1/*
2 * MJPEG/AVI1 to JPEG/JFIF bitstream format filter
3 * Copyright (c) 2010 Adrian Daerr and Nicolas George
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/*
23 * Adapted from mjpeg2jpeg.c, with original copyright:
24 * Paris 2010 Adrian Daerr, public domain
25 */
26
27#include <string.h>
28#include "avcodec.h"
29#include "mjpeg.h"
30
31static const uint8_t jpeg_header[] = {
32    0xff, 0xd8,                     // SOI
33    0xff, 0xe0,                     // APP0
34    0x00, 0x10,                     // APP0 header size (including
35                                    // this field, but excluding preceding)
36    0x4a, 0x46, 0x49, 0x46, 0x00,   // ID string 'JFIF\0'
37    0x01, 0x01,                     // version
38    0x00,                           // bits per type
39    0x00, 0x00,                     // X density
40    0x00, 0x00,                     // Y density
41    0x00,                           // X thumbnail size
42    0x00,                           // Y thumbnail size
43};
44
45static const int dht_segment_size = 420;
46static const uint8_t dht_segment_head[] = { 0xFF, 0xC4, 0x01, 0xA2, 0x00 };
47static const uint8_t dht_segment_frag[] = {
48    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
49    0x0a, 0x0b, 0x01, 0x00, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01,
50    0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
51};
52
53static uint8_t *append(uint8_t *buf, const uint8_t *src, int size)
54{
55    memcpy(buf, src, size);
56    return buf + size;
57}
58
59static uint8_t *append_dht_segment(uint8_t *buf)
60{
61    buf = append(buf, dht_segment_head, sizeof(dht_segment_head));
62    buf = append(buf, ff_mjpeg_bits_dc_luminance + 1, 16);
63    buf = append(buf, dht_segment_frag, sizeof(dht_segment_frag));
64    buf = append(buf, ff_mjpeg_val_dc, 12);
65    *(buf++) = 0x10;
66    buf = append(buf, ff_mjpeg_bits_ac_luminance + 1, 16);
67    buf = append(buf, ff_mjpeg_val_ac_luminance, 162);
68    *(buf++) = 0x11;
69    buf = append(buf, ff_mjpeg_bits_ac_chrominance + 1, 16);
70    buf = append(buf, ff_mjpeg_val_ac_chrominance, 162);
71    return buf;
72}
73
74static int mjpeg2jpeg_filter(AVBitStreamFilterContext *bsfc,
75                             AVCodecContext *avctx, const char *args,
76                             uint8_t **poutbuf, int *poutbuf_size,
77                             const uint8_t *buf, int buf_size,
78                             int keyframe)
79{
80    int input_skip, output_size;
81    uint8_t *output, *out;
82
83    if (buf_size < 12) {
84        av_log(avctx, AV_LOG_ERROR, "input is truncated\n");
85        return AVERROR_INVALIDDATA;
86    }
87    if (memcmp("AVI1", buf + 6, 4)) {
88        av_log(avctx, AV_LOG_ERROR, "input is not MJPEG/AVI1\n");
89        return AVERROR_INVALIDDATA;
90    }
91    input_skip = (buf[4] << 8) + buf[5] + 4;
92    if (buf_size < input_skip) {
93        av_log(avctx, AV_LOG_ERROR, "input is truncated\n");
94        return AVERROR_INVALIDDATA;
95    }
96    output_size = buf_size - input_skip +
97                  sizeof(jpeg_header) + dht_segment_size;
98    output = out = av_malloc(output_size);
99    if (!output)
100        return AVERROR(ENOMEM);
101    out = append(out, jpeg_header, sizeof(jpeg_header));
102    out = append_dht_segment(out);
103    out = append(out, buf + input_skip, buf_size - input_skip);
104    *poutbuf = output;
105    *poutbuf_size = output_size;
106    return 1;
107}
108
109AVBitStreamFilter ff_mjpeg2jpeg_bsf = {
110    .name           = "mjpeg2jpeg",
111    .filter         = mjpeg2jpeg_filter,
112};
113