xref: /third_party/ffmpeg/libavcodec/qoidec.c (revision cabdff1a)
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 <stdlib.h>
22
23#include "libavutil/imgutils.h"
24#include "avcodec.h"
25#include "internal.h"
26#include "bytestream.h"
27#include "codec_internal.h"
28#include "thread.h"
29#include "qoi.h"
30
31static int qoi_decode_frame(AVCodecContext *avctx, AVFrame *p,
32                            int *got_frame, AVPacket *avpkt)
33{
34    const uint8_t *buf = avpkt->data;
35    int ret, buf_size = avpkt->size;
36    int width, height, channels, space, run = 0;
37    uint8_t index[64][4] = { 0 };
38    uint8_t px[4] = { 0, 0, 0, 255 };
39    GetByteContext gb;
40    uint8_t *dst;
41    uint64_t len;
42
43    if (buf_size < 20)
44        return AVERROR_INVALIDDATA;
45
46    bytestream2_init(&gb, buf, buf_size);
47    bytestream2_skip(&gb, 4);
48    width  = bytestream2_get_be32(&gb);
49    height = bytestream2_get_be32(&gb);
50    channels = bytestream2_get_byte(&gb);
51    space = bytestream2_get_byte(&gb);
52    switch (space) {
53    case 0: break;
54    case 1: avctx->color_trc = AVCOL_TRC_LINEAR; break;
55    default: return AVERROR_INVALIDDATA;
56    }
57
58    if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
59        return ret;
60
61    switch (channels) {
62    case 3: avctx->pix_fmt = AV_PIX_FMT_RGB24; break;
63    case 4: avctx->pix_fmt = AV_PIX_FMT_RGBA;  break;
64    default: return AVERROR_INVALIDDATA;
65    }
66
67    if ((ret = ff_thread_get_buffer(avctx, p, 0)) < 0)
68        return ret;
69
70    dst = p->data[0];
71    len = width * height * channels;
72    for (int n = 0, off_x = 0; n < len; n += channels, off_x++) {
73        if (off_x >= width) {
74            off_x = 0;
75            dst += p->linesize[0];
76        }
77        if (run > 0) {
78            run--;
79        } else if (bytestream2_get_bytes_left(&gb) > 4) {
80            int chunk = bytestream2_get_byteu(&gb);
81
82            if (chunk == QOI_OP_RGB) {
83                bytestream2_get_bufferu(&gb, px, 3);
84            } else if (chunk == QOI_OP_RGBA) {
85                bytestream2_get_bufferu(&gb, px, 4);
86            } else if ((chunk & QOI_MASK_2) == QOI_OP_INDEX) {
87                memcpy(px, index[chunk], 4);
88            } else if ((chunk & QOI_MASK_2) == QOI_OP_DIFF) {
89                px[0] += ((chunk >> 4) & 0x03) - 2;
90                px[1] += ((chunk >> 2) & 0x03) - 2;
91                px[2] += ( chunk       & 0x03) - 2;
92            } else if ((chunk & QOI_MASK_2) == QOI_OP_LUMA) {
93                int b2 = bytestream2_get_byteu(&gb);
94                int vg = (chunk & 0x3f) - 32;
95                px[0] += vg - 8 + ((b2 >> 4) & 0x0f);
96                px[1] += vg;
97                px[2] += vg - 8 +  (b2       & 0x0f);
98            } else if ((chunk & QOI_MASK_2) == QOI_OP_RUN) {
99                run = chunk & 0x3f;
100            }
101
102            memcpy(index[QOI_COLOR_HASH(px) & 63], px, 4);
103        } else {
104            break;
105        }
106
107        memcpy(&dst[off_x * channels], px, channels);
108    }
109
110    p->key_frame = 1;
111    p->pict_type = AV_PICTURE_TYPE_I;
112
113    *got_frame   = 1;
114
115    return buf_size;
116}
117
118const FFCodec ff_qoi_decoder = {
119    .p.name         = "qoi",
120    .p.long_name    = NULL_IF_CONFIG_SMALL("QOI (Quite OK Image format) image"),
121    .p.type         = AVMEDIA_TYPE_VIDEO,
122    .p.id           = AV_CODEC_ID_QOI,
123    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
124    FF_CODEC_DECODE_CB(qoi_decode_frame),
125};
126