FFmpeg
c93.c
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1 /*
2  * Interplay C93 video decoder
3  * Copyright (c) 2007 Anssi Hannula <anssi.hannula@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 "avcodec.h"
23 #include "bytestream.h"
24 #include "codec_internal.h"
25 #include "decode.h"
26 
27 typedef struct C93DecoderContext {
31 
32 typedef enum {
40  C93_NOOP = 0x0E,
41  C93_8X8_INTRA = 0x0F,
42 } C93BlockType;
43 
44 #define WIDTH 320
45 #define HEIGHT 192
46 
47 #define C93_HAS_PALETTE 0x01
48 #define C93_FIRST_FRAME 0x02
49 
50 static av_cold int decode_end(AVCodecContext *avctx)
51 {
52  C93DecoderContext * const c93 = avctx->priv_data;
53 
54  av_frame_free(&c93->pictures[0]);
55  av_frame_free(&c93->pictures[1]);
56 
57  return 0;
58 }
59 
61 {
62  C93DecoderContext *s = avctx->priv_data;
63  avctx->pix_fmt = AV_PIX_FMT_PAL8;
64 
65  s->pictures[0] = av_frame_alloc();
66  s->pictures[1] = av_frame_alloc();
67  if (!s->pictures[0] || !s->pictures[1])
68  return AVERROR(ENOMEM);
69 
70  return 0;
71 }
72 
73 static inline int copy_block(AVCodecContext *avctx, uint8_t *to,
74  uint8_t *from, int offset, int height, int stride)
75 {
76  int i;
77  int width = height;
78  int from_x = offset % WIDTH;
79  int from_y = offset / WIDTH;
80  int overflow = from_x + width - WIDTH;
81 
82  if (!from) {
83  /* silently ignoring predictive blocks in first frame */
84  return 0;
85  }
86 
87  if (from_y + height > HEIGHT) {
88  av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n",
89  offset);
90  return AVERROR_INVALIDDATA;
91  }
92 
93  if (overflow > 0) {
94  width -= overflow;
95  for (i = 0; i < height; i++) {
96  memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow);
97  }
98  }
99 
100  for (i = 0; i < height; i++) {
101  memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width);
102  }
103 
104  return 0;
105 }
106 
107 static inline void draw_n_color(uint8_t *out, int stride, int width,
108  int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col)
109 {
110  int x, y;
111  for (y = 0; y < height; y++) {
112  if (grps)
113  cols[0] = grps[3 * (y >> 1)];
114  for (x = 0; x < width; x++) {
115  if (grps)
116  cols[1]= grps[(x >> 1) + 1];
117  out[x + y*stride] = cols[col & ((1 << bpp) - 1)];
118  col >>= bpp;
119  }
120  }
121 }
122 
123 static int decode_frame(AVCodecContext *avctx, AVFrame *rframe,
124  int *got_frame, AVPacket *avpkt)
125 {
126  const uint8_t *buf = avpkt->data;
127  int buf_size = avpkt->size;
128  C93DecoderContext * const c93 = avctx->priv_data;
129  AVFrame * const newpic = c93->pictures[c93->currentpic];
130  AVFrame * const oldpic = c93->pictures[c93->currentpic^1];
131  GetByteContext gb;
132  uint8_t *out;
133  int ret, i, x, y, b, bt = 0;
134  ptrdiff_t stride;
135 
136  if ((ret = ff_set_dimensions(avctx, WIDTH, HEIGHT)) < 0)
137  return ret;
138 
139  c93->currentpic ^= 1;
140 
141  if ((ret = ff_reget_buffer(avctx, newpic, 0)) < 0)
142  return ret;
143 
144  stride = newpic->linesize[0];
145 
146  bytestream2_init(&gb, buf, buf_size);
147  b = bytestream2_get_byte(&gb);
148  if (b & C93_FIRST_FRAME) {
149  newpic->pict_type = AV_PICTURE_TYPE_I;
150  newpic->key_frame = 1;
151  } else {
152  newpic->pict_type = AV_PICTURE_TYPE_P;
153  newpic->key_frame = 0;
154  }
155 
156  for (y = 0; y < HEIGHT; y += 8) {
157  out = newpic->data[0] + y * stride;
158  for (x = 0; x < WIDTH; x += 8) {
159  uint8_t *copy_from = oldpic->data[0];
160  uint8_t cols[4], grps[4];
161  C93BlockType block_type;
162 
163  if (!bt)
164  bt = bytestream2_get_byte(&gb);
165 
166  block_type= bt & 0x0F;
167  switch (block_type) {
168  case C93_8X8_FROM_PREV: {
169  int offset = bytestream2_get_le16(&gb);
170  if ((ret = copy_block(avctx, out, copy_from, offset, 8, stride)) < 0)
171  return ret;
172  break;
173  }
174 
175  case C93_4X4_FROM_CURR:
176  copy_from = newpic->data[0];
177  case C93_4X4_FROM_PREV:
178  for (int j = 0; j < 8; j += 4) {
179  for (i = 0; i < 8; i += 4) {
180  int offset = bytestream2_get_le16(&gb);
