1/*
2 * Mpeg video formats-related defines and utility functions
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include <stdint.h>
22
23#include "libavutil/common.h"
24#include "libavutil/frame.h"
25#include "libavutil/pixdesc.h"
26
27#include "avcodec.h"
28#include "mpegutils.h"
29
30void ff_draw_horiz_band(AVCodecContext *avctx,
31                        AVFrame *cur, AVFrame *last,
32                        int y, int h, int picture_structure,
33                        int first_field, int low_delay)
34{
35    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);
36    int vshift = desc->log2_chroma_h;
37    const int field_pic = picture_structure != PICT_FRAME;
38    if (field_pic) {
39        h <<= 1;
40        y <<= 1;
41    }
42
43    h = FFMIN(h, avctx->height - y);
44
45    if (field_pic && first_field &&
46        !(avctx->slice_flags & SLICE_FLAG_ALLOW_FIELD))
47        return;
48
49    if (avctx->draw_horiz_band) {
50        AVFrame *src;
51        int offset[AV_NUM_DATA_POINTERS];
52        int i;
53
54        if (cur->pict_type == AV_PICTURE_TYPE_B || low_delay ||
55           (avctx->slice_flags & SLICE_FLAG_CODED_ORDER))
56            src = cur;
57        else if (last)
58            src = last;
59        else
60            return;
61
62        if (cur->pict_type == AV_PICTURE_TYPE_B &&
63            picture_structure == PICT_FRAME &&
64            avctx->codec_id != AV_CODEC_ID_SVQ3) {
65            for (i = 0; i < AV_NUM_DATA_POINTERS; i++)
66                offset[i] = 0;
67        } else {
68            offset[0]= y * src->linesize[0];
69            offset[1]=
70            offset[2]= (y >> vshift) * src->linesize[1];
71            for (i = 3; i < AV_NUM_DATA_POINTERS; i++)
72                offset[i] = 0;
73        }
74
75        emms_c();
76
77        avctx->draw_horiz_band(avctx, src, offset,
78                               y, picture_structure, h);
79    }
80}
81