Libav 0.7.1
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00001 /* 00002 * Brute Force & Ignorance (BFI) video decoder 00003 * Copyright (c) 2008 Sisir Koppaka 00004 * 00005 * This file is part of Libav. 00006 * 00007 * Libav is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * Libav is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with Libav; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00029 #include "libavutil/common.h" 00030 #include "avcodec.h" 00031 #include "bytestream.h" 00032 00033 typedef struct BFIContext { 00034 AVCodecContext *avctx; 00035 AVFrame frame; 00036 uint8_t *dst; 00037 } BFIContext; 00038 00039 static av_cold int bfi_decode_init(AVCodecContext * avctx) 00040 { 00041 BFIContext *bfi = avctx->priv_data; 00042 avctx->pix_fmt = PIX_FMT_PAL8; 00043 bfi->dst = av_mallocz(avctx->width * avctx->height); 00044 return 0; 00045 } 00046 00047 static int bfi_decode_frame(AVCodecContext * avctx, void *data, 00048 int *data_size, AVPacket *avpkt) 00049 { 00050 const uint8_t *buf = avpkt->data, *buf_end = avpkt->data + avpkt->size; 00051 int buf_size = avpkt->size; 00052 BFIContext *bfi = avctx->priv_data; 00053 uint8_t *dst = bfi->dst; 00054 uint8_t *src, *dst_offset, colour1, colour2; 00055 uint8_t *frame_end = bfi->dst + avctx->width * avctx->height; 00056 uint32_t *pal; 00057 int i, j, height = avctx->height; 00058 00059 if (bfi->frame.data[0]) 00060 avctx->release_buffer(avctx, &bfi->frame); 00061 00062 bfi->frame.reference = 1; 00063 00064 if (avctx->get_buffer(avctx, &bfi->frame) < 0) { 00065 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 00066 return -1; 00067 } 00068 00069 /* Set frame parameters and palette, if necessary */ 00070 if (!avctx->frame_number) { 00071 bfi->frame.pict_type = AV_PICTURE_TYPE_I; 00072 bfi->frame.key_frame = 1; 00073 /* Setting the palette */ 00074 if(avctx->extradata_size>768) { 00075 av_log(NULL, AV_LOG_ERROR, "Palette is too large.\n"); 00076 return -1; 00077 } 00078 pal = (uint32_t *) bfi->frame.data[1]; 00079 for (i = 0; i < avctx->extradata_size / 3; i++) { 00080 int shift = 16; 00081 *pal = 0; 00082 for (j = 0; j < 3; j++, shift -= 8) 00083 *pal += 00084 ((avctx->extradata[i * 3 + j] << 2) | 00085 (avctx->extradata[i * 3 + j] >> 4)) << shift; 00086 pal++; 00087 } 00088 bfi->frame.palette_has_changed = 1; 00089 } else { 00090 bfi->frame.pict_type = AV_PICTURE_TYPE_P; 00091 bfi->frame.key_frame = 0; 00092 } 00093 00094 buf += 4; //Unpacked size, not required. 00095 00096 while (dst != frame_end) { 00097 static const uint8_t lentab[4]={0,2,0,1}; 00098 unsigned int byte = *buf++, av_uninit(offset); 00099 unsigned int code = byte >> 6; 00100 unsigned int length = byte & ~0xC0; 00101 00102 if (buf >= buf_end) { 00103 av_log(avctx, AV_LOG_ERROR, "Input resolution larger than actual frame.\n"); 00104 return -1; 00105 } 00106 00107 /* Get length and offset(if required) */ 00108 if (length == 0) { 00109 if (code == 1) { 00110 length = bytestream_get_byte(&buf); 00111 offset = bytestream_get_le16(&buf); 00112 } else { 00113 length = bytestream_get_le16(&buf); 00114 if (code == 2 && length == 0) 00115 break; 00116 } 00117 } else { 00118 if (code == 1) 00119 offset = bytestream_get_byte(&buf); 00120 } 00121 00122 /* Do boundary check */ 00123 if (dst + (length<<lentab[code]) > frame_end) 00124 break; 00125 00126 switch (code) { 00127 00128 case 0: //Normal Chain 00129 if (length >= buf_end - buf) { 00130 av_log(avctx, AV_LOG_ERROR, "Frame larger than buffer.\n"); 00131 return -1; 00132 } 00133 bytestream_get_buffer(&buf, dst, length); 00134 dst += length; 00135 break; 00136 00137 case 1: //Back Chain 00138 dst_offset = dst - offset; 00139 length *= 4; //Convert dwords to bytes. 00140 if (dst_offset < bfi->dst) 00141 break; 00142 while (length--) 00143 *dst++ = *dst_offset++; 00144 break; 00145 00146 case 2: //Skip Chain 00147 dst += length; 00148 break; 00149 00150 case 3: //Fill Chain 00151 colour1 = bytestream_get_byte(&buf); 00152 colour2 = bytestream_get_byte(&buf); 00153 while (length--) { 00154 *dst++ = colour1; 00155 *dst++ = colour2; 00156 } 00157 break; 00158 00159 } 00160 } 00161 00162 src = bfi->dst; 00163 dst = bfi->frame.data[0]; 00164 while (height--) { 00165 memcpy(dst, src, avctx->width); 00166 src += avctx->width; 00167 dst += bfi->frame.linesize[0]; 00168 } 00169 *data_size = sizeof(AVFrame); 00170 *(AVFrame *) data = bfi->frame; 00171 return buf_size; 00172 } 00173 00174 static av_cold int bfi_decode_close(AVCodecContext * avctx) 00175 { 00176 BFIContext *bfi = avctx->priv_data; 00177 if (bfi->frame.data[0]) 00178 avctx->release_buffer(avctx, &bfi->frame); 00179 av_free(bfi->dst); 00180 return 0; 00181 } 00182 00183 AVCodec ff_bfi_decoder = { 00184 .name = "bfi", 00185 .type = AVMEDIA_TYPE_VIDEO, 00186 .id = CODEC_ID_BFI, 00187 .priv_data_size = sizeof(BFIContext), 00188 .init = bfi_decode_init, 00189 .close = bfi_decode_close, 00190 .decode = bfi_decode_frame, 00191 .capabilities = CODEC_CAP_DR1, 00192 .long_name = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"), 00193 };