & 1);
y = 2 * s->mb_y + ((n & 2) >> 1);
wrap = s->b8_stride;
dc_val = s->dc_val[0];
} else {
x = s->mb_x;
y = s->mb_y;
wrap = s->mb_stride;
dc_val = s->dc_val[n - 4 + 1];
}
/* B C
* A X
*/
a = dc_val[(x - 1) + (y) * wrap];
c = dc_val[(x) + (y - 1) * wrap];
/* No prediction outside GOB boundary */
if(s->first_slice_line && n!=3){
if(n!=2) c= 1024;
if(n!=1 && s->mb_x == s->resync_mb_x) a= 1024;
}
/* just DC prediction */
if (a != 1024 && c != 1024)
pred_dc = (a + c) >> 1;
else if (a != 1024)
pred_dc = a;
else
pred_dc = c;
/* we assume pred is positive */
*dc_val_ptr = &dc_val[x + y * wrap];
return pred_dc;
}
void h263_encode_mb(MpegEncContext * s,
DCTELEM block[6][64],
int motion_x, int motion_y)
@ -1533,49 +1732,6 @@ void ff_h263_loop_filter(MpegEncContext * s){
}
}
#if CONFIG_ENCODERS
static int h263_pred_dc(MpegEncContext * s, int n, int16_t **dc_val_ptr)
{
int x, y, wrap, a, c, pred_dc;
int16_t *dc_val;
/* find prediction */
if (n < 4) {
x = 2 * s->mb_x + (n & 1);
y = 2 * s->mb_y + ((n & 2) >> 1);
wrap = s->b8_stride;
dc_val = s->dc_val[0];
} else {
x = s->mb_x;
y = s->mb_y;
wrap = s->mb_stride;
dc_val = s->dc_val[n - 4 + 1];
}
/* B C
* A X
*/
a = dc_val[(x - 1) + (y) * wrap];
c = dc_val[(x) + (y - 1) * wrap];
/* No prediction outside GOB boundary */
if(s->first_slice_line && n!=3){
if(n!=2) c= 1024;
if(n!=1 && s->mb_x == s->resync_mb_x) a= 1024;
}
/* just DC prediction */
if (a != 1024 && c != 1024)
pred_dc = (a + c) >> 1;
else if (a != 1024)
pred_dc = a;
else
pred_dc = c;
/* we assume pred is positive */
*dc_val_ptr = &dc_val[x + y * wrap];
return pred_dc;
}
#endif /* CONFIG_ENCODERS */
static void h263_pred_acdc(MpegEncContext * s, DCTELEM *block, int n)
{
int x, y, wrap, a, c, pred_dc, scale, i;
@ -1751,44 +1907,6 @@ void ff_h263_encode_motion(MpegEncContext * s, int val, int f_code)
}
}
/* Encode MV differences on H.263+ with Unrestricted MV mode */
static void h263p_encode_umotion(MpegEncContext * s, int val)
{
short sval = 0;
short i = 0;
short n_bits = 0;
short temp_val;
int code = 0;
int tcode;
if ( val == 0)
put_bits(&s->pb, 1, 1);
else if (val == 1)
put_bits(&s->pb, 3, 0);
else if (val == -1)
put_bits(&s->pb, 3, 2);
else {
sval = ((val < 0) ? (short)(-val):(short)val);
temp_val = sval;
while (temp_val != 0) {
temp_val = temp_val >> 1;
n_bits++;
}
i = n_bits - 1;
while (i > 0) {
tcode = (sval & (1 << (i-1))) >> (i-1);
tcode = (tcode << 1) | 1;
code = (code << 2) | tcode;
i--;
}
code = ((code << 1) | (val < 0)) << 1;
put_bits(&s->pb, (2*n_bits)+1, code);
}
}
static void init_mv_penalty_and_fcode(MpegEncContext *s)
{
int f_code;
@ -2100,134 +2218,6 @@ void h263_encode_init(MpegEncContext *s)
}
}
/**
* encodes a 8x8 block.
