Flash screen video encoder.
[libav.git] / libavcodec / flashsvenc.c
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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 flashsvenc.c
27 * Flash Screen Video encoder
28 * @author Alex Beregszaszi
29 * @author Benjamin Larsson
30 */
31
32/* Bitstream description
33 * The picture is divided into blocks that are zlib-compressed.
34 *
35 * The decoder is fed complete frames, the frameheader contains:
36 * 4bits of block width
37 * 12bits of frame width
38 * 4bits of block height
39 * 12bits of frame height
40 *
41 * Directly after the header are the compressed blocks. The blocks
42 * have their compressed size represented with 16bits in the beginig.
43 * If the size = 0 then the block is unchanged from the previous frame.
44 * All blocks are decompressed until the buffer is consumed.
45 *
46 * Encoding ideas, a basic encoder would just use a fixed block size.
47 * Block sizes can be multipels of 16, from 16 to 256. The blocks don't
48 * have to be quadratic. A brute force search with a set of different
49 * block sizes should give a better result than to just use a fixed size.
50 */
51
52/* TODO:
53 * Don't reencode the frame in brute force mode if the frame is a dupe. Speed up.
54 * Make the difference check faster.
55 */
56
57#include <stdio.h>
58#include <stdlib.h>
59#include <zlib.h>
60
61#include "common.h"
62#include "avcodec.h"
63#include "bitstream.h"
64#include "bytestream.h"
65
66
67typedef struct FlashSVContext {
68 AVCodecContext *avctx;
69 uint8_t *previous_frame;
70 AVFrame frame;
71 int first_frame;
72 int image_width, image_height;
73 int block_width, block_height;
74 uint8_t* tmpblock;
75 uint8_t* encbuffer;
76 int block_size;
77 z_stream zstream;
78} FlashSVContext;
79
80static int copy_region_enc(uint8_t *sptr, uint8_t *dptr,
81 int dx, int dy, int h, int w, int stride, uint8_t *pfptr) {
82 int i,j;
83 uint8_t *nsptr;
84 uint8_t *npfptr;
85 int diff = 0;
86
87 for (i = dx+h; i > dx; i--) {
88 nsptr = sptr+(i*stride)+dy*3;
89 npfptr = pfptr+(i*stride)+dy*3;
90 for (j=0 ; j<w*3 ; j++) {
91 diff |=npfptr[j]^nsptr[j];
92 dptr[j] = nsptr[j];
93 }
94 dptr += w*3;
95 }
96 if (diff)
97 return 1;
98 return 0;
99}
100
101static int flashsv_encode_init(AVCodecContext *avctx)
102{
103 FlashSVContext *s = (FlashSVContext *)avctx->priv_data;
104
105 s->avctx = avctx;
106
107 if ((avctx->width > 4095) || (avctx->height > 4095)) {
108 av_log(avctx, AV_LOG_ERROR, "Input dimensions too large, input must be max 4096x4096 !\n");
109 return -1;
110 }
111
112 if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {
113 return -1;
114 }
115
116 s->first_frame = 1;
117
118 // Needed if zlib unused or init aborted before deflateInit
119 memset(&(s->zstream), 0, sizeof(z_stream));
120/*
121 s->zstream.zalloc = NULL; //av_malloc;
122 s->zstream.zfree = NULL; //av_free;
123 s->zstream.opaque = NULL;
124 zret = deflateInit(&(s->zstream), 9);
125 if (zret != Z_OK) {
126 av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
127 return -1;
128 }
129*/
130
131 s->image_width = avctx->width;
132 s->image_height = avctx->height;
133
134 s->tmpblock = av_mallocz(3*256*256);
135 s->encbuffer = av_mallocz(s->image_width*s->image_height*3);
136
137 if (!s->tmpblock || !s->encbuffer) {
138 av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
139 return -1;
140 }
141
142 return 0;
143}
144
145
146static int encode_bitstream(FlashSVContext *s, AVFrame *p, uint8_t *buf, int buf_size,
147 int block_width, int block_height, uint8_t *previous_frame, int* I_frame) {
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
172 int hp = j*block_height; // horiz position in frame
173 int hs = (j<v_blocks)?block_height:v_part; // size of block
174
175 /* loop over all block rows */
176 for (i = 0; i < h_blocks + (h_part?1:0); i++)
177 {
178 int wp = i*block_width; // vert position in frame
179 int ws = (i<h_blocks)?block_width:h_part; // size of block
180 int ret=Z_OK;
181 uint8_t *ptr;
182
183 ptr = buf+buf_pos;
184
185 //copy the block to the temp buffer before compression (if it differs from the previous frame's block)
