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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
57typedef 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
69static 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
91static av_cold int flashsv_encode_end(AVCodecContext *avctx)
92{
93 FlashSVContext *s = avctx->priv_data;
94
95 deflateEnd(&s->zstream);
96
97 av_freep(&s->encbuffer);
98 av_freep(&s->previous_frame);
99 av_freep(&s->tmpblock);
100
101 return 0;
102}
103
104static av_cold int flashsv_encode_init(AVCodecContext *avctx)
105{
106 FlashSVContext *s = avctx->priv_data;
107
108 s->avctx = avctx;
109
110 if (avctx->width > 4095 || avctx->height > 4095) {
111 av_log(avctx, AV_LOG_ERROR,
112 "Input dimensions too large, input must be max 4095x4095 !\n");
113 return AVERROR_INVALIDDATA;
114 }
115
116 // Needed if zlib unused or init aborted before deflateInit
117 memset(&s->zstream, 0, sizeof(z_stream));
118
119 s->last_key_frame = 0;
120
121 s->image_width = avctx->width;
122 s->image_height = avctx->height;
123
124 s->tmpblock = av_mallocz(3 * 256 * 256);
125 s->encbuffer = av_mallocz(s->image_width * s->image_height * 3);
126
127 if (!s->tmpblock || !s->encbuffer) {
128 av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
129 return AVERROR(ENOMEM);
130 }
131
132 return 0;
133}
134
135
136static int encode_bitstream(FlashSVContext *s, const AVFrame *p, uint8_t *buf,
137 int buf_size, int block_width, int block_height,
138 uint8_t *previous_frame, int *I_frame)
139{
140
141 PutBitContext pb;
142 int h_blocks, v_blocks, h_part, v_part, i, j;
143 int buf_pos, res;
144 int pred_blocks = 0;
145
146 init_put_bits(&pb, buf, buf_size);
147
148 put_bits(&pb, 4, block_width / 16 - 1);
149 put_bits(&pb, 12, s->image_width);
150 put_bits(&pb, 4, block_height / 16 - 1);
151 put_bits(&pb, 12, s->image_height);
152 flush_put_bits(&pb);
153 buf_pos = 4;
154
155 h_blocks = s->image_width / block_width;
156 h_part = s->image_width % block_width;
157 v_blocks = s->image_height / block_height;
158 v_part = s->image_height % block_height;
159
160 /* loop over all block columns */
161 for (j = 0; j < v_blocks + (v_part ? 1 : 0); j++) {
162
163 int y_pos = j * block_height; // vertical position in frame
164 int cur_blk_height = (j < v_blocks) ? block_height : v_part;
165
166 /* loop over all block rows */
167 for (i = 0; i < h_blocks + (h_part ? 1 : 0); i++) {
168 int x_pos = i * block_width; // horizontal position in frame
169 int cur_blk_width = (i < h_blocks) ? block_width : h_part;
170 int ret = Z_OK;
171 uint8_t *ptr = buf + buf_pos;
172
173 /* copy the block to the temp buffer before compression
174 * (if it differs from the previous frame's block) */
175 res = copy_region_enc(p->data[0], s->tmpblock,
176 s->image_height - (y_pos + cur_blk_height + 1),
177 x_pos, cur_blk_height, cur_blk_width,
178 p->linesize[0], previous_frame);
179
180 if (res || *I_frame) {
181 unsigned long zsize = 3 * block_width * block_height;
182 ret = compress2(ptr + 2, &zsize, s->tmpblock,
183 3 * cur_blk_width * cur_blk_height, 9);
184
185 //ret = deflateReset(&s->zstream);
186 if (ret != Z_OK)
187 av_log(s->avctx, AV_LOG_ERROR,
188 "error while compressing block %dx%d\n", i, j);
189
190 bytestream_put_be16(&ptr, zsize);
191 buf_pos += zsize + 2;
192 ff_dlog(s->avctx, "buf_pos = %d\n", buf_pos);
193 } else {
194 pred_blocks++;
195 bytestream_put_be16(&ptr, 0);
196 buf_pos += 2;
197 }
198 }
199 }
200
201 if (pred_blocks)
202 *I_frame = 0;
203 else
204 *I_frame = 1;
205
206 return buf_pos;
207}
208
209
210static int flashsv_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
211 const AVFrame *pict, int *got_packet)
212{
213 FlashSVContext * const s = avctx->priv_data;
214 const AVFrame * const p = pict;
215 uint8_t *pfptr;
216 int res;
217 int I_frame = 0;
218 int opt_w = 4, opt_h = 4;
219
220 /* First frame needs to be a keyframe */
221 if (avctx->frame_number == 0) {
222 s->previous_frame = av_mallocz(FFABS(p->linesize[0]) * s->image_height);
223 if (!s->previous_frame) {
224 av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
225 return AVERROR(ENOMEM);
226 }
227 I_frame = 1;
228 }
229
230 if (p->linesize[0] < 0)
231 pfptr = s->previous_frame - (s->image_height - 1) * p->linesize[0];
232 else
233 pfptr = s->previous_frame;
234
235 /* Check the placement of keyframes */
236 if (avctx->gop_size > 0 &&
237 avctx->frame_number >= s->last_key_frame + avctx->gop_size) {
238 I_frame = 1;
239 }
240
241 if ((res = ff_alloc_packet2(avctx, pkt, s->image_width * s->image_height * 3, 0)) < 0)
242 return res;
243
244 pkt->size = encode_bitstream(s, p, pkt->data, pkt->size, opt_w * 16, opt_h * 16,
245 pfptr, &I_frame);
246
247 //save the current frame
248 if (p->linesize[0] > 0)
249 memcpy(s->previous_frame, p->data[0], s->image_height * p->linesize[0]);
250 else
251 memcpy(s->previous_frame,
252 p->data[0] + p->linesize[0] * (s->image_height - 1),
253 s->image_height * FFABS(p->linesize[0]));
254
255 //mark the frame type so the muxer can mux it correctly
256 if (I_frame) {
257#if FF_API_CODED_FRAME
258FF_DISABLE_DEPRECATION_WARNINGS
259 avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
260 avctx->coded_frame->key_frame = 1;
261FF_ENABLE_DEPRECATION_WARNINGS
262#endif
263 s->last_key_frame = avctx->frame_number;
264 ff_dlog(avctx, "Inserting keyframe at frame %d\n", avctx->frame_number);
265 } else {
266#if FF_API_CODED_FRAME
267FF_DISABLE_DEPRECATION_WARNINGS
268 avctx->coded_frame->pict_type = AV_PICTURE_TYPE_P;
269 avctx->coded_frame->key_frame = 0;
270FF_ENABLE_DEPRECATION_WARNINGS
271#endif
272 }
273
274 if (I_frame)
275 pkt->flags |= AV_PKT_FLAG_KEY;
276 *got_packet = 1;
277
278 return 0;
279}
280
281AVCodec 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};
292
generated by cgit at 2024-05-17 13:04:36 (GMT)