FFmpeg
aliaspixdec.c
Go to the documentation of this file.
1 /*
2  * Alias PIX image decoder
3  * Copyright (C) 2014 Vittorio Giovara <vittorio.giovara@gmail.com>
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavutil/intreadwrite.h"
23 
24 #include "avcodec.h"
25 #include "bytestream.h"
26 #include "codec_internal.h"
27 #include "decode.h"
28 
29 #define ALIAS_HEADER_SIZE 10
30 
31 static int decode_frame(AVCodecContext *avctx, AVFrame *f,
32  int *got_frame, AVPacket *avpkt)
33 {
34  GetByteContext gb;
35  int width, height, ret, bits_pixel, pixel;
36  uint8_t *out_buf;
37  uint8_t count;
38  int x, y;
39 
40  bytestream2_init(&gb, avpkt->data, avpkt->size);
41 
43  av_log(avctx, AV_LOG_ERROR, "Header too small %d.\n", avpkt->size);
44  return AVERROR_INVALIDDATA;
45  }
46 
47  width = bytestream2_get_be16u(&gb);
48  height = bytestream2_get_be16u(&gb);
49  bytestream2_skipu(&gb, 4); // obsolete X, Y offset
50  bits_pixel = bytestream2_get_be16u(&gb);
51 
52  if (bits_pixel == 24)
53  avctx->pix_fmt = AV_PIX_FMT_BGR24;
54  else if (bits_pixel == 8)
55  avctx->pix_fmt = AV_PIX_FMT_GRAY8;
56  else {
57  av_log(avctx, AV_LOG_ERROR, "Invalid pixel format.\n");
58  return AVERROR_INVALIDDATA;
59  }
60 
61  ret = ff_set_dimensions(avctx, width, height);
62  if (ret < 0)
63  return ret;
64 
65  if (bytestream2_get_bytes_left(&gb) < width*height / 255)
66  return AVERROR_INVALIDDATA;
67 
68  ret = ff_get_buffer(avctx, f, 0);
69  if (ret < 0)
70  return ret;
71 
72  x = 0;
73  y = 1;
74  out_buf = f->data[0];
75  while (bytestream2_get_bytes_left(&gb) > 0) {
76  int i;
77 
78  /* set buffer at the right position at every new line */
79  if (x == avctx->width) {
80  x = 0;
81  out_buf = f->data[0] + f->linesize[0] * y++;
82  if (y > avctx->height) {
83  av_log(avctx, AV_LOG_ERROR,
84  "Ended frame decoding with %d bytes left.\n",
86  return AVERROR_INVALIDDATA;
87  }
88  }
89 
90  /* read packet and copy data */
91  count = bytestream2_get_byteu(&gb);
92  if (!count || x + count > avctx->width) {
93  av_log(avctx, AV_LOG_ERROR, "Invalid run length %d.\n", count);
94  return AVERROR_INVALIDDATA;
95  }
96 
97  if (avctx->pix_fmt == AV_PIX_FMT_BGR24) {
98  pixel = bytestream2_get_be24(&gb);
99  for (i = 0; i < count; i++) {
100  AV_WB24(out_buf, pixel);
101  out_buf += 3;
102  }
103  } else { // AV_PIX_FMT_GRAY8
104  pixel = bytestream2_get_byte(&gb);
105  for (i = 0; i < count; i++)
106  *out_buf++ = pixel;
107  }
108 
109  x += i;
110  }
111 
112  if (x != width || y != height) {
113  av_log(avctx, AV_LOG_ERROR, "Picture stopped at %d,%d.\n", x, y);
114  return AVERROR_INVALIDDATA;
115  }
116 
117  *got_frame = 1;
118  return avpkt->size;
119 }
120 
122  .p.name = "alias_pix",
123  CODEC_LONG_NAME("Alias/Wavefront PIX image"),
124  .p.type = AVMEDIA_TYPE_VIDEO,
125  .p.id = AV_CODEC_ID_ALIAS_PIX,
126  .p.capabilities = AV_CODEC_CAP_DR1,
128 };
GetByteContext
Definition: bytestream.h:33
ff_alias_pix_decoder
const FFCodec ff_alias_pix_decoder
Definition: aliaspixdec.c:121
bytestream2_skipu
static av_always_inline void bytestream2_skipu(GetByteContext *g, unsigned int size)
Definition: bytestream.h:174
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:374
AVPacket::data
uint8_t * data
Definition: packet.h:520
FFCodec
Definition: codec_internal.h:126
AV_PIX_FMT_BGR24
@ AV_PIX_FMT_BGR24
packed RGB 8:8:8, 24bpp, BGRBGR...
Definition: pixfmt.h:76
ff_set_dimensions
int ff_set_dimensions(AVCodecContext *s, int width, int height)
Check that the provided frame dimensions are valid and set them on the codec context.
Definition: utils.c:94
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:130
ALIAS_HEADER_SIZE
#define ALIAS_HEADER_SIZE
Definition: aliaspixdec.c:29
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
width
#define width
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:286
intreadwrite.h
AV_CODEC_ID_ALIAS_PIX
@ AV_CODEC_ID_ALIAS_PIX
Definition: codec_id.h:229
decode.h
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:271
pixel
uint8_t pixel
Definition: tiny_ssim.c:41
AV_PIX_FMT_GRAY8
@ AV_PIX_FMT_GRAY8
Y , 8bpp.
Definition: pixfmt.h:81
bytestream2_get_bytes_left
static av_always_inline int bytestream2_get_bytes_left(GetByteContext *g)
Definition: bytestream.h:158
f
f
Definition: af_crystalizer.c:121
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1575
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AVPacket::size
int size
Definition: packet.h:521
codec_internal.h
AV_WB24
#define AV_WB24(p, d)
Definition: intreadwrite.h:446
height
#define height
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
decode_frame
static int decode_frame(AVCodecContext *avctx, AVFrame *f, int *got_frame, AVPacket *avpkt)
Definition: aliaspixdec.c:31
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:194
AVCodecContext::height
int height
Definition: avcodec.h:618
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:657
avcodec.h
ret
ret
Definition: filter_design.txt:187
AVCodecContext
main external API structure.
Definition: avcodec.h:445
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVPacket
This structure stores compressed data.
Definition: packet.h:497
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:618
bytestream.h
bytestream2_init
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:137
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61