1/* 2 * CPiA video decoder. 3 * Copyright (c) 2010 Hans de Goede <hdegoede@redhat.com> 4 * 5 * This decoder is based on the LGPL code available at 6 * https://v4l4j.googlecode.com/svn/v4l4j/trunk/libvideo/libv4lconvert/cpia1.c 7 * 8 * This file is part of FFmpeg. 9 * 10 * FFmpeg is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU Lesser General Public 12 * License as published by the Free Software Foundation; either 13 * version 2.1 of the License, or (at your option) any later version. 14 * 15 * FFmpeg is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 * Lesser General Public License for more details. 19 * 20 * You should have received a copy of the GNU Lesser General Public 21 * License along with FFmpeg; if not, write to the Free Software 22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 23 */ 24 25#include "avcodec.h" 26#include "get_bits.h" 27#include "internal.h" 28 29 30#define FRAME_HEADER_SIZE 64 31#define MAGIC_0 0x19 /**< First header byte */ 32#define MAGIC_1 0x68 /**< Second header byte */ 33#define SUBSAMPLE_420 0 34#define SUBSAMPLE_422 1 35#define YUVORDER_YUYV 0 36#define YUVORDER_UYVY 1 37#define NOT_COMPRESSED 0 38#define COMPRESSED 1 39#define NO_DECIMATION 0 40#define DECIMATION_ENAB 1 41#define EOL 0xfd /**< End Of Line marker */ 42#define EOI 0xff /**< End Of Image marker */ 43 44 45typedef struct { 46 AVFrame *frame; 47} CpiaContext; 48 49 50static int cpia_decode_frame(AVCodecContext *avctx, 51 void *data, int *got_frame, AVPacket* avpkt) 52{ 53 CpiaContext* const cpia = avctx->priv_data; 54 int i,j,ret; 55 56 uint8_t* const header = avpkt->data; 57 uint8_t* src; 58 int src_size; 59 uint16_t linelength; 60 uint8_t skip; 61 62 AVFrame *frame = cpia->frame; 63 uint8_t *y, *u, *v, *y_end, *u_end, *v_end; 64 65 // Check header 66 if ( avpkt->size < FRAME_HEADER_SIZE 67 || header[0] != MAGIC_0 || header[1] != MAGIC_1 68 || (header[17] != SUBSAMPLE_420 && header[17] != SUBSAMPLE_422) 69 || (header[18] != YUVORDER_YUYV && header[18] != YUVORDER_UYVY) 70 || (header[28] != NOT_COMPRESSED && header[28] != COMPRESSED) 71 || (header[29] != NO_DECIMATION && header[29] != DECIMATION_ENAB) 72 ) { 73 av_log(avctx, AV_LOG_ERROR, "Invalid header!\n"); 74 return AVERROR_INVALIDDATA; 75 } 76 77 // currently unsupported properties 78 if (header[17] == SUBSAMPLE_422) { 79 avpriv_report_missing_feature(avctx, "4:2:2 subsampling"); 80 return AVERROR_PATCHWELCOME; 81 } 82 if (header[18] == YUVORDER_UYVY) { 83 avpriv_report_missing_feature(avctx, "YUV byte order UYVY"); 84 return AVERROR_PATCHWELCOME; 85 } 86 if (header[29] == DECIMATION_ENAB) { 87 avpriv_report_missing_feature(avctx, "Decimation"); 88 return AVERROR_PATCHWELCOME; 89 } 90 91 src = header + FRAME_HEADER_SIZE; 92 src_size = avpkt->size - FRAME_HEADER_SIZE; 93 94 if (header[28] == NOT_COMPRESSED) { 95 frame->pict_type = AV_PICTURE_TYPE_I; 96 frame->key_frame = 1; 97 } else { 98 frame->pict_type = AV_PICTURE_TYPE_P; 99 frame->key_frame = 0; 100 } 101 102 // Get buffer filled with previous frame 103 if ((ret = ff_reget_buffer(avctx, frame)) < 0) 104 return ret; 105 106 107 for ( i = 0; 108 i < frame->height; 109 i++, src += linelength, src_size -= linelength 110 ) { 111 // Read line length, two byte little endian 112 linelength = AV_RL16(src); 113 src += 2; 114 115 if (src_size < linelength) { 116 av_frame_set_decode_error_flags(frame, FF_DECODE_ERROR_INVALID_BITSTREAM); 117 av_log(avctx, AV_LOG_WARNING, "Frame ended unexpectedly!