1/* 2 * Creative YUV (CYUV) Video Decoder 3 * by Mike Melanson (melanson@pcisys.net) 4 * based on "Creative YUV (CYUV) stream format for AVI": 5 * http://www.csse.monash.edu.au/~timf/videocodec/cyuv.txt 6 * 7 * Copyright (C) 2003 the ffmpeg project 8 * 9 * This file is part of FFmpeg. 10 * 11 * FFmpeg is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU Lesser General Public 13 * License as published by the Free Software Foundation; either 14 * version 2.1 of the License, or (at your option) any later version. 15 * 16 * FFmpeg is distributed in the hope that it will be useful, 17 * but WITHOUT ANY WARRANTY; without even the implied warranty of 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 19 * Lesser General Public License for more details. 20 * 21 * You should have received a copy of the GNU Lesser General Public 22 * License along with FFmpeg; if not, write to the Free Software 23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 24 */ 25 26/** 27 * @file libavcodec/cyuv.c 28 * Creative YUV (CYUV) Video Decoder. 29 */ 30 31#include <stdio.h> 32#include <stdlib.h> 33#include <string.h> 34#include <unistd.h> 35 36#include "avcodec.h" 37#include "dsputil.h" 38 39 40typedef struct CyuvDecodeContext { 41 AVCodecContext *avctx; 42 int width, height; 43 AVFrame frame; 44} CyuvDecodeContext; 45 46static av_cold int cyuv_decode_init(AVCodecContext *avctx) 47{ 48 CyuvDecodeContext *s = avctx->priv_data; 49 50 s->avctx = avctx; 51 s->width = avctx->width; 52 /* width needs to be divisible by 4 for this codec to work */ 53 if (s->width & 0x3) 54 return -1; 55 s->height = avctx->height; 56 avctx->pix_fmt = PIX_FMT_YUV411P; 57 58 return 0; 59} 60 61static int cyuv_decode_frame(AVCodecContext *avctx, 62 void *data, int *data_size, 63 const uint8_t *buf, int buf_size) 64{ 65 CyuvDecodeContext *s=avctx->priv_data; 66 67 unsigned char *y_plane; 68 unsigned char *u_plane; 69 unsigned char *v_plane; 70 int y_ptr; 71 int u_ptr; 72 int v_ptr; 73 74 /* prediction error tables (make it clear that they are signed values) */ 75 const signed char *y_table = (const signed char*)buf + 0; 76 const signed char *u_table = (const signed char*)buf + 16; 77 const signed char *v_table = (const signed char*)buf + 32; 78 79 unsigned char y_pred, u_pred, v_pred; 80 int stream_ptr; 81 unsigned char cur_byte; 82 int pixel_groups; 83 84 /* sanity check the buffer size: A buffer has 3x16-bytes tables 85 * followed by (height) lines each with 3 bytes to represent groups 86 * of 4 pixels. Thus, the total size of the buffer ought to be: 87 * (3 * 16) + height * (width * 3 / 4) */ 88 if (buf_size != 48 + s->height * (s->width * 3 / 4)) { 89 av_log(avctx, AV_LOG_ERROR, "ffmpeg: cyuv: got a buffer with %d bytes when %d were expected\n", 90 buf_size, 91 48 + s->height * (s->width * 3 / 4)); 92 return -1; 93 } 94 95 /* pixel data starts 48 bytes in, after 3x16-byte tables */ 96 stream_ptr = 48; 97 98 if(s->frame.data[0]) 99 avctx->release_buffer(avctx, &s->frame); 100 101 s->frame.buffer_hints = FF_BUFFER_HINTS_VALID; 102 s->frame.reference = 0; 103 if(avctx->get_buffer(avctx, &s->frame) < 0) { 104 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 105 return -1; 106 } 107 108 y_plane = s->frame.data[0]; 109 u_plane = s->frame.data[1]; 110 v_plane = s->frame.data[2]; 111 112 /* iterate through each line in the height */ 113 for (y_ptr = 0, u_ptr = 0, v_ptr = 0; 114 y_ptr < (s->height * s->frame.linesize[0]); 115 y_ptr += s->frame.linesize[0] - s->width, 116 u_ptr += s->frame.linesize[1] - s->width / 4, 117 v_ptr += s->frame.linesize[2] - s->width / 4) { 118 119 /* reset predictors */ 120 cur_byte = buf[stream_ptr++]; 121 u_plane[u_ptr++] = u_pred = cur_byte & 0xF0; 122 y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4; 123 124 cur_byte = buf[stream_ptr++]; 125 v_plane[v_ptr++] = v_pred = cur_byte & 0xF0; 126 y_pred += y_table[cur_byte & 0x0F]; 127 y_plane[y_ptr++] = y_pred; 128 129 cur_byte = buf[stream_ptr++]; 130 y_pred += y_table[cur_byte & 0x0F]; 131 y_plane[y_ptr++] = y_pred; 132 y_pred += y_table[(cur_byte & 0xF0) >> 4]; 133 y_plane[y_ptr++] = y_pred; 134 135 /* iterate through the remaining pixel groups (4 pixels/group) */ 136 pixel_groups = s->width / 4 - 1; 137 while (pixel_groups--) { 138 139 cur_byte = buf[stream_ptr++]; 140 u_pred += u_table[(cur_byte & 0xF0) >> 4]; 141 u_plane[u_ptr++] = u_pred; 142 y_pred += y_table[cur_byte & 0x0F]; 143 y_plane[y_ptr++] = y_pred; 144 145 cur_byte = buf[stream_ptr++]; 146 v_pred += v_table[(cur_byte & 0xF0) >> 4]; 147 v_plane[v_ptr++] = v_pred; 148 y_pred += y_table[cur_byte & 0x0F]; 149 y_plane[y_ptr++] = y_pred; 150 151 cur_byte = buf[stream_ptr++]; 152 y_pred += y_table[cur_byte & 0x0F]; 153 y_plane[y_ptr++] = y_pred; 154 y_pred += y_table[(cur_byte & 0xF0) >> 4]; 155 y_plane[y_ptr++] = y_pred; 156 157 } 158 } 159 160 *data_size=sizeof(AVFrame); 161 *(AVFrame*)data= s->frame; 162 163 return buf_size; 164} 165 166AVCodec cyuv_decoder = { 167 "cyuv", 168 CODEC_TYPE_VIDEO, 169 CODEC_ID_CYUV, 170 sizeof(CyuvDecodeContext), 171 cyuv_decode_init, 172 NULL, 173 NULL, 174 cyuv_decode_frame, 175 CODEC_CAP_DR1, 176 NULL, 177 .long_name = NULL_IF_CONFIG_SMALL("Creative YUV (CYUV)"), 178}; 179 180