1 /*
2 * TechnoTrend PVA (.pva) demuxer
3 * Copyright (c) 2007, 2008 Ivo van Poorten
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 "avio_internal.h"
24 #include "internal.h"
25 #include "mpeg.h"
26
27 #define PVA_MAX_PAYLOAD_LENGTH 0x17f8
28 #define PVA_VIDEO_PAYLOAD 0x01
29 #define PVA_AUDIO_PAYLOAD 0x02
30 #define PVA_MAGIC (('A' << 8) + 'V')
31
32 typedef struct PVAContext {
33 int continue_pes;
34 } PVAContext;
35
pva_check(const uint8_t *p)36 static int pva_check(const uint8_t *p) {
37 int length = AV_RB16(p + 6);
38 if (AV_RB16(p) != PVA_MAGIC || !p[2] || p[2] > 2 || p[4] != 0x55 ||
39 (p[5] & 0xe0) || length > PVA_MAX_PAYLOAD_LENGTH)
40 return -1;
41 return length + 8;
42 }
43
pva_probe(const AVProbeData * pd)44 static int pva_probe(const AVProbeData * pd) {
45 const unsigned char *buf = pd->buf;
46 int len = pva_check(buf);
47
48 if (len < 0)
49 return 0;
50
51 if (pd->buf_size >= len + 8 &&
52 pva_check(buf + len) >= 0)
53 return AVPROBE_SCORE_EXTENSION;
54
55 return AVPROBE_SCORE_MAX / 4;
56 }
57
pva_read_header(AVFormatContext *s)58 static int pva_read_header(AVFormatContext *s) {
59 AVStream *st;
60
61 if (!(st = avformat_new_stream(s, NULL)))
62 return AVERROR(ENOMEM);
63 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
64 st->codecpar->codec_id = AV_CODEC_ID_MPEG2VIDEO;
65 ffstream(st)->need_parsing = AVSTREAM_PARSE_FULL;
66 avpriv_set_pts_info(st, 32, 1, 90000);
67 av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);
68
69 if (!(st = avformat_new_stream(s, NULL)))
70 return AVERROR(ENOMEM);
71 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
72 st->codecpar->codec_id = AV_CODEC_ID_MP2;
73 ffstream(st)->need_parsing = AVSTREAM_PARSE_FULL;
74 avpriv_set_pts_info(st, 33, 1, 90000);
75 av_add_index_entry(st, 0, 0, 0, 0, AVINDEX_KEYFRAME);
76
77 /* the parameters will be extracted from the compressed bitstream */
78 return 0;
79 }
80
81 #define pva_log if (read_packet) av_log
82
read_part_of_packet(AVFormatContext *s, int64_t *pts, int *len, int *strid, int read_packet)83 static int read_part_of_packet(AVFormatContext *s, int64_t *pts,
84 int *len, int *strid, int read_packet) {
85 AVIOContext *pb = s->pb;
86 PVAContext *pvactx = s->priv_data;
87 int syncword, streamid, reserved, flags, length, pts_flag;
88 int64_t pva_pts = AV_NOPTS_VALUE, startpos;
89 int ret;
90
91 recover:
92 startpos = avio_tell(pb);
93
94 syncword = avio_rb16(pb);
95 streamid = avio_r8(pb);
96 avio_r8(pb); /* counter not used */
97 reserved = avio_r8(pb);
98 flags = avio_r8(pb);
99 length = avio_rb16(pb);
100
101 pts_flag = flags & 0x10;
102
103 if (syncword != PVA_MAGIC) {
104 pva_log(s, AV_LOG_ERROR, "invalid syncword\n");
105 return AVERROR(EIO);
106 }
107 if (streamid != PVA_VIDEO_PAYLOAD && streamid != PVA_AUDIO_PAYLOAD) {
108 pva_log(s, AV_LOG_ERROR, "invalid streamid\n");
109 return AVERROR(EIO);
110 }
111 if (reserved != 0x55) {
112 pva_log(s, AV_LOG_WARNING, "expected reserved byte to be 0x55\n");
113 }
114 if (length > PVA_MAX_PAYLOAD_LENGTH) {
115 pva_log(s, AV_LOG_ERROR, "invalid payload length %u\n", length);
116 return AVERROR(EIO);
117 }
118
119 if (streamid == PVA_VIDEO_PAYLOAD && pts_flag) {
120 pva_pts = avio_rb32(pb);
121 length -= 4;
122 } else if (streamid == PVA_AUDIO_PAYLOAD) {
123 /* PVA Audio Packets either start with a signaled PES packet or
