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