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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 <stdio.h> | |
48 | #include <stdlib.h> | |
49 | #include <zlib.h> | |
50 | ||
51 | #include "avcodec.h" | |
52 | #include "internal.h" | |
53 | #include "put_bits.h" | |
54 | #include "bytestream.h" | |
55 | ||
56 | ||
57 | typedef struct FlashSVContext { | |
58 | AVCodecContext *avctx; | |
59 | uint8_t *previous_frame; | |
60 | int image_width, image_height; | |
61 | int block_width, block_height; | |
62 | uint8_t *tmpblock; | |
63 | uint8_t *encbuffer; | |
64 | int block_size; | |
65 | z_stream zstream; | |
66 | int last_key_frame; | |
67 | } FlashSVContext; | |
68 | ||
69 | static int copy_region_enc(uint8_t *sptr, uint8_t *dptr, int dx, int dy, | |
70 | int h, int w, int stride, uint8_t *pfptr) | |
71 | { | |
72 | int i, j; | |
73 | uint8_t *nsptr; | |
74 | uint8_t *npfptr; | |
75 | int diff = 0; | |
76 | ||
77 | for (i = dx + h; i > dx; i--) { | |
78 | nsptr = sptr + i * stride + dy * 3; | |
79 | npfptr = pfptr + i * stride + dy * 3; | |
80 | for (j = 0; j < w * 3; j++) { | |
81 | diff |= npfptr[j] ^ nsptr[j]; | |
82 | dptr[j] = nsptr[j]; | |
83 | } | |
84 | dptr += w * 3; | |
85 | } | |
86 | if (diff) | |
87 | return 1; | |
88 | return 0; | |
89 | } | |
90 | ||
91 | static av_cold int flashsv_encode_end(AVCodecContext *avctx) | |
92 | { | |
93 | FlashSVContext *s = avctx->priv_data; | |
94 | ||
95 | deflateEnd(&s->zstream); | |
96 | ||
f6fa7814 DM |
97 | av_freep(&s->encbuffer); |
98 | av_freep(&s->previous_frame); | |
99 | av_freep(&s->tmpblock); | |
2ba45a60 DM |
100 | |
101 | av_frame_free(&avctx->coded_frame); | |
102 | ||
103 | return 0; | |
104 | } | |
105 | ||
106 | static av_cold int flashsv_encode_init(AVCodecContext *avctx) | |
107 | { | |
108 | FlashSVContext *s = avctx->priv_data; | |
109 | ||
110 | s->avctx = avctx; | |
111 | ||
112 | if (avctx->width > 4095 || avctx->height > 4095) { | |
113 | av_log(avctx, AV_LOG_ERROR, | |
114 | "Input dimensions too large, input must be max 4096x4096 !\n"); | |
115 | return AVERROR_INVALIDDATA; | |
116 | } | |
117 | ||
118 | // Needed if zlib unused or init aborted before deflateInit | |
119 | memset(&s->zstream, 0, sizeof(z_stream)); | |
120 | ||
121 | s->last_key_frame = 0; | |
122 | ||
123 | s->image_width = avctx->width; | |
124 | s->image_height = avctx->height; | |
125 | ||
126 | s->tmpblock = av_mallocz(3 * 256 * 256); | |
127 | s->encbuffer = av_mallocz(s->image_width * s->image_height * 3); | |
128 | ||
129 | if (!s->tmpblock || !s->encbuffer) { | |
130 | av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n"); | |
131 | return AVERROR(ENOMEM); | |
132 | } | |
133 | ||
134 | avctx->coded_frame = av_frame_alloc(); | |
135 | if (!avctx->coded_frame) { | |
136 | flashsv_encode_end(avctx); | |
137 | return AVERROR(ENOMEM); | |
138 | } | |
139 | ||
140 | return 0; | |
141 | } | |
142 | ||
143 | ||
144 | static int encode_bitstream(FlashSVContext *s, const AVFrame *p, uint8_t *buf, | |
145 | int buf_size, int block_width, int block_height, | |
146 | uint8_t *previous_frame, int *I_frame) | |
147 | { | |
148 | ||
149 | PutBitContext pb; | |
150 | int h_blocks, v_blocks, h_part, v_part, i, j; | |
151 | int buf_pos, res; | |
152 | int pred_blocks = 0; | |
153 | ||
154 | init_put_bits(&pb, buf, buf_size * 8); | |
155 | ||
156 | put_bits(&pb, 4, block_width / 16 - 1); | |
157 | put_bits(&pb, 12, s->image_width); | |
158 | put_bits(&pb, 4, block_height / 16 - 1); | |
159 | put_bits(&pb, 12, s->image_height); | |
160 | flush_put_bits(&pb); | |
161 | buf_pos = 4; | |
162 | ||
163 | h_blocks = s->image_width / block_width; | |
164 | h_part = s->image_width % block_width; | |
165 | v_blocks = s->image_height / block_height; | |
166 | v_part = s->image_height % block_height; | |
167 | ||
168 | /* loop over all block columns */ | |
169 | for (j = 0; j < v_blocks + (v_part ? 1 : 0); j++) { | |
170 | ||
171 | int y_pos = j * block_height; // vertical position in frame | |
172 | int cur_blk_height = (j < v_blocks) ? block_height : v_part; | |
173 | ||
174 | /* loop over all block rows */ | |
175 | for (i = 0; i < h_blocks + (h_part ? 1 : 0); i++) { | |
