2 * RTP H.263 Depacketizer, RFC 4629
3 * Copyright (c) 2010 Martin Storsjo
5 * This file is part of FFmpeg.
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.
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.
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
23 #include "rtpdec_formats.h"
24 #include "libavutil/attributes.h"
25 #include "libavutil/intreadwrite.h"
27 static av_cold
int h263_init(AVFormatContext
*ctx
, int st_index
,
32 ctx
->streams
[st_index
]->need_parsing
= AVSTREAM_PARSE_FULL
;
36 int ff_h263_handle_packet(AVFormatContext
*ctx
, PayloadContext
*data
,
37 AVStream
*st
, AVPacket
*pkt
, uint32_t *timestamp
,
38 const uint8_t *buf
, int len
, uint16_t seq
, int flags
)
42 int startcode
, vrc
, picture_header
;
45 av_log(ctx
, AV_LOG_ERROR
, "Too short H.263 RTP packet\n");
46 return AVERROR_INVALIDDATA
;
49 /* Decode the 16 bit H.263+ payload header, as described in section
50 * 5.1 of RFC 4629. The fields of this header are:
51 * - 5 reserved bits, should be ignored.
52 * - One bit (P, startcode), indicating a picture start, picture segment
53 * start or video sequence end. If set, two zero bytes should be
54 * prepended to the payload.
55 * - One bit (V, vrc), indicating the presence of an 8 bit Video
56 * Redundancy Coding field after this 16 bit header.
57 * - 6 bits (PLEN, picture_header), the length (in bytes) of an extra
58 * picture header, following the VRC field.
59 * - 3 bits (PEBIT), the number of bits to ignore of the last byte
60 * of the extra picture header. (Not used at the moment.)
62 header
= AV_RB16(buf
);
63 startcode
= (header
& 0x0400) >> 9;
64 vrc
= header
& 0x0200;
65 picture_header
= (header
& 0x01f8) >> 3;
70 /* Skip VRC header if present, not used at the moment. */
75 /* Skip extra picture header if present, not used at the moment. */
76 buf
+= picture_header
;
77 len
-= picture_header
;
81 av_log(ctx
, AV_LOG_ERROR
, "Too short H.263 RTP packet\n");
82 return AVERROR_INVALIDDATA
;
85 if (av_new_packet(pkt
, len
+ startcode
)) {
86 av_log(ctx
, AV_LOG_ERROR
, "Out of memory\n");
87 return AVERROR(ENOMEM
);
89 pkt
->stream_index
= st
->index
;
96 memcpy(ptr
, buf
, len
);
101 RTPDynamicProtocolHandler ff_h263_1998_dynamic_handler
= {
102 .enc_name
= "H263-1998",
103 .codec_type
= AVMEDIA_TYPE_VIDEO
,
104 .codec_id
= AV_CODEC_ID_H263
,
106 .parse_packet
= ff_h263_handle_packet
,
109 RTPDynamicProtocolHandler ff_h263_2000_dynamic_handler
= {
110 .enc_name
= "H263-2000",
111 .codec_type
= AVMEDIA_TYPE_VIDEO
,
112 .codec_id
= AV_CODEC_ID_H263
,
114 .parse_packet
= ff_h263_handle_packet
,