1/*
2 * MJPEG A dump header bitstream filter
3 * Copyright (c) 2006 Baptiste Coudurier
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/**
23 * @file
24 * MJPEG A dump header bitstream filter
25 * modifies bitstream to be decoded by quicktime
26 */
27
28#include "bsf.h"
29#include "bsf_internal.h"
30#include "bytestream.h"
31#include "mjpeg.h"
32
33
34static int mjpega_dump_header(AVBSFContext *ctx, AVPacket *out)
35{
36    AVPacket *in;
37    uint8_t *out_buf;
38    unsigned dqt = 0, dht = 0, sof0 = 0;
39    int ret = 0, i;
40
41    ret = ff_bsf_get_packet(ctx, &in);
42    if (ret < 0)
43        return ret;
44
45    ret = av_new_packet(out, in->size + 44);
46    if (ret < 0)
47        goto fail;
48
49    ret = av_packet_copy_props(out, in);
50    if (ret < 0)
51        goto fail;
52
53    out_buf = out->data;
54    bytestream_put_byte(&out_buf, 0xff);
55    bytestream_put_byte(&out_buf, SOI);
56    bytestream_put_byte(&out_buf, 0xff);
57    bytestream_put_byte(&out_buf, APP1);
58    bytestream_put_be16(&out_buf, 42); /* size */
59    bytestream_put_be32(&out_buf, 0);
60    bytestream_put_buffer(&out_buf, "mjpg", 4);
61    bytestream_put_be32(&out_buf, in->size + 44); /* field size */
62    bytestream_put_be32(&out_buf, in->size + 44); /* pad field size */
63    bytestream_put_be32(&out_buf, 0);             /* next ptr */
64
65    for (i = 0; i < in->size - 1; i++) {
66        if (in->data[i] == 0xff) {
67            switch (in->data[i + 1]) {
68            case DQT:  dqt  = i + 46; break;
69            case DHT:  dht  = i + 46; break;
70            case SOF0: sof0 = i + 46; break;
71            case SOS:
72                bytestream_put_be32(&out_buf, dqt); /* quant off */
73                bytestream_put_be32(&out_buf, dht); /* huff off */
74                bytestream_put_be32(&out_buf, sof0); /* image off */
75                bytestream_put_be32(&out_buf, i + 46); /* scan off */
76                bytestream_put_be32(&out_buf, i + 46 + AV_RB16(in->data + i + 2)); /* data off */
77                bytestream_put_buffer(&out_buf, in->data + 2, in->size - 2); /* skip already written SOI */
78
79                out->size = out_buf - out->data;
80                av_packet_free(&in);
81                return 0;
82            case APP1:
83                if (i + 8 < in->size && AV_RL32(in->data + i + 8) == AV_RL32("mjpg")) {
84                    av_log(ctx, AV_LOG_ERROR, "bitstream already formatted\n");
85                    av_packet_unref(out);
86                    av_packet_move_ref(out, in);
87                    av_packet_free(&in);
88                    return 0;
89                }
90            }
91        }
92    }
93    av_log(ctx, AV_LOG_ERROR, "could not find SOS marker in bitstream\n");
94fail:
95    av_packet_unref(out);
96    av_packet_free(&in);
97    return AVERROR_INVALIDDATA;
98}
99
100static const enum AVCodecID codec_ids[] = {
101    AV_CODEC_ID_MJPEG, AV_CODEC_ID_NONE,
102};
103
104const FFBitStreamFilter ff_mjpega_dump_header_bsf = {
105    .p.name      = "mjpegadump",
106    .p.codec_ids = codec_ids,
107    .filter      = mjpega_dump_header,
108};
109