1/*
2 * RTP parser for DV payload format (RFC 6469)
3 * Copyright (c) 2015 Thomas Volkert <thomas@homer-conferencing.com>
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 "libavutil/avstring.h"
23
24#include "avio_internal.h"
25#include "rtpdec.h"
26
27struct PayloadContext {
28    AVIOContext *buf;
29    uint32_t    timestamp;
30    int         bundled_audio;
31};
32
33static av_cold void dv_close_context(PayloadContext *data)
34{
35    ffio_free_dyn_buf(&data->buf);
36}
37
38static av_cold int dv_sdp_parse_fmtp_config(AVFormatContext *s,
39                                            AVStream *stream,
40                                            PayloadContext *dv_data,
41                                            const char *attr, const char *value)
42{
43    /* does the DV stream include audio? */
44    if (!strcmp(attr, "audio") && !strcmp(value, "bundled"))
45        dv_data->bundled_audio = 1;
46
47    /* extract the DV profile */
48    if (!strcmp(attr, "encode")) {
49        /* SD-VCR/525-60 */
50        /* SD-VCR/625-50 */
51        /* HD-VCR/1125-60 */
52        /* HD-VCR/1250-50 */
53        /* SDL-VCR/525-60 */
54        /* SDL-VCR/625-50 */
55        /* 314M-25/525-60 */
56        /* 314M-25/625-50 */
57        /* 314M-50/525-60 */
58        /* 314M-50/625-50 */
59        /* 370M/1080-60i */
60        /* 370M/1080-50i */
61        /* 370M/720-60p */
62        /* 370M/720-50p */
63        /* 306M/525-60 (for backward compatibility) */
64        /* 306M/625-50 (for backward compatibility) */
65    }
66
67    return 0;
68}
69
70static av_cold int dv_parse_sdp_line(AVFormatContext *ctx, int st_index,
71                                     PayloadContext *dv_data, const char *line)
72{
73    AVStream *current_stream;
74    const char *sdp_line_ptr = line;
75
76    if (st_index < 0)
77        return 0;
78
79    current_stream = ctx->streams[st_index];
80
81    if (av_strstart(sdp_line_ptr, "fmtp:", &sdp_line_ptr)) {
82        return ff_parse_fmtp(ctx, current_stream, dv_data, sdp_line_ptr,
83                             dv_sdp_parse_fmtp_config);
84    }
85
86    return 0;
87}
88
89static int dv_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_dv_ctx,
90                            AVStream *st, AVPacket *pkt, uint32_t *timestamp,
91                            const uint8_t *buf, int len, uint16_t seq,
92                            int flags)
93{
94    int res = 0;
95
96    /* drop data of previous packets in case of non-continuous (lossy) packet stream */
97    if (rtp_dv_ctx->buf && rtp_dv_ctx->timestamp != *timestamp) {
98        ffio_free_dyn_buf(&rtp_dv_ctx->buf);
99    }
100
101    /* sanity check for size of input packet: 1 byte payload at least */
102    if (len < 1) {
103        av_log(ctx, AV_LOG_ERROR, "Too short RTP/DV packet, got %d bytes\n", len);
104        return AVERROR_INVALIDDATA;
105    }
106
107    /* start frame buffering with new dynamic buffer */
108    if (!rtp_dv_ctx->buf) {
109        res = avio_open_dyn_buf(&rtp_dv_ctx->buf);
110        if (res < 0)
111            return res;
112        /* update the timestamp in the frame packet with the one from the RTP packet */
113        rtp_dv_ctx->timestamp = *timestamp;
114    }
115
116    /* write the fragment to the dyn. buffer */
117    avio_write(rtp_dv_ctx->buf, buf, len);
118
119    /* RTP marker bit means: last fragment of current frame was received;
120       otherwise, an additional fragment is needed for the current frame */
121    if (!(flags & RTP_FLAG_MARKER))
122        return AVERROR(EAGAIN);
123
124    /* close frame buffering and create resulting A/V packet */
125    res = ff_rtp_finalize_packet(pkt, &rtp_dv_ctx->buf, st->index);
126    if (res < 0)
127        return res;
128
129    return 0;
130}
131
132const RTPDynamicProtocolHandler ff_dv_dynamic_handler = {
133    .enc_name         = "DV",
134    .codec_type       = AVMEDIA_TYPE_VIDEO,
135    .codec_id         = AV_CODEC_ID_DVVIDEO,
136    .need_parsing     = AVSTREAM_PARSE_FULL,
137    .parse_sdp_a_line = dv_parse_sdp_line,
138    .priv_data_size   = sizeof(PayloadContext),
139    .close             = dv_close_context,
140    .parse_packet     = dv_handle_packet,
141};
142