blob: 05cac6e528dcb608289a2658ff0a6f30975a5c76
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->codecpar->codec_type = AVMEDIA_TYPE_VIDEO; |
43 | vst->codecpar->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_packet_unref(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 | }; |
93 |