186 res = copy_region_enc(p->data[0], s->tmpblock, s->image_height-(hp+hs+1), wp, hs, ws, p->linesize[0], previous_frame);
187
188 if (res || *I_frame) {
189 unsigned long zsize;
190 zsize = 3*block_width*block_height;
191 ret = compress2(ptr+2, &zsize, s->tmpblock, 3*ws*hs, 9);
192
193
194 //ret = deflateReset(&(s->zstream));
195 if (ret != Z_OK)
196 av_log(s->avctx, AV_LOG_ERROR, "error while compressing block %dx%d\n", i, j);
197 /*
198 s->zstream.next_in = s->tmpblock;
199 s->zstream.avail_in = 3*ws*hs;
200 s->zstream.total_in = 0;
201
202 s->zstream.next_out = ptr+2;
203 s->zstream.avail_out = buf_size-buf_pos-2;
204 s->zstream.total_out = 0;
205
206 ret = deflate(&(s->zstream), Z_FINISH);
207 if ((ret != Z_OK) && (ret != Z_STREAM_END))
208 av_log(s->avctx, AV_LOG_ERROR, "error while compressing block %dx%d\n", i, j);
209
210 size = s->zstream.total_out;
211 //av_log(avctx, AV_LOG_INFO, "compressed blocks: %d\n", size);
212 */
213 bytestream_put_be16(&ptr,(unsigned int)zsize);
214 buf_pos += zsize;
215 //av_log(avctx, AV_LOG_ERROR, "buf_pos = %d\n", buf_pos);
216 } else {
217 pred_blocks++;
218 bytestream_put_be16(&ptr,0);
219 }
220 }
221 }
222
223 if (pred_blocks)
224 *I_frame = 0;
225 else
226 *I_frame = 1;
227
228 return buf_pos;
229}
230
231
232static int flashsv_encode_frame(AVCodecContext *avctx, uint8_t *buf, int buf_size, void *data)
233{
234 FlashSVContext * const s = (FlashSVContext *)avctx->priv_data;
235 AVFrame *pict = data;
236 AVFrame * const p = &s->frame;
237 int res;
238 int I_frame = 0;
239 int opt_w, opt_h;
240
241 *p = *pict;
242
243 if (s->first_frame) {
244 s->previous_frame = av_mallocz(p->linesize[0]*s->image_height*3);
245 if (!s->previous_frame) {
246 av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
247 return -1;
248 }
249 I_frame = 1;
250 s->first_frame = 0;
251 }
252
253#if 0
254 int w, h;
255 int optim_sizes[16][16];
256 int smallest_size;
257 //Try all possible combinations and store the encoded frame sizes
258 for (w=1 ; w<17 ; w++) {
259 for (h=1 ; h<17 ; h++) {
260 optim_sizes[w-1][h-1] = encode_bitstream(s, p, s->encbuffer, s->image_width*s->image_height*4, w*16, h*16, s->previous_frame);
261 //av_log(avctx, AV_LOG_ERROR, "[%d][%d]size = %d\n",w,h,optim_sizes[w-1][h-1]);
262 }
263 }
264
265 //Search for the smallest framesize and encode the frame with those parameters
266 smallest_size=optim_sizes[0][0];
267 opt_w = 0;
268 opt_h = 0;
269 for (w=0 ; w<16 ; w++) {
270 for (h=0 ; h<16 ; h++) {
271 if (optim_sizes[w][h] < smallest_size) {
272 smallest_size = optim_sizes[w][h];
273 opt_w = w;
274 opt_h = h;
275 }
276 }
277 }
278 res = encode_bitstream(s, p, buf, buf_size, (opt_w+1)*16, (opt_h+1)*16, s->previous_frame);
279 av_log(avctx, AV_LOG_ERROR, "[%d][%d]optimal size = %d, res = %d|\n", opt_w, opt_h, smallest_size, res);
280
281 if (buf_size < res)
282 av_log(avctx, AV_LOG_ERROR, "buf_size %d < res %d\n", buf_size, res);
283
284#else
285 opt_w=1;
286 opt_h=1;
287
288 if (buf_size < s->image_width*s->image_height*3) {
289 //Conservative upper bound check for compressed data
290 av_log(avctx, AV_LOG_ERROR, "buf_size %d < %d\n", buf_size, s->image_width*s->image_height*3);
291 return -1;
292 }
293
294 res = encode_bitstream(s, p, buf, buf_size, opt_w*16, opt_h*16, s->previous_frame, &I_frame);
295#endif
296
297 //save the current frame
298 memcpy(s->previous_frame, p->data[0], s->image_height*p->linesize[0]*3);
299
300 //mark the frame type so the muxer can mux it correctly
301 if (I_frame) {
302 p->pict_type = FF_I_TYPE;
303 p->key_frame = 1;
304 } else {
305 p->pict_type = FF_P_TYPE;
306 p->key_frame = 0;
307 }
308
309 avctx->coded_frame = p;
310
311 return res;
312}
313
314static int flashsv_encode_end(AVCodecContext *avctx)
315{
316 FlashSVContext *s = (FlashSVContext *)avctx->priv_data;
317
318 deflateEnd(&(s->zstream));
319
320 av_free(s->encbuffer);
321 av_free(s->previous_frame);
322 av_free(s->tmpblock);
323
324 return 0;
325}
326
327AVCodec flashsv_encoder = {
328 "flashsv",
329 CODEC_TYPE_VIDEO,
330 CODEC_ID_FLASHSV,
331 sizeof(FlashSVContext),
332 flashsv_encode_init,
333 flashsv_encode_frame,
334 flashsv_encode_end,
335 .pix_fmts = (enum PixelFormat[]){PIX_FMT_BGR24, -1},
336};
337