00001 /* 00002 * CPiA video decoder. 00003 * Copyright (c) 2010 Hans de Goede <hdegoede@redhat.com> 00004 * 00005 * This decoder is based on the LGPL code available at 00006 * https://v4l4j.googlecode.com/svn/v4l4j/trunk/libvideo/libv4lconvert/cpia1.c 00007 * 00008 * This file is part of FFmpeg. 00009 * 00010 * FFmpeg is free software; you can redistribute it and/or 00011 * modify it under the terms of the GNU Lesser General Public 00012 * License as published by the Free Software Foundation; either 00013 * version 2.1 of the License, or (at your option) any later version. 00014 * 00015 * FFmpeg is distributed in the hope that it will be useful, 00016 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00017 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00018 * Lesser General Public License for more details. 00019 * 00020 * You should have received a copy of the GNU Lesser General Public 00021 * License along with FFmpeg; if not, write to the Free Software 00022 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00023 */ 00024 00025 #include "avcodec.h" 00026 #include "get_bits.h" 00027 00028 00029 #define FRAME_HEADER_SIZE 64 00030 #define MAGIC_0 0x19 00031 #define MAGIC_1 0x68 00032 #define SUBSAMPLE_420 0 00033 #define SUBSAMPLE_422 1 00034 #define YUVORDER_YUYV 0 00035 #define YUVORDER_UYVY 1 00036 #define NOT_COMPRESSED 0 00037 #define COMPRESSED 1 00038 #define NO_DECIMATION 0 00039 #define DECIMATION_ENAB 1 00040 #define EOL 0xfd 00041 #define EOI 0xff 00044 typedef struct { 00045 AVFrame frame; 00046 } CpiaContext; 00047 00048 00049 static int cpia_decode_frame(AVCodecContext* avctx, 00050 void* data, int* data_size, AVPacket* avpkt) 00051 { 00052 CpiaContext* const cpia = avctx->priv_data; 00053 int i,j,ret; 00054 00055 uint8_t* const header = avpkt->data; 00056 uint8_t* src; 00057 int src_size; 00058 uint16_t linelength; 00059 uint8_t skip; 00060 00061 AVFrame* const frame = &cpia->frame; 00062 uint8_t *y, *u, *v, *y_end, *u_end, *v_end; 00063 00064 // Check header 00065 if ( avpkt->size < FRAME_HEADER_SIZE 00066 || header[0] != MAGIC_0 || header[1] != MAGIC_1 00067 || (header[17] != SUBSAMPLE_420 && header[17] != SUBSAMPLE_422) 00068 || (header[18] != YUVORDER_YUYV && header[18] != YUVORDER_UYVY) 00069 || (header[28] != NOT_COMPRESSED && header[28] != COMPRESSED) 00070 || (header[29] != NO_DECIMATION && header[29] != DECIMATION_ENAB) 00071 ) { 00072 av_log(avctx, AV_LOG_ERROR, "Invalid header!\n"); 00073 return AVERROR_INVALIDDATA; 00074 } 00075 00076 // currently unsupported properties 00077 if (header[17] == SUBSAMPLE_422) { 00078 av_log(avctx, AV_LOG_ERROR, "Unsupported subsample!\n"); 00079 return AVERROR_PATCHWELCOME; 00080 } 00081 if (header[18] == YUVORDER_UYVY) { 00082 av_log(avctx, AV_LOG_ERROR, "Unsupported YUV byte order!\n"); 00083 return AVERROR_PATCHWELCOME; 00084 } 00085 if (header[29] == DECIMATION_ENAB) { 00086 av_log(avctx, AV_LOG_ERROR, "Decimation unsupported!\n"); 00087 return AVERROR_PATCHWELCOME; 00088 } 00089 00090 src = header + FRAME_HEADER_SIZE; 00091 src_size = avpkt->size - FRAME_HEADER_SIZE; 00092 00093 if (header[28] == NOT_COMPRESSED) { 00094 frame->pict_type = AV_PICTURE_TYPE_I; 00095 frame->key_frame = 1; 00096 } else { 00097 frame->pict_type = AV_PICTURE_TYPE_P; 00098 frame->key_frame = 0; 00099 } 00100 00101 // Get buffer filled with previous frame 00102 if ((ret = avctx->reget_buffer(avctx, frame)) < 0) { 00103 av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed!