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Support decoding yuv442 and yuv421 jpeg images.

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Fixes ticket #787.
This commit is contained in:
Carl Eugen Hoyos 2011-12-27 18:21:38 +01:00
parent 613cbf3168
commit 387d86077f
2 changed files with 30 additions and 0 deletions
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28
libavcodec/mjpegdec.c
View File

@ -337,12 +337,19 @@ int ff_mjpeg_decode_sof(MJpegDecodeContext *s)
}
assert(s->nb_components==3);
break;
case 0x12121100:
s->avctx->pix_fmt = s->cs_itu601 ? PIX_FMT_YUV444P : PIX_FMT_YUVJ444P;
s->avctx->color_range = s->cs_itu601 ? AVCOL_RANGE_MPEG : AVCOL_RANGE_JPEG;
s->yuv442 = 1;
break;
case 0x11000000:
s->avctx->pix_fmt = PIX_FMT_GRAY8;
break;
case 0x12111100:
case 0x22211100:
s->avctx->pix_fmt = s->cs_itu601 ? PIX_FMT_YUV440P : PIX_FMT_YUVJ440P;
s->avctx->color_range = s->cs_itu601 ? AVCOL_RANGE_MPEG : AVCOL_RANGE_JPEG;
s->yuv421 = pix_fmt_id == 0x22211100;
break;
case 0x21111100:
s->avctx->pix_fmt = s->cs_itu601 ? PIX_FMT_YUV422P : PIX_FMT_YUVJ422P;
@ -1091,6 +1098,27 @@ int ff_mjpeg_decode_sos(MJpegDecodeContext *s,
return -1;
}
}
if (s->yuv421) {
uint8_t *line = s->picture_ptr->data[2];
for (i = 0; i < s->height / 2; i++) {
for (index = s->width - 1; index; index--)
line[index] = (line[index / 2] + line[(index + 1) / 2]) >> 1;
line += s->linesize[2];
}
} else if (s->yuv442) {
uint8_t *dst = &((uint8_t *)s->picture_ptr->data[2])[(s->height - 1) * s->linesize[2]];
for (i = s->height - 1; i; i--) {
uint8_t *src1 = &((uint8_t *)s->picture_ptr->data[2])[i / 2 * s->linesize[2]];
uint8_t *src2 = &((uint8_t *)s->picture_ptr->data[2])[(i + 1) / 2 * s->linesize[2]];
if (src1 == src2) {
memcpy(dst, src1, s->width);
} else {
for (index = 0; index < s->width; index++)
dst[index] = (src1[index] + src2[index]) >> 1;
}
dst -= s->linesize[2];
}
}
emms_c();
return 0;
out_of_range:

2
libavcodec/mjpegdec.h
View File

@ -58,6 +58,8 @@ typedef struct MJpegDecodeContext {
int ls;
int progressive;
int rgb;
int yuv421;
int yuv442;
int rct; /* standard rct */
int pegasus_rct; /* pegasus reversible colorspace transform */
int bits; /* bits per component */