181  int from_x = offset % WIDTH;
182  int from_y = offset / WIDTH;
183  if (block_type == C93_4X4_FROM_CURR && from_y == y+j &&
184  (FFABS(from_x - x-i) < 4 || FFABS(from_x - x-i) > WIDTH-4)) {
185  avpriv_request_sample(avctx, "block overlap %d %d %d %d", from_x, x+i, from_y, y+j);
186  return AVERROR_INVALIDDATA;
187  }
188  if ((ret = copy_block(avctx, &out[j*stride+i],
189  copy_from, offset, 4, stride)) < 0)
190  return ret;
191  }
192  }
193  break;
194 
195  case C93_8X8_2COLOR:
196  bytestream2_get_buffer(&gb, cols, 2);
197  for (i = 0; i < 8; i++) {
198  draw_n_color(out + i*stride, stride, 8, 1, 1, cols,
199  NULL, bytestream2_get_byte(&gb));
200  }
201 
202  break;
203 
204  case C93_4X4_2COLOR:
205  case C93_4X4_4COLOR:
206  case C93_4X4_4COLOR_GRP:
207  for (int j = 0; j < 8; j += 4) {
208  for (i = 0; i < 8; i += 4) {
209  if (block_type == C93_4X4_2COLOR) {
210  bytestream2_get_buffer(&gb, cols, 2);
211  draw_n_color(out + i + j*stride, stride, 4, 4,
212  1, cols, NULL, bytestream2_get_le16(&gb));
213  } else if (block_type == C93_4X4_4COLOR) {
214  bytestream2_get_buffer(&gb, cols, 4);
215  draw_n_color(out + i + j*stride, stride, 4, 4,
216  2, cols, NULL, bytestream2_get_le32(&gb));
217  } else {
218  bytestream2_get_buffer(&gb, grps, 4);
219  draw_n_color(out + i + j*stride, stride, 4, 4,
220  1, cols, grps, bytestream2_get_le16(&gb));
221  }
222  }
223  }
224  break;
225 
226  case C93_NOOP:
227  break;
228 
229  case C93_8X8_INTRA:
230  for (int j = 0; j < 8; j++)
231  bytestream2_get_buffer(&gb, out + j*stride, 8);
232  break;
233 
234  default:
235  av_log(avctx, AV_LOG_ERROR, "unexpected type %x at %dx%d\n",
236  block_type, x, y);
237  return AVERROR_INVALIDDATA;
238  }
239  bt >>= 4;
240  out += 8;
241  }
242  }
243 
244  if (b & C93_HAS_PALETTE) {
245  uint32_t *palette = (uint32_t *) newpic->data[1];
246  for (i = 0; i < 256; i++) {
247  palette[i] = 0xFFU << 24 | bytestream2_get_be24(&gb);
248  }
249  newpic->palette_has_changed = 1;
250  } else {
251  if (oldpic->data[1])
252  memcpy(newpic->data[1], oldpic->data[1], 256 * 4);
253  }
254 
255  if ((ret = av_frame_ref(rframe, newpic)) < 0)
256  return ret;
257  *got_frame = 1;
258 
259  return buf_size;
260 }
261 
263  .p.name = "c93",
264  CODEC_LONG_NAME("Interplay C93"),
265  .p.type = AVMEDIA_TYPE_VIDEO,
266  .p.id = AV_CODEC_ID_C93,
267  .priv_data_size = sizeof(C93DecoderContext),
268  .init = decode_init,
269  .close = decode_end,
271  .p.capabilities = AV_CODEC_CAP_DR1,
272  .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
273 };
C93DecoderContext::currentpic
int currentpic
Definition: c93.c:29
C93_FIRST_FRAME
#define C93_FIRST_FRAME
Definition: c93.c:48
C93DecoderContext
Definition: c93.c:27
FF_CODEC_CAP_INIT_CLEANUP
#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: codec_internal.h:42
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
out
FILE * out
Definition: movenc.c:54
C93_8X8_2COLOR
@ C93_8X8_2COLOR
Definition: c93.c:36
GetByteContext
Definition: bytestream.h:33
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:116
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:325
AVPacket::data
uint8_t * data
Definition: packet.h:374
b
#define b
Definition: input.c:41
FFCodec
Definition: codec_internal.h:119
decode_frame
static int decode_frame(AVCodecContext *avctx, AVFrame *rframe, int *got_frame, AVPacket *avpkt)
Definition: c93.c:123
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:91
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:346
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:123
AVFrame::key_frame
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:417
av_frame_alloc
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:104
C93_NOOP
@ C93_NOOP
Definition: c93.c:40
C93_4X4_2COLOR
@ C93_4X4_2COLOR
Definition: c93.c:37
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
C93_HAS_PALETTE
#define C93_HAS_PALETTE
Definition: c93.c:47
av_cold
#define av_cold
Definition: attributes.h:90
width
#define width
