1/*
2 * CamStudio decoder
3 * Copyright (c) 2006 Reimar Doeffinger
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21#include <stdio.h>
22#include <stdlib.h>
23
24#include "avcodec.h"
25
26#if CONFIG_ZLIB
27#include <zlib.h>
28#endif
29#include "libavutil/lzo.h"
30
31typedef struct {
32    AVFrame pic;
33    int linelen, height, bpp;
34    unsigned int decomp_size;
35    unsigned char* decomp_buf;
36} CamStudioContext;
37
38static void copy_frame_default(AVFrame *f, const uint8_t *src,
39                               int linelen, int height) {
40    int i;
41    uint8_t *dst = f->data[0];
42    dst += (height - 1) * f->linesize[0];
43    for (i = height; i; i--) {
44        memcpy(dst, src, linelen);
45        src += linelen;
46        dst -= f->linesize[0];
47    }
48}
49
50static void add_frame_default(AVFrame *f, const uint8_t *src,
51                              int linelen, int height) {
52    int i, j;
53    uint8_t *dst = f->data[0];
54    dst += (height - 1) * f->linesize[0];
55    for (i = height; i; i--) {
56        for (j = linelen; j; j--)
57            *dst++ += *src++;
58        dst -= f->linesize[0] + linelen;
59    }
60}
61
62#ifndef WORDS_BIGENDIAN
63#define copy_frame_16 copy_frame_default
64#define copy_frame_32 copy_frame_default
65#define add_frame_16 add_frame_default
66#define add_frame_32 add_frame_default
67#else
68static void copy_frame_16(AVFrame *f, const uint8_t *src,
69                          int linelen, int height) {
70    int i, j;
71    uint8_t *dst = f->data[0];
72    dst += (height - 1) * f->linesize[0];
73    for (i = height; i; i--) {
74        for (j = linelen / 2; j; j--) {
75          dst[0] = src[1];
76          dst[1] = src[0];
77          src += 2;
78          dst += 2;
79        }
80        dst -= f->linesize[0] + linelen;
81    }
82}
83
84static void copy_frame_32(AVFrame *f, const uint8_t *src,
85                          int linelen, int height) {
86    int i, j;
87    uint8_t *dst = f->data[0];
88    dst += (height - 1) * f->linesize[0];
89    for (i = height; i; i--) {
90        for (j = linelen / 4; j; j--) {
91          dst[0] = src[3];
92          dst[1] = src[2];
93          dst[2] = src[1];
94          dst[3] = src[0];
95          src += 4;
96          dst += 4;
97        }
98        dst -= f->linesize[0] + linelen;
99    }
100}
101
102static void add_frame_16(AVFrame *f, const uint8_t *src,
103                         int linelen, int height) {
104    int i, j;
105    uint8_t *dst = f->data[0];
106    dst += (height - 1) * f->linesize[0];
107    for (i = height; i; i--) {
108        for (j = linelen / 2; j; j--) {
109          dst[0] += src[1];
110          dst[1] += src[0];
111          src += 2;
112          dst += 2;
113        }
114        dst -= f->linesize[0] + linelen;
115    }
116}
117
118static void add_frame_32(AVFrame *f, const uint8_t *src,
119                         int linelen, int height) {
120    int i, j;
121    uint8_t *dst = f->data[0];
122    dst += (height - 1) * f->linesize[0];
123    for (i = height; i; i--) {
124        for (j = linelen / 4; j; j--) {
125          dst[0] += src[3];
126          dst[1] += src[2];
127          dst[2] += src[1];
128          dst[3] += src[0];
129          src += 4;
130          dst += 4;
131        }
132        dst -= f->linesize[0] + linelen;
133    }
134}
135#endif
136
137static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
138                        const uint8_t *buf, int buf_size) {
139    CamStudioContext *c = avctx->priv_data;
140    AVFrame *picture = data;
141
142    if (buf_size < 2) {
143        av_log(avctx, AV_LOG_ERROR, "coded frame too small\n");
144        return -1;
145    }
146
147    if (c->pic.data[0])
148        avctx->release_buffer(avctx, &c->pic);
149    c->pic.reference = 1;
150    c->pic.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_READABLE |
151                          FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
