1 /*
2 * RTP parser for loss tolerant payload format for MP3 audio (RFC 5219)
3 * Copyright (c) 2015 Gilles Chanteperdrix <gch@xenomai.org>
4 *
5 * This file is part of FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22 #include "libavutil/attributes.h"
23 #include "libavutil/intreadwrite.h"
24
25 #include "avio_internal.h"
26 #include "rtpdec_formats.h"
27
28 struct PayloadContext {
29 unsigned adu_size;
30 unsigned cur_size;
31 uint32_t timestamp;
32 uint8_t *split_buf;
33 int split_pos, split_buf_size, split_pkts;
34 AVIOContext *fragment;
35 };
36
mpa_robust_close_context(PayloadContext * data)37 static void mpa_robust_close_context(PayloadContext *data)
38 {
39 ffio_free_dyn_buf(&data->fragment);
40 av_free(data->split_buf);
41 }
42
mpa_robust_parse_rtp_header(AVFormatContext * ctx,const uint8_t * buf,int len,unsigned * adu_size,unsigned * cont)43 static int mpa_robust_parse_rtp_header(AVFormatContext *ctx,
44 const uint8_t *buf, int len,
45 unsigned *adu_size, unsigned *cont)
46 {
47 unsigned header_size;
48
49 if (len < 2) {
50 av_log(ctx, AV_LOG_ERROR, "Invalid %d bytes packet\n", len);
51 return AVERROR_INVALIDDATA;
52 }
53
54 *cont = !!(buf[0] & 0x80);
55 if (!(buf[0] & 0x40)) {
56 header_size = 1;
57 *adu_size = buf[0] & ~0xc0;
58 } else {
59 header_size = 2;
60 *adu_size = AV_RB16(buf) & ~0xc000;
61 }
62
63 return header_size;
64 }
65
mpa_robust_parse_packet(AVFormatContext * ctx,PayloadContext * data,AVStream * st,AVPacket * pkt,uint32_t * timestamp,const uint8_t * buf,int len,uint16_t seq,int flags)66 static int mpa_robust_parse_packet(AVFormatContext *ctx, PayloadContext *data,
67 AVStream *st, AVPacket *pkt,
68 uint32_t *timestamp, const uint8_t *buf,
69 int len, uint16_t seq, int flags)
70 {
71 unsigned adu_size, continuation;
72 int err, header_size;
73
74 if (!buf) {
75 buf = &data->split_buf[data->split_pos];
76 len = data->split_buf_size - data->split_pos;
77
78 header_size = mpa_robust_parse_rtp_header(ctx, buf, len, &adu_size,
79 &continuation);
80 if (header_size < 0) {
81 av_freep(&data->split_buf);
82 return header_size;
83 }
84 buf += header_size;
85 len -= header_size;
86
87 if (continuation || adu_size > len) {
88 av_freep(&data->split_buf);
89 av_log(ctx, AV_LOG_ERROR, "Invalid frame\n");
90 return AVERROR_INVALIDDATA;
91 }
92
93 if ((err = av_new_packet(pkt, adu_size)) < 0) {
94 av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
95 return err;
96 }
97
98 pkt->stream_index = st->index;
99 memcpy(pkt->data, buf, adu_size);
100
101 data->split_pos += header_size + adu_size;
102
103 if (data->split_pos == data->split_buf_size) {
104 av_freep(&data->split_buf);
105 return 0;
106 }
107
108 return 1;
109 }
110
111
112 header_size = mpa_robust_parse_rtp_header(ctx, buf, len, &adu_size,
113 &continuation);
114 if (header_size < 0)
115 return header_size;
116
117 buf += header_size;
118 len -= header_size;
119
120 if (!continuation && adu_size <= len) {
121 /* One or more complete frames */
122
123 if ((err = av_new_packet(pkt, adu_size)) < 0) {
124 av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
125 return err;
126 }
127
128 pkt->stream_index = st->index;
129 memcpy(pkt->data, buf, adu_size);
130
131 buf += adu_size;
132 len -= adu_size;
133 if (len) {
134 data->split_buf_size = len;
135 data->split_buf = av_malloc(data->split_buf_size);
136 data->split_pos = 0;
137 if (!data->split_buf) {
138 av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
139 av_packet_unref(pkt);
140 return AVERROR(ENOMEM);
141 }
142 memcpy(data->split_buf, buf, data->split_buf_size);
143 return 1;
144 }
145 return 0;
146 } else if (!continuation) { /* && adu_size > len */
147 /* First fragment */
148 ffio_free_dyn_buf(&data->fragment);
149
150 data->adu_size = adu_size;
151 data->cur_size = len;
152 data->timestamp = *timestamp;
153
154 err = avio_open_dyn_buf(&data->fragment);
155 if (err < 0)
156 return err;
157
158 avio_write(data->fragment, buf, len);
159 return AVERROR(EAGAIN);
160 }
161 /* else continuation == 1 */
162
163 /* Fragment other than first */
164 if (!data->fragment) {
165 av_log(ctx, AV_LOG_WARNING,
166 "Received packet without a start fragment; dropping.\n");
167 return AVERROR(EAGAIN);
168 }
169 if (adu_size != data->adu_size ||
170 data->timestamp != *timestamp) {
171 ffio_free_dyn_buf(&data->fragment);
172 av_log(ctx, AV_LOG_ERROR, "Invalid packet received\n");
173 return AVERROR_INVALIDDATA;
174 }
175
176 avio_write(data->fragment, buf, len);
177 data->cur_size += len;
178
179 if (data->cur_size < data->adu_size)
180 return AVERROR(EAGAIN);
181
182 err = ff_rtp_finalize_packet(pkt, &data->fragment, st->index);
183 if (err < 0) {
184 av_log(ctx, AV_LOG_ERROR,
185 "Error occurred when getting fragment buffer.\n");
186 return err;
187 }
188
189 return 0;
190 }
191
192 const RTPDynamicProtocolHandler ff_mpeg_audio_robust_dynamic_handler = {
193 .enc_name = "mpa-robust",
194 .codec_type = AVMEDIA_TYPE_AUDIO,
195 .codec_id = AV_CODEC_ID_MP3ADU,
196 .need_parsing = AVSTREAM_PARSE_HEADERS,
197 .priv_data_size = sizeof(PayloadContext),
198 .close = mpa_robust_close_context,
199 .parse_packet = mpa_robust_parse_packet,
200 };
201