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  return AVERROR(ENOMEM);
68 
69  return 0;
70 }
71 
72 static inline int copy_block(AVCodecContext *avctx, uint8_t *to,
73  uint8_t *from, int offset, int height, int stride)
74 {
75  int i;
76  int width = height;
77  int from_x = offset % WIDTH;
78  int from_y = offset / WIDTH;
79  int overflow = from_x + width - WIDTH;
80 
81  if (!from) {
82  /* silently ignoring predictive blocks in first frame */
83  return 0;
84  }
85 
86  if (from_y + height > HEIGHT) {
87  av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n",
88  offset);
89  return AVERROR_INVALIDDATA;
90  }
91 
92  if (overflow > 0) {
93  width -= overflow;
94  for (i = 0; i < height; i++) {
95  memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow);
96  }
97  }
98 
99  for (i = 0; i < height; i++) {
100  memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width);
101  }
102 
103  return 0;
104 }
105 
106 static inline void draw_n_color(uint8_t *out, int stride, int width,
107  int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col)
108 {
109  int x, y;
110  for (y = 0; y < height; y++) {
111  if (grps)
112  cols[0] = grps[3 * (y >> 1)];
113  for (x = 0; x < width; x++) {
114  if (grps)
115  cols[1]= grps[(x >> 1) + 1];
116  out[x + y*stride] = cols[col & ((1 << bpp) - 1)];
117  col >>= bpp;
118  }
119  }
120 }
121 
122 static int decode_frame(AVCodecContext *avctx, void *data,
123  int *got_frame, AVPacket *avpkt)
124 {
125  const uint8_t *buf = avpkt->data;
126  int buf_size = avpkt->size;
127  C93DecoderContext * const c93 = avctx->priv_data;
128  AVFrame * const newpic = c93->pictures[c93->currentpic];
129  AVFrame * const oldpic = c93->pictures[c93->currentpic^1];
130  GetByteContext gb;
131  uint8_t *out;
132  int stride, ret, i, x, y, b, bt = 0;
133 
134  if ((ret = ff_set_dimensions(avctx, WIDTH, HEIGHT)) < 0)
135  return ret;
136 
137  c93->currentpic ^= 1;
138 
139  if ((ret = ff_reget_buffer(avctx, newpic, 0)) < 0)
140  return ret;
141 
142  stride = newpic->linesize[0];
143 
144  bytestream2_init(&gb, buf, buf_size);
145  b = bytestream2_get_byte(&gb);
146  if (b & C93_FIRST_FRAME) {
147  newpic->pict_type = AV_PICTURE_TYPE_I;
148  newpic->key_frame = 1;
149  } else {
150  newpic->pict_type = AV_PICTURE_TYPE_P;
151  newpic->key_frame = 0;
152  }
153 
154  for (y = 0; y < HEIGHT; y += 8) {
155  out = newpic->data[0] + y * stride;
156  for (x = 0; x < WIDTH; x += 8) {
157  uint8_t *copy_from = oldpic->data[0];
158  unsigned int offset, j;
159  uint8_t cols[4], grps[4];
160  C93BlockType block_type;
161 
162  if (!bt)
163  bt = bytestream2_get_byte(&gb);
164 
165  block_type= bt & 0x0F;
166  switch (block_type) {
167  case C93_8X8_FROM_PREV:
168  offset = bytestream2_get_le16(&gb);
169  if ((ret = copy_block(avctx, out, copy_from, offset, 8, stride)) < 0)
170  return ret;
171  break;
172 
173  case C93_4X4_FROM_CURR:
174  copy_from = newpic->data[0];
175  case C93_4X4_FROM_PREV:
176  for (j = 0; j < 8; j += 4) {
177  for (i = 0; i < 8; i += 4) {
178  int offset = bytestream2_get_le16(&gb);
179  int from_x = offset % WIDTH;
180  int from_y = offset / WIDTH;
181  if (block_type == C93_4X4_FROM_CURR && from_y == y+j &&
182  (FFABS(from_x - x-i) < 4 || FFABS(from_x - x-i) > WIDTH-4)) {
183  avpriv_request_sample(avctx, "block overlap %d %d %d %d", from_x, x+i, from_y, y+j);
184  return AVERROR_INVALIDDATA;
185  }
186  if ((ret = copy_block(avctx, &out[j*stride+i],
187  copy_from, offset, 4, stride)) < 0)
188  return ret;
189  }
190  }
191  break;
192 
193  case C93_8X8_2COLOR:
194  bytestream2_get_buffer(&gb, cols, 2);
195  for (i = 0; i < 8; i++) {
196  draw_n_color(out + i*stride, stride, 8, 1, 1, cols,
197  NULL, bytestream2_get_byte(&gb));
198  }
199 
200  break;
201 
202  case C93_4X4_2COLOR:
203  case C93_4X4_4COLOR:
204  case C93_4X4_4COLOR_GRP:
