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
24 * Winnov WNV1 codec.
25 */
26
27#include "avcodec.h"
28#include "get_bits.h"
29#include "libavutil/common.h"
30
31
32typedef struct WNV1Context{
33    AVCodecContext *avctx;
34    AVFrame pic;
35
36    int shift;
37    GetBitContext gb;
38} WNV1Context;
39
40static const uint16_t code_tab[16][2]={
41{0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},
42{0x000,1},
43{0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
44};
45
46#define CODE_VLC_BITS 9
47static VLC code_vlc;
48
49/* returns modified base_value */
50static inline int wnv1_get_code(WNV1Context *w, int base_value)
51{
52    int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
53
54    if(v==15)
55        return av_reverse[ get_bits(&w->gb, 8 - w->shift) ];
56    else
57        return base_value + ((v - 7)<<w->shift);
58}
59
60static int decode_frame(AVCodecContext *avctx,
61                        void *data, int *data_size,
62                        AVPacket *avpkt)
63{
64    const uint8_t *buf = avpkt->data;
65    int buf_size = avpkt->size;
66    WNV1Context * const l = avctx->priv_data;
67    AVFrame * const p= (AVFrame*)&l->pic;
68    unsigned char *Y,*U,*V;
69    int i, j;
70    int prev_y = 0, prev_u = 0, prev_v = 0;
71    uint8_t *rbuf;
72
73    rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
74    if(!rbuf){
75        av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
76        return -1;
77    }
78
79    if(p->data[0])
80        avctx->release_buffer(avctx, p);
81
82    p->reference = 0;
83    if(avctx->get_buffer(avctx, p) < 0){
84        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
85        av_free(rbuf);
86        return -1;
87    }
88    p->key_frame = 1;
89
90    for(i=8; i<buf_size; i++)
91        rbuf[i]= av_reverse[ buf[i] ];
92    init_get_bits(&l->gb, rbuf+8, (buf_size-8)*8);
93
94    if (buf[2] >> 4 == 6)
95        l->shift = 2;
96    else {
97        l->shift = 8 - (buf[2] >> 4);
98        if (l->shift > 4) {
99            av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
100            l->shift = 4;
101        }
102        if (l->shift < 1) {
103            av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
104            l->shift = 1;
105        }
106    }
107
108    Y = p->data[0];
109    U = p->data[1];
110    V = p->data[2];
111    for (j = 0; j < avctx->height; j++) {
112        for (i = 0; i < avctx->width / 2; i++) {
113            Y[i * 2] = wnv1_get_code(l, prev_y);
114            prev_u = U[i] = wnv1_get_code(l, prev_u);
115            prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
116            prev_v = V[i] = wnv1_get_code(l, prev_v);
117        }
118        Y += p->linesize[0];
119        U += p->linesize[1];
120        V += p->linesize[2];
121    }
122
123
124    *data_size = sizeof(AVFrame);
125    *(AVFrame*)data = l->pic;
126    av_free(rbuf);
127
128    return buf_size;
129}
130
131static av_cold int decode_init(AVCodecContext *avctx){
132    WNV1Context * const l = avctx->priv_data;
133    static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];
134
135    l->avctx = avctx;
136    avctx->pix_fmt = PIX_FMT_YUV422P;
137
138    code_vlc.table = code_table;
139    code_vlc.table_allocated = 1 << CODE_VLC_BITS;
140    init_vlc(&code_vlc, CODE_VLC_BITS, 16,
141             &code_tab[0][1], 4, 2,
142             &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
143
144    return 0;
145}
146
147static av_cold int decode_end(AVCodecContext *avctx){
148    WNV1Context * const l = avctx->priv_data;
149    AVFrame *pic = &l->pic;
150
151    if (pic->data[0])
152        avctx->release_buffer(avctx, pic);
153
154    return 0;
155}
156
157AVCodec wnv1_decoder = {
158    "wnv1",
159    AVMEDIA_TYPE_VIDEO,
160    CODEC_ID_WNV1,
161    sizeof(WNV1Context),
162    decode_init,
163    NULL,
164    decode_end,
165    decode_frame,
166    CODEC_CAP_DR1,
167    .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
168};
169