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1 /*
2  * Common code for the RTP depacketization of MPEG-1/2 formats.
3  * Copyright (c) 2002 Fabrice Bellard
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 "libavutil/attributes.h"
23 #include "libavutil/intreadwrite.h"
24 #include "rtpdec_formats.h"
25 
mpeg_parse_packet(AVFormatContext * ctx,PayloadContext * data,AVStream * st,AVPacket * pkt,uint32_t * timestamp,const uint8_t * buf,int len,uint16_t seq,int flags)26 static int mpeg_parse_packet(AVFormatContext *ctx, PayloadContext *data,
27                              AVStream *st, AVPacket *pkt, uint32_t *timestamp,
28                              const uint8_t *buf, int len, uint16_t seq,
29                              int flags)
30 {
31     unsigned int h;
32     int ret;
33     if (len <= 4)
34         return AVERROR_INVALIDDATA;
35     h    = AV_RB32(buf);
36     buf += 4;
37     len -= 4;
38     if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && h & (1 << 26)) {
39         /* MPEG-2 */
40         if (len <= 4)
41             return AVERROR_INVALIDDATA;
42         buf += 4;
43         len -= 4;
44     }
45     if ((ret = av_new_packet(pkt, len)) < 0)
46         return ret;
47     memcpy(pkt->data, buf, len);
48     pkt->stream_index = st->index;
49     return 0;
50 }
51 
52 const RTPDynamicProtocolHandler ff_mpeg_audio_dynamic_handler = {
53     .codec_type        = AVMEDIA_TYPE_AUDIO,
54     .codec_id          = AV_CODEC_ID_MP3,
55     .need_parsing      = AVSTREAM_PARSE_FULL,
56     .parse_packet      = mpeg_parse_packet,
57     .static_payload_id = 14,
58 };
59 
60 const RTPDynamicProtocolHandler ff_mpeg_video_dynamic_handler = {
61     .codec_type        = AVMEDIA_TYPE_VIDEO,
62     .codec_id          = AV_CODEC_ID_MPEG2VIDEO,
63     .need_parsing      = AVSTREAM_PARSE_FULL,
64     .parse_packet      = mpeg_parse_packet,
65     .static_payload_id = 32,
66 };
67