libavcodec/cpia.c

   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 "libavutil/intreadwrite.h"
  26 #include "avcodec.h"
  27 #include "codec_internal.h"
  28 #include "decode.h"
  29
  30
  31 #define FRAME_HEADER_SIZE 64
  32 #define MAGIC_0         0x19    /**< First header byte */
  33 #define MAGIC_1         0x68    /**< Second header byte */
  34 #define SUBSAMPLE_420      0
  35 #define SUBSAMPLE_422      1
  36 #define YUVORDER_YUYV      0
  37 #define YUVORDER_UYVY      1
  38 #define NOT_COMPRESSED     0
  39 #define COMPRESSED         1
  40 #define NO_DECIMATION      0
  41 #define DECIMATION_ENAB    1
  42 #define EOL             0xfd    /**< End Of Line marker */
  43 #define EOI             0xff    /**< End Of Image marker */
  44
  45
  46 typedef struct {
  47     AVFrame *frame;
  48 } CpiaContext;
  49
  50
  51 static int cpia_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
  52                              int *got_frame, AVPacket* avpkt)
  53 {
  54     CpiaContext* const cpia = avctx->priv_data;
  55     int i,j,ret;
  56
  57     const uint8_t *const header = avpkt->data;
  58     const uint8_t *src;
  59     int src_size;
  60     uint16_t linelength;
  61     uint8_t skip;
  62
  63     AVFrame *frame = cpia->frame;
  64     uint8_t *y, *u, *v, *y_end, *u_end, *v_end;
  65
  66     // Check header
  67     if ( avpkt->size < FRAME_HEADER_SIZE + avctx->height * 3
  68       || header[0] != MAGIC_0 || header[1] != MAGIC_1
  69       || (header[17] != SUBSAMPLE_420 && header[17] != SUBSAMPLE_422)
  70       || (header[18] != YUVORDER_YUYV && header[18] != YUVORDER_UYVY)
  71       || (header[28] != NOT_COMPRESSED && header[28] != COMPRESSED)
  72       || (header[29] != NO_DECIMATION && header[29] != DECIMATION_ENAB)
  73     ) {
  74         av_log(avctx, AV_LOG_ERROR, "Invalid header!\n");
  75         return AVERROR_INVALIDDATA;
  76     }
  77
  78     // currently unsupported properties
  79     if (header[17] == SUBSAMPLE_422) {
  80         avpriv_report_missing_feature(avctx, "4:2:2 subsampling");
  81         return AVERROR_PATCHWELCOME;
  82     }
  83     if (header[18] == YUVORDER_UYVY) {
  84         avpriv_report_missing_feature(avctx, "YUV byte order UYVY");
  85         return AVERROR_PATCHWELCOME;
  86     }
  87     if (header[29] == DECIMATION_ENAB) {
  88         avpriv_report_missing_feature(avctx, "Decimation");
  89         return AVERROR_PATCHWELCOME;
  90     }
  91
  92     src = header + FRAME_HEADER_SIZE;
  93     src_size = avpkt->size - FRAME_HEADER_SIZE;
  94
  95     if (header[28] == NOT_COMPRESSED) {
  96         frame->pict_type = AV_PICTURE_TYPE_I;
  97         frame->flags |= AV_FRAME_FLAG_KEY;
  98     } else {
  99         frame->pict_type = AV_PICTURE_TYPE_P;
 100         frame->flags &= ~AV_FRAME_FLAG_KEY;
 101     }
 102
 103     // Get buffer filled with previous frame
 104     if ((ret = ff_reget_buffer(avctx, frame, 0)) < 0)
 105         return ret;
 106
 107
 108     for ( i = 0;
 109           i < frame->height;
 110           i++, src += linelength, src_size -= linelength
 111     ) {
 112         // Read line length, two byte little endian
 113         linelength = AV_RL16(src);
 114         src += 2;
 115         src_size -= 2;
 116
 117         if (src_size < linelength) {
 118             frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
 119             av_log(avctx, AV_LOG_WARNING, "Frame ended unexpectedly!\n");
 120             break;
 121         }
 122         if (src[linelength - 1] != EOL) {
 123             frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
 124             av_log(avctx, AV_LOG_WARNING, "Wrong line length %d or line not terminated properly (found 0x%02x)!\n", linelength, src[linelength - 1]);
 125             break;
 126         }
 127
 128         /* Update the data pointers. Y data is on every line.