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:298
s
#define s(width, name)
Definition: cbs_vp9.c:256
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts_bsf.c:363
from
const char * from
Definition: jacosubdec.c:66
to
const char * to
Definition: webvttdec.c:35
decode.h
decode_init
static av_cold int decode_init(AVCodecContext *avctx)
Definition: c93.c:60
C93BlockType
C93BlockType
Definition: c93.c:32
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:264
decode_end
static av_cold int decode_end(AVCodecContext *avctx)
Definition: c93.c:50
FFABS
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
Definition: common.h:64
NULL
#define NULL
Definition: coverity.c:32
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
bytestream2_get_buffer
static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g, uint8_t *dst, unsigned int size)
Definition: bytestream.h:267
C93_4X4_FROM_CURR
@ C93_4X4_FROM_CURR
Definition: c93.c:35
AVFrame::pict_type
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:422
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:375
av_frame_ref
int av_frame_ref(AVFrame *dst, const AVFrame *src)
Set up a new reference to the data described by the source frame.
Definition: frame.c:353
codec_internal.h
for
for(k=2;k<=8;++k)
Definition: h264pred_template.c:425
C93_8X8_FROM_PREV
@ C93_8X8_FROM_PREV
Definition: c93.c:33
WIDTH
#define WIDTH
Definition: c93.c:44
height
#define height
offset
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Definition: writing_filters.txt:86
C93_4X4_4COLOR
@ C93_4X4_4COLOR
Definition: c93.c:39
C93_4X4_4COLOR_GRP
@ C93_4X4_4COLOR_GRP
Definition: c93.c:38
copy_from
static int copy_from(IpvideoContext *s, AVFrame *src, AVFrame *dst, int delta_x, int delta_y)
Definition: interplayvideo.c:78
HEIGHT
#define HEIGHT
Definition: c93.c:45
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
AV_CODEC_ID_C93
@ AV_CODEC_ID_C93
Definition: codec_id.h:154
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:211
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:608
avcodec.h
stride
#define stride
Definition: h264pred_template.c:537
AV_PIX_FMT_PAL8
@ AV_PIX_FMT_PAL8
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:77
draw_n_color
static void draw_n_color(uint8_t *out, int stride, int width, int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col)
Definition: c93.c:107
ff_reget_buffer
int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Identical in function to ff_get_buffer(), except it reuses the existing buffer if available.
Definition: decode.c:1568
ret
ret
Definition: filter_design.txt:187
C93_8X8_INTRA
@ C93_8X8_INTRA
Definition: c93.c:41
U
#define U(x)
Definition: vpx_arith.h:37
AVCodecContext
main external API structure.
Definition: avcodec.h:398
AVFrame::palette_has_changed
int palette_has_changed
Tell user application that palette has changed from previous frame.
Definition: frame.h:487
C93DecoderContext::pictures
AVFrame * pictures[2]
Definition: c93.c:28
C93_4X4_FROM_PREV
@ C93_4X4_FROM_PREV
Definition: c93.c:34
ff_c93_decoder
const FFCodec ff_c93_decoder
Definition: c93.c:262
AV_PICTURE_TYPE_P
@ AV_PICTURE_TYPE_P
Predicted.
Definition: avutil.h:275
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
overflow
Undefined Behavior In the C some operations are like signed integer overflow
Definition: undefined.txt:3
avpriv_request_sample
#define avpriv_request_sample(...)
Definition: tableprint_vlc.h:36
AVPacket
This structure stores compressed data.
Definition: packet.h:351
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:425
bytestream.h
bytestream2_init
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:137
AVFrame::linesize
int linesize[AV_NUM_DATA_POINTERS]
For video, a positive or negative value, which is typically indicating the size in bytes of each pict...
Definition: frame.h:370
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
copy_block
static int copy_block(AVCodecContext *avctx, uint8_t *to, uint8_t *from, int offset, int height, int stride)
Definition: c93.c:73