| 1 | /*
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| 2 | * Winnov WNV1 codec
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| 3 | * Copyright (c) 2005 Konstantin Shishkov
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| 4 | *
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| 5 | * This library is free software; you can redistribute it and/or
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| 6 | * modify it under the terms of the GNU Lesser General Public
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| 7 | * License as published by the Free Software Foundation; either
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| 8 | * version 2 of the License, or (at your option) any later version.
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| 9 | *
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| 10 | * This library is distributed in the hope that it will be useful,
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| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 13 | * Lesser General Public License for more details.
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| 14 | *
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| 15 | * You should have received a copy of the GNU Lesser General Public
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| 16 | * License along with this library; if not, write to the Free Software
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| 17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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| 18 | *
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| 19 | */
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| 20 |
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| 21 | /**
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| 22 | * @file wnv1.c
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| 23 | * Winnov WNV1 codec.
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| 24 | */
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| 25 |
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| 26 | #include "avcodec.h"
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| 27 | #include "common.h"
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| 28 | #include "bitstream.h"
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| 29 |
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| 30 |
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| 31 | typedef struct WNV1Context{
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| 32 | AVCodecContext *avctx;
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| 33 | AVFrame pic;
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| 34 |
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| 35 | int shift;
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| 36 | GetBitContext gb;
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| 37 | } WNV1Context;
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| 38 |
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| 39 | static uint16_t code_tab[16][2]={
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| 40 | {0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},
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| 41 | {0x000,1},
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| 42 | {0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
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| 43 | };
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| 44 |
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| 45 | #define CODE_VLC_BITS 9
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| 46 | static VLC code_vlc;
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| 47 |
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| 48 | /* returns modified base_value */
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| 49 | static inline int wnv1_get_code(WNV1Context *w, int base_value)
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| 50 | {
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| 51 | int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
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| 52 |
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| 53 | if(v==15)
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| 54 | return ff_reverse[ get_bits(&w->gb, 8 - w->shift) ];
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| 55 | else
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| 56 | return base_value + ((v - 7)<<w->shift);
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| 57 | }
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| 58 |
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| 59 | static int decode_frame(AVCodecContext *avctx,
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| 60 | void *data, int *data_size,
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| 61 | uint8_t *buf, int buf_size)
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| 62 | {
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| 63 | WNV1Context * const l = avctx->priv_data;
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| 64 | AVFrame * const p= (AVFrame*)&l->pic;
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| 65 | unsigned char *Y,*U,*V;
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| 66 | int i, j;
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| 67 | int prev_y = 0, prev_u = 0, prev_v = 0;
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| 68 |
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| 69 | if(p->data[0])
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| 70 | avctx->release_buffer(avctx, p);
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| 71 |
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| 72 | p->reference = 0;
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| 73 | if(avctx->get_buffer(avctx, p) < 0){
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| 74 | av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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| 75 | return -1;
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| 76 | }
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| 77 | p->key_frame = 1;
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| 78 |
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| 79 | for(i=8; i<buf_size; i++)
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| 80 | buf[i]= ff_reverse[ buf[i] ]; //FIXME ensure that the buffer is modifyable or use a temp one
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| 81 | init_get_bits(&l->gb, buf+8, (buf_size-8)*8);
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| 82 |
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| 83 | if (buf[2] >> 4 == 6)
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| 84 | l->shift = 2;
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| 85 | else {
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| 86 | l->shift = 8 - (buf[2] >> 4);
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| 87 | if (l->shift > 4) {
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| 88 | av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
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| 89 | l->shift = 4;
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| 90 | }
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| 91 | if (l->shift < 1) {
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| 92 | av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
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| 93 | l->shift = 1;
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| 94 | }
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| 95 | }
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| 96 |
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| 97 | Y = p->data[0];
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| 98 | U = p->data[1];
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| 99 | V = p->data[2];
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| 100 | for (j = 0; j < avctx->height; j++) {
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| 101 | for (i = 0; i < avctx->width / 2; i++) {
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| 102 | Y[i * 2] = wnv1_get_code(l, prev_y);
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| 103 | prev_u = U[i] = wnv1_get_code(l, prev_u);
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| 104 | prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
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| 105 | prev_v = V[i] = wnv1_get_code(l, prev_v);
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| 106 | }
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| 107 | Y += p->linesize[0];
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| 108 | U += p->linesize[1];
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| 109 | V += p->linesize[2];
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| 110 | }
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| 111 |
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| 112 |
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| 113 | *data_size = sizeof(AVFrame);
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| 114 | *(AVFrame*)data = l->pic;
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| 115 |
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| 116 | return buf_size;
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| 117 | }
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| 118 |
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| 119 | static int decode_init(AVCodecContext *avctx){
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| 120 | WNV1Context * const l = avctx->priv_data;
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| 121 |
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| 122 | l->avctx = avctx;
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| 123 | avctx->pix_fmt = PIX_FMT_YUV422P;
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| 124 |
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| 125 | if(!code_vlc.table){
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| 126 | init_vlc(&code_vlc, CODE_VLC_BITS, 16,
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| 127 | &code_tab[0][1], 4, 2,
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| 128 | &code_tab[0][0], 4, 2, 1);
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| 129 | }
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| 130 |
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| 131 | return 0;
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| 132 | }
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| 133 |
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| 134 | AVCodec wnv1_decoder = {
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| 135 | "wnv1",
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| 136 | CODEC_TYPE_VIDEO,
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| 137 | CODEC_ID_WNV1,
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| 138 | sizeof(WNV1Context),
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| 139 | decode_init,
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| 140 | NULL,
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| 141 | NULL,
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| 142 | decode_frame,
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| 143 | CODEC_CAP_DR1,
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| 144 | };
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