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 "internal.h"
27
28#define ALIAS_HEADER_SIZE 10
29
30static av_cold int encode_init(AVCodecContext *avctx)
31{
32    avctx->coded_frame = av_frame_alloc();
33    if (!avctx->coded_frame)
34        return AVERROR(ENOMEM);
35    return 0;
36}
37
38static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
39                        const AVFrame *frame, int *got_packet)
40{
41    int width, height, bits_pixel, i, j, length, ret;
42    uint8_t *in_buf, *buf;
43
44    avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
45    avctx->coded_frame->key_frame = 1;
46
47    width  = avctx->width;
48    height = avctx->height;
49
50    if (width > 65535 || height > 65535 ||
51        width * height >= INT_MAX / 4 - ALIAS_HEADER_SIZE) {
52        av_log(avctx, AV_LOG_ERROR, "Invalid image size %dx%d.\n", width, height);
53        return AVERROR_INVALIDDATA;
54    }
55
56    switch (avctx->pix_fmt) {
57    case AV_PIX_FMT_GRAY8:
58        bits_pixel = 8;
59        break;
60    case AV_PIX_FMT_BGR24:
61        bits_pixel = 24;
62        break;
63    default:
64        return AVERROR(EINVAL);
65    }
66
67    length = ALIAS_HEADER_SIZE + 4 * width * height; // max possible
68    if ((ret = ff_alloc_packet(pkt, length)) < 0) {
69        av_log(avctx, AV_LOG_ERROR, "Error getting output packet of size %d.\n", length);
70        return ret;
71    }
72
73    buf = pkt->data;
74
75    /* Encode header. */
76    bytestream_put_be16(&buf, width);
77    bytestream_put_be16(&buf, height);
78    bytestream_put_be32(&buf, 0); /* X, Y offset */
79    bytestream_put_be16(&buf, bits_pixel);
80
81    for (j = 0; j < height; j++) {
82        in_buf = frame->data[0] + frame->linesize[0] * j;
83        for (i = 0; i < width; ) {
84            int count = 0;
85            int pixel;
86
87            if (avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
88                pixel = *in_buf;
89                while (count < 255 && count + i < width && pixel == *in_buf) {
90                    count++;
91                    in_buf++;
92                }
93                bytestream_put_byte(&buf, count);
94                bytestream_put_byte(&buf, pixel);
95            } else { /* AV_PIX_FMT_BGR24 */
96                pixel = AV_RB24(in_buf);
97                while (count < 255 && count + i < width &&
98                       pixel == AV_RB24(in_buf)) {
99                    count++;
100                    in_buf += 3;
101                }
102                bytestream_put_byte(&buf, count);
103                bytestream_put_be24(&buf, pixel);
104            }
105            i += count;
106        }
107    }
108
109    /* Total length */
110    av_shrink_packet(pkt, buf - pkt->data);
111    pkt->flags |= AV_PKT_FLAG_KEY;
112    *got_packet = 1;
113
114    return 0;
115}
116
117static av_cold int encode_close(AVCodecContext *avctx)
118{
119    av_frame_free(&avctx->coded_frame);
120    return 0;
121}
122
123AVCodec ff_alias_pix_encoder = {
124    .name      = "alias_pix",
125    .long_name = NULL_IF_CONFIG_SMALL("Alias/Wavefront PIX image"),
126    .type      = AVMEDIA_TYPE_VIDEO,
127    .id        = AV_CODEC_ID_ALIAS_PIX,
128    .init      = encode_init,
129    .encode2   = encode_frame,
130    .close     = encode_close,
131    .pix_fmts  = (const enum AVPixelFormat[]) {
132        AV_PIX_FMT_BGR24, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
133    },
134};
135