205  for (j = 0; j < 8; j += 4) {
206  for (i = 0; i < 8; i += 4) {
207  if (block_type == C93_4X4_2COLOR) {
208  bytestream2_get_buffer(&gb, cols, 2);
209  draw_n_color(out + i + j*stride, stride, 4, 4,
210  1, cols, NULL, bytestream2_get_le16(&gb));
211  } else if (block_type == C93_4X4_4COLOR) {
212  bytestream2_get_buffer(&gb, cols, 4);
213  draw_n_color(out + i + j*stride, stride, 4, 4,
214  2, cols, NULL, bytestream2_get_le32(&gb));
215  } else {
216  bytestream2_get_buffer(&gb, grps, 4);
217  draw_n_color(out + i + j*stride, stride, 4, 4,
218  1, cols, grps, bytestream2_get_le16(&gb));
219  }
220  }
221  }
222  break;
223 
224  case C93_NOOP:
225  break;
226 
227  case C93_8X8_INTRA:
228  for (j = 0; j < 8; j++)
229  bytestream2_get_buffer(&gb, out + j*stride, 8);
230  break;
231 
232  default:
233  av_log(avctx, AV_LOG_ERROR, "unexpected type %x at %dx%d\n",
234  block_type, x, y);
235  return AVERROR_INVALIDDATA;
236  }
237  bt >>= 4;
238  out += 8;
239  }
240  }
241 
242  if (b & C93_HAS_PALETTE) {
243  uint32_t *palette = (uint32_t *) newpic->data[1];
244  for (i = 0; i < 256; i++) {
245  palette[i] = 0xFFU << 24 | bytestream2_get_be24(&gb);
246  }
247  newpic->palette_has_changed = 1;
248  } else {
249  if (oldpic->data[1])
250  memcpy(newpic->data[1], oldpic->data[1], 256 * 4);
251  }
252 
253  if ((ret = av_frame_ref(data, newpic)) < 0)
254  return ret;
255  *got_frame = 1;
256 
257  return buf_size;
258 }
259 
261  .name = "c93",
262  .long_name = NULL_IF_CONFIG_SMALL("Interplay C93"),
263  .type = AVMEDIA_TYPE_VIDEO,
264  .id = AV_CODEC_ID_C93,
265  .priv_data_size = sizeof(C93DecoderContext),
266  .init = decode_init,
267  .close = decode_end,
268  .decode = decode_frame,
269  .capabilities = AV_CODEC_CAP_DR1,
271 };
#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: internal.h:48
#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:308
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:106
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
#define avpriv_request_sample(...)
int size
Definition: packet.h:364
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:736
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:133
AVCodec.
Definition: codec.h:190
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:260
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:106
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:88
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:190
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:456
const char * from
Definition: jacosubdec.c:65
#define height
uint8_t * data
Definition: packet.h:363
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: c93.c:122
#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 AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
#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:203
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:153
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:1978
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: codec.h:197
#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:391
#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:339
main external API structure.
Definition: avcodec.h:526
int palette_has_changed
Tell user application that palette has changed from previous frame.
Definition: frame.h:465
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:322
GLint GLenum GLboolean GLsizei stride
Definition: opengl_enc.c:104
common internal api header.
void * priv_data
Definition: avcodec.h:553
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:72
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:386
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: packet.h:340
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:50
int currentpic
Definition: c93.c:28
for(j=16;j >0;--j)
int i
Definition: input.c:407
Predicted.
Definition: avutil.h:275