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lavc, lavu: move frame cropping to a convenience function

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Signed-off-by: Anton Khirnov <anton@khirnov.net>

Merged from Libav commit 47399ccdfd.
This commit is contained in:
wm4
2017-07-22 23:05:13 +02:00
parent 45759540a5
commit caa12027ba
5 changed files with 140 additions and 88 deletions
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100
libavutil/frame.c
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@ -782,3 +782,103 @@ const char *av_frame_side_data_name(enum AVFrameSideDataType type)
}
return NULL;
}
static int calc_cropping_offsets(size_t offsets[4], const AVFrame *frame,
const AVPixFmtDescriptor *desc)
{
int i, j;
for (i = 0; frame->data[i]; i++) {
const AVComponentDescriptor *comp = NULL;
int shift_x = (i == 1 || i == 2) ? desc->log2_chroma_w : 0;
int shift_y = (i == 1 || i == 2) ? desc->log2_chroma_h : 0;
if (desc->flags & (AV_PIX_FMT_FLAG_PAL | AV_PIX_FMT_FLAG_PSEUDOPAL) && i == 1) {
offsets[i] = 0;
break;
}
/* find any component descriptor for this plane */
for (j = 0; j < desc->nb_components; j++) {
if (desc->comp[j].plane == i) {
comp = &desc->comp[j];
break;
}
}
if (!comp)
return AVERROR_BUG;
offsets[i] = (frame->crop_top >> shift_y) * frame->linesize[i] +
(frame->crop_left >> shift_x) * comp->step;
}
return 0;
}
int av_frame_apply_cropping(AVFrame *frame, int flags)
{
const AVPixFmtDescriptor *desc;
size_t offsets[4];
int i;
if (!(frame->width > 0 && frame->height > 0))
return AVERROR(EINVAL);
if (frame->crop_left >= INT_MAX - frame->crop_right ||
frame->crop_top >= INT_MAX - frame->crop_bottom ||
(frame->crop_left + frame->crop_right) >= frame->width ||
(frame->crop_top + frame->crop_bottom) >= frame->height)
return AVERROR(ERANGE);
desc = av_pix_fmt_desc_get(frame->format);
if (!desc)
return AVERROR_BUG;
/* Apply just the right/bottom cropping for hwaccel formats. Bitstream
* formats cannot be easily handled here either (and corresponding decoders
* should not export any cropping anyway), so do the same for those as well.
* */
if (desc->flags & (AV_PIX_FMT_FLAG_BITSTREAM | AV_PIX_FMT_FLAG_HWACCEL)) {
frame->width -= frame->crop_right;
frame->height -= frame->crop_bottom;
frame->crop_right = 0;
frame->crop_bottom = 0;
return 0;
}
/* calculate the offsets for each plane */
calc_cropping_offsets(offsets, frame, desc);
/* adjust the offsets to avoid breaking alignment */
if (!(flags & AV_FRAME_CROP_UNALIGNED)) {
int log2_crop_align = frame->crop_left ? ff_ctz(frame->crop_left) : INT_MAX;
int min_log2_align = INT_MAX;
for (i = 0; frame->data[i]; i++) {
int log2_align = offsets[i] ? ff_ctz(offsets[i]) : INT_MAX;
min_log2_align = FFMIN(log2_align, min_log2_align);
}
/* we assume, and it should always be true, that the data alignment is
* related to the cropping alignment by a constant power-of-2 factor */
if (log2_crop_align < min_log2_align)
return AVERROR_BUG;
if (min_log2_align < 5) {
frame->crop_left &= ~((1 << (5 + log2_crop_align - min_log2_align)) - 1);
calc_cropping_offsets(offsets, frame, desc);
}
}
for (i = 0; frame->data[i]; i++)
frame->data[i] += offsets[i];
frame->width -= (frame->crop_left + frame->crop_right);
frame->height -= (frame->crop_top + frame->crop_bottom);
frame->crop_left = 0;
frame->crop_right = 0;
frame->crop_top = 0;
frame->crop_bottom = 0;
return 0;
}