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avcodec/mpeg4video: Move ff_mpeg4_pred_dc() to decoder

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Only used by the decoder now that the encoder solves
out-of-slice predictions by setting the out-of-slice
values appropriately.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt
2025-06-13 23:15:08 +02:00
parent 56fd45d2a9
commit 689cde75ee
2 changed files with 45 additions and 46 deletions
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44
libavcodec/mpeg4video.h
View File

@ -37,48 +37,4 @@ void ff_mpeg4_init_direct_mv(MpegEncContext *s);
*/
int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my);
/**
* Predict the dc.
* @param n block index (0-3 are luma, 4-5 are chroma)
* @param dir_ptr pointer to an integer where the prediction direction will be stored
*/
static inline int ff_mpeg4_pred_dc(MpegEncContext *s, int n, int *dir_ptr)
{
int a, b, c, wrap, pred;
const int16_t *const dc_val = s->dc_val + s->block_index[n];
/* find prediction */
wrap = s->block_wrap[n];
/* B C
* A X
*/
a = dc_val[-1];
b = dc_val[-1 - wrap];
c = dc_val[-wrap];
/* outside slice handling (we can't do that by memset as we need the
* dc for error resilience) */
if (s->first_slice_line && n != 3) {
if (n != 2)
b = c = 1024;
if (n != 1 && s->mb_x == s->resync_mb_x)
b = a = 1024;
}
if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1) {
if (n == 0 || n == 4 || n == 5)
b = 1024;
}
if (abs(a - b) < abs(b - c)) {
pred = c;
*dir_ptr = 1; /* top */
} else {
pred = a;
*dir_ptr = 0; /* left */
}
return pred;
}
#endif /* AVCODEC_MPEG4VIDEO_H */

47
libavcodec/mpeg4videodec.c
View File

@ -888,6 +888,49 @@ static inline int get_amv(Mpeg4DecContext *ctx, int n)
return sum;
}
/**
* Predict the dc.
* @param n block index (0-3 are luma, 4-5 are chroma)
* @param dir_ptr pointer to an integer where the prediction direction will be stored
*/
static inline int mpeg4_pred_dc(MpegEncContext *s, int n, int *dir_ptr)
{
const int16_t *const dc_val = s->dc_val + s->block_index[n];
const int wrap = s->block_wrap[n];
int pred;
/* find prediction */
/* B C
* A X
*/
int a = dc_val[-1];
int b = dc_val[-1 - wrap];
int c = dc_val[-wrap];
/* outside slice handling (we can't do that by memset as we need the
* dc for error resilience) */
if (s->first_slice_line && n != 3) {
if (n != 2)
b = c = 1024;
if (n != 1 && s->mb_x == s->resync_mb_x)
b = a = 1024;
}
if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1) {
if (n == 0 || n == 4 || n == 5)
b = 1024;
}
if (abs(a - b) < abs(b - c)) {
pred = c;
*dir_ptr = 1; /* top */
} else {
pred = a;
*dir_ptr = 0; /* left */
}
return pred;
}
static inline int mpeg4_get_level_dc(MpegEncContext *s, int n, int pred, int level)
{
int scale = n < 4 ? s->y_dc_scale : s->c_dc_scale;
@ -971,7 +1014,7 @@ static inline int mpeg4_decode_dc(MpegEncContext *s, int n, int *dir_ptr)
}
}
pred = ff_mpeg4_pred_dc(s, n, dir_ptr);
pred = mpeg4_pred_dc(s, n, dir_ptr);
return mpeg4_get_level_dc(s, n, pred, level);
}
@ -1362,7 +1405,7 @@ static inline int mpeg4_decode_block(Mpeg4DecContext *ctx, int16_t *block,
i = 0;
} else {
i = -1;
pred = ff_mpeg4_pred_dc(s, n, &dc_pred_dir);
pred = mpeg4_pred_dc(s, n, &dc_pred_dir);
}
if (!coded)
goto not_coded;