From 5e5583efe41662294c5e1b76499ba338557f808d Mon Sep 17 00:00:00 2001 From: Gilles Chanteperdrix Date: Fri, 13 Feb 2015 22:51:34 +0100 Subject: libavformat: add AC3 RTP depacketization (RFC 4184) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Martin Storsjö --- libavformat/rtpdec_ac3.c | 157 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 157 insertions(+) create mode 100644 libavformat/rtpdec_ac3.c (limited to 'libavformat/rtpdec_ac3.c') diff --git a/libavformat/rtpdec_ac3.c b/libavformat/rtpdec_ac3.c new file mode 100644 index 0000000000..a5943892c5 --- /dev/null +++ b/libavformat/rtpdec_ac3.c @@ -0,0 +1,157 @@ +/* + * RTP parser for AC3 payload format (RFC 4184) + * Copyright (c) 2015 Gilles Chanteperdrix + * + * This file is part of Libav. + * + * Libav 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. + * + * Libav 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 Libav; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "avformat.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 av_cold int ac3_init(AVFormatContext *s, int st_index, + PayloadContext *data) +{ + if (st_index < 0) + return 0; + s->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL; + return 0; +} + +static PayloadContext *ac3_new_context(void) +{ + return av_mallocz(sizeof(PayloadContext)); +} + +static void free_fragment(PayloadContext *data) +{ + if (data->fragment) { + uint8_t *p; + avio_close_dyn_buf(data->fragment, &p); + av_free(p); + data->fragment = NULL; + } +} + +static void ac3_free_context(PayloadContext *data) +{ + free_fragment(data); + av_free(data); +} + +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 */ + free_fragment(data); + + 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) { + free_fragment(data); + 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) { + free_fragment(data); + 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, + .init = ac3_init, + .alloc = ac3_new_context, + .free = ac3_free_context, + .parse_packet = ac3_handle_packet, +}; -- cgit v1.2.3