aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/rtpdec_latm.c
blob: 6ab3f783d724a28d01a1f347984fdca0bb7a1482 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
/*
 * RTP Depacketization of MP4A-LATM, RFC 3016
 * Copyright (c) 2010 Martin Storsjo
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "rtpdec_formats.h"
#include "internal.h"
#include "libavutil/avstring.h"
#include "libavcodec/get_bits.h"

struct PayloadContext {
    AVIOContext *dyn_buf;
    uint8_t *buf;
    int pos, len;
    uint32_t timestamp;
};

static PayloadContext *latm_new_context(void)
{
    return av_mallocz(sizeof(PayloadContext));
}

static void latm_free_context(PayloadContext *data)
{
    if (!data)
        return;
    if (data->dyn_buf) {
        uint8_t *p;
        avio_close_dyn_buf(data->dyn_buf, &p);
        av_free(p);
    }
    av_free(data->buf);
    av_free(data);
}

static int 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)
{
    int ret, cur_len;

    if (buf) {
        if (!data->dyn_buf || data->timestamp != *timestamp) {
            av_freep(&data->buf);
            if (data->dyn_buf)
                avio_close_dyn_buf(data->dyn_buf, &data->buf);
            data->dyn_buf = NULL;
            av_freep(&data->buf);

            data->timestamp = *timestamp;
            if ((ret = avio_open_dyn_buf(&data->dyn_buf)) < 0)
                return ret;
        }
        avio_write(data->dyn_buf, buf, len);

        if (!(flags & RTP_FLAG_MARKER))
            return AVERROR(EAGAIN);
        av_free(data->buf);
        data->len = avio_close_dyn_buf(data->dyn_buf, &data->buf);
        data->dyn_buf = NULL;
        data->pos = 0;
    }

    if (!data->buf) {
        av_log(ctx, AV_LOG_ERROR, "No data available yet\n");
        return AVERROR(EIO);
    }

    cur_len = 0;
    while (data->pos < data->len) {
        uint8_t val = data->buf[data->pos++];
        cur_len += val;
        if (val != 0xff)
            break;
    }
    if (data->pos + cur_len > data->len) {
        av_log(ctx, AV_LOG_ERROR, "Malformed LATM packet\n");
        return AVERROR(EIO);
    }

    if ((ret = av_new_packet(pkt, cur_len)) < 0)
        return ret;
    memcpy(pkt->data, data->buf + data->pos, cur_len);
    data->pos += cur_len;
    pkt->stream_index = st->index;
    return data->pos < data->len;
}

static int parse_fmtp_config(AVStream *st, char *value)
{
    int len = ff_hex_to_data(NULL, value), i, ret = 0;
    GetBitContext gb;
    uint8_t *config;
    int audio_mux_version, same_time_framing, num_programs, num_layers;

    /* Pad this buffer, too, to avoid out of bounds reads with get_bits below */
    config = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE);
    if (!config)
        return AVERROR(ENOMEM);
    ff_hex_to_data(config, value);
    init_get_bits(&gb, config, len*8);
    audio_mux_version = get_bits(&gb, 1);
    same_time_framing = get_bits(&gb, 1);
    skip_bits(&gb, 6); /* num_sub_frames */
    num_programs      = get_bits(&gb, 4);
    num_layers        = get_bits(&gb, 3);
    if (audio_mux_version != 0 || same_time_framing != 1 || num_programs != 0 ||
        num_layers != 0) {
        av_log(NULL, AV_LOG_WARNING, "Unsupported LATM config (%d,%d,%d,%d)\n",
                                     audio_mux_version, same_time_framing,
                                     num_programs, num_layers);
        ret = AVERROR_PATCHWELCOME;
        goto end;
    }
    av_freep(&st->codec->extradata);
    st->codec->extradata_size = (get_bits_left(&gb) + 7)/8;
    st->codec->extradata = av_mallocz(st->codec->extradata_size +
                                      FF_INPUT_BUFFER_PADDING_SIZE);
    if (!st->codec->extradata) {
        ret = AVERROR(ENOMEM);
        goto end;
    }
    for (i = 0; i < st->codec->extradata_size; i++)
        st->codec->extradata[i] = get_bits(&gb, 8);

end:
    av_free(config);
    return ret;
}

static int parse_fmtp(AVFormatContext *s,
                      AVStream *stream, PayloadContext *data,
                      char *attr, char *value)
{
    int res;

    if (!strcmp(attr, "config")) {
        res = parse_fmtp_config(stream, value);
        if (res < 0)
            return res;
    } else if (!strcmp(attr, "cpresent")) {
        int cpresent = atoi(value);
        if (cpresent != 0)
            avpriv_request_sample(s,
                                  "RTP MP4A-LATM with in-band configuration");
    }

    return 0;
}

static int latm_parse_sdp_line(AVFormatContext *s, int st_index,
                               PayloadContext *data, const char *line)
{
    const char *p;

    if (st_index < 0)
        return 0;

    if (av_strstart(line, "fmtp:", &p))
        return ff_parse_fmtp(s, s->streams[st_index], data, p, parse_fmtp);

    return 0;
}

RTPDynamicProtocolHandler ff_mp4a_latm_dynamic_handler = {
    .enc_name           = "MP4A-LATM",
    .codec_type         = AVMEDIA_TYPE_AUDIO,
    .codec_id           = AV_CODEC_ID_AAC,
    .parse_sdp_a_line   = latm_parse_sdp_line,
    .alloc              = latm_new_context,
    .free               = latm_free_context,
    .parse_packet       = latm_parse_packet
};