1/*
2 * Brute Force & Ignorance (BFI) video decoder
3 * Copyright (c) 2008 Sisir Koppaka
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
22/**
23 * @file
24 * @brief Brute Force & Ignorance (.bfi) video decoder
25 * @author Sisir Koppaka ( sisir.koppaka at gmail dot com )
26 * @see http://wiki.multimedia.cx/index.php?title=BFI
27 */
28
29#include "libavutil/common.h"
30#include "avcodec.h"
31#include "bytestream.h"
32#include "internal.h"
33
34typedef struct BFIContext {
35    AVCodecContext *avctx;
36    uint8_t *dst;
37    uint32_t pal[256];
38} BFIContext;
39
40static av_cold int bfi_decode_init(AVCodecContext *avctx)
41{
42    BFIContext *bfi = avctx->priv_data;
43    avctx->pix_fmt  = AV_PIX_FMT_PAL8;
44    bfi->dst        = av_mallocz(avctx->width * avctx->height);
45    if (!bfi->dst)
46        return AVERROR(ENOMEM);
47    return 0;
48}
49
50static int bfi_decode_frame(AVCodecContext *avctx, void *data,
51                            int *got_frame, AVPacket *avpkt)
52{
53    AVFrame *frame = data;
54    GetByteContext g;
55    int buf_size    = avpkt->size;
56    BFIContext *bfi = avctx->priv_data;
57    uint8_t *dst    = bfi->dst;
58    uint8_t *src, *dst_offset, colour1, colour2;
59    uint8_t *frame_end = bfi->dst + avctx->width * avctx->height;
60    uint32_t *pal;
61    int i, j, ret, height = avctx->height;
62
63    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
64        return ret;
65
66    bytestream2_init(&g, avpkt->data, buf_size);
67
68    /* Set frame parameters and palette, if necessary */
69    if (!avctx->frame_number) {
70        frame->pict_type = AV_PICTURE_TYPE_I;
71        frame->key_frame = 1;
72        /* Setting the palette */
73        if (avctx->extradata_size > 768) {
74            av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n");
75            return AVERROR_INVALIDDATA;
76        }
77        pal = (uint32_t *)frame->data[1];
78        for (i = 0; i < avctx->extradata_size / 3; i++) {
79            int shift = 16;
80            *pal = 0xFFU << 24;
81            for (j = 0; j < 3; j++, shift -= 8)
82                *pal += ((avctx->extradata[i * 3 + j] << 2) |
83                         (avctx->extradata[i * 3 + j] >> 4)) << shift;
84            pal++;
85        }
86        memcpy(bfi->pal, frame->data[1], sizeof(bfi->pal));
87        frame->palette_has_changed = 1;
88    } else {
89        frame->pict_type = AV_PICTURE_TYPE_P;
90        frame->key_frame = 0;
91        frame->palette_has_changed = 0;
92        memcpy(frame->data[1], bfi->pal, sizeof(bfi->pal));
93    }
94
95    bytestream2_skip(&g, 4); // Unpacked size, not required.
96
97    while (dst != frame_end) {
98        static const uint8_t lentab[4] = { 0, 2, 0, 1 };
99        unsigned int byte   = bytestream2_get_byte(&g), av_uninit(offset);
100        unsigned int code   = byte >> 6;
101        unsigned int length = byte & ~0xC0;
102
103        if (!bytestream2_get_bytes_left(&g)) {
104            av_log(avctx, AV_LOG_ERROR,
105                   "Input resolution larger than actual frame.\n");
106            return AVERROR_INVALIDDATA;
107        }
108
109        /* Get length and offset (if required) */
110        if (length == 0) {
111            if (code == 1) {
112                length = bytestream2_get_byte(&g);
113                offset = bytestream2_get_le16(&g);
114            } else {
115                length = bytestream2_get_le16(&g);
116                if (code == 2 && length == 0)
117                    break;
118            }
119        } else {
120            if (code == 1)
121                offset = bytestream2_get_byte(&g);
122        }
123
124        /* Do boundary check */
125        if (dst + (length << lentab[code]) > frame_end)
126            break;
127
128        switch (code) {
129        case 0:                // normal chain
130            if (length >= bytestream2_get_bytes_left(&g)) {
131                av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n");
132                return AVERROR_INVALIDDATA;
133            }
134            bytestream2_get_buffer(&g, dst, length);
135            dst += length;
136            break;
137        case 1:                // back chain
138            dst_offset = dst - offset;
139            length    *= 4;     // Convert dwords to bytes.
140            if (dst_offset < bfi->dst)
141                break;
142            while (length--)
143                *dst++ = *dst_offset++;
144            break;
145        case 2:                // skip chain
146            dst += length;
147            break;
148        case 3:                // fill chain
149            colour1 = bytestream2_get_byte(&g);
150            colour2 = bytestream2_get_byte(&g);
151            while (length--) {
152                *dst++ = colour1;
153                *dst++ = colour2;
154            }
155            break;
156        }
157    }
158
159    src = bfi->dst;
160    dst = frame->data[0];
161    while (height--) {
162        memcpy(dst, src, avctx->width);
163        src += avctx->width;
164        dst += frame->linesize[0];
165    }
166    *got_frame = 1;
167
168    return buf_size;
169}
170
171static av_cold int bfi_decode_close(AVCodecContext *avctx)
172{
173    BFIContext *bfi = avctx->priv_data;
174    av_free(bfi->dst);
175    return 0;
176}
177
178AVCodec ff_bfi_decoder = {
179    .name           = "bfi",
180    .long_name      = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
181    .type           = AVMEDIA_TYPE_VIDEO,
182    .id             = AV_CODEC_ID_BFI,
183    .priv_data_size = sizeof(BFIContext),
184    .init           = bfi_decode_init,
185    .close          = bfi_decode_close,
186    .decode         = bfi_decode_frame,
187    .capabilities   = CODEC_CAP_DR1,
188};
189