\n"); 118 break; 119 } 120 if (src[linelength - 1] != EOL) { 121 av_frame_set_decode_error_flags(frame, FF_DECODE_ERROR_INVALID_BITSTREAM); 122 av_log(avctx, AV_LOG_WARNING, "Wrong line length %d or line not terminated properly (found 0x%02x)!\n", linelength, src[linelength - 1]); 123 break; 124 } 125 126 /* Update the data pointers. Y data is on every line. 127 * U and V data on every second line 128 */ 129 y = &frame->data[0][i * frame->linesize[0]]; 130 u = &frame->data[1][(i >> 1) * frame->linesize[1]]; 131 v = &frame->data[2][(i >> 1) * frame->linesize[2]]; 132 y_end = y + frame->linesize[0] - 1; 133 u_end = u + frame->linesize[1] - 1; 134 v_end = v + frame->linesize[2] - 1; 135 136 if ((i & 1) && header[17] == SUBSAMPLE_420) { 137 /* We are on a odd line and 420 subsample is used. 138 * On this line only Y values are specified, one per pixel. 139 */ 140 for (j = 0; j < linelength - 1; j++) { 141 if (y > y_end) { 142 av_frame_set_decode_error_flags(frame, FF_DECODE_ERROR_INVALID_BITSTREAM); 143 av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n"); 144 break; 145 } 146 if ((src[j] & 1) && header[28] == COMPRESSED) { 147 /* It seems that odd lines are always uncompressed, but 148 * we do it according to specification anyways. 149 */ 150 skip = src[j] >> 1; 151 y += skip; 152 } else { 153 *(y++) = src[j]; 154 } 155 } 156 } else if (header[17] == SUBSAMPLE_420) { 157 /* We are on an even line and 420 subsample is used. 158 * On this line each pair of pixels is described by four bytes. 159 */ 160 for (j = 0; j < linelength - 4; ) { 161 if (y + 1 > y_end || u > u_end || v > v_end) { 162 av_frame_set_decode_error_flags(frame, FF_DECODE_ERROR_INVALID_BITSTREAM); 163 av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n"); 164 break; 165 } 166 if ((src[j] & 1) && header[28] == COMPRESSED) { 167 // Skip amount of pixels and move forward one byte 168 skip = src[j] >> 1; 169 y += skip; 170 u += skip >> 1; 171 v += skip >> 1; 172 j++; 173 } else { 174 // Set image data as specified and move forward 4 bytes 175 *(y++) = src[j]; 176 *(u++) = src[j+1]; 177 *(y++) = src[j+2]; 178 *(v++) = src[j+3]; 179 j += 4; 180 } 181 } 182 } 183 } 184 185 *got_frame = 1; 186 if ((ret = av_frame_ref(data, cpia->frame)) < 0) 187 return ret; 188 189 return avpkt->size; 190} 191 192static av_cold int cpia_decode_init(AVCodecContext *avctx) 193{ 194 CpiaContext *s = avctx->priv_data; 195 196 // output pixel format 197 avctx->pix_fmt = AV_PIX_FMT_YUV420P; 198 199 /* The default timebase set by the v4l2 demuxer leads to probing which is buggy. 200 * Set some reasonable time_base to skip this. 201 */ 202 if (avctx->time_base.num == 1 && avctx->time_base.den == 1000000) { 203 avctx->time_base.num = 1; 204 avctx->time_base.den = 60; 205 } 206 207 s->frame = av_frame_alloc(); 208 if (!s->frame) 209 return AVERROR(ENOMEM); 210 211 return 0; 212} 213 214static av_cold int cpia_decode_end(AVCodecContext *avctx) 215{ 216 CpiaContext *s = avctx->priv_data; 217 218 av_frame_free(&s->frame); 219 220 return 0; 221} 222 223AVCodec ff_cpia_decoder = { 224 .name = "cpia", 225 .long_name = NULL_IF_CONFIG_SMALL("CPiA video format"), 226 .type = AVMEDIA_TYPE_VIDEO, 227 .id = AV_CODEC_ID_CPIA, 228 .priv_data_size = sizeof(CpiaContext), 229 .init = cpia_decode_init, 230 .close = cpia_decode_end, 231 .decode = cpia_decode_frame, 232 .capabilities = CODEC_CAP_DR1, 233}; 234