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
mjpega_dump_header(AVBSFContext * ctx,AVPacket * out)34 static 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");
94 fail:
95 av_packet_unref(out);
96 av_packet_free(&in);
97 return AVERROR_INVALIDDATA;
98 }
99
100 static const enum AVCodecID codec_ids[] = {
101 AV_CODEC_ID_MJPEG, AV_CODEC_ID_NONE,
102 };
103
104 const AVBitStreamFilter ff_mjpega_dump_header_bsf = {
105 .name = "mjpegadump",
106 .filter = mjpega_dump_header,
107 .codec_ids = codec_ids,
108 };
109