aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/rtpdec_qcelp.c
blob: ceae50426ba0774d8c5584138cf90ac435216867 (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
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
/**
 * RTP Depacketization of QCELP/PureVoice, RFC 2658
 * Copyright (c) 2010 Martin Storsjo
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "rtpdec_formats.h"

static const uint8_t frame_sizes[] = {
    1, 4, 8, 17, 35
};

typedef struct {
    int pos;
    int size;
    /* The largest frame is 35 bytes, only 10 frames are allowed per
     * packet, and we return the first one immediately, so allocate
     * space for 9 frames */
    uint8_t data[35*9];
} InterleavePacket;

struct PayloadContext {
    int interleave_size;
    int interleave_index;
    InterleavePacket group[6];
    int group_finished;

    /* The maximum packet size, 10 frames of 35 bytes each, and one
     * packet header byte. */
    uint8_t  next_data[1 + 35*10];
    int      next_size;
    uint32_t next_timestamp;
};

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

static void qcelp_free_context(PayloadContext *data)
{
    av_free(data);
}

static int return_stored_frame(AVFormatContext *ctx, PayloadContext *data,
                               AVStream *st, AVPacket *pkt, uint32_t *timestamp,
                               const uint8_t *buf, int len);

static int store_packet(AVFormatContext *ctx, PayloadContext *data,
                        AVStream *st, AVPacket *pkt, uint32_t *timestamp,
                        const uint8_t *buf, int len)
{
    int interleave_size, interleave_index;
    int frame_size, ret;
    InterleavePacket* ip;

    if (len < 2)
        return AVERROR_INVALIDDATA;

    interleave_size  = buf[0] >> 3 & 7;
    interleave_index = buf[0]      & 7;

    if (interleave_size > 5) {
        av_log(ctx, AV_LOG_ERROR, "Invalid interleave size %d\n",
                                   interleave_size);
        return AVERROR_INVALIDDATA;
    }
    if (interleave_index > interleave_size) {
        av_log(ctx, AV_LOG_ERROR, "Invalid interleave index %d/%d\n",
                                   interleave_index, interleave_size);
        return AVERROR_INVALIDDATA;
    }
    if (interleave_size != data->interleave_size) {
        int i;
        /* First packet, or changed interleave size */
        data->interleave_size = interleave_size;
        data->interleave_index = 0;
        for (i = 0; i < 6; i++)
            data->group[i].size = 0;
    }

    if (interleave_index < data->interleave_index) {
        /* Wrapped around - missed the last packet of the previous group. */
        if (data->group_finished) {
            /* No more data in the packets in this interleaving group, just
             * start processing the next one */
            data->interleave_index = 0;
        } else {
            /* Stash away the current packet, emit everything we have of the
             * previous group. */
            for (; data->interleave_index <= interleave_size;
                 data->interleave_index++)
                data->group[data->interleave_index].size = 0;

            if (len > sizeof(data->next_data))
                return AVERROR_INVALIDDATA;
            memcpy(data->next_data, buf, len);
            data->next_size = len;
            data->next_timestamp = *timestamp;
            *timestamp = RTP_NOTS_VALUE;

            data->interleave_index = 0;
            return return_stored_frame(ctx, data, st, pkt, timestamp, buf, len);
        }
    }
    if (interleave_index > data->interleave_index) {
        /* We missed a packet */
        for (; data->interleave_index < interleave_index;
             data->interleave_index++)
            data->group[data->interleave_index].size = 0;
    }
    data->interleave_index = interleave_index;

    if (buf[1] >= FF_ARRAY_ELEMS(frame_sizes))
        return AVERROR_INVALIDDATA;
    frame_size = frame_sizes[buf[1]];
    if (1 + frame_size > len)
        return AVERROR_INVALIDDATA;

    if (len - 1 - frame_size > sizeof(data->group[0].data))
        return AVERROR_INVALIDDATA;

    if ((ret = av_new_packet(pkt, frame_size)) < 0)
        return ret;
    memcpy(pkt->data, &buf[1], frame_size);
    pkt->stream_index = st->index;

    ip = &data->group[data->interleave_index];
    ip->size = len - 1 - frame_size;
    ip->pos = 0;
    memcpy(ip->data, &buf[1 + frame_size], ip->size);
    /* Each packet must contain the same number of frames according to the
     * RFC. If there's no data left in this packet, there shouldn't be any
     * in any of the other frames in the interleaving group either. */
    data->group_finished = ip->size == 0;

    if (interleave_index == interleave_size) {
        data->interleave_index = 0;
        return !data->group_finished;
    } else {
        data->interleave_index++;
        return 0;
    }
}

static int return_stored_frame(AVFormatContext *ctx, PayloadContext *data,
                               AVStream *st, AVPacket *pkt, uint32_t *timestamp,
                               const uint8_t *buf, int len)
{
    InterleavePacket* ip = &data->group[data->interleave_index];
    int frame_size, ret;

    if (data->group_finished && data->interleave_index == 0) {
        *timestamp = data->next_timestamp;
        ret = store_packet(ctx, data, st, pkt, timestamp, data->next_data,
                           data->next_size);
        data->next_size = 0;
        return ret;
    }

    if (ip->size == 0) {
        /* No stored data for this interleave block, output an empty packet */
        if ((ret = av_new_packet(pkt, 1)) < 0)
            return ret;
        pkt->data[0] = 0; // Blank - could also be 14, Erasure
    } else {
        if (ip->pos >= ip->size)
            return AVERROR_INVALIDDATA;
        if (ip->data[ip->pos] >= FF_ARRAY_ELEMS(frame_sizes))
            return AVERROR_INVALIDDATA;
        frame_size = frame_sizes[ip->data[ip->pos]];
        if (ip->pos + frame_size > ip->size)
            return AVERROR_INVALIDDATA;

        if ((ret = av_new_packet(pkt, frame_size)) < 0)
            return ret;
        memcpy(pkt->data, &ip->data[ip->pos], frame_size);

        ip->pos += frame_size;
        data->group_finished = ip->pos >= ip->size;
    }
    pkt->stream_index = st->index;

    if (data->interleave_index == data->interleave_size) {
        data->interleave_index = 0;
        if (!data->group_finished)
            return 1;
        else
            return data->next_size > 0;
    } else {
        data->interleave_index++;
        return 1;
    }
}

static int qcelp_parse_packet(AVFormatContext *ctx, PayloadContext *data,
                              AVStream *st, AVPacket *pkt, uint32_t *timestamp,
                              const uint8_t *buf, int len, int flags)
{
    if (buf)
        return store_packet(ctx, data, st, pkt, timestamp, buf, len);
    else
        return return_stored_frame(ctx, data, st, pkt, timestamp, buf, len);
}

RTPDynamicProtocolHandler ff_qcelp_dynamic_handler = {
    .enc_name           = "x-Purevoice",
    .codec_type         = AVMEDIA_TYPE_AUDIO,
    .codec_id           = CODEC_ID_QCELP,
    .static_payload_id  = 12,
    .open               = qcelp_new_context,
    .close              = qcelp_free_context,
    .parse_packet       = qcelp_parse_packet
};