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 FFmpeg.
13 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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/attributes.h"
31 #include "libavutil/intreadwrite.h"
32 #include "libavcodec/get_bits.h"
34 struct PayloadContext {
42 static PayloadContext *h263_new_context(void)
44 return av_mallocz(sizeof(PayloadContext));
47 static void h263_free_context(PayloadContext *data)
53 avio_close_dyn_buf(data->buf, &p);
59 static av_cold int h263_init(AVFormatContext *ctx, int st_index, PayloadContext *data)
63 ctx->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;
67 static int h263_handle_packet(AVFormatContext *ctx, PayloadContext *data,
68 AVStream *st, AVPacket *pkt, uint32_t *timestamp,
69 const uint8_t *buf, int len, uint16_t seq,
72 /* Corresponding to header fields in the RFC */
73 int f, p, i, sbit, ebit, src, r;
77 return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf, len,
80 if (data->buf && data->timestamp != *timestamp) {
81 /* Dropping old buffered, unfinished data */
83 avio_close_dyn_buf(data->buf, &p);
89 av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet: %d\n", len);
90 return AVERROR_INVALIDDATA;
99 r = ((buf[1] & 0x01) << 3) | ((buf[2] & 0xe0) >> 5);
103 if (len < header_size) {
104 av_log(ctx, AV_LOG_ERROR,
105 "Too short H.263 RTP packet: %d bytes, %d header bytes\n",
107 return AVERROR_INVALIDDATA;
114 if (len < header_size) {
115 av_log(ctx, AV_LOG_ERROR,
116 "Too short H.263 RTP packet: %d bytes, %d header bytes\n",
118 return AVERROR_INVALIDDATA;
123 sbit = (buf[0] >> 3) & 0x7;
125 src = (buf[1] & 0xe0) >> 5;
126 if (!(buf[0] & 0xf8)) { /* Reserved bits in RFC 2429/4629 are zero */
127 if ((src == 0 || src >= 6) && r) {
128 /* Invalid src for this format, and bits that should be zero
129 * according to RFC 2190 aren't zero. */
130 av_log(ctx, AV_LOG_WARNING,
131 "Interpreting H263 RTP data as RFC 2429/4629 even though "
132 "signalled with a static payload type.\n");
134 return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf,
143 /* Check the picture start code, only start buffering a new frame
144 * if this is correct */
145 if (len > 4 && AV_RB32(buf) >> 10 == 0x20) {
146 ret = avio_open_dyn_buf(&data->buf);
149 data->timestamp = *timestamp;
151 /* Frame not started yet, skipping */
152 return AVERROR(EAGAIN);
156 if (data->endbyte_bits || sbit) {
157 if (data->endbyte_bits == sbit) {
158 data->endbyte |= buf[0] & (0xff >> sbit);
159 data->endbyte_bits = 0;
162 avio_w8(data->buf, data->endbyte);
164 /* Start/end skip bits not matching - missed packets? */
166 init_get_bits(&gb, buf, len*8 - ebit);
167 skip_bits(&gb, sbit);
168 if (data->endbyte_bits) {
169 data->endbyte |= get_bits(&gb, 8 - data->endbyte_bits);
170 avio_w8(data->buf, data->endbyte);
172 while (get_bits_left(&gb) >= 8)
173 avio_w8(data->buf, get_bits(&gb, 8));
174 data->endbyte_bits = get_bits_left(&gb);
175 if (data->endbyte_bits)
176 data->endbyte = get_bits(&gb, data->endbyte_bits) <<
177 (8 - data->endbyte_bits);
184 avio_write(data->buf, buf, len - 1);
185 data->endbyte_bits = 8 - ebit;
186 data->endbyte = buf[len - 1] & (0xff << ebit);
188 avio_write(data->buf, buf, len);
191 if (!(flags & RTP_FLAG_MARKER))
192 return AVERROR(EAGAIN);
194 if (data->endbyte_bits)
195 avio_w8(data->buf, data->endbyte);
196 data->endbyte_bits = 0;
198 ret = ff_rtp_finalize_packet(pkt, &data->buf, st->index);
202 pkt->flags |= AV_PKT_FLAG_KEY;
207 RTPDynamicProtocolHandler ff_h263_rfc2190_dynamic_handler = {
208 .codec_type = AVMEDIA_TYPE_VIDEO,
209 .codec_id = AV_CODEC_ID_H263,
211 .parse_packet = h263_handle_packet,
212 .alloc = h263_new_context,
213 .free = h263_free_context,
214 .static_payload_id = 34,