 129          * U and V data on every second line
 130          */
 131         y = &frame->data[0][i * frame->linesize[0]];
 132         u = &frame->data[1][(i >> 1) * frame->linesize[1]];
 133         v = &frame->data[2][(i >> 1) * frame->linesize[2]];
 134         y_end = y + frame->linesize[0] - 1;
 135         u_end = u + frame->linesize[1] - 1;
 136         v_end = v + frame->linesize[2] - 1;
 137
 138         if ((i & 1) && header[17] == SUBSAMPLE_420) {
 139             /* We are on an odd line and 420 subsample is used.
 140              * On this line only Y values are specified, one per pixel.
 141              */
 142             for (j = 0; j < linelength - 1; j++) {
 143                 if (y > y_end) {
 144                     frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
 145                     av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n");
 146                     break;
 147                 }
 148                 if ((src[j] & 1) && header[28] == COMPRESSED) {
 149                     /* It seems that odd lines are always uncompressed, but
 150                      * we do it according to specification anyways.
 151                      */
 152                     skip = src[j] >> 1;
 153                     y += skip;
 154                 } else {
 155                     *(y++) = src[j];
 156                 }
 157             }
 158         } else if (header[17] == SUBSAMPLE_420) {
 159             /* We are on an even line and 420 subsample is used.
 160              * On this line each pair of pixels is described by four bytes.
 161              */
 162             for (j = 0; j < linelength - 4; ) {
 163                 if (y + 1 > y_end || u > u_end || v > v_end) {
 164                     frame->decode_error_flags = FF_DECODE_ERROR_INVALID_BITSTREAM;
 165                     av_log(avctx, AV_LOG_WARNING, "Decoded data exceeded linesize!\n");
 166                     break;
 167                 }
 168                 if ((src[j] & 1) && header[28] == COMPRESSED) {
 169                     // Skip amount of pixels and move forward one byte
 170                     skip = src[j] >> 1;
 171                     y += skip;
 172                     u += skip >> 1;
 173                     v += skip >> 1;
 174                     j++;
 175                 } else {
 176                     // Set image data as specified and move forward 4 bytes
 177                     *(y++) = src[j];
 178                     *(u++) = src[j+1];
 179                     *(y++) = src[j+2];
 180                     *(v++) = src[j+3];
 181                     j += 4;
 182                 }
 183             }
 184         }
 185     }
 186
 187     *got_frame = 1;
 188     if ((ret = av_frame_ref(rframe, cpia->frame)) < 0)
 189         return ret;
 190
 191     return avpkt->size;
 192 }
 193
 194 static av_cold int cpia_decode_init(AVCodecContext *avctx)
 195 {
 196     CpiaContext *s = avctx->priv_data;
 197
 198     // output pixel format
 199     avctx->pix_fmt = AV_PIX_FMT_YUV420P;
 200
 201     s->frame = av_frame_alloc();
 202     if (!s->frame)
 203         return AVERROR(ENOMEM);
 204
 205     return 0;
 206 }
 207
 208 static av_cold int cpia_decode_end(AVCodecContext *avctx)
 209 {
 210     CpiaContext *s = avctx->priv_data;
 211
 212     av_frame_free(&s->frame);
 213
 214     return 0;
 215 }
 216
 217 const FFCodec ff_cpia_decoder = {
 218     .p.name         = "cpia",
 219     CODEC_LONG_NAME("CPiA video format"),
 220     .p.type         = AVMEDIA_TYPE_VIDEO,
 221     .p.id           = AV_CODEC_ID_CPIA,
 222     .priv_data_size = sizeof(CpiaContext),
 223     .init           = cpia_decode_init,
 224     .close          = cpia_decode_end,
 225     FF_CODEC_DECODE_CB(cpia_decode_frame),
 226     .p.capabilities = AV_CODEC_CAP_DR1,
 227 };