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#include "internal.h"
26#include "libavutil/common.h"
27
28#if CONFIG_ZLIB
29#include <zlib.h>
30#endif
31#include "libavutil/lzo.h"
32
33typedef struct {
34    AVFrame *pic;
35    int linelen, height, bpp;
36    unsigned int decomp_size;
37    unsigned char* decomp_buf;
38} CamStudioContext;
39
40static void copy_frame_default(AVFrame *f, const uint8_t *src,
41                               int linelen, int height) {
42    int i, src_stride = FFALIGN(linelen, 4);
43    uint8_t *dst = f->data[0];
44    dst += (height - 1) * f->linesize[0];
45    for (i = height; i; i--) {
46        memcpy(dst, src, linelen);
47        src += src_stride;
48        dst -= f->linesize[0];
49    }
50}
51
52static void add_frame_default(AVFrame *f, const uint8_t *src,
53                              int linelen, int height) {
54    int i, j, src_stride = FFALIGN(linelen, 4);
55    uint8_t *dst = f->data[0];
56    dst += (height - 1) * f->linesize[0];
57    for (i = height; i; i--) {
58        for (j = linelen; j; j--)
59            *dst++ += *src++;
60        src += src_stride - linelen;
61        dst -= f->linesize[0] + linelen;
62    }
63}
64
65static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
66                        AVPacket *avpkt) {
67    const uint8_t *buf = avpkt->data;
68    int buf_size = avpkt->size;
69    CamStudioContext *c = avctx->priv_data;
70    int ret;
71
72    if (buf_size < 2) {
73        av_log(avctx, AV_LOG_ERROR, "coded frame too small\n");
74        return AVERROR_INVALIDDATA;
75    }
76
77    if ((ret = ff_reget_buffer(avctx, c->pic)) < 0)
78        return ret;
79
80    // decompress data
81    switch ((buf[0] >> 1) & 7) {
82        case 0: { // lzo compression
83            int outlen = c->decomp_size, inlen = buf_size - 2;
84            if (av_lzo1x_decode(c->decomp_buf, &outlen, &buf[2], &inlen))
85                av_log(avctx, AV_LOG_ERROR, "error during lzo decompression\n");
86            break;
87        }
88        case 1: { // zlib compression
89#if CONFIG_ZLIB
90            unsigned long dlen = c->decomp_size;
91            if (uncompress(c->decomp_buf, &dlen, &buf[2], buf_size - 2) != Z_OK)
92                av_log(avctx, AV_LOG_ERROR, "error during zlib decompression\n");
93            break;
94#else
95            av_log(avctx, AV_LOG_ERROR, "compiled without zlib support\n");
96            return AVERROR(ENOSYS);
97#endif
98        }
99        default:
100            av_log(avctx, AV_LOG_ERROR, "unknown compression\n");
101            return AVERROR_INVALIDDATA;
102    }
103
104    // flip upside down, add difference frame
105    if (buf[0] & 1) { // keyframe
106        c->pic->pict_type = AV_PICTURE_TYPE_I;
107        c->pic->key_frame = 1;
108              copy_frame_default(c->pic, c->decomp_buf,
109                                 c->linelen, c->height);
110    } else {
111        c->pic->pict_type = AV_PICTURE_TYPE_P;
112        c->pic->key_frame = 0;
113              add_frame_default(c->pic, c->decomp_buf,
114                                c->linelen, c->height);
115    }
116
117    *got_frame = 1;
118    if ((ret = av_frame_ref(data, c->pic)) < 0)
119        return ret;
120
121    return buf_size;
122}
123
124static av_cold int decode_init(AVCodecContext *avctx) {
125    CamStudioContext *c = avctx->priv_data;
126    int stride;
127    switch (avctx->bits_per_coded_sample) {
128        case 16: avctx->pix_fmt = AV_PIX_FMT_RGB555LE; break;
129        case 24: avctx->pix_fmt = AV_PIX_FMT_BGR24; break;
130        case 32: avctx->pix_fmt = AV_PIX_FMT_BGRA; break;
131        default:
132            av_log(avctx, AV_LOG_ERROR,
133                   "CamStudio codec error: invalid depth %i bpp\n",
134                   avctx->bits_per_coded_sample);
135            return AVERROR_INVALIDDATA;
136    }
137    c->bpp = avctx->bits_per_coded_sample;
138    c->linelen = avctx->width * avctx->bits_per_coded_sample / 8;
139    c->height = avctx->height;
140    stride = FFALIGN(c->linelen, 4);
141    c->decomp_size = c->height * stride;
142    c->decomp_buf = av_malloc(c->decomp_size + AV_LZO_OUTPUT_PADDING);
143    if (!c->decomp_buf) {
144        av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
145        return AVERROR(ENOMEM);
146    }
147    c->pic = av_frame_alloc();
148    if (!c->pic)
149        return AVERROR(ENOMEM);
150    return 0;
151}
152
153static av_cold int decode_end(AVCodecContext *avctx) {
154    CamStudioContext *c = avctx->priv_data;
155    av_freep(&c->decomp_buf);
156    av_frame_free(&c->pic);
157    return 0;
158}
159
160AVCodec ff_cscd_decoder = {
161    .name           = "camstudio",
162    .long_name      = NULL_IF_CONFIG_SMALL("CamStudio"),
163    .type           = AVMEDIA_TYPE_VIDEO,
164    .id             = AV_CODEC_ID_CSCD,
165    .priv_data_size = sizeof(CamStudioContext),
166    .init           = decode_init,
167    .close          = decode_end,
168    .decode         = decode_frame,
169    .capabilities   = CODEC_CAP_DR1,
170};
171