1 /*
2 * Flash Screen Video encoder
3 * Copyright (C) 2004 Alex Beregszaszi
4 * Copyright (C) 2006 Benjamin Larsson
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /* Encoding development sponsored by http://fh-campuswien.ac.at */
24
25 /**
26 * @file
27 * Flash Screen Video encoder
28 * @author Alex Beregszaszi
29 * @author Benjamin Larsson
30 *
31 * A description of the bitstream format for Flash Screen Video version 1/2
32 * is part of the SWF File Format Specification (version 10), which can be
33 * downloaded from http://www.adobe.com/devnet/swf.html.
34 */
35
36 /*
37 * Encoding ideas: A basic encoder would just use a fixed block size.
38 * Block sizes can be multiples of 16, from 16 to 256. The blocks don't
39 * have to be quadratic. A brute force search with a set of different
40 * block sizes should give a better result than to just use a fixed size.
41 *
42 * TODO:
43 * Don't reencode the frame in brute force mode if the frame is a dupe.
44 * Speed up. Make the difference check faster.
45 */
46
47 #include <stdint.h>
48 #include <zlib.h>
49
51
57
58 /* These values are hardcoded for now. */
59 #define BLOCK_WIDTH (4 * 16U)
60 #define BLOCK_HEIGHT (4 * 16U)
61
71
73 int h,
int w,
int stride,
const uint8_t *pfptr)
74 {
77
78 for (
i = dx +
h;
i > dx;
i--) {
79 const uint8_t *nsptr = sptr +
i *
stride + dy * 3;
80 const uint8_t *npfptr = pfptr +
i *
stride + dy * 3;
81 for (j = 0; j <
w * 3; j++) {
82 diff |= npfptr[j] ^ nsptr[j];
83 dptr[j] = nsptr[j];
84 }
86 }
88 return 1;
89 return 0;
90 }
91
93 {
95
97
98 return 0;
99 }
100
102 {
104 int h_blocks, v_blocks, nb_blocks;
105
107
110 "Input dimensions too large, input must be max 4095x4095 !\n");
112 }
113
114 s->last_key_frame = 0;
115
116 s->image_width = avctx->
width;
117 s->image_height = avctx->
height;
118
121 nb_blocks = h_blocks * v_blocks;
123
124 return 0;
125 }
126
127
129 int buf_size, int block_width, int block_height,
130 const uint8_t *previous_frame, int *I_frame)
131 {
132
134 int h_blocks, v_blocks, h_part, v_part,
i, j;
135 int buf_pos, res;
136 int pred_blocks = 0;
137
139
140 put_bits(&pb, 4, block_width / 16 - 1);
142 put_bits(&pb, 4, block_height / 16 - 1);
145 buf_pos = 4;
146
147 h_blocks =
s->image_width / block_width;
148 h_part =
s->image_width % block_width;
149 v_blocks =
s->image_height / block_height;
150 v_part =
s->image_height % block_height;
151
152 /* loop over all block columns */
153 for (j = 0; j < v_blocks + (v_part ? 1 : 0); j++) {
154
155 int y_pos = j * block_height; // vertical position in frame
156 int cur_blk_height = (j < v_blocks) ? block_height : v_part;
157
158 /* loop over all block rows */
159 for (
i = 0;
i < h_blocks + (h_part ? 1 : 0);
i++) {
160 int x_pos =
i * block_width;
// horizontal position in frame
161 int cur_blk_width = (
i < h_blocks) ? block_width : h_part;
163 uint8_t *ptr = buf + buf_pos;
164
165 /* copy the block to the temp buffer before compression
166 * (if it differs from the previous frame's block) */
168 s->image_height - (y_pos + cur_blk_height + 1),
169 x_pos, cur_blk_height, cur_blk_width,
171
172 if (res || *I_frame) {
173 unsigned long zsize = 3 * block_width * block_height;
174 ret = compress2(ptr + 2, &zsize,
s->tmpblock,
175 3 * cur_blk_width * cur_blk_height, 9);
176
179 "error while compressing block %dx%d\n",
i, j);
180
181 bytestream_put_be16(&ptr, zsize);
182 buf_pos += zsize + 2;
183 ff_dlog(
s->avctx,
"buf_pos = %d\n", buf_pos);
184 } else {
185 pred_blocks++;
186 bytestream_put_be16(&ptr, 0);
187 buf_pos += 2;
188 }
189 }
190 }
191
192 if (pred_blocks)
193 *I_frame = 0;
194 else
195 *I_frame = 1;
196
197 return buf_pos;
198 }
199
200
202 const AVFrame *pict,
int *got_packet)
203 {
205 const uint8_t *prev_frame =
s->previous_frame;
206 int res;
207 int I_frame = 0;
208 int opt_w = 4, opt_h = 4;
209
210 /* First frame needs to be a keyframe */
211 if (!
s->previous_frame) {
212 prev_frame = pict->
data[0];
213 I_frame = 1;
214 }
215
216 /* Check the placement of keyframes */
219 I_frame = 1;
220 }
221
223 if (res < 0)
224 return res;
225
227 opt_w * 16, opt_h * 16,
228 prev_frame, &I_frame);
229
230 //mark the frame type so the muxer can mux it correctly
231 if (I_frame) {
233 ff_dlog(avctx,
"Inserting keyframe at frame %"PRId64
"\n", avctx->
frame_num);
234 }
235
236 if (I_frame)
238 *got_packet = 1;
239
240 //save the current frame
242 if (res < 0)
243 return res;
244 s->previous_frame = pict->
data[0];
245
246 return 0;
247 }
248
260 };