1/*
2 * Alias PIX image decoder
3 * Copyright (C) 2014 Vittorio Giovara <vittorio.giovara@gmail.com>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "libavutil/intreadwrite.h"
23
24#include "avcodec.h"
25#include "bytestream.h"
26#include "codec_internal.h"
27#include "internal.h"
28
29#define ALIAS_HEADER_SIZE 10
30
31static int decode_frame(AVCodecContext *avctx, AVFrame *f,
32                        int *got_frame, AVPacket *avpkt)
33{
34    GetByteContext gb;
35    int width, height, ret, bits_pixel, pixel;
36    uint8_t *out_buf;
37    uint8_t count;
38    int x, y;
39
40    bytestream2_init(&gb, avpkt->data, avpkt->size);
41
42    if (bytestream2_get_bytes_left(&gb) < ALIAS_HEADER_SIZE) {
43        av_log(avctx, AV_LOG_ERROR, "Header too small %d.\n", avpkt->size);
44        return AVERROR_INVALIDDATA;
45    }
46
47    width  = bytestream2_get_be16u(&gb);
48    height = bytestream2_get_be16u(&gb);
49    bytestream2_skipu(&gb, 4); // obsolete X, Y offset
50    bits_pixel = bytestream2_get_be16u(&gb);
51
52    if (bits_pixel == 24)
53        avctx->pix_fmt = AV_PIX_FMT_BGR24;
54    else if (bits_pixel == 8)
55        avctx->pix_fmt = AV_PIX_FMT_GRAY8;
56    else {
57        av_log(avctx, AV_LOG_ERROR, "Invalid pixel format.\n");
58        return AVERROR_INVALIDDATA;
59    }
60
61    ret = ff_set_dimensions(avctx, width, height);
62    if (ret < 0)
63        return ret;
64
65    if (bytestream2_get_bytes_left(&gb) < width*height / 255)
66        return AVERROR_INVALIDDATA;
67
68    ret = ff_get_buffer(avctx, f, 0);
69    if (ret < 0)
70        return ret;
71
72    f->pict_type = AV_PICTURE_TYPE_I;
73    f->key_frame = 1;
74
75    x = 0;
76    y = 1;
77    out_buf = f->data[0];
78    while (bytestream2_get_bytes_left(&gb) > 0) {
79        int i;
80
81        /* set buffer at the right position at every new line */
82        if (x == avctx->width) {
83            x = 0;
84            out_buf = f->data[0] + f->linesize[0] * y++;
85            if (y > avctx->height) {
86                av_log(avctx, AV_LOG_ERROR,
87                       "Ended frame decoding with %d bytes left.\n",
88                       bytestream2_get_bytes_left(&gb));
89                return AVERROR_INVALIDDATA;
90            }
91        }
92
93        /* read packet and copy data */
94        count = bytestream2_get_byteu(&gb);
95        if (!count || x + count > avctx->width) {
96            av_log(avctx, AV_LOG_ERROR, "Invalid run length %d.\n", count);
97            return AVERROR_INVALIDDATA;
98        }
99
100        if (avctx->pix_fmt == AV_PIX_FMT_BGR24) {
101            pixel = bytestream2_get_be24(&gb);
102            for (i = 0; i < count; i++) {
103                AV_WB24(out_buf, pixel);
104                out_buf += 3;
105            }
106        } else { // AV_PIX_FMT_GRAY8
107            pixel = bytestream2_get_byte(&gb);
108            for (i = 0; i < count; i++)
109                *out_buf++ = pixel;
110        }
111
112        x += i;
113    }
114
115    if (x != width || y != height) {
116        av_log(avctx, AV_LOG_ERROR, "Picture stopped at %d,%d.\n", x, y);
117        return AVERROR_INVALIDDATA;
118    }
119
120    *got_frame = 1;
121    return avpkt->size;
122}
123
124const FFCodec ff_alias_pix_decoder = {
125    .p.name         = "alias_pix",
126    .p.long_name    = NULL_IF_CONFIG_SMALL("Alias/Wavefront PIX image"),
127    .p.type         = AVMEDIA_TYPE_VIDEO,
128    .p.id           = AV_CODEC_ID_ALIAS_PIX,
129    .p.capabilities = AV_CODEC_CAP_DR1,
130    FF_CODEC_DECODE_CB(decode_frame),
131};
132