Statistics
| Branch: | Revision:

ffmpeg / libavformat / rtpdec_latm.c @ 9261e6cf

History | View | Annotate | Download (5.66 KB)

1
/**
2
 * RTP Depacketization of MP4A-LATM, RFC 3016
3
 * Copyright (c) 2010 Martin Storsjo
4
 *
5
 * This file is part of Libav.
6
 *
7
 * Libav 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
 * Libav 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 Libav; if not, write to the Free Software
19
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20
 */
21

    
22
#include "rtpdec_formats.h"
23
#include "internal.h"
24
#include "libavutil/avstring.h"
25
#include "libavcodec/get_bits.h"
26
#include <strings.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 PayloadContext *latm_new_context(void)
36
{
37
    return av_mallocz(sizeof(PayloadContext));
38
}
39

    
40
static void latm_free_context(PayloadContext *data)
41
{
42
    if (!data)
43
        return;
44
    if (data->dyn_buf) {
45
        uint8_t *p;
46
        avio_close_dyn_buf(data->dyn_buf, &p);
47
        av_free(p);
48
    }
49
    av_free(data->buf);
50
    av_free(data);
51
}
52

    
53
static int latm_parse_packet(AVFormatContext *ctx, PayloadContext *data,
54
                             AVStream *st, AVPacket *pkt, uint32_t *timestamp,
55
                             const uint8_t *buf, int len, int flags)
56
{
57
    int ret, cur_len;
58

    
59
    if (buf) {
60
        if (!data->dyn_buf || data->timestamp != *timestamp) {
61
            av_freep(&data->buf);
62
            if (data->dyn_buf)
63
                avio_close_dyn_buf(data->dyn_buf, &data->buf);
64
            data->dyn_buf = NULL;
65
            av_freep(&data->buf);
66

    
67
            data->timestamp = *timestamp;
68
            if ((ret = avio_open_dyn_buf(&data->dyn_buf)) < 0)
69
                return ret;
70
        }
71
        avio_write(data->dyn_buf, buf, len);
72

    
73
        if (!(flags & RTP_FLAG_MARKER))
74
            return AVERROR(EAGAIN);
75
        av_free(data->buf);
76
        data->len = avio_close_dyn_buf(data->dyn_buf, &data->buf);
77
        data->dyn_buf = NULL;
78
        data->pos = 0;
79
    }
80

    
81
    if (!data->buf) {
82
        av_log(ctx, AV_LOG_ERROR, "No data available yet\n");
83
        return AVERROR(EIO);
84
    }
85

    
86
    cur_len = 0;
87
    while (data->pos < data->len) {
88
        uint8_t val = data->buf[data->pos++];
89
        cur_len += val;
90
        if (val != 0xff)
91
            break;
92
    }
93
    if (data->pos + cur_len > data->len) {
94
        av_log(ctx, AV_LOG_ERROR, "Malformed LATM packet\n");
95
        return AVERROR(EIO);
96
    }
97

    
98
    if ((ret = av_new_packet(pkt, cur_len)) < 0)
99
        return ret;
100
    memcpy(pkt->data, data->buf + data->pos, cur_len);
101
    data->pos += cur_len;
102
    pkt->stream_index = st->index;
103
    return data->pos < data->len;
104
}
105

    
106
static int parse_fmtp_config(AVStream *st, char *value)
107
{
108
    int len = ff_hex_to_data(NULL, value), i, ret = 0;
109
    GetBitContext gb;
110
    uint8_t *config;
111
    int audio_mux_version, same_time_framing, num_sub_frames,
112
        num_programs, num_layers;
113

    
114
    /* Pad this buffer, too, to avoid out of bounds reads with get_bits below */
115
    config = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE);
116
    if (!config)
117
        return AVERROR(ENOMEM);
118
    ff_hex_to_data(config, value);
119
    init_get_bits(&gb, config, len*8);
120
    audio_mux_version = get_bits(&gb, 1);
121
    same_time_framing = get_bits(&gb, 1);
122
    num_sub_frames    = get_bits(&gb, 6);
123
    num_programs      = get_bits(&gb, 4);
124
    num_layers        = get_bits(&gb, 3);
125
    if (audio_mux_version != 0 || same_time_framing != 1 || num_programs != 0 ||
126
        num_layers != 0) {
127
        av_log(NULL, AV_LOG_WARNING, "Unsupported LATM config (%d,%d,%d,%d)\n",
128
                                     audio_mux_version, same_time_framing,
129
                                     num_programs, num_layers);
130
        ret = AVERROR_PATCHWELCOME;
131
        goto end;
132
    }
133
    av_freep(&st->codec->extradata);
134
    st->codec->extradata_size = (get_bits_left(&gb) + 7)/8;
135
    st->codec->extradata = av_mallocz(st->codec->extradata_size +
136
                                      FF_INPUT_BUFFER_PADDING_SIZE);
137
    if (!st->codec->extradata) {
138
        ret = AVERROR(ENOMEM);
139
        goto end;
140
    }
141
    for (i = 0; i < st->codec->extradata_size; i++)
142
        st->codec->extradata[i] = get_bits(&gb, 8);
143

    
144
end:
145
    av_free(config);
146
    return ret;
147
}
148

    
149
static int parse_fmtp(AVStream *stream, PayloadContext *data,
150
                      char *attr, char *value)
151
{
152
    int res;
153

    
154
    if (!strcmp(attr, "config")) {
155
        res = parse_fmtp_config(stream, value);
156
        if (res < 0)
157
            return res;
158
    } else if (!strcmp(attr, "cpresent")) {
159
        int cpresent = atoi(value);
160
        if (cpresent != 0)
161
            av_log_missing_feature(NULL, "RTP MP4A-LATM with in-band "
162
                                         "configuration", 1);
163
    }
164

    
165
    return 0;
166
}
167

    
168
static int latm_parse_sdp_line(AVFormatContext *s, int st_index,
169
                               PayloadContext *data, const char *line)
170
{
171
    const char *p;
172

    
173
    if (av_strstart(line, "fmtp:", &p))
174
        return ff_parse_fmtp(s->streams[st_index], data, p, parse_fmtp);
175

    
176
    return 0;
177
}
178

    
179
RTPDynamicProtocolHandler ff_mp4a_latm_dynamic_handler = {
180
    .enc_name           = "MP4A-LATM",
181
    .codec_type         = AVMEDIA_TYPE_AUDIO,
182
    .codec_id           = CODEC_ID_AAC,
183
    .parse_sdp_a_line   = latm_parse_sdp_line,
184
    .alloc              = latm_new_context,
185
    .free               = latm_free_context,
186
    .parse_packet       = latm_parse_packet
187
};