* @param block the 8x8 block
* @param n block index (0-3 are luma, 4-5 are chroma)
*/
static void h263_encode_block(MpegEncContext * s, DCTELEM * block, int n)
{
int level, run, last, i, j, last_index, last_non_zero, sign, slevel, code;
RLTable *rl;
rl = &rl_inter;
if (s->mb_intra && !s->h263_aic) {
/* DC coef */
level = block[0];
/* 255 cannot be represented, so we clamp */
if (level > 254) {
level = 254;
block[0] = 254;
}
/* 0 cannot be represented also */
else if (level < 1) {
level = 1;
block[0] = 1;
}
if (level == 128) //FIXME check rv10
put_bits(&s->pb, 8, 0xff);
else
put_bits(&s->pb, 8, level);
i = 1;
} else {
i = 0;
if (s->h263_aic && s->mb_intra)
rl = &rl_intra_aic;
if(s->alt_inter_vlc && !s->mb_intra){
int aic_vlc_bits=0;
int inter_vlc_bits=0;
int wrong_pos=-1;
int aic_code;
last_index = s->block_last_index[n];
last_non_zero = i - 1;
for (; i <= last_index; i++) {
j = s->intra_scantable.permutated[i];
level = block[j];
if (level) {
run = i - last_non_zero - 1;
last = (i == last_index);
if(level<0) level= -level;
code = get_rl_index(rl, last, run, level);
aic_code = get_rl_index(&rl_intra_aic, last, run, level);
inter_vlc_bits += rl->table_vlc[code][1]+1;
aic_vlc_bits += rl_intra_aic.table_vlc[aic_code][1]+1;
if (code == rl->n) {
inter_vlc_bits += 1+6+8-1;
}
if (aic_code == rl_intra_aic.n) {
aic_vlc_bits += 1+6+8-1;
wrong_pos += run + 1;
}else
wrong_pos += wrong_run[aic_code];
last_non_zero = i;
}
}
i = 0;
if(aic_vlc_bits < inter_vlc_bits && wrong_pos > 63)
rl = &rl_intra_aic;
}
}
/* AC coefs */
last_index = s->block_last_index[n];
last_non_zero = i - 1;
for (; i <= last_index; i++) {
j = s->intra_scantable.permutated[i];
level = block[j];
if (level) {
run = i - last_non_zero - 1;
last = (i == last_index);
sign = 0;
slevel = level;
if (level < 0) {
sign = 1;
level = -level;
}
code = get_rl_index(rl, last, run, level);
put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
if (code == rl->n) {
if(s->h263_flv <= 1){
put_bits(&s->pb, 1, last);
put_bits(&s->pb, 6, run);
assert(slevel != 0);
if(level < 128)
put_sbits(&s->pb, 8, slevel);
else{
put_bits(&s->pb, 8, 128);
put_sbits(&s->pb, 5, slevel);
put_sbits(&s->pb, 6, slevel>>5);
}
}else{
if(level < 64) { // 7-bit level
put_bits(&s->pb, 1, 0);
put_bits(&s->pb, 1, last);
put_bits(&s->pb, 6, run);
put_sbits(&s->pb, 7, slevel);
} else {
/* 11-bit level */
put_bits(&s->pb, 1, 1);
put_bits(&s->pb, 1, last);
put_bits(&s->pb, 6, run);
put_sbits(&s->pb, 11, slevel);
}
}
} else {
put_bits(&s->pb, 1, sign);
}
last_non_zero = i;
}
}
}
/***************************************************/
/**
* add mpeg4 stuffing bits (01...1)
@ -3325,6 +3315,43 @@ int ff_h263_resync(MpegEncContext *s){
return -1;
}
static int h263_decode_motion(MpegEncContext * s, int pred, int f_code)
{
int code, val, sign, shift, l;
code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
if (code == 0)
return pred;
if (code < 0)
return 0xffff;
sign = get_bits1(&s->gb);
shift = f_code - 1;
val = code;
if (shift) {
val = (val - 1) << shift;
val |= get_bits(&s->gb, shift);
val++;
}
if (sign)
val = -val;
val += pred;
/* modulo decoding */
if (!s->h263_long_vectors) {
l = INT_BIT - 5 - f_code;
val = (val<<l)>>l;
} else {
/* horrible h263 long vector mode */
if (pred < -31 && val < -63)
val += 64;
if (pred > 32 && val > 63)
val -= 64;
}
return val;
}
/**
* gets the average motion vector for a GMC MB.
