FFmpeg: libavcodec/cdgraphics.c Source File
Go to the documentation of this file. 1 /*
2 * CD Graphics Video Decoder
3 * Copyright (c) 2009 Michael Tison
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
26
27 /**
28 * @file
29 * @brief CD Graphics Video Decoder
30 * @author Michael Tison
31 * @see http://wiki.multimedia.cx/index.php?title=CD_Graphics
32 * @see http://www.ccs.neu.edu/home/bchafy/cdb/info/cdg
33 */
34
35 /// default screen sizes
36 #define CDG_FULL_WIDTH 300
37 #define CDG_FULL_HEIGHT 216
38 #define CDG_DISPLAY_WIDTH 294
39 #define CDG_DISPLAY_HEIGHT 204
40 #define CDG_BORDER_WIDTH 6
41 #define CDG_BORDER_HEIGHT 12
42
43 /// masks
44 #define CDG_COMMAND 0x09
46
47 /// instruction codes
48 #define CDG_INST_MEMORY_PRESET 1
49 #define CDG_INST_BORDER_PRESET 2
50 #define CDG_INST_TILE_BLOCK 6
51 #define CDG_INST_SCROLL_PRESET 20
52 #define CDG_INST_SCROLL_COPY 24
53 #define CDG_INST_TRANSPARENT_COL 28
54 #define CDG_INST_LOAD_PAL_LO 30
55 #define CDG_INST_LOAD_PAL_HIGH 31
56 #define CDG_INST_TILE_BLOCK_XOR 38
57
58 /// data sizes
59 #define CDG_PACKET_SIZE 24
60 #define CDG_DATA_SIZE 16
61 #define CDG_TILE_HEIGHT 12
62 #define CDG_TILE_WIDTH 6
63 #define CDG_MINIMUM_PKT_SIZE 6
64 #define CDG_MINIMUM_SCROLL_SIZE 3
65 #define CDG_HEADER_SIZE 8
66 #define CDG_PALETTE_SIZE 16
67
75
77 {
79
83
86
89 }
90
92 {
93 int y;
97
98 if (!(
data[1] & 0x0F)) {
99 /// fill the top and bottom borders
103
104 /// fill the side borders
109 }
110 }
111 }
112
114 {
118 int array_offset = low ? 0 : 8;
119 uint32_t *palette = (uint32_t *) cc->
frame->
data[1];
120
123 r = ((
color >> 8) & 0x000F) * 17;
124 g = ((
color >> 4) & 0x000F) * 17;
125 b = ((
color ) & 0x000F) * 17;
126 palette[
i + array_offset] = (uint32_t)cc->
alpha[
i + array_offset] << 24 |
r << 16 |
g << 8 |
b;
127 }
129 }
130
132 {
133 unsigned ci, ri;
135 int x, y;
136 int ai;
139
142
147
150 if (!((
data[4 + y] >> (5 - x)) & 0x01))
152 else
154
155 ai = ci + x + (
stride * (ri + y));
159 }
160 }
161
162 return 0;
163 }
164
169
171 int in_tl_x, int in_tl_y, uint8_t *in,
173 {
174 int y;
175
176 in += in_tl_x + in_tl_y *
stride;
178 for (y = 0; y <
h; y++)
180 }
181
184 {
185 int y;
186
187 for (y = tl_y; y < tl_y +
h; y++)
189 }
190
192 int in_tl_x, int in_tl_y, uint8_t *in,
194 {
195 if (roll) {
198 } else {
200 }
201 }
202
204 AVFrame *new_frame,
int roll_over)
205 {
207 int hscmd, h_off, hinc, vscmd, v_off, vinc;
208 int y;
211 uint8_t *
out = new_frame->
data[0];
212
214 hscmd = (
data[1] & 0x30) >> 4;
215 vscmd = (
data[2] & 0x30) >> 4;
216
219
220 /// find the difference and save the offset for cdg_tile_block usage
225
227 vinc -= 12;
229 vinc += 12;
231 hinc -= 6;
233 hinc += 6;
234
235 if (!hinc && !vinc)
236 return;
237
239
244
245 if (vinc > 0)
249 else if (vinc < 0)
253
254 if (hinc > 0)
258 else if (hinc < 0)
262
263 }
264
267 {
269 int buf_size = avpkt->
size;
274
278 }
282 }
283
285
292 }
293
294 command = bytestream2_get_byte(&gb);
295 inst = bytestream2_get_byte(&gb);
299
301 switch (inst) {
303 if (!(cdg_data[1] & 0x0F))
304 memset(cc->
frame->
data[0], cdg_data[0] & 0x0F,
306 break;
312 }
313
315 break;
318 break;
324 }
325
330 }
331 break;
337 }
338
341
347 break;
350 cc->
alpha[
i] = 255 - ((cdg_data[
i] & 0x3f) << 2);
351 break;
352 default:
353 break;
354 }
355
356 if (!
