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 "libavutil/thread.h" 28 29#define BITSTREAM_READER_LE 30#include "avcodec.h" 31#include "codec_internal.h" 32#include "get_bits.h" 33#include "internal.h" 34 35static const uint8_t code_tab[16][2] = { 36 { 7, 1 }, { 8, 3 }, { 6, 3 }, { 9, 4 }, { 5, 4 }, { 10, 5 }, { 4, 5 }, 37 { 11, 6 }, { 3, 6 }, { 12, 7 }, { 2, 7 }, { 13, 8 }, { 1, 8 }, { 14, 9 }, 38 { 0, 9 }, { 15, 8 } 39}; 40 41#define CODE_VLC_BITS 9 42static VLC code_vlc; 43 44/* returns modified base_value */ 45static inline int wnv1_get_code(GetBitContext *gb, int shift, int base_value) 46{ 47 int v = get_vlc2(gb, code_vlc.table, CODE_VLC_BITS, 1); 48 49 if (v == 8) 50 return get_bits(gb, 8 - shift) << shift; 51 else 52 return base_value + v * (1 << shift); 53} 54 55static int decode_frame(AVCodecContext *avctx, AVFrame *p, 56 int *got_frame, AVPacket *avpkt) 57{ 58 const uint8_t *buf = avpkt->data; 59 int buf_size = avpkt->size; 60 GetBitContext gb; 61 unsigned char *Y,*U,*V; 62 int i, j, ret, shift; 63 int prev_y = 0, prev_u = 0, prev_v = 0; 64 65 if (buf_size < 8 + avctx->height * (avctx->width/2)/8) { 66 av_log(avctx, AV_LOG_ERROR, "Packet size %d is too small\n", buf_size); 67 return AVERROR_INVALIDDATA; 68 } 69 70 if ((ret = ff_get_buffer(avctx, p, 0)) < 0) 71 return ret; 72 p->key_frame = 1; 73 74 if ((ret = init_get_bits8(&gb, buf + 8, buf_size - 8)) < 0) 75 return ret; 76 77 if (buf[2] >> 4 == 6) 78 shift = 2; 79 else { 80 shift = 8 - (buf[2] >> 4); 81 if (shift > 4) { 82 avpriv_request_sample(avctx, 83 "Unknown WNV1 frame header value %i", 84 buf[2] >> 4); 85 shift = 4; 86 } 87 if (shift < 1) { 88 avpriv_request_sample(avctx, 89 "Unknown WNV1 frame header value %i", 90 buf[2] >> 4); 91 shift = 1; 92 } 93 } 94 95 Y = p->data[0]; 96 U = p->data[1]; 97 V = p->data[2]; 98 for (j = 0; j < avctx->height; j++) { 99 for (i = 0; i < avctx->width / 2; i++) { 100 Y[i * 2] = wnv1_get_code(&gb, shift, prev_y); 101 prev_u = U[i] = wnv1_get_code(&gb, shift, prev_u); 102 prev_y = Y[(i * 2) + 1] = wnv1_get_code(&gb, shift, Y[i * 2]); 103 prev_v = V[i] = wnv1_get_code(&gb, shift, prev_v); 104 } 105 Y += p->linesize[0]; 106 U += p->linesize[1]; 107 V += p->linesize[2]; 108 } 109 110 111 *got_frame = 1; 112 113 return buf_size; 114} 115 116static av_cold void wnv1_init_static(void) 117{ 118 INIT_VLC_STATIC_FROM_LENGTHS(&code_vlc, CODE_VLC_BITS, 16, 119 &code_tab[0][1], 2, 120 &code_tab[0][0], 2, 1, 121 -7, INIT_VLC_OUTPUT_LE, 1 << CODE_VLC_BITS); 122} 123 124static av_cold int decode_init(AVCodecContext *avctx) 125{ 126 static AVOnce init_static_once = AV_ONCE_INIT; 127 128 if (avctx->width <= 1) 129 return AVERROR_INVALIDDATA; 130 131 avctx->pix_fmt = AV_PIX_FMT_YUV422P; 132 133 ff_thread_once(&init_static_once, wnv1_init_static); 134 135 return 0; 136} 137 138const FFCodec ff_wnv1_decoder = { 139 .p.name = "wnv1", 140 .p.long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"), 141 .p.type = AVMEDIA_TYPE_VIDEO, 142 .p.id = AV_CODEC_ID_WNV1, 143 .init = decode_init, 144 FF_CODEC_DECODE_CB(decode_frame), 145 .p.capabilities = AV_CODEC_CAP_DR1, 146 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, 147}; 148