176 | int x_pos = i * block_width; // horizontal position in frame | |
177 | int cur_blk_width = (i < h_blocks) ? block_width : h_part; | |
178 | int ret = Z_OK; | |
179 | uint8_t *ptr = buf + buf_pos; | |
180 | ||
181 | /* copy the block to the temp buffer before compression | |
182 | * (if it differs from the previous frame's block) */ | |
183 | res = copy_region_enc(p->data[0], s->tmpblock, | |
184 | s->image_height - (y_pos + cur_blk_height + 1), | |
185 | x_pos, cur_blk_height, cur_blk_width, | |
186 | p->linesize[0], previous_frame); | |
187 | ||
188 | if (res || *I_frame) { | |
189 | unsigned long zsize = 3 * block_width * block_height; | |
190 | ret = compress2(ptr + 2, &zsize, s->tmpblock, | |
191 | 3 * cur_blk_width * cur_blk_height, 9); | |
192 | ||
193 | //ret = deflateReset(&s->zstream); | |
194 | if (ret != Z_OK) | |
195 | av_log(s->avctx, AV_LOG_ERROR, | |
196 | "error while compressing block %dx%d\n", i, j); | |
197 | ||
198 | bytestream_put_be16(&ptr, zsize); | |
199 | buf_pos += zsize + 2; | |
200 | av_dlog(s->avctx, "buf_pos = %d\n", buf_pos); | |
201 | } else { | |
202 | pred_blocks++; | |
203 | bytestream_put_be16(&ptr, 0); | |
204 | buf_pos += 2; | |
205 | } | |
206 | } | |
207 | } | |
208 | ||
209 | if (pred_blocks) | |
210 | *I_frame = 0; | |
211 | else | |
212 | *I_frame = 1; | |
213 | ||
214 | return buf_pos; | |
215 | } | |
216 | ||
217 | ||
218 | static int flashsv_encode_frame(AVCodecContext *avctx, AVPacket *pkt, | |
219 | const AVFrame *pict, int *got_packet) | |
220 | { | |
221 | FlashSVContext * const s = avctx->priv_data; | |
222 | const AVFrame * const p = pict; | |
223 | uint8_t *pfptr; | |
224 | int res; | |
225 | int I_frame = 0; | |
226 | int opt_w = 4, opt_h = 4; | |
227 | ||
228 | /* First frame needs to be a keyframe */ | |
229 | if (avctx->frame_number == 0) { | |
230 | s->previous_frame = av_mallocz(FFABS(p->linesize[0]) * s->image_height); | |
231 | if (!s->previous_frame) { | |
232 | av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n"); | |
233 | return AVERROR(ENOMEM); | |
234 | } | |
235 | I_frame = 1; | |
236 | } | |
237 | ||
238 | if (p->linesize[0] < 0) | |
239 | pfptr = s->previous_frame - (s->image_height - 1) * p->linesize[0]; | |
240 | else | |
241 | pfptr = s->previous_frame; | |
242 | ||
243 | /* Check the placement of keyframes */ | |
244 | if (avctx->gop_size > 0 && | |
245 | avctx->frame_number >= s->last_key_frame + avctx->gop_size) { | |
246 | I_frame = 1; | |
247 | } | |
248 | ||
249 | if ((res = ff_alloc_packet2(avctx, pkt, s->image_width * s->image_height * 3)) < 0) | |
250 | return res; | |
251 | ||
252 | pkt->size = encode_bitstream(s, p, pkt->data, pkt->size, opt_w * 16, opt_h * 16, | |
253 | pfptr, &I_frame); | |
254 | ||
255 | //save the current frame | |
256 | if (p->linesize[0] > 0) | |
257 | memcpy(s->previous_frame, p->data[0], s->image_height * p->linesize[0]); | |
258 | else | |
259 | memcpy(s->previous_frame, | |
260 | p->data[0] + p->linesize[0] * (s->image_height - 1), | |
261 | s->image_height * FFABS(p->linesize[0])); | |
262 | ||
263 | //mark the frame type so the muxer can mux it correctly | |
264 | if (I_frame) { | |
265 | avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I; | |
266 | avctx->coded_frame->key_frame = 1; | |
267 | s->last_key_frame = avctx->frame_number; | |
268 | av_dlog(avctx, "Inserting keyframe at frame %d\n", avctx->frame_number); | |
269 | } else { | |
270 | avctx->coded_frame->pict_type = AV_PICTURE_TYPE_P; | |
271 | avctx->coded_frame->key_frame = 0; | |
272 | } | |
273 | ||
274 | if (avctx->coded_frame->key_frame) | |
275 | pkt->flags |= AV_PKT_FLAG_KEY; | |
276 | *got_packet = 1; | |
277 | ||
278 | return 0; | |
279 | } | |
280 | ||
281 | AVCodec ff_flashsv_encoder = { | |
282 | .name = "flashsv", | |
283 | .long_name = NULL_IF_CONFIG_SMALL("Flash Screen Video"), | |
284 | .type = AVMEDIA_TYPE_VIDEO, | |
285 | .id = AV_CODEC_ID_FLASHSV, | |
286 | .priv_data_size = sizeof(FlashSVContext), | |
287 | .init = flashsv_encode_init, | |
288 | .encode2 = flashsv_encode_frame, | |
289 | .close = flashsv_encode_end, | |
290 | .pix_fmts = (const enum AVPixelFormat[]){ AV_PIX_FMT_BGR24, AV_PIX_FMT_NONE }, | |
291 | }; |