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/intreadwrite.h"
26 int ff_h263_handle_packet(AVFormatContext *ctx, PayloadContext *data,
27 AVStream *st, AVPacket *pkt, uint32_t *timestamp,
28 const uint8_t *buf, int len, int flags)
32 int startcode, vrc, picture_header;
35 av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet\n");
36 return AVERROR_INVALIDDATA;
39 /* Decode the 16 bit H.263+ payload header, as described in section
40 * 5.1 of RFC 4629. The fields of this header are:
41 * - 5 reserved bits, should be ignored.
42 * - One bit (P, startcode), indicating a picture start, picture segment
43 * start or video sequence end. If set, two zero bytes should be
44 * prepended to the payload.
45 * - One bit (V, vrc), indicating the presence of an 8 bit Video
46 * Redundancy Coding field after this 16 bit header.
47 * - 6 bits (PLEN, picture_header), the length (in bytes) of an extra
48 * picture header, following the VRC field.
49 * - 3 bits (PEBIT), the number of bits to ignore of the last byte
50 * of the extra picture header. (Not used at the moment.)
52 header = AV_RB16(buf);
53 startcode = (header & 0x0400) >> 9;
54 vrc = header & 0x0200;
55 picture_header = (header & 0x01f8) >> 3;
60 /* Skip VRC header if present, not used at the moment. */
65 /* Skip extra picture header if present, not used at the moment. */
66 buf += picture_header;
67 len -= picture_header;
71 av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet\n");
72 return AVERROR_INVALIDDATA;
75 if (av_new_packet(pkt, len + startcode)) {
76 av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
77 return AVERROR(ENOMEM);
79 pkt->stream_index = st->index;
86 memcpy(ptr, buf, len);
91 RTPDynamicProtocolHandler ff_h263_1998_dynamic_handler = {
92 .enc_name = "H263-1998",
93 .codec_type = AVMEDIA_TYPE_VIDEO,
94 .codec_id = AV_CODEC_ID_H263,
95 .parse_packet = ff_h263_handle_packet,
98 RTPDynamicProtocolHandler ff_h263_2000_dynamic_handler = {
99 .enc_name = "H263-2000",
100 .codec_type = AVMEDIA_TYPE_VIDEO,
101 .codec_id = AV_CODEC_ID_H263,
102 .parse_packet = ff_h263_handle_packet,