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 Libav. 10 * 11 * Libav 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 * Libav 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 Libav; 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 28 * Creative YUV (CYUV) Video Decoder. 29 */ 30 31#include <stdio.h> 32#include <stdlib.h> 33#include <string.h> 34 35#include "avcodec.h" 36#include "dsputil.h" 37 38 39typedef struct CyuvDecodeContext { 40 AVCodecContext *avctx; 41 int width, height; 42 AVFrame frame; 43} CyuvDecodeContext; 44 45static av_cold int cyuv_decode_init(AVCodecContext *avctx) 46{ 47 CyuvDecodeContext *s = avctx->priv_data; 48 49 s->avctx = avctx; 50 s->width = avctx->width; 51 /* width needs to be divisible by 4 for this codec to work */ 52 if (s->width & 0x3) 53 return -1; 54 s->height = avctx->height; 55 avctx->pix_fmt = PIX_FMT_YUV411P; 56 57 return 0; 58} 59 60static int cyuv_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 CyuvDecodeContext *s=avctx->priv_data; 67 68 unsigned char *y_plane; 69 unsigned char *u_plane; 70 unsigned char *v_plane; 71 int y_ptr; 72 int u_ptr; 73 int v_ptr; 74 75 /* prediction error tables (make it clear that they are signed values) */ 76 const signed char *y_table = (const signed char*)buf + 0; 77 const signed char *u_table = (const signed char*)buf + 16; 78 const signed char *v_table = (const signed char*)buf + 32; 79 80 unsigned char y_pred, u_pred, v_pred; 81 int stream_ptr; 82 unsigned char cur_byte; 83 int pixel_groups; 84 85 if (avctx->codec_id == CODEC_ID_AURA) { 86 y_table = u_table; 87 u_table = v_table; 88 } 89 /* sanity check the buffer size: A buffer has 3x16-bytes tables 90 * followed by (height) lines each with 3 bytes to represent groups 91 * of 4 pixels. Thus, the total size of the buffer ought to be: 92 * (3 * 16) + height * (width * 3 / 4) */ 93 if (buf_size != 48 + s->height * (s->width * 3 / 4)) { 94 av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n", 95 buf_size, 48 + s->height * (s->width * 3 / 4)); 96 return -1; 97 } 98 99 /* pixel data starts 48 bytes in, after 3x16-byte tables */ 100 stream_ptr = 48; 101 102 if (s->frame.data[0]) 103 avctx->release_buffer(avctx, &s->frame); 104 105 s->frame.buffer_hints = FF_BUFFER_HINTS_VALID; 106 s->frame.reference = 0; 107 if (avctx->get_buffer(avctx, &s->frame) < 0) { 108 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 109 return -1; 110 } 111 112 y_plane = s->frame.data[0]; 113 u_plane = s->frame.data[1]; 114 v_plane = s->frame.data[2]; 115 116 /* iterate through each line in the height */ 117 for (y_ptr = 0, u_ptr = 0, v_ptr = 0; 118 y_ptr < (s->height * s->frame.linesize[0]); 119 y_ptr += s->frame.linesize[0] - s->width, 120 u_ptr += s->frame.linesize[1] - s->width / 4, 121 v_ptr += s->frame.linesize[2] - s->width / 4) { 122 123 /* reset predictors */ 124 cur_byte = buf[stream_ptr++]; 125 u_plane[u_ptr++] = u_pred = cur_byte & 0xF0; 126 y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4; 127 128 cur_byte = buf[stream_ptr++]; 129 v_plane[v_ptr++] = v_pred = cur_byte & 0xF0; 130 y_pred += y_table[cur_byte & 0x0F]; 131 y_plane[y_ptr++] = y_pred; 132 133 cur_byte = buf[stream_ptr++]; 134 y_pred += y_table[cur_byte & 0x0F]; 135 y_plane[y_ptr++] = y_pred; 136 y_pred += y_table[(cur_byte & 0xF0) >> 4]; 137 y_plane[y_ptr++] = y_pred; 138 139 /* iterate through the remaining pixel groups (4 pixels/group) */ 140 pixel_groups = s->width / 4 - 1; 141 while (pixel_groups--) { 142 143 cur_byte = buf[stream_ptr++]; 144 u_pred += u_table[(cur_byte & 0xF0) >> 4]; 145 u_plane[u_ptr++] = u_pred; 146 y_pred += y_table[cur_byte & 0x0F]; 147 y_plane[y_ptr++] = y_pred; 148 149 cur_byte = buf[stream_ptr++]; 150 v_pred += v_table[(cur_byte & 0xF0) >> 4]; 151 v_plane[v_ptr++] = v_pred; 152 y_pred += y_table[cur_byte & 0x0F]; 153 y_plane[y_ptr++] = y_pred; 154 155 cur_byte = buf[stream_ptr++]; 156 y_pred += y_table[cur_byte & 0x0F]; 157 y_plane[y_ptr++] = y_pred; 158 y_pred += y_table[(cur_byte & 0xF0) >> 4]; 159 y_plane[y_ptr++] = y_pred; 160 161 } 162 } 163 164 *data_size=sizeof(AVFrame); 165 *(AVFrame*)data= s->frame; 166 167 return buf_size; 168} 169 170static av_cold int cyuv_decode_end(AVCodecContext *avctx) 171{ 172 CyuvDecodeContext *s = avctx->priv_data; 173 174 if (s->frame.data[0]) 175 avctx->release_buffer(avctx, &s->frame); 176 177 return 0; 178} 179 180#if CONFIG_AURA_DECODER 181AVCodec ff_aura_decoder = { 182 .name = "aura", 183 .type = AVMEDIA_TYPE_VIDEO, 184 .id = CODEC_ID_AURA, 185 .priv_data_size = sizeof(CyuvDecodeContext), 186 .init = cyuv_decode_init, 187 .close = cyuv_decode_end, 188 .decode = cyuv_decode_frame, 189 .capabilities = CODEC_CAP_DR1, 190 .long_name = NULL_IF_CONFIG_SMALL("Auravision AURA"), 191}; 192#endif 193 194#if CONFIG_CYUV_DECODER 195AVCodec ff_cyuv_decoder = { 196 .name = "cyuv", 197 .type = AVMEDIA_TYPE_VIDEO, 198 .id = CODEC_ID_CYUV, 199 .priv_data_size = sizeof(CyuvDecodeContext), 200 .init = cyuv_decode_init, 201 .close = cyuv_decode_end, 202 .decode = cyuv_decode_frame, 203 .capabilities = CODEC_CAP_DR1, 204 .long_name = NULL_IF_CONFIG_SMALL("Creative YUV (CYUV)"), 205}; 206#endif 207