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utvideo: proper median prediction for interlaced videos

This commit is contained in:
Kostya Shishkov 2012-01-01 17:44:08 +01:00
parent c04a954da6
commit 490dcda6b6
1 changed files with 94 additions and 7 deletions
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101
libavcodec/utvideo.c
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@ -282,6 +282,77 @@ static void restore_median(uint8_t *src, int step, int stride,
}
}
/* UtVideo interlaced mode treats every two lines as a single one,
* so restoring function should take care of possible padding between
* two parts of the same "line".
*/
static void restore_median_il(uint8_t *src, int step, int stride,
int width, int height, int slices, int rmode)
{
int i, j, slice;
int A, B, C;
uint8_t *bsrc;
int slice_start, slice_height;
const int cmask = ~(rmode ? 3 : 1);
const int stride2 = stride << 1;
for (slice = 0; slice < slices; slice++) {
slice_start = ((slice * height) / slices) & cmask;
slice_height = ((((slice + 1) * height) / slices) & cmask) - slice_start;
slice_height >>= 1;
bsrc = src + slice_start * stride;
// first line - left neighbour prediction
bsrc[0] += 0x80;
A = bsrc[0];
for (i = step; i < width * step; i += step) {
bsrc[i] += A;
A = bsrc[i];
}
for (i = 0; i < width * step; i += step) {
bsrc[stride + i] += A;
A = bsrc[stride + i];
}
bsrc += stride2;
if (slice_height == 1)
continue;
// second line - first element has top predition, the rest uses median
C = bsrc[-stride2];
bsrc[0] += C;
A = bsrc[0];
for (i = step; i < width * step; i += step) {
B = bsrc[i - stride2];
bsrc[i] += mid_pred(A, B, (uint8_t)(A + B - C));
C = B;
A = bsrc[i];
}
for (i = 0; i < width * step; i += step) {
B = bsrc[i - stride];
bsrc[stride + i] += mid_pred(A, B, (uint8_t)(A + B - C));
C = B;
A = bsrc[stride + i];
}
bsrc += stride2;
// the rest of lines use continuous median prediction
for (j = 2; j < slice_height; j++) {
for (i = 0; i < width * step; i += step) {
B = bsrc[i - stride2];
bsrc[i] += mid_pred(A, B, (uint8_t)(A + B - C));
C = B;
A = bsrc[i];
}
for (i = 0; i < width * step; i += step) {
B = bsrc[i - stride];
bsrc[i + stride] += mid_pred(A, B, (uint8_t)(A + B - C));
C = B;
A = bsrc[i + stride];
}
bsrc += stride2;
}
}
}
static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
@ -381,10 +452,18 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPac
c->frame_pred == PRED_LEFT);
if (ret)
return ret;
if (c->frame_pred == PRED_MEDIAN)
restore_median(c->pic.data[i], 1, c->pic.linesize[i],
avctx->width >> !!i, avctx->height >> !!i,
c->slices, !i);
if (c->frame_pred == PRED_MEDIAN) {
if (!c->interlaced) {
restore_median(c->pic.data[i], 1, c->pic.linesize[i],
avctx->width >> !!i, avctx->height >> !!i,
c->slices, !i);
} else {
restore_median_il(c->pic.data[i], 1, c->pic.linesize[i],
avctx->width >> !!i,
avctx->height >> !!i,
c->slices, !i);
}
}
}
break;
case PIX_FMT_YUV422P:
@ -395,9 +474,17 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPac
c->frame_pred == PRED_LEFT);
if (ret)
return ret;
if (c->frame_pred == PRED_MEDIAN)
restore_median(c->pic.data[i], 1, c->pic.linesize[i],
avctx->width >> !!i, avctx->height, c->slices, 0);
if (c->frame_pred == PRED_MEDIAN) {
if (!c->interlaced) {
restore_median(c->pic.data[i], 1, c->pic.linesize[i],
avctx->width >> !!i, avctx->height,
c->slices, 0);
} else {
restore_median_il(c->pic.data[i], 1, c->pic.linesize[i],
avctx->width >> !!i, avctx->height,
c->slices, 0);
}
}
}
break;
}