* @param n either 0 for the x component or 1 for y
@ -3762,6 +3789,30 @@ static int mpeg4_decode_partitioned_mb(MpegEncContext *s, DCTELEM block[6][64])
}
}
/* Decodes RVLC of H.263+ UMV */
static int h263p_decode_umotion(MpegEncContext * s, int pred)
{
int code = 0, sign;
if (get_bits1(&s->gb)) /* Motion difference = 0 */
return pred;
code = 2 + get_bits1(&s->gb);
while (get_bits1(&s->gb))
{
code <<= 1;
code += get_bits1(&s->gb);
}
sign = code & 1;
code >>= 1;
code = (sign) ? (pred - code) : (pred + code);
dprintf(s->avctx,"H.263+ UMV Motion = %d\n", code);
return code;
}
/**
* read the next MVs for OBMC. yes this is a ugly hack, feel free to send a patch :)
*/
@ -3870,6 +3921,136 @@ static void h263_decode_dquant(MpegEncContext *s){
ff_set_qscale(s, s->qscale);
}
static int h263_decode_block(MpegEncContext * s, DCTELEM * block,
int n, int coded)
{
int code, level, i, j, last, run;
RLTable *rl = &rl_inter;
const uint8_t *scan_table;
GetBitContext gb= s->gb;
scan_table = s->intra_scantable.permutated;
if (s->h263_aic && s->mb_intra) {
rl = &rl_intra_aic;
i = 0;
if (s->ac_pred) {
if (s->h263_aic_dir)
scan_table = s->intra_v_scantable.permutated; /* left */
else
scan_table = s->intra_h_scantable.permutated; /* top */
}
} else if (s->mb_intra) {
/* DC coef */
if(s->codec_id == CODEC_ID_RV10){
#if CONFIG_RV10_DECODER
if (s->rv10_version == 3 && s->pict_type == FF_I_TYPE) {
int component, diff;
component = (n <= 3 ? 0 : n - 4 + 1);
level = s->last_dc[component];
if (s->rv10_first_dc_coded[component]) {
diff = rv_decode_dc(s, n);
if (diff == 0xffff)
return -1;
level += diff;
level = level & 0xff; /* handle wrap round */
s->last_dc[component] = level;
} else {
s->rv10_first_dc_coded[component] = 1;
}
} else {
level = get_bits(&s->gb, 8);
if (level == 255)
level = 128;
}
#endif
}else{
level = get_bits(&s->gb, 8);
if((level&0x7F) == 0){
av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
if(s->error_recognition >= FF_ER_COMPLIANT)
return -1;
}
if (level == 255)
level = 128;
}
block[0] = level;
i = 1;
} else {
i = 0;
}
if (!coded) {
if (s->mb_intra && s->h263_aic)
goto not_coded;
s->block_last_index[n] = i - 1;
return 0;
}
retry:
for(;;) {
code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);
if (code < 0){
av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
return -1;
}
if (code == rl->n) {
/* escape */
if (s->h263_flv > 1) {
int is11 = get_bits1(&s->gb);
last = get_bits1(&s->gb);
run = get_bits(&s->gb, 6);
if(is11){
level = get_sbits(&s->gb, 11);
} else {
level = get_sbits(&s->gb, 7);
}
} else {
last = get_bits1(&s->gb);
run = get_bits(&s->gb, 6);
level = (int8_t)get_bits(&s->gb, 8);
if(level == -128){
if (s->codec_id == CODEC_ID_RV10) {
/* XXX: should patch encoder too */
level = get_sbits(&s->gb, 12);
}else{
level = get_bits(&s->gb, 5);
level |= get_sbits(&s->gb, 6)<<5;
}
}
}
} else {
run = rl->table_run[code];
level = rl->table_level[code];
last = code >= rl->last;
if (get_bits1(&s->gb))
level = -level;
}
i += run;
if (i >= 64){
if(s->alt_inter_vlc && rl == &rl_inter && !s->mb_intra){
//Looks like a hack but no, it's the way it is supposed to work ...
