blob: 48b2d9cf98b4bb40b6d48454bb631c6ff4e16f61
1 | /* |
2 | * RTP parser for AC3 payload format (RFC 4184) |
3 | * Copyright (c) 2015 Gilles Chanteperdrix <gch@xenomai.org> |
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 "avformat.h" |
23 | #include "avio_internal.h" |
24 | #include "rtpdec_formats.h" |
25 | |
26 | #define RTP_AC3_PAYLOAD_HEADER_SIZE 2 |
27 | |
28 | struct PayloadContext { |
29 | unsigned nr_frames; |
30 | unsigned last_frame; |
31 | uint32_t timestamp; |
32 | AVIOContext *fragment; |
33 | }; |
34 | |
35 | static void ac3_close_context(PayloadContext *data) |
36 | { |
37 | ffio_free_dyn_buf(&data->fragment); |
38 | } |
39 | |
40 | static int ac3_handle_packet(AVFormatContext *ctx, PayloadContext *data, |
41 | AVStream *st, AVPacket *pkt, uint32_t *timestamp, |
42 | const uint8_t *buf, int len, uint16_t seq, |
43 | int flags) |
44 | { |
45 | unsigned frame_type; |
46 | unsigned nr_frames; |
47 | int err; |
48 | |
49 | if (len < RTP_AC3_PAYLOAD_HEADER_SIZE + 1) { |
50 | av_log(ctx, AV_LOG_ERROR, "Invalid %d bytes packet\n", len); |
51 | return AVERROR_INVALIDDATA; |
52 | } |
53 | |
54 | frame_type = buf[0] & 0x3; |
55 | nr_frames = buf[1]; |
56 | buf += RTP_AC3_PAYLOAD_HEADER_SIZE; |
57 | len -= RTP_AC3_PAYLOAD_HEADER_SIZE; |
58 | |
59 | switch (frame_type) { |
60 | case 0: /* One or more complete frames */ |
61 | if (!nr_frames) { |
62 | av_log(ctx, AV_LOG_ERROR, "Invalid AC3 packet data\n"); |
63 | return AVERROR_INVALIDDATA; |
64 | } |
65 | if (av_new_packet(pkt, len)) { |
66 | av_log(ctx, AV_LOG_ERROR, "Out of memory.\n"); |
67 | return AVERROR(ENOMEM); |
68 | } |
69 | |
70 | pkt->stream_index = st->index; |
71 | memcpy(pkt->data, buf, len); |
72 | return 0; |
73 | |
74 | case 1: |
75 | case 2: /* First fragment */ |
76 | ffio_free_dyn_buf(&data->fragment); |
77 | |
78 | data->last_frame = 1; |
79 | data->nr_frames = nr_frames; |
80 | err = avio_open_dyn_buf(&data->fragment); |
81 | if (err < 0) |
82 | return err; |
83 | |
84 | avio_write(data->fragment, buf, len); |
85 | data->timestamp = *timestamp; |
86 | return AVERROR(EAGAIN); |
87 | |
88 | case 3: /* Fragment other than first */ |
89 | if (!data->fragment) { |
90 | av_log(ctx, AV_LOG_WARNING, |
91 | "Received packet without a start fragment; dropping.\n"); |
92 | return AVERROR(EAGAIN); |
93 | } |
94 | if (nr_frames != data->nr_frames || |
95 | data->timestamp != *timestamp) { |
96 | ffio_free_dyn_buf(&data->fragment); |
97 | av_log(ctx, AV_LOG_ERROR, "Invalid packet received\n"); |
98 | return AVERROR_INVALIDDATA; |
99 | } |
100 | |
101 | avio_write(data->fragment, buf, len); |
102 | data->last_frame++; |
103 | } |
104 | |
105 | if (!(flags & RTP_FLAG_MARKER)) |
106 | return AVERROR(EAGAIN); |
107 | |
108 | if (data->last_frame != data->nr_frames) { |
109 | ffio_free_dyn_buf(&data->fragment); |
110 | av_log(ctx, AV_LOG_ERROR, "Missed %d packets\n", |
111 | data->nr_frames - data->last_frame); |
112 | return AVERROR_INVALIDDATA; |
113 | } |
114 | |
115 | err = ff_rtp_finalize_packet(pkt, &data->fragment, st->index); |
116 | if (err < 0) { |
117 | av_log(ctx, AV_LOG_ERROR, |
118 | "Error occurred when getting fragment buffer.\n"); |
119 | return err; |
120 | } |
121 | |
122 | return 0; |
123 | } |
124 | |
125 | RTPDynamicProtocolHandler ff_ac3_dynamic_handler = { |
126 | .enc_name = "ac3", |
127 | .codec_type = AVMEDIA_TYPE_AUDIO, |
128 | .codec_id = AV_CODEC_ID_AC3, |
129 | .need_parsing = AVSTREAM_PARSE_FULL, |
130 | .priv_data_size = sizeof(PayloadContext), |
131 | .close = ac3_close_context, |
132 | .parse_packet = ac3_handle_packet, |
133 | }; |
134 |