ffmpeg/libavcodec/yuv4dec.c

   1 /*
   2  * libquicktime yuv4 decoder
   3  *
   4  * Copyright (c) 2011 Carl Eugen Hoyos
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include "avcodec.h"
  24 #include "internal.h"
  25
  26 static av_cold int yuv4_decode_init(AVCodecContext *avctx)
  27 {
  28     avctx->pix_fmt = AV_PIX_FMT_YUV420P;
  29
  30     return 0;
  31 }
  32
  33 static int yuv4_decode_frame(AVCodecContext *avctx, void *data,
  34                              int *got_frame, AVPacket *avpkt)
  35 {
  36     AVFrame *pic = data;
  37     const uint8_t *src = avpkt->data;
  38     uint8_t *y, *u, *v;
  39     int i, j, ret;
  40
  41     if (avpkt->size < 6 * (avctx->width + 1 >> 1) * (avctx->height + 1 >> 1)) {
  42         av_log(avctx, AV_LOG_ERROR, "Insufficient input data.\n");
  43         return AVERROR(EINVAL);
  44     }
  45
  46     if ((ret = ff_get_buffer(avctx, pic, 0)) < 0)
  47         return ret;
  48
  49     pic->key_frame = 1;
  50     pic->pict_type = AV_PICTURE_TYPE_I;
  51
  52     y = pic->data[0];
  53     u = pic->data[1];
  54     v = pic->data[2];
  55
  56     for (i = 0; i < (avctx->height + 1) >> 1; i++) {
  57         for (j = 0; j < (avctx->width + 1) >> 1; j++) {
  58             u[j] = *src++ ^ 0x80;
  59             v[j] = *src++ ^ 0x80;
  60             y[                   2 * j    ] = *src++;
  61             y[                   2 * j + 1] = *src++;
  62             y[pic->linesize[0] + 2 * j    ] = *src++;
  63             y[pic->linesize[0] + 2 * j + 1] = *src++;
  64         }
  65
  66         y += 2 * pic->linesize[0];
  67         u +=     pic->linesize[1];
  68         v +=     pic->linesize[2];
  69     }
  70
  71     *got_frame = 1;
  72
  73     return avpkt->size;
  74 }
  75
  76 AVCodec ff_yuv4_decoder = {
  77     .name         = "yuv4",
  78     .long_name    = NULL_IF_CONFIG_SMALL("Uncompressed packed 4:2:0"),
  79     .type         = AVMEDIA_TYPE_VIDEO,
  80     .id           = AV_CODEC_ID_YUV4,
  81     .init         = yuv4_decode_init,
  82     .decode       = yuv4_decode_frame,
  83     .capabilities = CODEC_CAP_DR1,
  84 };