rl = &rl_intra_aic;
i = 0;
s->gb= gb;
s->dsp.clear_block(block);
goto retry;
}
av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
return -1;
}
j = scan_table[i];
block[j] = level;
if (last)
break;
i++;
}
not_coded:
if (s->mb_intra && s->h263_aic) {
h263_pred_acdc(s, block, n);
i = 63;
}
s->block_last_index[n] = i;
return 0;
}
static int h263_skip_b_part(MpegEncContext *s, int cbp)
{
DECLARE_ALIGNED(16, DCTELEM, dblock[64]);
@ -4501,197 +4682,6 @@ end:
return SLICE_OK;
}
static int h263_decode_motion(MpegEncContext * s, int pred, int f_code)
{
int code, val, sign, shift, l;
code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
if (code == 0)
return pred;
if (code < 0)
return 0xffff;
sign = get_bits1(&s->gb);
shift = f_code - 1;
val = code;
if (shift) {
val = (val - 1) << shift;
val |= get_bits(&s->gb, shift);
val++;
}
if (sign)
val = -val;
val += pred;
/* modulo decoding */
if (!s->h263_long_vectors) {
l = INT_BIT - 5 - f_code;
val = (val<<l)>>l;
} else {
/* horrible h263 long vector mode */
if (pred < -31 && val < -63)
val += 64;
if (pred > 32 && val > 63)
val -= 64;
}
return val;
}
/* Decodes RVLC of H.263+ UMV */
static int h263p_decode_umotion(MpegEncContext * s, int pred)
{
int code = 0, sign;
if (get_bits1(&s->gb)) /* Motion difference = 0 */
return pred;
code = 2 + get_bits1(&s->gb);
while (get_bits1(&s->gb))
{
code <<= 1;
code += get_bits1(&s->gb);
}
sign = code & 1;
code >>= 1;
code = (sign) ? (pred - code) : (pred + code);
dprintf(s->avctx,"H.263+ UMV Motion = %d\n", code);
return code;
}
static int h263_decode_block(MpegEncContext * s, DCTELEM * block,
int n, int coded)
{
int code, level, i, j, last, run;
RLTable *rl = &rl_inter;
const uint8_t *scan_table;
GetBitContext gb= s->gb;
scan_table = s->intra_scantable.permutated;
if (s->h263_aic && s->mb_intra) {
rl = &rl_intra_aic;
i = 0;
if (s->ac_pred) {
if (s->h263_aic_dir)
scan_table = s->intra_v_scantable.permutated; /* left */
else
scan_table = s->intra_h_scantable.permutated; /* top */
}
} else if (s->mb_intra) {
/* DC coef */
if(s->codec_id == CODEC_ID_RV10){
#if CONFIG_RV10_DECODER
if (s->rv10_version == 3 && s->pict_type == FF_I_TYPE) {
int component, diff;
component = (n <= 3 ? 0 : n - 4 + 1);
level = s->last_dc[component];
if (s->rv10_first_dc_coded[component]) {
diff = rv_decode_dc(s, n);
if (diff == 0xffff)
return -1;
level += diff;
level = level & 0xff; /* handle wrap round */
s->last_dc[component] = level;
} else {
s->rv10_first_dc_coded[component] = 1;
}
} else {
level = get_bits(&s->gb, 8);
if (level == 255)
level = 128;
}
#endif
}else{
level = get_bits(&s->gb, 8);
if((level&0x7F) == 0){
av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
if(s->error_recognition >= FF_ER_COMPLIANT)
return -1;
}
if (level == 255)
level = 128;
}
block[0] = level;
i = 1;
} else {
i = 0;
}
if (!coded) {
if (s->mb_intra && s->h263_aic)
goto not_coded;
s->block_last_index[n] = i - 1;
return 0;
}
retry:
for(;;) {
code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);
if (code < 0){
av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
return -1;
}
if (code == rl->n) {
/* escape */
if (s->h263_flv > 1) {
int is11 = get_bits1(&s->gb);
last = get_bits1(&s->gb);
run = get_bits(&s->gb, 6);
if(is11){
level = get_sbits(&s->gb, 11);
} else {
level = get_sbits(&s->gb, 7);
}
} else {
last = get_bits1(&s->gb);
run = get_bits(&s->gb, 6);
level = (int8_t)get_bits(&s->gb, 8);
if(level == -128){
if (s->codec_id == CODEC_ID_RV10) {
/* XXX: should patch encoder too */
level = get_sbits(&s->gb, 12);
}else{
level = get_bits(&s->gb, 5);
level |= get_sbits(&s->gb, 6)<<5;
}
}
}
} else {
run = rl->table_run[code];
level = rl->table_level[code];
last = code >= rl->last;
if (get_bits1(&s->gb))
level = -level;
}
i += run;
if (i >= 64){
if(s->alt_inter_vlc && rl == &rl_inter && !s->mb_intra){
//Looks like a hack but no, it's the way it is supposed to work ...
rl = &rl_intra_aic;
i = 0;
s->gb= gb;
s->dsp.clear_block(block);
goto retry;
}
av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
return -1;
}
j = scan_table[i];
block[j] = level;
if (last)
break;
i++;
}
not_coded:
if (s->mb_intra && s->h263_aic) {
h263_pred_acdc(s, block, n);
i = 63;
}
s->block_last_index[n] = i;
return 0;
}
/**
* decodes the dc value.
* @param n block index (0-3 are luma, 4-5 are chroma)