| 1 | /* |
| 2 | * RTP Depacketization of MP4A-LATM, RFC 3016 |
| 3 | * Copyright (c) 2010 Martin Storsjo |
| 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 "rtpdec_formats.h" |
| 23 | #include "internal.h" |
| 24 | #include "libavutil/avstring.h" |
| 25 | #include "libavcodec/get_bits.h" |
| 26 | |
| 27 | struct PayloadContext { |
| 28 | AVIOContext *dyn_buf; |
| 29 | uint8_t *buf; |
| 30 | int pos, len; |
| 31 | uint32_t timestamp; |
| 32 | }; |
| 33 | |
| 34 | static PayloadContext *latm_new_context(void) |
| 35 | { |
| 36 | return av_mallocz(sizeof(PayloadContext)); |
| 37 | } |
| 38 | |
| 39 | static void latm_free_context(PayloadContext *data) |
| 40 | { |
| 41 | if (!data) |
| 42 | return; |
| 43 | if (data->dyn_buf) { |
| 44 | uint8_t *p; |
| 45 | avio_close_dyn_buf(data->dyn_buf, &p); |
| 46 | av_free(p); |
| 47 | } |
| 48 | av_free(data->buf); |
| 49 | av_free(data); |
| 50 | } |
| 51 | |
| 52 | static int latm_parse_packet(AVFormatContext *ctx, PayloadContext *data, |
| 53 | AVStream *st, AVPacket *pkt, uint32_t *timestamp, |
| 54 | const uint8_t *buf, int len, uint16_t seq, |
| 55 | 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_programs, num_layers; |
| 112 | |
| 113 | /* Pad this buffer, too, to avoid out of bounds reads with get_bits below */ |
| 114 | config = av_mallocz(len + FF_INPUT_BUFFER_PADDING_SIZE); |
| 115 | if (!config) |
| 116 | return AVERROR(ENOMEM); |
| 117 | ff_hex_to_data(config, value); |
| 118 | init_get_bits(&gb, config, len*8); |
| 119 | audio_mux_version = get_bits(&gb, 1); |
| 120 | same_time_framing = get_bits(&gb, 1); |
| 121 | skip_bits(&gb, 6); /* num_sub_frames */ |
| 122 | num_programs = get_bits(&gb, 4); |
| 123 | num_layers = get_bits(&gb, 3); |
| 124 | if (audio_mux_version != 0 || same_time_framing != 1 || num_programs != 0 || |
| 125 | num_layers != 0) { |
| 126 | av_log(NULL, AV_LOG_WARNING, "Unsupported LATM config (%d,%d,%d,%d)\n", |
| 127 | audio_mux_version, same_time_framing, |
| 128 | num_programs, num_layers); |
| 129 | ret = AVERROR_PATCHWELCOME; |
| 130 | goto end; |
| 131 | } |
| 132 | av_freep(&st->codec->extradata); |
| 133 | if (ff_alloc_extradata(st->codec, (get_bits_left(&gb) + 7)/8)) { |
| 134 | ret = AVERROR(ENOMEM); |
| 135 | goto end; |
| 136 | } |
| 137 | for (i = 0; i < st->codec->extradata_size; i++) |
| 138 | st->codec->extradata[i] = get_bits(&gb, 8); |
| 139 | |
| 140 | end: |
| 141 | av_free(config); |
| 142 | return ret; |
| 143 | } |
| 144 | |
| 145 | static int parse_fmtp(AVFormatContext *s, |
| 146 | AVStream *stream, PayloadContext *data, |
| 147 | char *attr, char *value) |
| 148 | { |
| 149 | int res; |
| 150 | |
| 151 | if (!strcmp(attr, "config")) { |
| 152 | res = parse_fmtp_config(stream, value); |
| 153 | if (res < 0) |
| 154 | return res; |
| 155 | } else if (!strcmp(attr, "cpresent")) { |
| 156 | int cpresent = atoi(value); |
| 157 | if (cpresent != 0) |
| 158 | avpriv_request_sample(s, |
| 159 | "RTP MP4A-LATM with in-band configuration"); |
| 160 | } |
| 161 | |
| 162 | return 0; |
| 163 | } |
| 164 | |
| 165 | static int latm_parse_sdp_line(AVFormatContext *s, int st_index, |
| 166 | PayloadContext *data, const char *line) |
| 167 | { |
| 168 | const char *p; |
| 169 | |
| 170 | if (st_index < 0) |
| 171 | return 0; |
| 172 | |
| 173 | if (av_strstart(line, "fmtp:", &p)) |
| 174 | return ff_parse_fmtp(s, 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 = AV_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 | }; |