aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/pcxenc.c
blob: 865d7bdbd3f237b77d7ef918ae373dbc00785b46 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
/*
 * PC Paintbrush PCX (.pcx) image encoder
 * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * PCX image encoder
 * @author Daniel Verkamp
 * @see http://www.qzx.com/pc-gpe/pcx.txt
 */

#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"

typedef struct PCXContext {
    AVFrame picture;
} PCXContext;

static const uint32_t monoblack_pal[16] = { 0x000000, 0xFFFFFF };

static av_cold int pcx_encode_init(AVCodecContext *avctx)
{
    PCXContext *s = avctx->priv_data;

    avcodec_get_frame_defaults(&s->picture);
    avctx->coded_frame = &s->picture;

    return 0;
}

/**
 * PCX run-length encoder
 * @param dst output buffer
 * @param dst_size size of output buffer
 * @param src input buffer
 * @param src_plane_size size of one plane of input buffer in bytes
 * @param nplanes number of planes in input buffer
 * @return number of bytes written to dst or -1 on error
 * @bug will not work for nplanes != 1 && bpp != 8
 */
static int pcx_rle_encode(      uint8_t *dst, int dst_size,
                          const uint8_t *src, int src_plane_size, int nplanes)
{
    int p;
    const uint8_t *dst_start = dst;

    // check worst-case upper bound on dst_size
    if (dst_size < 2LL * src_plane_size * nplanes || src_plane_size <= 0)
        return -1;

    for (p = 0; p < nplanes; p++) {
        int count = 1;
        const uint8_t *src_plane = src + p;
        const uint8_t *src_plane_end = src_plane + src_plane_size * nplanes;
        uint8_t prev = *src_plane;
        src_plane += nplanes;

        for (; ; src_plane += nplanes) {
            if (src_plane < src_plane_end && *src_plane == prev && count < 0x3F) {
                // current byte is same as prev
                ++count;
            } else {
                // output prev * count
                if (count != 1 || prev >= 0xC0)
                    *dst++ = 0xC0 | count;
                *dst++ = prev;

                if (src_plane == src_plane_end)
                    break;

                // start new run
                count = 1;
                prev = *src_plane;
            }
        }
    }

    return dst - dst_start;
}

static int pcx_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
                            const AVFrame *frame, int *got_packet)
{
    PCXContext *s = avctx->priv_data;
    AVFrame *const pict = &s->picture;
    const uint8_t *buf_end;
    uint8_t *buf;

    int bpp, nplanes, i, y, line_bytes, written, ret, max_pkt_size;
    const uint32_t *pal = NULL;
    const uint8_t *src;

    *pict = *frame;
    pict->pict_type = AV_PICTURE_TYPE_I;
    pict->key_frame = 1;

    if (avctx->width > 65535 || avctx->height > 65535) {
        av_log(avctx, AV_LOG_ERROR, "image dimensions do not fit in 16 bits\n");
        return -1;
    }

    switch (avctx->pix_fmt) {
    case PIX_FMT_RGB24:
        bpp = 8;
        nplanes = 3;
        break;
    case PIX_FMT_RGB8:
    case PIX_FMT_BGR8:
    case PIX_FMT_RGB4_BYTE:
    case PIX_FMT_BGR4_BYTE:
    case PIX_FMT_GRAY8:
    case PIX_FMT_PAL8:
        bpp = 8;
        nplanes = 1;
        pal = (uint32_t *)pict->data[1];
        break;
    case PIX_FMT_MONOBLACK:
        bpp = 1;
        nplanes = 1;
        pal = monoblack_pal;
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "unsupported pixfmt\n");
        return -1;
    }

    line_bytes = (avctx->width * bpp + 7) >> 3;
    line_bytes = (line_bytes + 1) & ~1;

    max_pkt_size = 128 + avctx->height * 2 * line_bytes * nplanes + (pal ? 256*3 + 1 : 0);
    if ((ret = ff_alloc_packet(pkt, max_pkt_size)) < 0) {
        av_log(avctx, AV_LOG_ERROR, "Error getting output packet of size %d.\n", max_pkt_size);
        return ret;
    }
    buf     = pkt->data;
    buf_end = pkt->data + pkt->size;

    bytestream_put_byte(&buf, 10);                  // manufacturer
    bytestream_put_byte(&buf, 5);                   // version
    bytestream_put_byte(&buf, 1);                   // encoding
    bytestream_put_byte(&buf, bpp);                 // bits per pixel per plane
    bytestream_put_le16(&buf, 0);                   // x min
    bytestream_put_le16(&buf, 0);                   // y min
    bytestream_put_le16(&buf, avctx->width - 1);    // x max
    bytestream_put_le16(&buf, avctx->height - 1);   // y max
    bytestream_put_le16(&buf, 0);                   // horizontal DPI
    bytestream_put_le16(&buf, 0);                   // vertical DPI
    for (i = 0; i < 16; i++)
        bytestream_put_be24(&buf, pal ? pal[i] : 0);// palette (<= 16 color only)
    bytestream_put_byte(&buf, 0);                   // reserved
    bytestream_put_byte(&buf, nplanes);             // number of planes
    bytestream_put_le16(&buf, line_bytes);          // scanline plane size in bytes

    while (buf - pkt->data < 128)
        *buf++= 0;

    src = pict->data[0];

    for (y = 0; y < avctx->height; y++) {
        if ((written = pcx_rle_encode(buf, buf_end - buf,
                                      src, line_bytes, nplanes)) < 0) {
            av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
            return -1;
        }
        buf += written;
        src += pict->linesize[0];
    }

    if (nplanes == 1 && bpp == 8) {
        if (buf_end - buf < 257) {
            av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
            return -1;
        }
        bytestream_put_byte(&buf, 12);
        for (i = 0; i < 256; i++) {
            bytestream_put_be24(&buf, pal[i]);
        }
    }

    pkt->size   = buf - pkt->data;
    pkt->flags |= AV_PKT_FLAG_KEY;
    *got_packet = 1;

    return 0;
}

AVCodec ff_pcx_encoder = {
    .name           = "pcx",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = CODEC_ID_PCX,
    .priv_data_size = sizeof(PCXContext),
    .init           = pcx_encode_init,
    .encode2        = pcx_encode_frame,
    .pix_fmts       = (const enum PixelFormat[]){
        PIX_FMT_RGB24,
        PIX_FMT_RGB8, PIX_FMT_BGR8, PIX_FMT_RGB4_BYTE, PIX_FMT_BGR4_BYTE,
        PIX_FMT_GRAY8, PIX_FMT_PAL8,
        PIX_FMT_MONOBLACK,
        PIX_FMT_NONE
    },
    .long_name      = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
};