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#if !HAVE_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                        AVPacket *avpkt) {
139    const uint8_t *buf = avpkt->data;
140    int buf_size = avpkt->size;
141    CamStudioContext *c = avctx->priv_data;
142    AVFrame *picture = data;
143
144    if (buf_size < 2) {
145        av_log(avctx, AV_LOG_ERROR, "coded frame too small\n");
146        return -1;
147    }
148
149    if (c->pic.data[0])
150        avctx->release_buffer(avctx, &c->pic);
151    c->pic.reference = 1;
152    c->pic.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_READABLE |
153                          FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
154    if (avctx->get_buffer(avctx, &c->pic) < 0) {
155        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
156        return -1;
157    }
158
159    // decompress data
160    switch ((buf[0] >> 1) & 7) {
161        case 0: { // lzo compression
162            int outlen = c->decomp_size, inlen = buf_size - 2;
163            if (av_lzo1x_decode(c->decomp_buf, &outlen, &buf[2], &inlen))
164                av_log(avctx, AV_LOG_ERROR, "error during lzo decompression\n");
165            break;
166        }
167        case 1: { // zlib compression
168#if CONFIG_ZLIB
169            unsigned long dlen = c->decomp_size;
170            if (uncompress(c->decomp_buf, &dlen, &buf[2], buf_size - 2) != Z_OK)
171                av_log(avctx, AV_LOG_ERROR, "error during zlib decompression\n");
172            break;
173#else
174            av_log(avctx, AV_LOG_ERROR, "compiled without zlib support\n");
175            return -1;
176#endif
177        }
178        default:
179            av_log(avctx, AV_LOG_ERROR, "unknown compression\n");
180            return -1;
181    }
182
183    // flip upside down, add difference frame
184    if (buf[0] & 1) { // keyframe
185        c->pic.pict_type = FF_I_TYPE;
186        c->pic.key_frame = 1;
187        switch (c->bpp) {
188          case 16:
189              copy_frame_16(&c->pic, c->decomp_buf, c->linelen, c->height);
190              break;
191          case 32:
192              copy_frame_32(&c->pic, c->decomp_buf, c->linelen, c->height);
193              break;
194          default:
195              copy_frame_default(&c->pic, c->decomp_buf, c->linelen, c->height);
196        }
197    } else {
198        c->pic.pict_type = FF_P_TYPE;
199        c->pic.key_frame = 0;
200        switch (c->bpp) {
201          case 16:
202              add_frame_16(&c->pic, c->decomp_buf, c->linelen, c->height);
203              break;
204          case 32:
205              add_frame_32(&c->pic, c->decomp_buf, c->linelen, c->height);
206              break;
207          default:
208              add_frame_default(&c->pic, c->decomp_buf, c->linelen, c->height);
209        }
210    }
211
212    *picture = c->pic;
213    *data_size = sizeof(AVFrame);
214    return buf_size;
215}
216
217static av_cold int decode_init(AVCodecContext *avctx) {
218    CamStudioContext *c = avctx->priv_data;
219    switch (avctx->bits_per_coded_sample) {
220        case 16: avctx->pix_fmt = PIX_FMT_RGB555; break;
221        case 24: avctx->pix_fmt = PIX_FMT_BGR24; break;
222        case 32: avctx->pix_fmt = PIX_FMT_RGB32; break;
223        default:
224            av_log(avctx, AV_LOG_ERROR,
225                   "CamStudio codec error: invalid depth %i bpp\n",
226                   avctx->bits_per_coded_sample);
227             return 1;
228    }
229    c->bpp = avctx->bits_per_coded_sample;
230    c->pic.data[0] = NULL;
231    c->linelen = avctx->width * avctx->bits_per_coded_sample / 8;
232    c->height = avctx->height;
233    c->decomp_size = c->height * c->linelen;
234    c->decomp_buf = av_malloc(c->decomp_size + AV_LZO_OUTPUT_PADDING);
235    if (!c->decomp_buf) {
236        av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
237        return 1;
238    }
239    return 0;
240}
241
242static av_cold int decode_end(AVCodecContext *avctx) {
243    CamStudioContext *c = avctx->priv_data;
244    av_freep(&c->decomp_buf);
245    if (c->pic.data[0])
246        avctx->release_buffer(avctx, &c->pic);
247    return 0;
248}
249
250AVCodec cscd_decoder = {
251    "camstudio",
252    AVMEDIA_TYPE_VIDEO,
253    CODEC_ID_CSCD,
254    sizeof(CamStudioContext),
255    decode_init,
256    NULL,
257    decode_end,
258    decode_frame,
259    CODEC_CAP_DR1,
260    .long_name = NULL_IF_CONFIG_SMALL("CamStudio"),
261};
262
263