152    if (avctx->get_buffer(avctx, &c->pic) < 0) {
153        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
154        return -1;
155    }
156
157    // decompress data
158    switch ((buf[0] >> 1) & 7) {
159        case 0: { // lzo compression
160            int outlen = c->decomp_size, inlen = buf_size - 2;
161            if (av_lzo1x_decode(c->decomp_buf, &outlen, &buf[2], &inlen))
162                av_log(avctx, AV_LOG_ERROR, "error during lzo decompression\n");
163            break;
164        }
165        case 1: { // zlib compression
166#if CONFIG_ZLIB
167            unsigned long dlen = c->decomp_size;
168            if (uncompress(c->decomp_buf, &dlen, &buf[2], buf_size - 2) != Z_OK)
169                av_log(avctx, AV_LOG_ERROR, "error during zlib decompression\n");
170            break;
171#else
172            av_log(avctx, AV_LOG_ERROR, "compiled without zlib support\n");
173            return -1;
174#endif
175        }
176        default:
177            av_log(avctx, AV_LOG_ERROR, "unknown compression\n");
178            return -1;
179    }
180
181    // flip upside down, add difference frame
182    if (buf[0] & 1) { // keyframe
183        c->pic.pict_type = FF_I_TYPE;
184        c->pic.key_frame = 1;
185        switch (c->bpp) {
186          case 16:
187              copy_frame_16(&c->pic, c->decomp_buf, c->linelen, c->height);
188              break;
189          case 32:
190              copy_frame_32(&c->pic, c->decomp_buf, c->linelen, c->height);
191              break;
192          default:
193              copy_frame_default(&c->pic, c->decomp_buf, c->linelen, c->height);
194        }
195    } else {
196        c->pic.pict_type = FF_P_TYPE;
197        c->pic.key_frame = 0;
198        switch (c->bpp) {
199          case 16:
200              add_frame_16(&c->pic, c->decomp_buf, c->linelen, c->height);
201              break;
202          case 32:
203              add_frame_32(&c->pic, c->decomp_buf, c->linelen, c->height);
204              break;
205          default:
206              add_frame_default(&c->pic, c->decomp_buf, c->linelen, c->height);
207        }
208    }
209
210    *picture = c->pic;
211    *data_size = sizeof(AVFrame);
212    return buf_size;
213}
214
215static av_cold int decode_init(AVCodecContext *avctx) {
216    CamStudioContext *c = avctx->priv_data;
217    if (avcodec_check_dimensions(avctx, avctx->height, avctx->width) < 0) {
218        return 1;
219    }
220    switch (avctx->bits_per_coded_sample) {
221        case 16: avctx->pix_fmt = PIX_FMT_RGB555; break;
222        case 24: avctx->pix_fmt = PIX_FMT_BGR24; break;
223        case 32: avctx->pix_fmt = PIX_FMT_RGB32; break;
224        default:
225            av_log(avctx, AV_LOG_ERROR,
226                   "CamStudio codec error: invalid depth %i bpp\n",
227                   avctx->bits_per_coded_sample);
228             return 1;
229    }
230    c->bpp = avctx->bits_per_coded_sample;
231    c->pic.data[0] = NULL;
232    c->linelen = avctx->width * avctx->bits_per_coded_sample / 8;
233    c->height = avctx->height;
234    c->decomp_size = c->height * c->linelen;
235    c->decomp_buf = av_malloc(c->decomp_size + AV_LZO_OUTPUT_PADDING);
236    if (!c->decomp_buf) {
237        av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
238        return 1;
239    }
240    return 0;
241}
242
243static av_cold int decode_end(AVCodecContext *avctx) {
244    CamStudioContext *c = avctx->priv_data;
245    av_freep(&c->decomp_buf);
246    if (c->pic.data[0])
247        avctx->release_buffer(avctx, &c->pic);
248    return 0;
249}
250
251AVCodec cscd_decoder = {
252    "camstudio",
253    CODEC_TYPE_VIDEO,
254    CODEC_ID_CSCD,
255    sizeof(CamStudioContext),
256    decode_init,
257    NULL,
258    decode_end,
259    decode_frame,
260    CODEC_CAP_DR1,
261    .long_name = NULL_IF_CONFIG_SMALL("CamStudio"),
262};
263
264