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 "internal.h"
25 
26 typedef struct C93DecoderContext {
30 
31 typedef enum {
39  C93_NOOP = 0x0E,
40  C93_8X8_INTRA = 0x0F,
41 } C93BlockType;
42 
43 #define WIDTH 320
44 #define HEIGHT 192
45 
46 #define C93_HAS_PALETTE 0x01
47 #define C93_FIRST_FRAME 0x02
48 
49 static av_cold int decode_end(AVCodecContext *avctx)
50 {
51  C93DecoderContext * const c93 = avctx->priv_data;
52 
53  av_frame_free(&c93->pictures[0]);
54  av_frame_free(&c93->pictures[1]);
55 
56  return 0;
57 }
58 
60 {
61  C93DecoderContext *s = avctx->priv_data;
62  avctx->pix_fmt = AV_PIX_FMT_PAL8;
63 
64  s->pictures[0] = av_frame_alloc();
65  s->pictures[1] = av_frame_alloc();
66  if (!s->pictures[0] || !s->pictures[1]) {
67  decode_end(avctx);
68  return AVERROR(ENOMEM);
69  }
70 
71  return 0;
72 }
73 
74 static inline int copy_block(AVCodecContext *avctx, uint8_t *to,
75  uint8_t *from, int offset, int height, int stride)
76 {
77  int i;
78  int width = height;
79  int from_x = offset % WIDTH;
80  int from_y = offset / WIDTH;
81  int overflow = from_x + width - WIDTH;
82 
83  if (!from) {
84  /* silently ignoring predictive blocks in first frame */
85  return 0;
86  }
87 
88  if (from_y + height > HEIGHT) {
89  av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n",
90  offset);
91  return AVERROR_INVALIDDATA;
92  }
93 
94  if (overflow > 0) {
95  width -= overflow;
96  for (i = 0; i < height; i++) {
97  memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow);
98  }
99  }
100 
101  for (i = 0; i < height; i++) {
102  memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width);
103  }
104 
105  return 0;
106 }
107 
108 static inline void draw_n_color(uint8_t *out, int stride, int width,
109  int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col)
110 {
111  int x, y;
112  for (y = 0; y < height; y++) {
113  if (grps)
114  cols[0] = grps[3 * (y >> 1)];
115  for (x = 0; x < width; x++) {
116  if (grps)
117  cols[1]= grps[(x >> 1) + 1];
118  out[x + y*stride] = cols[col & ((1 << bpp) - 1)];
119  col >>= bpp;
120  }
121  }
122 }
123 
124 static int decode_frame(AVCodecContext *avctx, void *data,
125  int *got_frame, AVPacket *avpkt)
126 {
127  const uint8_t *buf = avpkt->data;
128  int buf_size = avpkt->size;
129  C93DecoderContext * const c93 = avctx->priv_data;
130  AVFrame * const newpic = c93->pictures[c93->currentpic];
131  AVFrame * const oldpic = c93->pictures[c93->currentpic^1];
132  GetByteContext gb;
133  uint8_t *out;
134  int stride, ret, i, x, y, b, bt = 0;
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  unsigned int offset, j;
161  uint8_t cols[4], grps[4];
162  C93BlockType block_type;
163 
164  if (!bt)
165  bt = bytestream2_get_byte(&gb);
166 
167  block_type= bt & 0x0F;
168  switch (block_type) {
169  case C93_8X8_FROM_PREV:
170  offset = bytestream2_get_le16(&gb);
171  if ((ret = copy_block(avctx, out, copy_from, offset, 8, stride)) < 0)
172  return ret;
173  break;
174 
175  case C93_4X4_FROM_CURR:
176  copy_from = newpic->data[0];
177  case C93_4X4_FROM_PREV:
178  for (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 (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 (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(data, newpic)) < 0)
256  return ret;
257  *got_frame = 1;
258 
259  return buf_size;
260 }
261 
263  .name = "c93",
264  .long_name = NULL_IF_CONFIG_SMALL("Interplay C93"),
265  .type = AVMEDIA_TYPE_VIDEO,
266  .id = AV_CODEC_ID_C93,
267  .priv_data_size = sizeof(C93DecoderContext),
268  .init = decode_init,
269  .close = decode_end,
270  .decode = decode_frame,
271  .capabilities = AV_CODEC_CAP_DR1,
272  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
273 };
#define NULL
Definition: coverity.c:32
#define WIDTH
Definition: c93.c:43
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
This structure describes decoded (raw) audio or video data.
Definition: frame.h:295
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:100
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:104
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
#define avpriv_request_sample(...)
int size
Definition: avcodec.h:1481
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1778
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:133
AVCodec.
Definition: avcodec.h:3492
Undefined Behavior In the C some operations are like signed integer overflow
Definition: undefined.txt:3
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
AVCodec ff_c93_decoder
Definition: c93.c:262
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:108
static av_cold int decode_init(AVCodecContext *avctx)
Definition: c93.c:59
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:40
uint8_t
#define av_cold
Definition: attributes.h:82
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:189
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:77
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
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:443
const char * from
Definition: jacosubdec.c:65
#define height
uint8_t * data
Definition: avcodec.h:1480
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: c93.c:124
#define av_log(a,...)
const char * to
Definition: webvttdec.c:34
static av_cold int decode_end(AVCodecContext *avctx)
Definition: c93.c:49
#define U(x)
Definition: vp56_arith.h:37
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define C93_HAS_PALETTE
Definition: c93.c:46
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:202
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
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:2015
static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g, uint8_t *dst, unsigned int size)
Definition: bytestream.h:263
const char * name
Name of the codec implementation.
Definition: avcodec.h:3499
#define C93_FIRST_FRAME
Definition: c93.c:47
#define b
Definition: input.c:41
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:378
#define width
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
Definition: common.h:72
#define s(width, name)
Definition: cbs_vp9.c:257
static int copy_from(IpvideoContext *s, AVFrame *src, AVFrame *dst, int delta_x, int delta_y)
Libavcodec external API header.
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:326
main external API structure.
Definition: avcodec.h:1568
void * buf
Definition: avisynth_c.h:766
int palette_has_changed
Tell user application that palette has changed from previous frame.
Definition: frame.h:452
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
GLint GLenum GLboolean GLsizei stride
Definition: opengl_enc.c:104
common internal api header.
void * priv_data
Definition: avcodec.h:1595
C93BlockType
Definition: c93.c:31
static int copy_block(AVCodecContext *avctx, uint8_t *to, uint8_t *from, int offset, int height, int stride)
Definition: c93.c:74
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:373
FILE * out
Definition: movenc.c:54
AVFrame * pictures[2]
Definition: c93.c:27
#define HEIGHT
Definition: c93.c:44
#define stride
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
Definition: c93.c:39
This structure stores compressed data.
Definition: avcodec.h:1457
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:984
int currentpic
Definition: c93.c:28
for(j=16;j >0;--j)
Predicted.
Definition: avutil.h:275