mirror of https://git.ffmpeg.org/ffmpeg.git
134 lines
4.1 KiB
C
134 lines
4.1 KiB
C
/*
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* RTP parser for AC3 payload format (RFC 4184)
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* Copyright (c) 2015 Gilles Chanteperdrix <gch@xenomai.org>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avformat.h"
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#include "avio_internal.h"
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#include "rtpdec_formats.h"
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#define RTP_AC3_PAYLOAD_HEADER_SIZE 2
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struct PayloadContext {
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unsigned nr_frames;
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unsigned last_frame;
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uint32_t timestamp;
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AVIOContext *fragment;
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};
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static void ac3_close_context(PayloadContext *data)
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{
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ffio_free_dyn_buf(&data->fragment);
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}
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static int ac3_handle_packet(AVFormatContext *ctx, PayloadContext *data,
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AVStream *st, AVPacket *pkt, uint32_t *timestamp,
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const uint8_t *buf, int len, uint16_t seq,
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int flags)
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{
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unsigned frame_type;
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unsigned nr_frames;
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int err;
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if (len < RTP_AC3_PAYLOAD_HEADER_SIZE + 1) {
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av_log(ctx, AV_LOG_ERROR, "Invalid %d bytes packet\n", len);
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return AVERROR_INVALIDDATA;
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}
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frame_type = buf[0] & 0x3;
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nr_frames = buf[1];
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buf += RTP_AC3_PAYLOAD_HEADER_SIZE;
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len -= RTP_AC3_PAYLOAD_HEADER_SIZE;
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switch (frame_type) {
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case 0: /* One or more complete frames */
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if (!nr_frames) {
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av_log(ctx, AV_LOG_ERROR, "Invalid AC3 packet data\n");
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return AVERROR_INVALIDDATA;
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}
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if ((err = av_new_packet(pkt, len)) < 0) {
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av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
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return err;
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}
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pkt->stream_index = st->index;
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memcpy(pkt->data, buf, len);
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return 0;
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case 1:
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case 2: /* First fragment */
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ffio_free_dyn_buf(&data->fragment);
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data->last_frame = 1;
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data->nr_frames = nr_frames;
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err = avio_open_dyn_buf(&data->fragment);
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if (err < 0)
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return err;
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avio_write(data->fragment, buf, len);
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data->timestamp = *timestamp;
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return AVERROR(EAGAIN);
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case 3: /* Fragment other than first */
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if (!data->fragment) {
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av_log(ctx, AV_LOG_WARNING,
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"Received packet without a start fragment; dropping.\n");
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return AVERROR(EAGAIN);
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}
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if (nr_frames != data->nr_frames ||
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data->timestamp != *timestamp) {
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ffio_free_dyn_buf(&data->fragment);
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av_log(ctx, AV_LOG_ERROR, "Invalid packet received\n");
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return AVERROR_INVALIDDATA;
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}
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avio_write(data->fragment, buf, len);
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data->last_frame++;
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}
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if (!(flags & RTP_FLAG_MARKER))
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return AVERROR(EAGAIN);
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if (data->last_frame != data->nr_frames) {
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ffio_free_dyn_buf(&data->fragment);
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av_log(ctx, AV_LOG_ERROR, "Missed %d packets\n",
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data->nr_frames - data->last_frame);
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return AVERROR_INVALIDDATA;
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}
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err = ff_rtp_finalize_packet(pkt, &data->fragment, st->index);
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if (err < 0) {
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av_log(ctx, AV_LOG_ERROR,
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"Error occurred when getting fragment buffer.\n");
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return err;
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}
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return 0;
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}
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const RTPDynamicProtocolHandler ff_ac3_dynamic_handler = {
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.enc_name = "ac3",
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.codec_type = AVMEDIA_TYPE_AUDIO,
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.codec_id = AV_CODEC_ID_AC3,
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.need_parsing = AVSTREAM_PARSE_FULL,
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.priv_data_size = sizeof(PayloadContext),
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.close = ac3_close_context,
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.parse_packet = ac3_handle_packet,
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};
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