\n"); 00104 return ret; 00105 } 00106 00107 00108 for ( i = 0; 00109 i < frame->height; 00110 i++, src += linelength, src_size -= linelength 00111 ) { 00112 // Read line length, two byte little endian 00113 linelength = AV_RL16(src); 00114 src += 2; 00115 00116 if (src_size < linelength) { 00117 frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM; 00118 av_log(avctx, AV_LOG_WARNING, "Frame ended enexpectedly!\n"); 00119 break; 00120 } 00121 if (src[linelength - 1] != EOL) { 00122 frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM; 00123 av_log(avctx, AV_LOG_WARNING, "Wrong line length %d or line not terminated properly (found 0x%02x)!\n", linelength, src[linelength - 1]); 00124 break; 00125 } 00126 00127 /* Update the data pointers. Y data is on every line. 00128 * U and V data on every second line 00129 */ 00130 y = &frame->data[0][i * frame->linesize[0]]; 00131 u = &frame->data[1][(i >> 1) * frame->linesize[1]]; 00132 v = &frame->data[2][(i >> 1) * frame->linesize[2]]; 00133 y_end = y + frame->linesize[0] - 1; 00134 u_end = u + frame->linesize[1] - 1; 00135 v_end = v + frame->linesize[2] - 1; 00136 00137 if ((i & 1) && header[17] == SUBSAMPLE_420) { 00138 /* We are on a odd line and 420 subsample is used. 00139 * On this line only Y values are specified, one per pixel. 00140 */ 00141 for (j = 0; j < linelength - 1; j++) { 00142 if (y > y_end) { 00143 frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM; 00144 av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n"); 00145 break; 00146 } 00147 if ((src[j] & 1) && header[28] == COMPRESSED) { 00148 /* It seems that odd lines are always uncompressed, but 00149 * we do it according to specification anyways. 00150 */ 00151 skip = src[j] >> 1; 00152 y += skip; 00153 } else { 00154 *(y++) = src[j]; 00155 } 00156 } 00157 } else if (header[17] == SUBSAMPLE_420) { 00158 /* We are on an even line and 420 subsample is used. 00159 * On this line each pair of pixels is described by four bytes. 00160 */ 00161 for (j = 0; j < linelength - 4; ) { 00162 if (y + 1 > y_end || u > u_end || v > v_end) { 00163 frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM; 00164 av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n"); 00165 break; 00166 } 00167 if ((src[j] & 1) && header[28] == COMPRESSED) { 00168 // Skip amount of pixels and move forward one byte 00169 skip = src[j] >> 1; 00170 y += skip; 00171 u += skip >> 1; 00172 v += skip >> 1; 00173 j++; 00174 } else { 00175 // Set image data as specified and move forward 4 bytes 00176 *(y++) = src[j]; 00177 *(u++) = src[j+1]; 00178 *(y++) = src[j+2]; 00179 *(v++) = src[j+3]; 00180 j += 4; 00181 } 00182 } 00183 } 00184 } 00185 00186 *data_size = sizeof(AVFrame); 00187 *(AVFrame*) data = *frame; 00188 00189 return avpkt->size; 00190 } 00191 00192 static av_cold int cpia_decode_init(AVCodecContext *avctx) 00193 { 00194 // output pixel format 00195 avctx->pix_fmt = PIX_FMT_YUV420P; 00196 00197 /* The default timebase set by the v4l2 demuxer leads to probing which is buggy. 00198 * Set some reasonable time_base to skip this. 00199 */ 00200 if (avctx->time_base.num == 1 && avctx->time_base.den == 1000000) { 00201 avctx->time_base.num = 1; 00202 avctx->time_base.den = 60; 00203 } 00204 00205 return 0; 00206 } 00207 00208 00209 AVCodec ff_cpia_decoder = { 00210 .name = "cpia", 00211 .type = AVMEDIA_TYPE_VIDEO, 00212 .id = AV_CODEC_ID_CPIA, 00213 .priv_data_size = sizeof(CpiaContext), 00214 .init = cpia_decode_init, 00215 .decode = cpia_decode_frame, 00216 .capabilities = CODEC_CAP_DR1, 00217 .long_name = NULL_IF_CONFIG_SMALL("CPiA video format"), 00218 };