1/*
2 * Tiertex Limited SEQ Video Decoder
3 * Copyright (c) 2006 Gregory Montoir (cyx@users.sourceforge.net)
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * Tiertex Limited SEQ video decoder
25 */
26
27#include "avcodec.h"
28#define BITSTREAM_READER_LE
29#include "get_bits.h"
30
31
32typedef struct SeqVideoContext {
33    AVCodecContext *avctx;
34    AVFrame frame;
35} SeqVideoContext;
36
37
38static const unsigned char *seq_unpack_rle_block(const unsigned char *src,
39                                                 const unsigned char *src_end,
40                                                 unsigned char *dst, int dst_size)
41{
42    int i, len, sz;
43    GetBitContext gb;
44    int code_table[64];
45
46    /* get the rle codes */
47    init_get_bits(&gb, src, (src_end - src) * 8);
48    for (i = 0, sz = 0; i < 64 && sz < dst_size; i++) {
49        if (get_bits_left(&gb) < 4)
50            return NULL;
51        code_table[i] = get_sbits(&gb, 4);
52        sz += FFABS(code_table[i]);
53    }
54    src += (get_bits_count(&gb) + 7) / 8;
55
56    /* do the rle unpacking */
57    for (i = 0; i < 64 && dst_size > 0; i++) {
58        len = code_table[i];
59        if (len < 0) {
60            len = -len;
61            if (src_end - src < 1)
62                return NULL;
63            memset(dst, *src++, FFMIN(len, dst_size));
64        } else {
65            if (src_end - src < len)
66                return NULL;
67            memcpy(dst, src, FFMIN(len, dst_size));
68            src += len;
69        }
70        dst += len;
71        dst_size -= len;
72    }
73    return src;
74}
75
76static const unsigned char *seq_decode_op1(SeqVideoContext *seq,
77                                           const unsigned char *src,
78                                           const unsigned char *src_end,
79                                           unsigned char *dst)
80{
81    const unsigned char *color_table;
82    int b, i, len, bits;
83    GetBitContext gb;
84    unsigned char block[8 * 8];
85
86    if (src_end - src < 1)
87        return NULL;
88    len = *src++;
89    if (len & 0x80) {
90        switch (len & 3) {
91        case 1:
92            src = seq_unpack_rle_block(src, src_end, block, sizeof(block));
93            for (b = 0; b < 8; b++) {
94                memcpy(dst, &block[b * 8], 8);
95                dst += seq->frame.linesize[0];
96            }
97            break;
98        case 2:
99            src = seq_unpack_rle_block(src, src_end, block, sizeof(block));
100            for (i = 0; i < 8; i++) {
101                for (b = 0; b < 8; b++)
102                    dst[b * seq->frame.linesize[0]] = block[i * 8 + b];
103                ++dst;
104            }
105            break;
106        }
107    } else {
108        if (len <= 0)
109            return NULL;
110        bits = ff_log2_tab[len - 1] + 1;
111        if (src_end - src < len + 8 * bits)
112            return NULL;
113        color_table = src;
114        src += len;
115        init_get_bits(&gb, src, bits * 8 * 8); src += bits * 8;
116        for (b = 0; b < 8; b++) {
117            for (i = 0; i < 8; i++)
118                dst[i] = color_table[get_bits(&gb, bits)];
119            dst += seq->frame.linesize[0];
120        }
121    }
122
123    return src;
124}
125
126static const unsigned char *seq_decode_op2(SeqVideoContext *seq,
127                                           const unsigned char *src,
128                                           const unsigned char *src_end,
129                                           unsigned char *dst)
130{
131    int i;
132
133    if (src_end - src < 8 * 8)
134        return NULL;
135
136    for (i = 0; i < 8; i++) {
137        memcpy(dst, src, 8);
138        src += 8;
139        dst += seq->frame.linesize[0];
140    }
141
142    return src;
143}
144
145static const unsigned char *seq_decode_op3(SeqVideoContext *seq,
