fixed double free - fixed probe function
[libav.git] / libav / mpegts.c
CommitLineData
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1/*
2 * MPEG2 transport stream (aka DVB) demux
3 * Copyright (c) 2002 Gerard Lantau.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 */
19#include "avformat.h"
20
21#define TS_FEC_PACKET_SIZE 204
22#define TS_PACKET_SIZE 188
23#define NB_PID_MAX 8192
24
25enum MpegTSState {
26 MPEGTS_HEADER = 0,
27 MPEGTS_PESHEADER_FILL,
28 MPEGTS_PESHEADER_FLAGS,
29 MPEGTS_PESHEADER_SIZE,
30 MPEGTS_PESHEADER_READ,
31 MPEGTS_PAYLOAD,
32 MPEGTS_SKIP,
33};
34
35/* enough for PES header + length */
36#define MAX_HEADER_SIZE 6
37
38typedef struct MpegTSStream {
39 int pid;
40 enum MpegTSState state;
41 int last_cc; /* last cc code (-1 if first packet) */
42 /* used to get the format */
43 int header_size;
44 int payload_size;
45 int pes_header_size;
46 AVStream *st;
47 unsigned char header[MAX_HEADER_SIZE];
48} MpegTSStream;
49
50typedef struct MpegTSContext {
51 int raw_packet_size; /* raw packet size, including FEC if present */
52 MpegTSStream *pids[NB_PID_MAX];
53} MpegTSContext;
54
55/* autodetect fec presence. Must have at least 1024 bytes */
56static int get_packet_size(const unsigned char *buf, int size)
57{
58 int i;
59
60 if (size < (TS_FEC_PACKET_SIZE * 5 + 1))
61 return -1;
62 for(i=0;i<5;i++) {
63 if (buf[i * TS_PACKET_SIZE] != 0x47)
64 goto try_fec;
65 }
66 return TS_PACKET_SIZE;
67 try_fec:
68 for(i=0;i<5;i++) {
69 if (buf[i * TS_FEC_PACKET_SIZE] != 0x47)
70 return -1;
71 }
72 return TS_FEC_PACKET_SIZE;
73}
74
75static int mpegts_probe(AVProbeData *p)
76{
77 int size;
78 size = get_packet_size(p->buf, p->buf_size);
79 if (size < 0)
80 return 0;
81 return AVPROBE_SCORE_MAX;
82}
83
84static int mpegts_read_header(AVFormatContext *s,
85 AVFormatParameters *ap)
86{
87 MpegTSContext *ts = s->priv_data;
88 ByteIOContext *pb = &s->pb;
89 unsigned char buf[1024];
90 int len;
91 INT64 pos;
92
93 /* read the first 1024 bytes to get packet size */
94 pos = url_ftell(pb);
95 len = get_buffer(pb, buf, sizeof(buf));
96 if (len != sizeof(buf))
97 goto fail;
98 ts->raw_packet_size = get_packet_size(buf, sizeof(buf));
99 if (ts->raw_packet_size <= 0)
100 goto fail;
101 /* go again to the start */
102 url_fseek(pb, pos, SEEK_SET);
103 return 0;
104 fail:
105 return -1;
106}
107
108/* return non zero if a packet could be constructed */
109static int mpegts_push_data(AVFormatContext *s, MpegTSStream *tss,
110 AVPacket *pkt,
111 const unsigned char *buf, int buf_size, int is_start)
112{
113 AVStream *st;
114 const unsigned char *p;
115 int len, code, codec_type, codec_id;
116
117 if (is_start) {
118 tss->state = MPEGTS_HEADER;
119 tss->header_size = 0;
120 }
121 p = buf;
122 while (buf_size > 0) {
123 len = buf_size;
124 switch(tss->state) {
125 case MPEGTS_HEADER:
126 if (len > MAX_HEADER_SIZE - tss->header_size)
127 len = MAX_HEADER_SIZE - tss->header_size;
128 memcpy(tss->header, p, len);
129 tss->header_size += len;
130 p += len;
131 buf_size -= len;
132 if (tss->header_size == MAX_HEADER_SIZE) {
133 /* we got all the PES or section header. We can now
134 decide */
135#if 0
136 av_hex_dump(tss->header, tss->header_size);
137#endif
138 if (tss->header[0] == 0x00 && tss->header[1] == 0x00 &&
139 tss->header[2] == 0x01) {
140 /* it must be an mpeg2 PES stream */
141 /* XXX: add AC3 support */
142 code = tss->header[3] | 0x100;
143 if (!((code >= 0x1c0 && code <= 0x1df) ||
144 (code >= 0x1e0 && code <= 0x1ef)))
145 goto skip;
146 if (!tss->st) {
147 /* allocate stream */
148 if (code >= 0x1c0 && code <= 0x1df) {
149 codec_type = CODEC_TYPE_AUDIO;
150 codec_id = CODEC_ID_MP2;
151 } else {
152 codec_type = CODEC_TYPE_VIDEO;
153 codec_id = CODEC_ID_MPEG1VIDEO;
154 }
155 st = av_new_stream(s, tss->pid);
156 if (st) {
157 st->priv_data = tss;
158 st->codec.codec_type = codec_type;
159 st->codec.codec_id = codec_id;
