path: root/libavformat/rtpdec_latm.c (plain)
blob: a25c07fe52f4d34120b22b1a61109fd93b87e2d2

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
35	static void latm_close_context(PayloadContext *data)
36	{
37	ffio_free_dyn_buf(&data->dyn_buf);
38	av_freep(&data->buf);
39	}
40
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
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	init_get_bits(&gb, config, len*8);
105	audio_mux_version = get_bits(&gb, 1);
106	same_time_framing = get_bits(&gb, 1);
107	skip_bits(&gb, 6); /* num_sub_frames */
108	num_programs = get_bits(&gb, 4);
109	num_layers = get_bits(&gb, 3);
110	if (audio_mux_version != 0 || same_time_framing != 1 || num_programs != 0 ||
111	num_layers != 0) {
112	avpriv_report_missing_feature(NULL, "LATM config (%d,%d,%d,%d)",
113	audio_mux_version, same_time_framing,
114	num_programs, num_layers);
115	ret = AVERROR_PATCHWELCOME;
116	goto end;
117	}
118	av_freep(&st->codecpar->extradata);
119	if (ff_alloc_extradata(st->codecpar, (get_bits_left(&gb) + 7)/8)) {
120	ret = AVERROR(ENOMEM);
121	goto end;
122	}
123	for (i = 0; i < st->codecpar->extradata_size; i++)
124	st->codecpar->extradata[i] = get_bits(&gb, 8);
125
126	end:
127	av_free(config);
128	return ret;
129	}
130
131	static int parse_fmtp(AVFormatContext *s,
132	AVStream *stream, PayloadContext *data,
133	const char *attr, const char *value)
134	{
135	int res;
136
137	if (!strcmp(attr, "config")) {
138	res = parse_fmtp_config(stream, value);
139	if (res < 0)
140	return res;
141	} else if (!strcmp(attr, "cpresent")) {
142	int cpresent = atoi(value);
143	if (cpresent != 0)
144	avpriv_request_sample(s,
145	"RTP MP4A-LATM with in-band configuration");
146	}
147
148	return 0;
149	}
150
151	static int latm_parse_sdp_line(AVFormatContext *s, int st_index,
152	PayloadContext *data, const char *line)
153	{
154	const char *p;
155
156	if (st_index < 0)
157	return 0;
158
159	if (av_strstart(line, "fmtp:", &p))
160	return ff_parse_fmtp(s, s->streams[st_index], data, p, parse_fmtp);
161
162	return 0;
163	}
164
165	RTPDynamicProtocolHandler ff_mp4a_latm_dynamic_handler = {
166	.enc_name = "MP4A-LATM",
167	.codec_type = AVMEDIA_TYPE_AUDIO,
168	.codec_id = AV_CODEC_ID_AAC,
169	.priv_data_size = sizeof(PayloadContext),
170	.parse_sdp_a_line = latm_parse_sdp_line,
171	.close = latm_close_context,
172	.parse_packet = latm_parse_packet,
173	};
174