1/*
2 * Winnov WNV1 codec
3 * Copyright (c) 2005 Konstantin Shishkov
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 libavcodec/wnv1.c
24 * Winnov WNV1 codec.
25 */
26
27#include "avcodec.h"
28#include "bitstream.h"
29
30
31typedef struct WNV1Context{
32    AVCodecContext *avctx;
33    AVFrame pic;
34
35    int shift;
36    GetBitContext gb;
37} WNV1Context;
38
39static const uint16_t code_tab[16][2]={
40{0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},
41{0x000,1},
42{0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
43};
44
45#define CODE_VLC_BITS 9
46static VLC code_vlc;
47
48/* returns modified base_value */
49static inline int wnv1_get_code(WNV1Context *w, int base_value)
50{
51    int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
52
53    if(v==15)
54        return ff_reverse[ get_bits(&w->gb, 8 - w->shift) ];
55    else
56        return base_value + ((v - 7)<<w->shift);
57}
58
59static int decode_frame(AVCodecContext *avctx,
60                        void *data, int *data_size,
61                        const uint8_t *buf, int buf_size)
62{
63    WNV1Context * const l = avctx->priv_data;
64    AVFrame * const p= (AVFrame*)&l->pic;
65    unsigned char *Y,*U,*V;
66    int i, j;
67    int prev_y = 0, prev_u = 0, prev_v = 0;
68    uint8_t *rbuf;
69
70    rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
71    if(!rbuf){
72        av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
73        return -1;
74    }
75
76    if(p->data[0])
77        avctx->release_buffer(avctx, p);
78
79    p->reference = 0;
80    if(avctx->get_buffer(avctx, p) < 0){
81        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
82        av_free(rbuf);
83        return -1;
84    }
85    p->key_frame = 1;
86
87    for(i=8; i<buf_size; i++)
88        rbuf[i]= ff_reverse[ buf[i] ];
89    init_get_bits(&l->gb, rbuf+8, (buf_size-8)*8);
90
91    if (buf[2] >> 4 == 6)
92        l->shift = 2;
93    else {
94        l->shift = 8 - (buf[2] >> 4);
95        if (l->shift > 4) {
96            av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
97            l->shift = 4;
98        }
99        if (l->shift < 1) {
100            av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
101            l->shift = 1;
102        }
103    }
104
105    Y = p->data[0];
106    U = p->data[1];
107    V = p->data[2];
108    for (j = 0; j < avctx->height; j++) {
109        for (i = 0; i < avctx->width / 2; i++) {
110            Y[i * 2] = wnv1_get_code(l, prev_y);
111            prev_u = U[i] = wnv1_get_code(l, prev_u);
112            prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
113            prev_v = V[i] = wnv1_get_code(l, prev_v);
114        }
115        Y += p->linesize[0];
116        U += p->linesize[1];
117        V += p->linesize[2];
118    }
119
120
121    *data_size = sizeof(AVFrame);
122    *(AVFrame*)data = l->pic;
123    av_free(rbuf);
124
125    return buf_size;
126}
127
128static av_cold int decode_init(AVCodecContext *avctx){
129    WNV1Context * const l = avctx->priv_data;
130
131    l->avctx = avctx;
132    avctx->pix_fmt = PIX_FMT_YUV422P;
133
134    if(!code_vlc.table){
135        init_vlc(&code_vlc, CODE_VLC_BITS, 16,
136                    &code_tab[0][1], 4, 2,
137                    &code_tab[0][0], 4, 2, 1);
138    }
139
140    return 0;
141}
142
143AVCodec wnv1_decoder = {
144    "wnv1",
145    CODEC_TYPE_VIDEO,
146    CODEC_ID_WNV1,
147    sizeof(WNV1Context),
148    decode_init,
149    NULL,
150    NULL,
151    decode_frame,
152    CODEC_CAP_DR1,
153    .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
154};
155