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2ba45a60 DM |
1 | /* |
2 | * CD Graphics Demuxer | |
3 | * Copyright (c) 2009 Michael Tison | |
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 "avformat.h" | |
23 | #include "internal.h" | |
24 | ||
25 | #define CDG_PACKET_SIZE 24 | |
26 | #define CDG_COMMAND 0x09 | |
27 | #define CDG_MASK 0x3F | |
28 | ||
29 | typedef struct CDGContext { | |
30 | int got_first_packet; | |
31 | } CDGContext; | |
32 | ||
33 | static int read_header(AVFormatContext *s) | |
34 | { | |
35 | AVStream *vst; | |
36 | int ret; | |
37 | ||
38 | vst = avformat_new_stream(s, NULL); | |
39 | if (!vst) | |
40 | return AVERROR(ENOMEM); | |
41 | ||
42 | vst->codec->codec_type = AVMEDIA_TYPE_VIDEO; | |
43 | vst->codec->codec_id = AV_CODEC_ID_CDGRAPHICS; | |
44 | ||
45 | /// 75 sectors/sec * 4 packets/sector = 300 packets/sec | |
46 | avpriv_set_pts_info(vst, 32, 1, 300); | |
47 | ||
48 | ret = avio_size(s->pb); | |
49 | if (ret < 0) { | |
50 | av_log(s, AV_LOG_WARNING, "Cannot calculate duration as file size cannot be determined\n"); | |
51 | } else | |
52 | vst->duration = (ret * vst->time_base.den) / (CDG_PACKET_SIZE * 300); | |
53 | ||
54 | return 0; | |
55 | } | |
56 | ||
57 | static int read_packet(AVFormatContext *s, AVPacket *pkt) | |
58 | { | |
59 | CDGContext *priv = s->priv_data; | |
60 | int ret; | |
61 | ||
62 | while (1) { | |
63 | ret = av_get_packet(s->pb, pkt, CDG_PACKET_SIZE); | |
64 | if (ret < 1 || (pkt->data[0] & CDG_MASK) == CDG_COMMAND) | |
65 | break; | |
66 | av_free_packet(pkt); | |
67 | } | |
68 | ||
69 | if (!priv->got_first_packet) { | |
70 | pkt->flags |= AV_PKT_FLAG_KEY; | |
71 | priv->got_first_packet = 1; | |
72 | } | |
73 | ||
74 | pkt->stream_index = 0; | |
75 | pkt->dts= | |
76 | pkt->pts= pkt->pos / CDG_PACKET_SIZE; | |
77 | ||
78 | if(ret>5 && (pkt->data[0]&0x3F) == 9 && (pkt->data[1]&0x3F)==1 && !(pkt->data[2+2+1] & 0x0F)){ | |
79 | pkt->flags = AV_PKT_FLAG_KEY; | |
80 | } | |
81 | return ret; | |
82 | } | |
83 | ||
84 | AVInputFormat ff_cdg_demuxer = { | |
85 | .name = "cdg", | |
86 | .long_name = NULL_IF_CONFIG_SMALL("CD Graphics"), | |
87 | .priv_data_size = sizeof(CDGContext), | |
88 | .read_header = read_header, | |
89 | .read_packet = read_packet, | |
90 | .flags = AVFMT_GENERIC_INDEX, | |
91 | .extensions = "cdg", | |
92 | }; |