1/*
2 * Alias PIX image encoder
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 "encode.h"
28
29#define ALIAS_HEADER_SIZE 10
30
31static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
32                        const AVFrame *frame, int *got_packet)
33{
34    int width, height, bits_pixel, length, ret;
35    uint8_t *buf;
36
37    width  = avctx->width;
38    height = avctx->height;
39
40    if (width > 65535 || height > 65535 ||
41        width * height >= INT_MAX / 4 - ALIAS_HEADER_SIZE) {
42        av_log(avctx, AV_LOG_ERROR, "Invalid image size %dx%d.\n", width, height);
43        return AVERROR_INVALIDDATA;
44    }
45
46    switch (avctx->pix_fmt) {
47    case AV_PIX_FMT_GRAY8:
48        bits_pixel = 8;
49        break;
50    case AV_PIX_FMT_BGR24:
51        bits_pixel = 24;
52        break;
53    default:
54        return AVERROR(EINVAL);
55    }
56
57    length = ALIAS_HEADER_SIZE + 4 * width * height; // max possible
58    if ((ret = ff_alloc_packet(avctx, pkt, length)) < 0)
59        return ret;
60
61    buf = pkt->data;
62
63    /* Encode header. */
64    bytestream_put_be16(&buf, width);
65    bytestream_put_be16(&buf, height);
66    bytestream_put_be32(&buf, 0); /* X, Y offset */
67    bytestream_put_be16(&buf, bits_pixel);
68
69    for (int j = 0, bytes_pixel = bits_pixel >> 3; j < height; j++) {
70        const uint8_t *in_buf = frame->data[0] + frame->linesize[0] * j;
71        const uint8_t *const line_end = in_buf + bytes_pixel * width;
72        while (in_buf < line_end) {
73            int count = 0;
74            int pixel;
75
76            if (avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
77                pixel = *in_buf;
78                while (count < 255 && in_buf < line_end && pixel == *in_buf) {
79                    count++;
80                    in_buf++;
81                }
82                bytestream_put_byte(&buf, count);
83                bytestream_put_byte(&buf, pixel);
84            } else { /* AV_PIX_FMT_BGR24 */
85                pixel = AV_RB24(in_buf);
86                while (count < 255 && in_buf < line_end &&
87                       pixel == AV_RB24(in_buf)) {
88                    count++;
89                    in_buf += 3;
90                }
91                bytestream_put_byte(&buf, count);
92                bytestream_put_be24(&buf, pixel);
93            }
94        }
95    }
96
97    /* Total length */
98    av_shrink_packet(pkt, buf - pkt->data);
99    *got_packet = 1;
100
101    return 0;
102}
103
104const FFCodec ff_alias_pix_encoder = {
105    .p.name    = "alias_pix",
106    .p.long_name = NULL_IF_CONFIG_SMALL("Alias/Wavefront PIX image"),
107    .p.type    = AVMEDIA_TYPE_VIDEO,
108    .p.id      = AV_CODEC_ID_ALIAS_PIX,
109    FF_CODEC_ENCODE_CB(encode_frame),
110    .p.pix_fmts = (const enum AVPixelFormat[]) {
111        AV_PIX_FMT_BGR24, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
112    },
113};
114