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 *encbuffer;
63 int block_size;
64 int last_key_frame;
65 uint8_t tmpblock[3 * 256 * 256];
66 } FlashSVContext;
67
copy_region_enc(uint8_t * sptr,uint8_t * dptr,int dx,int dy,int h,int w,int stride,uint8_t * pfptr)68 static int copy_region_enc(uint8_t *sptr, uint8_t *dptr, int dx, int dy,
69 int h, int w, int stride, uint8_t *pfptr)
70 {
71 int i, j;
72 uint8_t *nsptr;
73 uint8_t *npfptr;
74 int diff = 0;
75
76 for (i = dx + h; i > dx; i--) {
77 nsptr = sptr + i * stride + dy * 3;
78 npfptr = pfptr + i * stride + dy * 3;
79 for (j = 0; j < w * 3; j++) {
80 diff |= npfptr[j] ^ nsptr[j];
81 dptr[j] = nsptr[j];
82 }
83 dptr += w * 3;
84 }
85 if (diff)
86 return 1;
87 return 0;
88 }
89
flashsv_encode_end(AVCodecContext * avctx)90 static av_cold int flashsv_encode_end(AVCodecContext *avctx)
91 {
92 FlashSVContext *s = avctx->priv_data;
93
94 av_freep(&s->encbuffer);
95 av_freep(&s->previous_frame);
96
97 return 0;
98 }
99
flashsv_encode_init(AVCodecContext * avctx)100 static av_cold int flashsv_encode_init(AVCodecContext *avctx)
101 {
102 FlashSVContext *s = avctx->priv_data;
103
104 s->avctx = avctx;
105
106 if (avctx->width > 4095 || avctx->height > 4095) {
107 av_log(avctx, AV_LOG_ERROR,
108 "Input dimensions too large, input must be max 4095x4095 !\n");
109 return AVERROR_INVALIDDATA;
110 }
111
112 s->last_key_frame = 0;
113
114 s->image_width = avctx->width;
115 s->image_height = avctx->height;
116
117 s->encbuffer = av_mallocz(s->image_width * s->image_height * 3);
118
119 if (!s->encbuffer) {
120 av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
121 return AVERROR(ENOMEM);
122 }
123
124 return 0;
125 }
126
127
encode_bitstream(FlashSVContext * s,const AVFrame * p,uint8_t * buf,int buf_size,int block_width,int block_height,uint8_t * previous_frame,int * I_frame)128 static int encode_bitstream(FlashSVContext *s, const AVFrame *p, uint8_t *buf,
129 int buf_size, int block_width, int block_height,
130 uint8_t *previous_frame, int *I_frame)
131 {
132
133 PutBitContext pb;
134 int h_blocks, v_blocks, h_part, v_part, i, j;
135 int buf_pos, res;
136 int pred_blocks = 0;
137
138 init_put_bits(&pb, buf, buf_size);
139
140 put_bits(&pb, 4, block_width / 16 - 1);
141 put_bits(&pb, 12, s->image_width);
142 put_bits(&pb, 4, block_height / 16 - 1);
143 put_bits(&pb, 12, s->image_height);
144 flush_put_bits(&pb);
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;
162 int ret = Z_OK;
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) */
167 res = copy_region_enc(p->data[0], s->tmpblock,
168 s->image_height - (y_pos + cur_blk_height + 1),
169 x_pos, cur_blk_height, cur_blk_width,
170 p->linesize[0], previous_frame);
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
177 if (ret != Z_OK)
178 av_log(s->avctx, AV_LOG_ERROR,
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
flashsv_encode_frame(AVCodecContext * avctx,AVPacket * pkt,const AVFrame * pict,int * got_packet)201 static int flashsv_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
202 const AVFrame *pict, int *got_packet)
203 {
204 FlashSVContext * const s = avctx->priv_data;
205 const AVFrame * const p = pict;
206 uint8_t *pfptr;
207 int res;
208 int I_frame = 0;
209 int opt_w = 4, opt_h = 4;
210
211 /* First frame needs to be a keyframe */
212 if (avctx->frame_number == 0) {
213 s->previous_frame = av_mallocz(FFABS(p->linesize[0]) * s->image_height);
214 if (!s->previous_frame) {
215 av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
216 return AVERROR(ENOMEM);
217 }
218 I_frame = 1;
219 }
220
221 if (p->linesize[0] < 0)
222 pfptr = s->previous_frame - (s->image_height - 1) * p->linesize[0];
223 else
224 pfptr = s->previous_frame;
225
226 /* Check the placement of keyframes */
227 if (avctx->gop_size > 0 &&
228 avctx->frame_number >= s->last_key_frame + avctx->gop_size) {
229 I_frame = 1;
230 }
231
232 if ((res = ff_alloc_packet2(avctx, pkt, s->image_width * s->image_height * 3, 0)) < 0)
233 return res;
234
235 pkt->size = encode_bitstream(s, p, pkt->data, pkt->size, opt_w * 16, opt_h * 16,
236 pfptr, &I_frame);
237
238 //save the current frame
239 if (p->linesize[0] > 0)
240 memcpy(s->previous_frame, p->data[0], s->image_height * p->linesize[0]);
241 else
242 memcpy(s->previous_frame,
243 p->data[0] + p->linesize[0] * (s->image_height - 1),
244 s->image_height * FFABS(p->linesize[0]));
245
246 //mark the frame type so the muxer can mux it correctly
247 if (I_frame) {
248 #if FF_API_CODED_FRAME
249 FF_DISABLE_DEPRECATION_WARNINGS
250 avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
251 avctx->coded_frame->key_frame = 1;
252 FF_ENABLE_DEPRECATION_WARNINGS
253 #endif
254 s->last_key_frame = avctx->frame_number;
255 ff_dlog(avctx, "Inserting keyframe at frame %d\n", avctx->frame_number);
256 } else {
257 #if FF_API_CODED_FRAME
258 FF_DISABLE_DEPRECATION_WARNINGS
259 avctx->coded_frame->pict_type = AV_PICTURE_TYPE_P;
260 avctx->coded_frame->key_frame = 0;
261 FF_ENABLE_DEPRECATION_WARNINGS
262 #endif
263 }
264
265 if (I_frame)
266 pkt->flags |= AV_PKT_FLAG_KEY;
267 *got_packet = 1;
268
269 return 0;
270 }
271
272 AVCodec ff_flashsv_encoder = {
273 .name = "flashsv",
274 .long_name = NULL_IF_CONFIG_SMALL("Flash Screen Video"),
275 .type = AVMEDIA_TYPE_VIDEO,
276 .id = AV_CODEC_ID_FLASHSV,
277 .priv_data_size = sizeof(FlashSVContext),
278 .init = flashsv_encode_init,
279 .encode2 = flashsv_encode_frame,
280 .close = flashsv_encode_end,
281 .pix_fmts = (const enum AVPixelFormat[]){ AV_PIX_FMT_BGR24, AV_PIX_FMT_NONE },
282 };
283