247 lines
7.2 KiB
C
247 lines
7.2 KiB
C
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/*
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* Session Announcement Protocol (RFC 2974) demuxer
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* Copyright (c) 2010 Martin Storsjo
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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 "libavutil/avassert.h"
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#include "libavutil/avstring.h"
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#include "libavutil/intreadwrite.h"
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#include "network.h"
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#include "os_support.h"
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#include "internal.h"
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#include "avio_internal.h"
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#include "url.h"
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#include "rtpdec.h"
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#if HAVE_POLL_H
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#include <poll.h>
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#endif
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struct SAPState {
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URLContext *ann_fd;
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AVFormatContext *sdp_ctx;
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AVIOContext sdp_pb;
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uint16_t hash;
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char *sdp;
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int eof;
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};
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static int sap_probe(const AVProbeData *p)
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{
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if (av_strstart(p->filename, "sap:", NULL))
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return AVPROBE_SCORE_MAX;
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return 0;
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}
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static int sap_read_close(AVFormatContext *s)
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{
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struct SAPState *sap = s->priv_data;
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if (sap->sdp_ctx)
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avformat_close_input(&sap->sdp_ctx);
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ffurl_closep(&sap->ann_fd);
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av_freep(&sap->sdp);
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ff_network_close();
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return 0;
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}
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static int sap_read_header(AVFormatContext *s)
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{
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struct SAPState *sap = s->priv_data;
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char host[1024], path[1024], url[1024];
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uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
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int port;
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int ret, i;
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ff_const59 AVInputFormat* infmt;
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if (!ff_network_init())
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return AVERROR(EIO);
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av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,
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path, sizeof(path), s->url);
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if (port < 0)
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port = 9875;
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if (!host[0]) {
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/* Listen for announcements on sap.mcast.net if no host was specified */
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av_strlcpy(host, "224.2.127.254", sizeof(host));
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}
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ff_url_join(url, sizeof(url), "udp", NULL, host, port, "?localport=%d",
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port);
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ret = ffurl_open_whitelist(&sap->ann_fd, url, AVIO_FLAG_READ,
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&s->interrupt_callback, NULL,
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s->protocol_whitelist, s->protocol_blacklist, NULL);
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if (ret)
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goto fail;
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while (1) {
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int addr_type, auth_len;
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int pos;
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ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf) - 1);
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if (ret == AVERROR(EAGAIN))
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continue;
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if (ret < 0)
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goto fail;
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recvbuf[ret] = '\0'; /* Null terminate for easier parsing */
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if (ret < 8) {
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av_log(s, AV_LOG_WARNING, "Received too short packet\n");
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continue;
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}
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if ((recvbuf[0] & 0xe0) != 0x20) {
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av_log(s, AV_LOG_WARNING, "Unsupported SAP version packet "
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"received\n");
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continue;
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}
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if (recvbuf[0] & 0x04) {
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av_log(s, AV_LOG_WARNING, "Received stream deletion "
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"announcement\n");
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continue;
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}
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addr_type = recvbuf[0] & 0x10;
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auth_len = recvbuf[1];
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sap->hash = AV_RB16(&recvbuf[2]);
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pos = 4;
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if (addr_type)
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pos += 16; /* IPv6 */
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else
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pos += 4; /* IPv4 */
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pos += auth_len * 4;
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if (pos + 4 >= ret) {
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av_log(s, AV_LOG_WARNING, "Received too short packet\n");
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continue;
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}
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#define MIME "application/sdp"
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if (strcmp(&recvbuf[pos], MIME) == 0) {
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pos += strlen(MIME) + 1;
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} else if (strncmp(&recvbuf[pos], "v=0\r\n", 5) == 0) {
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// Direct SDP without a mime type
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} else {
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av_log(s, AV_LOG_WARNING, "Unsupported mime type %s\n",
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&recvbuf[pos]);
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continue;
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}
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sap->sdp = av_strdup(&recvbuf[pos]);
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if (!sap->sdp) {
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ret = AVERROR(ENOMEM);
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goto fail;
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}
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break;
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}
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av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sap->sdp);
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ffio_init_context(&sap->sdp_pb, sap->sdp, strlen(sap->sdp), 0, NULL, NULL,
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NULL, NULL);
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infmt = av_find_input_format("sdp");
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if (!infmt)
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goto fail;
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sap->sdp_ctx = avformat_alloc_context();
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if (!sap->sdp_ctx) {
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ret = AVERROR(ENOMEM);
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goto fail;
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}
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sap->sdp_ctx->max_delay = s->max_delay;
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sap->sdp_ctx->pb = &sap->sdp_pb;
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sap->sdp_ctx->interrupt_callback = s->interrupt_callback;
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if ((ret = ff_copy_whiteblacklists(sap->sdp_ctx, s)) < 0)
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goto fail;
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ret = avformat_open_input(&sap->sdp_ctx, "temp.sdp", infmt, NULL);
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if (ret < 0)
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goto fail;
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if (sap->sdp_ctx->ctx_flags & AVFMTCTX_NOHEADER)
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s->ctx_flags |= AVFMTCTX_NOHEADER;
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for (i = 0; i < sap->sdp_ctx->nb_streams; i++) {
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AVStream *st = avformat_new_stream(s, NULL);
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if (!st) {
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ret = AVERROR(ENOMEM);
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goto fail;
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}
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st->id = i;
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avcodec_parameters_copy(st->codecpar, sap->sdp_ctx->streams[i]->codecpar);
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st->time_base = sap->sdp_ctx->streams[i]->time_base;
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}
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return 0;
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fail:
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sap_read_close(s);
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return ret;
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}
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static int sap_fetch_packet(AVFormatContext *s, AVPacket *pkt)
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{
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struct SAPState *sap = s->priv_data;
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int fd = ffurl_get_file_handle(sap->ann_fd);
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int n, ret;
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struct pollfd p = {fd, POLLIN, 0};
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uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
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if (sap->eof)
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return AVERROR_EOF;
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while (1) {
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n = poll(&p, 1, 0);
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if (n <= 0 || !(p.revents & POLLIN))
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break;
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ret = ffurl_read(sap->ann_fd, recvbuf, sizeof(recvbuf));
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if (ret >= 8) {
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uint16_t hash = AV_RB16(&recvbuf[2]);
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/* Should ideally check the source IP address, too */
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if (recvbuf[0] & 0x04 && hash == sap->hash) {
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/* Stream deletion */
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sap->eof = 1;
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return AVERROR_EOF;
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}
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}
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}
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ret = av_read_frame(sap->sdp_ctx, pkt);
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if (ret < 0)
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return ret;
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if (s->ctx_flags & AVFMTCTX_NOHEADER) {
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while (sap->sdp_ctx->nb_streams > s->nb_streams) {
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int i = s->nb_streams;
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AVStream *st = avformat_new_stream(s, NULL);
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if (!st) {
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return AVERROR(ENOMEM);
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}
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st->id = i;
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avcodec_parameters_copy(st->codecpar, sap->sdp_ctx->streams[i]->codecpar);
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st->time_base = sap->sdp_ctx->streams[i]->time_base;
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}
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}
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return ret;
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}
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AVInputFormat ff_sap_demuxer = {
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.name = "sap",
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.long_name = NULL_IF_CONFIG_SMALL("SAP input"),
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.priv_data_size = sizeof(struct SAPState),
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.read_probe = sap_probe,
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.read_header = sap_read_header,
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.read_packet = sap_fetch_packet,
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.read_close = sap_read_close,
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.flags = AVFMT_NOFILE,
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};
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