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_handle_packet(AVFormatContext *ctx, PayloadContext *data,
59 AVStream *st, AVPacket *pkt, uint32_t *timestamp,
60 const uint8_t *buf, int len, int flags)
62 /* Corresponding to header fields in the RFC */
63 int f, p, i, sbit, ebit, src, r;
67 return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf, len,
70 if (data->buf && data->timestamp != *timestamp) {
71 /* Dropping old buffered, unfinished data */
73 avio_close_dyn_buf(data->buf, &p);
79 av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet: %d\n", len);
80 return AVERROR_INVALIDDATA;
89 r = ((buf[1] & 0x01) << 3) | ((buf[2] & 0xe0) >> 5);
93 if (len < header_size) {
94 av_log(ctx, AV_LOG_ERROR,
95 "Too short H.263 RTP packet: %d bytes, %d header bytes\n",
97 return AVERROR_INVALIDDATA;
104 if (len < header_size) {
105 av_log(ctx, AV_LOG_ERROR,
106 "Too short H.263 RTP packet: %d bytes, %d header bytes\n",
108 return AVERROR_INVALIDDATA;
113 sbit = (buf[0] >> 3) & 0x7;
115 src = (buf[1] & 0xe0) >> 5;
116 if (!(buf[0] & 0xf8)) { /* Reserved bits in RFC 2429/4629 are zero */
117 if ((src == 0 || src >= 6) && r) {
118 /* Invalid src for this format, and bits that should be zero
119 * according to RFC 2190 aren't zero. */
120 av_log(ctx, AV_LOG_WARNING,
121 "Interpreting H263 RTP data as RFC 2429/4629 even though "
122 "signalled with a static payload type.\n");
124 return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf,
133 /* Check the picture start code, only start buffering a new frame
134 * if this is correct */
135 if (len > 4 && AV_RB32(buf) >> 10 == 0x20) {
136 int ret = avio_open_dyn_buf(&data->buf);
139 data->timestamp = *timestamp;
141 /* Frame not started yet, skipping */
142 return AVERROR(EAGAIN);
146 if (data->endbyte_bits || sbit) {
147 if (data->endbyte_bits == sbit) {
148 data->endbyte |= buf[0] & (0xff >> sbit);
149 data->endbyte_bits = 0;
152 avio_w8(data->buf, data->endbyte);
154 /* Start/end skip bits not matching - missed packets? */
156 init_get_bits(&gb, buf, len*8 - ebit);
157 skip_bits(&gb, sbit);
158 if (data->endbyte_bits) {
159 data->endbyte |= get_bits(&gb, 8 - data->endbyte_bits);
160 avio_w8(data->buf, data->endbyte);
162 while (get_bits_left(&gb) >= 8)
163 avio_w8(data->buf, get_bits(&gb, 8));
164 data->endbyte_bits = get_bits_left(&gb);
165 if (data->endbyte_bits)
166 data->endbyte = get_bits(&gb, data->endbyte_bits) <<
167 (8 - data->endbyte_bits);
174 avio_write(data->buf, buf, len - 1);
175 data->endbyte_bits = 8 - ebit;
176 data->endbyte = buf[len - 1] & (0xff << ebit);
178 avio_write(data->buf, buf, len);
181 if (!(flags & RTP_FLAG_MARKER))
182 return AVERROR(EAGAIN);
184 if (data->endbyte_bits)
185 avio_w8(data->buf, data->endbyte);
186 data->endbyte_bits = 0;
189 pkt->size = avio_close_dyn_buf(data->buf, &pkt->data);
190 pkt->destruct = av_destruct_packet;
191 pkt->stream_index = st->index;
193 pkt->flags |= AV_PKT_FLAG_KEY;
199 RTPDynamicProtocolHandler ff_h263_rfc2190_dynamic_handler = {
200 .codec_type = AVMEDIA_TYPE_VIDEO,
201 .codec_id = CODEC_ID_H263,
202 .parse_packet = h263_handle_packet,
203 .alloc = h263_new_context,
204 .free = h263_free_context,
205 .static_payload_id = 34,