124 * are a continuation of the previous PES packet. New PES packets
125 * always start at the beginning of a PVA Packet, never somewhere in
126 * the middle. */
127 if (!pvactx->continue_pes) {
128 int pes_signal, pes_header_data_length, pes_packet_length,
129 pes_flags;
130 unsigned char pes_header_data[256];
131
132 pes_signal = avio_rb24(pb);
133 avio_r8(pb);
134 pes_packet_length = avio_rb16(pb);
135 pes_flags = avio_rb16(pb);
136 pes_header_data_length = avio_r8(pb);
137
138 if (avio_feof(pb)) {
139 return AVERROR_EOF;
140 }
141
142 if (pes_signal != 1 || pes_header_data_length == 0) {
143 pva_log(s, AV_LOG_WARNING, "expected non empty signaled PES packet, "
144 "trying to recover\n");
145 avio_skip(pb, length - 9);
146 if (!read_packet)
147 return AVERROR(EIO);
148 goto recover;
149 }
150
151 ret = ffio_read_size(pb, pes_header_data, pes_header_data_length);
152 if (ret < 0)
153 return ret;
154 length -= 9 + pes_header_data_length;
155
156 pes_packet_length -= 3 + pes_header_data_length;
157
158 pvactx->continue_pes = pes_packet_length;
159
160 if (pes_flags & 0x80 && (pes_header_data[0] & 0xf0) == 0x20) {
161 if (pes_header_data_length < 5) {
162 pva_log(s, AV_LOG_ERROR, "header too short\n");
163 avio_skip(pb, length);
164 return AVERROR_INVALIDDATA;
165 }
166 pva_pts = ff_parse_pes_pts(pes_header_data);
167 }
168 }
169
170 pvactx->continue_pes -= length;
171
172 if (pvactx->continue_pes < 0) {
173 pva_log(s, AV_LOG_WARNING, "audio data corruption\n");
174 pvactx->continue_pes = 0;
175 }
176 }
177
178 if (pva_pts != AV_NOPTS_VALUE)
179 av_add_index_entry(s->streams[streamid-1], startpos, pva_pts, 0, 0, AVINDEX_KEYFRAME);
180
181 *pts = pva_pts;
182 *len = length;
183 *strid = streamid;
184 return 0;
185 }
186
pva_read_packet(AVFormatContext *s, AVPacket *pkt)187 static int pva_read_packet(AVFormatContext *s, AVPacket *pkt) {
188 AVIOContext *pb = s->pb;
189 int64_t pva_pts;
190 int ret, length, streamid;
191
192 if (read_part_of_packet(s, &pva_pts, &length, &streamid, 1) < 0 ||
193 (ret = av_get_packet(pb, pkt, length)) <= 0)
194 return AVERROR(EIO);
195
196 pkt->stream_index = streamid - 1;
197 pkt->pts = pva_pts;
198
199 return ret;
200 }
201
pva_read_timestamp(struct AVFormatContext *s, int stream_index, int64_t *pos, int64_t pos_limit)202 static int64_t pva_read_timestamp(struct AVFormatContext *s, int stream_index,
203 int64_t *pos, int64_t pos_limit) {
204 AVIOContext *pb = s->pb;
205 PVAContext *pvactx = s->priv_data;
206 int length, streamid;
207 int64_t res = AV_NOPTS_VALUE;
208
209 pos_limit = FFMIN(*pos+PVA_MAX_PAYLOAD_LENGTH*8, (uint64_t)*pos+pos_limit);
210
211 while (*pos < pos_limit) {
212 res = AV_NOPTS_VALUE;
213 avio_seek(pb, *pos, SEEK_SET);
214
215 pvactx->continue_pes = 0;
216 if (read_part_of_packet(s, &res, &length, &streamid, 0)) {
217 (*pos)++;
218 continue;
219 }
220 if (streamid - 1 != stream_index || res == AV_NOPTS_VALUE) {
221 *pos = avio_tell(pb) + length;
222 continue;
223 }
224 break;
225 }
226
227 pvactx->continue_pes = 0;
228 return res;
229 }
230
231 const AVInputFormat ff_pva_demuxer = {
232 .name = "pva",
233 .long_name = NULL_IF_CONFIG_SMALL("TechnoTrend PVA"),
234 .priv_data_size = sizeof(PVAContext),
235 .read_probe = pva_probe,
236 .read_header = pva_read_header,
237 .read_packet = pva_read_packet,
238 .read_timestamp = pva_read_timestamp,
239 };
240