FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
mpegutils.c
Go to the documentation of this file.
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 
31  AVFrame *cur, AVFrame *last,
32  int y, int h, int picture_structure,
33  int first_field, int low_delay)
34 {
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 &&
47  return;
48 
49  if (avctx->draw_horiz_band) {
50  AVFrame *src;
52  int i;
53 
54  if (cur->pict_type == AV_PICTURE_TYPE_B || low_delay ||
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 }
#define AV_NUM_DATA_POINTERS
Definition: frame.h:188
#define SLICE_FLAG_ALLOW_FIELD
allow draw_horiz_band() with field slices (MPEG-2 field pics)
Definition: avcodec.h:2277
const AVPixFmtDescriptor * av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:2333
This structure describes decoded (raw) audio or video data.
Definition: frame.h:187
const char * desc
Definition: nvenc.c:60
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1960
#define src
Definition: vp8dsp.c:254
void ff_draw_horiz_band(AVCodecContext *avctx, AVFrame *cur, AVFrame *last, int y, int h, int picture_structure, int first_field, int low_delay)
Draw a horizontal band if supported.
Definition: mpegutils.c:30
static int first_field(const struct video_data *s)
Definition: v4l2.c:230
uint8_t log2_chroma_h
Amount to shift the luma height right to find the chroma height.
Definition: pixdesc.h:101
static const uint8_t offset[127][2]
Definition: vf_spp.c:92
reference-counted frame API
void(* draw_horiz_band)(struct AVCodecContext *s, const AVFrame *src, int offset[AV_NUM_DATA_POINTERS], int y, int type, int height)
If non NULL, 'draw_horiz_band' is called by the libavcodec decoder to draw a horizontal band...
Definition: avcodec.h:1993
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:261
#define FFMIN(a, b)
Definition: common.h:96
Libavcodec external API header.
enum AVCodecID codec_id
Definition: avcodec.h:1749
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:218
Descriptor that unambiguously describes how the bits of a pixel are stored in the up to 4 data planes...
Definition: pixdesc.h:81
main external API structure.
Definition: avcodec.h:1732
int slice_flags
slice flags
Definition: avcodec.h:2275
common internal and external API header
Bi-dir predicted.
Definition: avutil.h:276
#define PICT_FRAME
Definition: mpegutils.h:39
#define SLICE_FLAG_CODED_ORDER
draw_horiz_band() is called in coded order instead of display
Definition: avcodec.h:2276
for(j=16;j >0;--j)