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lagarith: add YUY2 decoding support 

Unlike other variants, for YUY2 we need to use different prediction:
* on line 0 for luma we should left predict starting from the second pixel
* on line 1 we should left predict first 4 pixels for luma and 2 for chroma
* median prediction employed here is taken directly from HuffYUV
This commit is contained in:
Kostya Shishkov 2012-05-07 19:43:52 +02:00
parent 58637a0b24
commit 464e9ab011
1 changed files with 71 additions and 3 deletions
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74
libavcodec/lagarith.c
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@ -269,6 +269,40 @@ static void lag_pred_line(LagarithContext *l, uint8_t *buf,
}
}
static void lag_pred_line_yuy2(LagarithContext *l, uint8_t *buf,
int width, int stride, int line,
int is_luma)
{
int L, TL;
if (!line) {
if (is_luma) {
buf++;
width--;
}
l->dsp.add_hfyu_left_prediction(buf + 1, buf + 1, width - 1, buf[0]);
return;
}
if (line == 1) {
const int HEAD = is_luma ? 4 : 2;
int i;
L = buf[width - stride - 1];
TL = buf[HEAD - stride - 1];
for (i = 0; i < HEAD; i++) {
L += buf[i];
buf[i] = L;
}
buf += HEAD;
width -= HEAD;
} else {
TL = buf[width - (2 * stride) - 1];
L = buf[width - stride - 1];
}
l->dsp.add_hfyu_median_prediction(buf, buf - stride, buf, width,
&L, &TL);
}
static int lag_decode_line(LagarithContext *l, lag_rac *rac,
uint8_t *dst, int width, int stride,
int esc_count)
@ -432,9 +466,17 @@ static int lag_decode_arith_plane(LagarithContext *l, uint8_t *dst,
return -1;
}
for (i = 0; i < height; i++) {
lag_pred_line(l, dst, width, stride, i);
dst += stride;
if (l->avctx->pix_fmt != PIX_FMT_YUV422P) {
for (i = 0; i < height; i++) {
lag_pred_line(l, dst, width, stride, i);
dst += stride;
}
} else {
for (i = 0; i < height; i++) {
lag_pred_line_yuy2(l, dst, width, stride, i,
width == l->avctx->width);
dst += stride;
}
}
return 0;
@ -557,6 +599,32 @@ static int lag_decode_frame(AVCodecContext *avctx,
srcs[i] += l->rgb_stride;
}
break;
case FRAME_ARITH_YUY2:
avctx->pix_fmt = PIX_FMT_YUV422P;
if (avctx->get_buffer(avctx, p) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
if (offset_ry >= buf_size ||
offset_gu >= buf_size ||
offset_bv >= buf_size) {
av_log(avctx, AV_LOG_ERROR,
"Invalid frame offsets\n");
return AVERROR_INVALIDDATA;
}
lag_decode_arith_plane(l, p->data[0], avctx->width, avctx->height,
p->linesize[0], buf + offset_ry,
buf_size - offset_ry);
lag_decode_arith_plane(l, p->data[2], avctx->width / 2,
avctx->height, p->linesize[2],
buf + offset_gu, buf_size - offset_gu);
lag_decode_arith_plane(l, p->data[1], avctx->width / 2,
avctx->height, p->linesize[1],
buf + offset_bv, buf_size - offset_bv);
break;
case FRAME_ARITH_YV12:
avctx->pix_fmt = PIX_FMT_YUV420P;