frame->data[0]) {
360 }
361 *got_frame = 1;
362 } else {
363 *got_frame = 0;
364 }
365
367 }
368
370 {
372
374 return;
375
379 }
380
382 {
384
386
387 return 0;
388 }
389
391 .
p.
name =
"cdgraphics",
402 };
static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data, AVFrame *new_frame, int roll_over)
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
static int cdg_decode_frame(AVCodecContext *avctx, AVFrame *frame, int *got_frame, AVPacket *avpkt)
#define CDG_INST_SCROLL_PRESET
#define CDG_INST_LOAD_PAL_HIGH
uint8_t alpha[CDG_PALETTE_SIZE]
#define CDG_MINIMUM_PKT_SIZE
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
#define CDG_INST_TRANSPARENT_COL
This structure describes decoded (raw) audio or video data.
static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b)
#define CDG_INST_TILE_BLOCK_XOR
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
static av_always_inline void bytestream2_skip(GetByteContext *g, unsigned int size)
AVCodec p
The public AVCodec.
static void cdg_decode_flush(AVCodecContext *avctx)
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
static void cdg_border_preset(CDGraphicsContext *cc, uint8_t *data)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
static av_cold int cdg_decode_init(AVCodecContext *avctx)
#define CDG_BORDER_HEIGHT
#define FF_CODEC_DECODE_CB(func)
#define AV_GET_BUFFER_FLAG_REF
The decoder will keep a reference to the frame and may reuse it later.
static int command(AVFilterContext *ctx, const char *cmd, const char *arg, char *res, int res_len, int flags)
#define CDG_MINIMUM_SCROLL_SIZE
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
#define CDG_FULL_WIDTH
default screen sizes
const FFCodec ff_cdgraphics_decoder
static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out, int in_tl_x, int in_tl_y, uint8_t *in, int w, int h, int stride)
static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g, uint8_t *dst, unsigned int size)
static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low)
static av_cold int cdg_decode_end(AVCodecContext *avctx)
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
int av_frame_ref(AVFrame *dst, const AVFrame *src)
Set up a new reference to the data described by the source frame.
static const uint32_t color[16+AV_CLASS_CATEGORY_NB]
#define CDG_INST_TILE_BLOCK
#define i(width, name, range_min, range_max)
#define CDG_INST_BORDER_PRESET
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
void av_frame_unref(AVFrame *frame)
Unreference all the buffers referenced by frame and reset the frame fields.
#define CDG_INST_SCROLL_COPY
const char * name
Name of the codec implementation.
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
@ AV_PIX_FMT_PAL8
8 bits with AV_PIX_FMT_RGB32 palette
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.
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
main external API structure.
int palette_has_changed
Tell user application that palette has changed from previous frame.
#define CDG_INST_MEMORY_PRESET
instruction codes
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.
int frame_number
Frame counter, set by libavcodec.
static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out, int color, int w, int h, int stride)
This structure stores compressed data.
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
int linesize[AV_NUM_DATA_POINTERS]
For video, a positive or negative value, which is typically indicating the size in bytes of each pict...
#define CDG_INST_LOAD_PAL_LO
static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out, int in_tl_x, int in_tl_y, uint8_t *in, int color, int w, int h, int stride, int roll)
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