146                                           const unsigned char *src,
147                                           const unsigned char *src_end,
148                                           unsigned char *dst)
149{
150    int pos, offset;
151
152    do {
153        if (src_end - src < 2)
154            return NULL;
155        pos = *src++;
156        offset = ((pos >> 3) & 7) * seq->frame.linesize[0] + (pos & 7);
157        dst[offset] = *src++;
158    } while (!(pos & 0x80));
159
160    return src;
161}
162
163static int seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int data_size)
164{
165    const unsigned char *data_end = data + data_size;
166    GetBitContext gb;
167    int flags, i, j, x, y, op;
168    unsigned char c[3];
169    unsigned char *dst;
170    uint32_t *palette;
171
172    flags = *data++;
173
174    if (flags & 1) {
175        palette = (uint32_t *)seq->frame.data[1];
176        if (data_end - data < 256 * 3)
177            return AVERROR_INVALIDDATA;
178        for (i = 0; i < 256; i++) {
179            for (j = 0; j < 3; j++, data++)
180                c[j] = (*data << 2) | (*data >> 4);
181            palette[i] = AV_RB24(c);
182        }
183        seq->frame.palette_has_changed = 1;
184    }
185
186    if (flags & 2) {
187        if (data_end - data < 128)
188            return AVERROR_INVALIDDATA;
189        init_get_bits(&gb, data, 128 * 8); data += 128;
190        for (y = 0; y < 128; y += 8)
191            for (x = 0; x < 256; x += 8) {
192                dst = &seq->frame.data[0][y * seq->frame.linesize[0] + x];
193                op = get_bits(&gb, 2);
194                switch (op) {
195                case 1:
196                    data = seq_decode_op1(seq, data, data_end, dst);
197                    break;
198                case 2:
199                    data = seq_decode_op2(seq, data, data_end, dst);
200                    break;
201                case 3:
202                    data = seq_decode_op3(seq, data, data_end, dst);
203                    break;
204                }
205                if (!data)
206                    return AVERROR_INVALIDDATA;
207            }
208    }
209    return 0;
210}
211
212static av_cold int seqvideo_decode_init(AVCodecContext *avctx)
213{
214    SeqVideoContext *seq = avctx->priv_data;
215
216    seq->avctx = avctx;
217    avctx->pix_fmt = PIX_FMT_PAL8;
218
219    seq->frame.data[0] = NULL;
220
221    return 0;
222}
223
224static int seqvideo_decode_frame(AVCodecContext *avctx,
225                                 void *data, int *data_size,
226                                 AVPacket *avpkt)
227{
228    const uint8_t *buf = avpkt->data;
229    int buf_size = avpkt->size;
230
231    SeqVideoContext *seq = avctx->priv_data;
232
233    seq->frame.reference = 1;
234    seq->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
235    if (avctx->reget_buffer(avctx, &seq->frame)) {
236        av_log(seq->avctx, AV_LOG_ERROR, "tiertexseqvideo: reget_buffer() failed\n");
237        return -1;
238    }
239
240    if (seqvideo_decode(seq, buf, buf_size))
241        return AVERROR_INVALIDDATA;
242
243    *data_size = sizeof(AVFrame);
244    *(AVFrame *)data = seq->frame;
245
246    return buf_size;
247}
248
249static av_cold int seqvideo_decode_end(AVCodecContext *avctx)
250{
251    SeqVideoContext *seq = avctx->priv_data;
252
253    if (seq->frame.data[0])
254        avctx->release_buffer(avctx, &seq->frame);
255
256    return 0;
257}
258
259AVCodec ff_tiertexseqvideo_decoder = {
260    .name           = "tiertexseqvideo",
261    .type           = AVMEDIA_TYPE_VIDEO,
262    .id             = CODEC_ID_TIERTEXSEQVIDEO,
263    .priv_data_size = sizeof(SeqVideoContext),
264    .init           = seqvideo_decode_init,
265    .close          = seqvideo_decode_end,
266    .decode         = seqvideo_decode_frame,
267    .capabilities   = CODEC_CAP_DR1,
268    .long_name = NULL_IF_CONFIG_SMALL("Tiertex Limited SEQ video"),
269};
270