/* * RTP parser for AC3 payload format (RFC 4184) * Copyright (c) 2015 Gilles Chanteperdrix <gch@xenomai.org> * * 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 "avformat.h" #include "avio_internal.h" #include "rtpdec_formats.h" #define RTP_AC3_PAYLOAD_HEADER_SIZE 2 struct PayloadContext { unsigned nr_frames; unsigned last_frame; uint32_t timestamp; AVIOContext *fragment; }; static void ac3_close_context(PayloadContext *data) { ffio_free_dyn_buf(&data->fragment); } static int ac3_handle_packet(AVFormatContext *ctx, PayloadContext *data, AVStream *st, AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len, uint16_t seq, int flags) { unsigned frame_type; unsigned nr_frames; int err; if (len < RTP_AC3_PAYLOAD_HEADER_SIZE + 1) { av_log(ctx, AV_LOG_ERROR, "Invalid %d bytes packet\n", len); return AVERROR_INVALIDDATA; } frame_type = buf[0] & 0x3; nr_frames = buf[1]; buf += RTP_AC3_PAYLOAD_HEADER_SIZE; len -= RTP_AC3_PAYLOAD_HEADER_SIZE; switch (frame_type) { case 0: /* One or more complete frames */ if (!nr_frames) { av_log(ctx, AV_LOG_ERROR, "Invalid AC3 packet data\n"); return AVERROR_INVALIDDATA; } if (av_new_packet(pkt, len)) { av_log(ctx, AV_LOG_ERROR, "Out of memory.\n"); return AVERROR(ENOMEM); } pkt->stream_index = st->index; memcpy(pkt->data, buf, len); return 0; case 1: case 2: /* First fragment */ ffio_free_dyn_buf(&data->fragment); data->last_frame = 1; data->nr_frames = nr_frames; err = avio_open_dyn_buf(&data->fragment); if (err < 0) return err; avio_write(data->fragment, buf, len); data->timestamp = *timestamp; return AVERROR(EAGAIN); case 3: /* Fragment other than first */ if (!data->fragment) { av_log(ctx, AV_LOG_WARNING, "Received packet without a start fragment; dropping.\n"); return AVERROR(EAGAIN); } if (nr_frames != data->nr_frames || data->timestamp != *timestamp) { ffio_free_dyn_buf(&data->fragment); av_log(ctx, AV_LOG_ERROR, "Invalid packet received\n"); return AVERROR_INVALIDDATA; } avio_write(data->fragment, buf, len); data->last_frame++; } if (!(flags & RTP_FLAG_MARKER)) return AVERROR(EAGAIN); if (data->last_frame != data->nr_frames) { ffio_free_dyn_buf(&data->fragment); av_log(ctx, AV_LOG_ERROR, "Missed %d packets\n", data->nr_frames - data->last_frame); return AVERROR_INVALIDDATA; } err = ff_rtp_finalize_packet(pkt, &data->fragment, st->index); if (err < 0) { av_log(ctx, AV_LOG_ERROR, "Error occurred when getting fragment buffer.\n"); return err; } return 0; } RTPDynamicProtocolHandler ff_ac3_dynamic_handler = { .enc_name = "ac3", .codec_type = AVMEDIA_TYPE_AUDIO, .codec_id = AV_CODEC_ID_AC3, .need_parsing = AVSTREAM_PARSE_FULL, .priv_data_size = sizeof(PayloadContext), .close = ac3_close_context, .parse_packet = ac3_handle_packet, };