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
31typedef struct {
32    int continue_pes;
33} PVAContext;
34
35static 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
43static int pva_probe(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
57static int pva_read_header(AVFormatContext *s) {
58    AVStream *st;
59
60    if (!(st = avformat_new_stream(s, NULL)))
61        return AVERROR(ENOMEM);
62    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
63    st->codec->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->codec->codec_type = AVMEDIA_TYPE_AUDIO;
71    st->codec->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
82static 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
90recover:
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 (pes_signal != 1 || pes_header_data_length == 0) {
138                pva_log(s, AV_LOG_WARNING, "expected non empty signaled PES packet, "
139                                          "trying to recover\n");
140                avio_skip(pb, length - 9);
141                if (!read_packet)
142                    return AVERROR(EIO);
143                goto recover;
144            }
145
146            ret = avio_read(pb, pes_header_data, pes_header_data_length);
147            if (ret != pes_header_data_length)
148                return ret < 0 ? ret : AVERROR_INVALIDDATA;
149            length -= 9 + pes_header_data_length;
150
151            pes_packet_length -= 3 + pes_header_data_length;
152
153            pvactx->continue_pes = pes_packet_length;
154
155            if (pes_flags & 0x80 && (pes_header_data[0] & 0xf0) == 0x20) {
156                if (pes_header_data_length < 5) {
157                    pva_log(s, AV_LOG_ERROR, "header too short\n");
158                    avio_skip(pb, length);
159                    return AVERROR_INVALIDDATA;
160                }
161                pva_pts = ff_parse_pes_pts(pes_header_data);
162            }
163        }
164
165        pvactx->continue_pes -= length;
166
167        if (pvactx->continue_pes < 0) {
168            pva_log(s, AV_LOG_WARNING, "audio data corruption\n");
169            pvactx->continue_pes = 0;
170        }
171    }
172
173    if (pva_pts != AV_NOPTS_VALUE)
174        av_add_index_entry(s->streams[streamid-1], startpos, pva_pts, 0, 0, AVINDEX_KEYFRAME);
175
176    *pts   = pva_pts;
177    *len   = length;
178    *strid = streamid;
179    return 0;
180}
181
182static int pva_read_packet(AVFormatContext *s, AVPacket *pkt) {
183    AVIOContext *pb = s->pb;
184    int64_t pva_pts;
185    int ret, length, streamid;
186
187    if (read_part_of_packet(s, &pva_pts, &length, &streamid, 1) < 0 ||
188       (ret = av_get_packet(pb, pkt, length)) <= 0)
189        return AVERROR(EIO);
190
191    pkt->stream_index = streamid - 1;
192    pkt->pts = pva_pts;
193
194    return ret;
195}
196
197static int64_t pva_read_timestamp(struct AVFormatContext *s, int stream_index,
198                                          int64_t *pos, int64_t pos_limit) {
199    AVIOContext *pb = s->pb;
200    PVAContext *pvactx = s->priv_data;
201    int length, streamid;
202    int64_t res = AV_NOPTS_VALUE;
203
204    pos_limit = FFMIN(*pos+PVA_MAX_PAYLOAD_LENGTH*8, (uint64_t)*pos+pos_limit);
205
206    while (*pos < pos_limit) {
207        res = AV_NOPTS_VALUE;
208        avio_seek(pb, *pos, SEEK_SET);
209
210        pvactx->continue_pes = 0;
211        if (read_part_of_packet(s, &res, &length, &streamid, 0)) {
212            (*pos)++;
213            continue;
214        }
215        if (streamid - 1 != stream_index || res == AV_NOPTS_VALUE) {
216            *pos = avio_tell(pb) + length;
217            continue;
218        }
219        break;
220    }
221
222    pvactx->continue_pes = 0;
223    return res;
224}
225
226AVInputFormat ff_pva_demuxer = {
227    .name           = "pva",
228    .long_name      = NULL_IF_CONFIG_SMALL("TechnoTrend PVA"),
229    .priv_data_size = sizeof(PVAContext),
230    .read_probe     = pva_probe,
231    .read_header    = pva_read_header,
232    .read_packet    = pva_read_packet,
233    .read_timestamp = pva_read_timestamp,
234};
235