1 /*
2 * RTP Depacketization of MP4A-LATM, RFC 3016
3 * Copyright (c) 2010 Martin Storsjo
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 "avio_internal.h"
23 #include "rtpdec_formats.h"
24 #include "internal.h"
25 #include "libavutil/avstring.h"
26 #include "libavcodec/get_bits.h"
27
28 struct PayloadContext {
29 AVIOContext *dyn_buf;
30 uint8_t *buf;
31 int pos, len;
32 uint32_t timestamp;
33 };
34
latm_close_context(PayloadContext * data)35 static void latm_close_context(PayloadContext *data)
36 {
37 ffio_free_dyn_buf(&data->dyn_buf);
38 av_freep(&data->buf);
39 }
40
latm_parse_packet(AVFormatContext * ctx,PayloadContext * data,AVStream * st,AVPacket * pkt,uint32_t * timestamp,const uint8_t * buf,int len,uint16_t seq,int flags)41 static int latm_parse_packet(AVFormatContext *ctx, PayloadContext *data,
42 AVStream *st, AVPacket *pkt, uint32_t *timestamp,
43 const uint8_t *buf, int len, uint16_t seq,
44 int flags)
45 {
46 int ret, cur_len;
47
48 if (buf) {
49 if (!data->dyn_buf || data->timestamp != *timestamp) {
50 av_freep(&data->buf);
51 ffio_free_dyn_buf(&data->dyn_buf);
52
53 data->timestamp = *timestamp;
54 if ((ret = avio_open_dyn_buf(&data->dyn_buf)) < 0)
55 return ret;
56 }
57 avio_write(data->dyn_buf, buf, len);
58
59 if (!(flags & RTP_FLAG_MARKER))
60 return AVERROR(EAGAIN);
61 av_freep(&data->buf);
62 data->len = avio_close_dyn_buf(data->dyn_buf, &data->buf);
63 data->dyn_buf = NULL;
64 data->pos = 0;
65 }
66
67 if (!data->buf) {
68 av_log(ctx, AV_LOG_ERROR, "No data available yet\n");
69 return AVERROR(EIO);
70 }
71
72 cur_len = 0;
73 while (data->pos < data->len) {
74 uint8_t val = data->buf[data->pos++];
75 cur_len += val;
76 if (val != 0xff)
77 break;
78 }
79 if (data->pos + cur_len > data->len) {
80 av_log(ctx, AV_LOG_ERROR, "Malformed LATM packet\n");
81 return AVERROR(EIO);
82 }
83
84 if ((ret = av_new_packet(pkt, cur_len)) < 0)
85 return ret;
86 memcpy(pkt->data, data->buf + data->pos, cur_len);
87 data->pos += cur_len;
88 pkt->stream_index = st->index;
89 return data->pos < data->len;
90 }
91
parse_fmtp_config(AVStream * st,const char * value)92 static int parse_fmtp_config(AVStream *st, const char *value)
93 {
94 int len = ff_hex_to_data(NULL, value), i, ret = 0;
95 GetBitContext gb;
96 uint8_t *config;
97 int audio_mux_version, same_time_framing, num_programs, num_layers;
98
99 /* Pad this buffer, too, to avoid out of bounds reads with get_bits below */
100 config = av_mallocz(len + AV_INPUT_BUFFER_PADDING_SIZE);
101 if (!config)
102 return AVERROR(ENOMEM);
103 ff_hex_to_data(config, value);
104 ret = init_get_bits(&gb, config, len*8);
105 if (ret < 0)
106 return ret;
107 audio_mux_version = get_bits(&gb, 1);
108 same_time_framing = get_bits(&gb, 1);
109 skip_bits(&gb, 6); /* num_sub_frames */
110 num_programs = get_bits(&gb, 4);
111 num_layers = get_bits(&gb, 3);
112 if (audio_mux_version != 0 || same_time_framing != 1 || num_programs != 0 ||
113 num_layers != 0) {
114 avpriv_report_missing_feature(NULL, "LATM config (%d,%d,%d,%d)",
115 audio_mux_version, same_time_framing,
116 num_programs, num_layers);
117 ret = AVERROR_PATCHWELCOME;
118 goto end;
119 }
120 ret = ff_alloc_extradata(st->codecpar, (get_bits_left(&gb) + 7)/8);
121 if (ret < 0) {
122 goto end;
123 }
124 for (i = 0; i < st->codecpar->extradata_size; i++)
125 st->codecpar->extradata[i] = get_bits(&gb, 8);
126
127 end:
128 av_free(config);
129 return ret;
130 }
131
parse_fmtp(AVFormatContext * s,AVStream * stream,PayloadContext * data,const char * attr,const char * value)132 static int parse_fmtp(AVFormatContext *s,
133 AVStream *stream, PayloadContext *data,
134 const char *attr, const char *value)
135 {
136 int res;
137
138 if (!strcmp(attr, "config")) {
139 res = parse_fmtp_config(stream, value);
140 if (res < 0)
141 return res;
142 } else if (!strcmp(attr, "cpresent")) {
143 int cpresent = atoi(value);
144 if (cpresent != 0)
145 avpriv_request_sample(s,
146 "RTP MP4A-LATM with in-band configuration");
147 }
148
149 return 0;
150 }
151
latm_parse_sdp_line(AVFormatContext * s,int st_index,PayloadContext * data,const char * line)152 static int latm_parse_sdp_line(AVFormatContext *s, int st_index,
153 PayloadContext *data, const char *line)
154 {
155 const char *p;
156
157 if (st_index < 0)
158 return 0;
159
160 if (av_strstart(line, "fmtp:", &p))
161 return ff_parse_fmtp(s, s->streams[st_index], data, p, parse_fmtp);
162
163 return 0;
164 }
165
166 const RTPDynamicProtocolHandler ff_mp4a_latm_dynamic_handler = {
167 .enc_name = "MP4A-LATM",
168 .codec_type = AVMEDIA_TYPE_AUDIO,
169 .codec_id = AV_CODEC_ID_AAC,
170 .priv_data_size = sizeof(PayloadContext),
171 .parse_sdp_a_line = latm_parse_sdp_line,
172 .close = latm_close_context,
173 .parse_packet = latm_parse_packet,
174 };
175