136 lines
4.3 KiB
C
136 lines
4.3 KiB
C
/*
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* RTP packetization for Xiph audio and video
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* Copyright (c) 2010 Josh Allmann
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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 "libavutil/avassert.h"
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#include "libavutil/intreadwrite.h"
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#include "avformat.h"
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#include "rtpenc.h"
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/**
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* Packetize Xiph frames into RTP according to
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* RFC 5215 (Vorbis) and the Theora RFC draft.
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* (http://svn.xiph.org/trunk/theora/doc/draft-ietf-avt-rtp-theora-00.txt)
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*/
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void ff_rtp_send_xiph(AVFormatContext *s1, const uint8_t *buff, int size)
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{
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RTPMuxContext *s = s1->priv_data;
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AVStream *st = s1->streams[0];
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int max_pkt_size, xdt, frag;
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uint8_t *q;
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max_pkt_size = s->max_payload_size - 6; // ident+frag+tdt/vdt+pkt_num+pkt_length
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// set xiph data type
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switch (*buff) {
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case 0x01: // vorbis id
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case 0x05: // vorbis setup
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case 0x80: // theora header
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case 0x82: // theora tables
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xdt = 1; // packed config payload
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break;
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case 0x03: // vorbis comments
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case 0x81: // theora comments
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xdt = 2; // comment payload
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break;
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default:
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xdt = 0; // raw data payload
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break;
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}
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// Set ident.
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// Probably need a non-fixed way of generating
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// this, but it has to be done in SDP and passed in from there.
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q = s->buf;
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*q++ = (RTP_XIPH_IDENT >> 16) & 0xff;
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*q++ = (RTP_XIPH_IDENT >> 8) & 0xff;
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*q++ = (RTP_XIPH_IDENT ) & 0xff;
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// set fragment
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// 0 - whole frame (possibly multiple frames)
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// 1 - first fragment
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// 2 - fragment continuation
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// 3 - last fragment
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frag = size <= max_pkt_size ? 0 : 1;
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if (!frag && !xdt) { // do we have a whole frame of raw data?
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uint8_t *end_ptr = s->buf + 6 + max_pkt_size; // what we're allowed to write
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uint8_t *ptr = s->buf_ptr + 2 + size; // what we're going to write
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int remaining = end_ptr - ptr;
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av_assert1(s->num_frames <= s->max_frames_per_packet);
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if (s->num_frames > 0 &&
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(remaining < 0 ||
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s->num_frames == s->max_frames_per_packet ||
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av_compare_ts(s->cur_timestamp - s->timestamp, st->time_base,
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s1->max_delay, AV_TIME_BASE_Q) >= 0)) {
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// send previous packets now; no room for new data, or too much delay
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ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0);
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s->num_frames = 0;
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}
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// buffer current frame to send later
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if (0 == s->num_frames)
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s->timestamp = s->cur_timestamp;
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s->num_frames++;
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// Set packet header. Normally, this is OR'd with frag and xdt,
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// but those are zero, so omitted here
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*q++ = s->num_frames;
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if (s->num_frames > 1)
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q = s->buf_ptr; // jump ahead if needed
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AV_WB16(q, size);
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q += 2;
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memcpy(q, buff, size);
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q += size;
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s->buf_ptr = q;
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return;
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} else if (s->num_frames) {
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// immediately send buffered frames if buffer is not raw data,
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// or if current frame is fragmented.
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ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0);
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}
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s->timestamp = s->cur_timestamp;
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s->num_frames = 0;
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s->buf_ptr = q;
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while (size > 0) {
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int len = (!frag || frag == 3) ? size : max_pkt_size;
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q = s->buf_ptr;
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// set packet headers
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*q++ = (frag << 6) | (xdt << 4); // num_frames = 0
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AV_WB16(q, len);
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q += 2;
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// set packet body
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memcpy(q, buff, len);
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q += len;
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buff += len;
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size -= len;
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ff_rtp_send_data(s1, s->buf, q - s->buf, 0);
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frag = size <= max_pkt_size ? 3 : 2;
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}
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}
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