libavcodec/qoidec.c

   1 /*
   2  * QOI image format
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include "avcodec.h"
  22 #include "bytestream.h"
  23 #include "codec_internal.h"
  24 #include "decode.h"
  25 #include "thread.h"
  26 #include "qoi.h"
  27
  28 static int qoi_decode_frame(AVCodecContext *avctx, AVFrame *p,
  29                             int *got_frame, AVPacket *avpkt)
  30 {
  31     int width, height, channels, space, run = 0;
  32     uint8_t index[64][4] = { 0 };
  33     uint8_t px[4] = { 0, 0, 0, 255 };
  34     GetByteContext gb;
  35     uint8_t *dst;
  36     uint64_t len;
  37     int ret;
  38
  39     if (avpkt->size < 20)
  40         return AVERROR_INVALIDDATA;
  41
  42     bytestream2_init(&gb, avpkt->data, avpkt->size);
  43     bytestream2_skip(&gb, 4);
  44     width  = bytestream2_get_be32(&gb);
  45     height = bytestream2_get_be32(&gb);
  46     channels = bytestream2_get_byte(&gb);
  47     space = bytestream2_get_byte(&gb);
  48     switch (space) {
  49     case 0: break;
  50     case 1: avctx->color_trc = AVCOL_TRC_LINEAR; break;
  51     default: return AVERROR_INVALIDDATA;
  52     }
  53
  54     if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
  55         return ret;
  56
  57     switch (channels) {
  58     case 3: avctx->pix_fmt = AV_PIX_FMT_RGB24; break;
  59     case 4: avctx->pix_fmt = AV_PIX_FMT_RGBA;  break;
  60     default: return AVERROR_INVALIDDATA;
  61     }
  62
  63     if (avctx->skip_frame >= AVDISCARD_ALL)
  64         return avpkt->size;
  65
  66     if ((ret = ff_thread_get_buffer(avctx, p, 0)) < 0)
  67         return ret;
  68
  69     dst = p->data[0];
  70     len = width * height * channels;
  71     for (int n = 0, off_x = 0; n < len; n += channels, off_x++) {
  72         if (off_x >= width) {
  73             off_x = 0;
  74             dst += p->linesize[0];
  75         }
  76         if (run > 0) {
  77             run--;
  78         } else if (bytestream2_get_bytes_left(&gb) > 4) {
  79             int chunk = bytestream2_get_byteu(&gb);
  80
  81             if (chunk == QOI_OP_RGB) {
  82                 bytestream2_get_bufferu(&gb, px, 3);
  83             } else if (chunk == QOI_OP_RGBA) {
  84                 bytestream2_get_bufferu(&gb, px, 4);
  85             } else if ((chunk & QOI_MASK_2) == QOI_OP_INDEX) {
  86                 memcpy(px, index[chunk], 4);
  87             } else if ((chunk & QOI_MASK_2) == QOI_OP_DIFF) {
  88                 px[0] += ((chunk >> 4) & 0x03) - 2;
  89                 px[1] += ((chunk >> 2) & 0x03) - 2;
  90                 px[2] += ( chunk       & 0x03) - 2;
  91             } else if ((chunk & QOI_MASK_2) == QOI_OP_LUMA) {
  92                 int b2 = bytestream2_get_byteu(&gb);
  93                 int vg = (chunk & 0x3f) - 32;
  94                 px[0] += vg - 8 + ((b2 >> 4) & 0x0f);
  95                 px[1] += vg;
  96                 px[2] += vg - 8 +  (b2       & 0x0f);
  97             } else if ((chunk & QOI_MASK_2) == QOI_OP_RUN) {
  98                 run = chunk & 0x3f;
  99             }
 100
 101             memcpy(index[QOI_COLOR_HASH(px) & 63], px, 4);
 102         } else {
 103             break;
 104         }
 105
 106         memcpy(&dst[off_x * channels], px, channels);
 107     }
 108
 109     *got_frame   = 1;
 110
 111     return avpkt->size;
 112 }
 113
 114 const FFCodec ff_qoi_decoder = {
 115     .p.name         = "qoi",
 116     CODEC_LONG_NAME("QOI (Quite OK Image format) image"),
 117     .p.type         = AVMEDIA_TYPE_VIDEO,
 118     .p.id           = AV_CODEC_ID_QOI,
 119     .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
 120     .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM,
 121     FF_CODEC_DECODE_CB(qoi_decode_frame),
 122 };