160 tss->st = st;
161 }
162 }
163 tss->state = MPEGTS_PESHEADER_FILL;
164 tss->payload_size = (tss->header[4] << 8) | tss->header[5];
165 if (tss->payload_size == 0)
166 tss->payload_size = 65536;
167 } else {
168 /* otherwise, it should be a table */
169 /* skip packet */
170 skip:
171 tss->state = MPEGTS_SKIP;
172 continue;
173 }
174 }
175 break;
176 /**********************************************/
177 /* PES packing parsing */
178 case MPEGTS_PESHEADER_FILL:
179 /* skip filling */
180 code = *p++;
181 buf_size--;
182 tss->payload_size--;
183 if (code != 0xff) {
184 if ((code & 0xc0) != 0x80)
185 goto skip;
186 tss->state = MPEGTS_PESHEADER_FLAGS;
187 }
188 break;
189 case MPEGTS_PESHEADER_FLAGS:
190 code = *p++;
191 buf_size--;
192 tss->payload_size--;
193 tss->state = MPEGTS_PESHEADER_SIZE;
194 break;
195 case MPEGTS_PESHEADER_SIZE:
196 tss->pes_header_size = *p++;
197 buf_size--;
198 tss->payload_size--;
199 tss->state = MPEGTS_PESHEADER_READ;
200 break;
201 case MPEGTS_PESHEADER_READ:
202 /* currently we do nothing except skipping */
203 if (len > tss->pes_header_size)
204 len = tss->pes_header_size;
205 p += len;
206 buf_size -= len;
207 tss->pes_header_size -= len;
208 tss->payload_size -= len;
209 if (tss->pes_header_size == 0)
210 tss->state = MPEGTS_PAYLOAD;
211 break;
212 case MPEGTS_PAYLOAD:
213 if (len > tss->payload_size)
214 len = tss->payload_size;
215 if (len > 0) {
216 if (tss->st && av_new_packet(pkt, buf_size) == 0) {
217 memcpy(pkt->data, p, buf_size);
218 pkt->stream_index = tss->st->index;
219 return 1;
220 }
221 tss->payload_size -= len;
222 }
223 buf_size = 0;
224 break;
225 case MPEGTS_SKIP:
226 buf_size = 0;
227 break;
228 }
229 }
230 return 0;
231}
232
233static int mpegts_read_packet(AVFormatContext *s,
234 AVPacket *pkt)
235{
236 MpegTSContext *ts = s->priv_data;
237 MpegTSStream *tss;
238 ByteIOContext *pb = &s->pb;
239 unsigned char packet[TS_FEC_PACKET_SIZE];
240 int len, pid, cc, cc_ok, afc;
241 const unsigned char *p;
242
243 for(;;) {
244 len = get_buffer(pb, packet, ts->raw_packet_size);
245 if (len != ts->raw_packet_size)
246 return AVERROR_IO;
247 /* check paquet sync byte */
248 /* XXX: accept to resync ? */
249 if (packet[0] != 0x47)
250 return AVERROR_INVALIDDATA;
251
252 pid = ((packet[1] & 0x1f) << 8) | packet[2];
253 tss = ts->pids[pid];
254 if (tss == NULL) {
255 /* if no pid found, then add a pid context */
256 tss = av_mallocz(sizeof(MpegTSStream));
257 if (!tss)
258 continue;
259 ts->pids[pid] = tss;
260 tss->pid = pid;
261 tss->last_cc = -1;
262 // printf("new pid=0x%x\n", pid);
263 }
264
265 /* continuity check (currently not used) */
266 cc = (packet[3] & 0xf);
267 cc_ok = (tss->last_cc < 0) || ((((tss->last_cc + 1) & 0x0f) == cc));
268 tss->last_cc = cc;
269
270 /* skip adaptation field */
271 afc = (packet[3] >> 4) & 3;
272 p = packet + 4;
273 if (afc == 0) /* reserved value */
274 continue;
275 if (afc == 2) /* adaptation field only */
276 continue;
277 if (afc == 3) {
278 /* skip adapation field */
279 p += p[0] + 1;
280 }
281 /* if past the end of packet, ignore */
282 if (p >= packet + TS_PACKET_SIZE)
283 continue;
284
285 if (mpegts_push_data(s, tss, pkt, p, TS_PACKET_SIZE - (p - packet),
286 packet[1] & 0x40))
287 break;
288 }
289 return 0;
290}
291
292static int mpegts_read_close(AVFormatContext *s)
293{
294 MpegTSContext *ts = s->priv_data;
295 int i;
296 for(i=0;i<NB_PID_MAX;i++)
754ebe34 297 av_free(ts->pids[i]);
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298 return 0;
299}
300
301AVInputFormat mpegts_demux = {
302 "mpegts",
303 "MPEG2 transport stream format",
304 sizeof(MpegTSContext),
305 mpegts_probe,
306 mpegts_read_header,
307 mpegts_read_packet,
308 mpegts_read_close,
309 flags: AVFMT_NOHEADER | AVFMT_SHOW_IDS,
310};
311
312int mpegts_init(void)
313{
314 av_register_input_format(&mpegts_demux);
315 return 0;
316}