2 * RTP H.263 Depacketizer, RFC 2190
3 * Copyright (c) 2012 Martin Storsjo
4 * Based on the GStreamer H.263 Depayloder:
5 * Copyright 2005 Wim Taymans
6 * Copyright 2007 Edward Hervey
7 * Copyright 2007 Nokia Corporation
8 * Copyright 2007 Collabora Ltd, Philippe Kalaf
9 * Copyright 2010 Mark Nauwelaerts
11 * This file is part of Libav.
13 * Libav is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU Lesser General Public
15 * License as published by the Free Software Foundation; either
16 * version 2.1 of the License, or (at your option) any later version.
18 * Libav is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
21 * Lesser General Public License for more details.
23 * You should have received a copy of the GNU Lesser General Public
24 * License along with Libav; if not, write to the Free Software
25 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
29 #include "rtpdec_formats.h"
30 #include "libavutil/intreadwrite.h"
31 #include "libavcodec/get_bits.h"
33 struct PayloadContext {
41 static PayloadContext *h263_new_context(void)
43 return av_mallocz(sizeof(PayloadContext));
46 static void h263_free_context(PayloadContext *data)
52 avio_close_dyn_buf(data->buf, &p);
58 static int h263_init(AVFormatContext *ctx, int st_index, PayloadContext *data)
62 ctx->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;
66 static int h263_handle_packet(AVFormatContext *ctx, PayloadContext *data,
67 AVStream *st, AVPacket *pkt, uint32_t *timestamp,
68 const uint8_t *buf, int len, uint16_t seq,
71 /* Corresponding to header fields in the RFC */
72 int f, p, i, sbit, ebit, src, r;
76 return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf, len,
79 if (data->buf && data->timestamp != *timestamp) {
80 /* Dropping old buffered, unfinished data */
82 avio_close_dyn_buf(data->buf, &p);
88 av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet: %d\n", len);
89 return AVERROR_INVALIDDATA;
98 r = ((buf[1] & 0x01) << 3) | ((buf[2] & 0xe0) >> 5);
102 if (len < header_size) {
103 av_log(ctx, AV_LOG_ERROR,
104 "Too short H.263 RTP packet: %d bytes, %d header bytes\n",
106 return AVERROR_INVALIDDATA;
113 if (len < header_size) {
114 av_log(ctx, AV_LOG_ERROR,
115 "Too short H.263 RTP packet: %d bytes, %d header bytes\n",
117 return AVERROR_INVALIDDATA;
122 sbit = (buf[0] >> 3) & 0x7;
124 src = (buf[1] & 0xe0) >> 5;
125 if (!(buf[0] & 0xf8)) { /* Reserved bits in RFC 2429/4629 are zero */
126 if ((src == 0 || src >= 6) && r) {
127 /* Invalid src for this format, and bits that should be zero
128 * according to RFC 2190 aren't zero. */
129 av_log(ctx, AV_LOG_WARNING,
130 "Interpreting H263 RTP data as RFC 2429/4629 even though "
131 "signalled with a static payload type.\n");
133 return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf,
142 /* Check the picture start code, only start buffering a new frame
143 * if this is correct */
144 if (len > 4 && AV_RB32(buf) >> 10 == 0x20) {
145 ret = avio_open_dyn_buf(&data->buf);
148 data->timestamp = *timestamp;
150 /* Frame not started yet, skipping */
151 return AVERROR(EAGAIN);
155 if (data->endbyte_bits || sbit) {
156 if (data->endbyte_bits == sbit) {
157 data->endbyte |= buf[0] & (0xff >> sbit);
158 data->endbyte_bits = 0;
161 avio_w8(data->buf, data->endbyte);
163 /* Start/end skip bits not matching - missed packets? */
165 init_get_bits(&gb, buf, len*8 - ebit);
166 skip_bits(&gb, sbit);
167 if (data->endbyte_bits) {
168 data->endbyte |= get_bits(&gb, 8 - data->endbyte_bits);
169 avio_w8(data->buf, data->endbyte);
171 while (get_bits_left(&gb) >= 8)
172 avio_w8(data->buf, get_bits(&gb, 8));
173 data->endbyte_bits = get_bits_left(&gb);
174 if (data->endbyte_bits)
175 data->endbyte = get_bits(&gb, data->endbyte_bits) <<
176 (8 - data->endbyte_bits);
183 avio_write(data->buf, buf, len - 1);
184 data->endbyte_bits = 8 - ebit;
185 data->endbyte = buf[len - 1] & (0xff << ebit);
187 avio_write(data->buf, buf, len);
190 if (!(flags & RTP_FLAG_MARKER))
191 return AVERROR(EAGAIN);
193 if (data->endbyte_bits)
194 avio_w8(data->buf, data->endbyte);
195 data->endbyte_bits = 0;
197 ret = ff_rtp_finalize_packet(pkt, &data->buf, st->index);
201 pkt->flags |= AV_PKT_FLAG_KEY;
206 RTPDynamicProtocolHandler ff_h263_rfc2190_dynamic_handler = {
207 .codec_type = AVMEDIA_TYPE_VIDEO,
208 .codec_id = AV_CODEC_ID_H263,
210 .parse_packet = h263_handle_packet,
211 .alloc = h263_new_context,
212 .free = h263_free_context,
213 .static_payload_id = 34,