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ffmpeg / libavformat / sdp.c @ 3143f133

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/*
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 * copyright (c) 2007 Luca Abeni
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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/avstring.h"
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#include "libavutil/base64.h"
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#include "avformat.h"
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#include "avc.h"
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#include "rtp.h"
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#ifdef CONFIG_RTP_MUXER
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#define MAX_EXTRADATA_SIZE ((INT_MAX - 10) / 2)
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struct sdp_session_level {
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    int sdp_version;      /**< protocol version (currently 0) */
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    int id;               /**< session id */
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    int version;          /**< session version */
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    int start_time;       /**< session start time (NTP time, in seconds),
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                             or 0 in case of permanent session */
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    int end_time;         /**< session end time (NTP time, in seconds),
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                               or 0 if the session is not bounded */
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    int ttl;              /**< TTL, in case of multicast stream */
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    const char *user;     /**< username of the session's creator */
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    const char *src_addr; /**< IP address of the machine from which the session was created */
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    const char *dst_addr; /**< destination IP address (can be multicast) */
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    const char *name;     /**< session name (can be an empty string) */
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};
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static void dest_write(char *buff, int size, const char *dest_addr, int ttl)
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{
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    if (dest_addr) {
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        if (ttl > 0) {
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            av_strlcatf(buff, size, "c=IN IP4 %s/%d\r\n", dest_addr, ttl);
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        } else {
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            av_strlcatf(buff, size, "c=IN IP4 %s\r\n", dest_addr);
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        }
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    }
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}
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static void sdp_write_header(char *buff, int size, struct sdp_session_level *s)
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{
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    av_strlcatf(buff, size, "v=%d\r\n"
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                            "o=- %d %d IN IP4 %s\r\n"
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                            "t=%d %d\r\n"
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                            "s=%s\r\n"
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                            "a=tool:libavformat " AV_STRINGIFY(LIBAVFORMAT_VERSION) "\r\n",
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                            s->sdp_version,
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                            s->id, s->version, s->src_addr,
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                            s->start_time, s->end_time,
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                            s->name[0] ? s->name : "No Name");
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    dest_write(buff, size, s->dst_addr, s->ttl);
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}
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static int get_address(char *dest_addr, int size, int *ttl, const char *url)
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{
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    int port;
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    const char *p;
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    url_split(NULL, 0, NULL, 0, dest_addr, size, &port, NULL, 0, url);
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    *ttl = 0;
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    p = strchr(url, '?');
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    if (p) {
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        char buff[64];
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        int is_multicast = find_info_tag(buff, sizeof(buff), "multicast", p);
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        if (is_multicast) {
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            if (find_info_tag(buff, sizeof(buff), "ttl", p)) {
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                *ttl = strtol(buff, NULL, 10);
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            } else {
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                *ttl = 5;
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            }
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        }
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    }
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    return port;
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}
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#define MAX_PSET_SIZE 1024
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static char *extradata2psets(AVCodecContext *c)
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{
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    char *psets, *p;
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    const uint8_t *r;
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    const char *pset_string = "; sprop-parameter-sets=";
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    if (c->extradata_size > MAX_EXTRADATA_SIZE) {
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        av_log(c, AV_LOG_ERROR, "Too many extra data!\n");
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        return NULL;
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    }
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    psets = av_mallocz(MAX_PSET_SIZE);
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    if (psets == NULL) {
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        av_log(c, AV_LOG_ERROR, "Cannot allocate memory for the parameter sets\n");
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        return NULL;
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    }
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    memcpy(psets, pset_string, strlen(pset_string));
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    p = psets + strlen(pset_string);
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    r = ff_avc_find_startcode(c->extradata, c->extradata + c->extradata_size);
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    while (r < c->extradata + c->extradata_size) {
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        const uint8_t *r1;
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        while (!*(r++));
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        r1 = ff_avc_find_startcode(r, c->extradata + c->extradata_size);
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        if (p != (psets + strlen(pset_string))) {
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            *p = ',';
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            p++;
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        }
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        if (av_base64_encode(p, MAX_PSET_SIZE - (p - psets), r, r1 - r) == NULL) {
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            av_log(c, AV_LOG_ERROR, "Cannot BASE64 encode %td %td!\n", MAX_PSET_SIZE - (p - psets), r1 - r);
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            av_free(psets);
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            return NULL;
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        }
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        p += strlen(p);
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        r = r1;
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    }
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    return psets;
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}
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static void digit_to_char(char *dst, uint8_t src)
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{
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    if (src < 10) {
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        *dst = '0' + src;
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    } else {
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        *dst = 'A' + src - 10;
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    }
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}
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static char *data_to_hex(char *buff, const uint8_t *src, int s)
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{
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    int i;
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    for(i = 0; i < s; i++) {
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        digit_to_char(buff + 2 * i, src[i] >> 4);
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        digit_to_char(buff + 2 * i + 1, src[i] & 0xF);
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    }
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    return buff;
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}
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static char *extradata2config(AVCodecContext *c)
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{
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    char *config;
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    if (c->extradata_size > MAX_EXTRADATA_SIZE) {
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        av_log(c, AV_LOG_ERROR, "Too many extra data!\n");
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        return NULL;
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    }
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    config = av_malloc(10 + c->extradata_size * 2);
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    if (config == NULL) {
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        av_log(c, AV_LOG_ERROR, "Cannot allocate memory for the config info\n");
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        return NULL;
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    }
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    memcpy(config, "; config=", 9);
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    data_to_hex(config + 9, c->extradata, c->extradata_size);
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    config[9 + c->extradata_size * 2] = 0;
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    return config;
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}
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static char *sdp_media_attributes(char *buff, int size, AVCodecContext *c, int payload_type)
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{
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    char *config = NULL;
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    switch (c->codec_id) {
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        case CODEC_ID_H264:
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            if (c->extradata_size) {
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                config = extradata2psets(c);
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            }
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            av_strlcatf(buff, size, "a=rtpmap:%d H264/90000\r\n"
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                                    "a=fmtp:%d packetization-mode=1%s\r\n",
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                                     payload_type,
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                                     payload_type, config ? config : "");
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            break;
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        case CODEC_ID_MPEG4:
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            if (c->extradata_size) {
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                config = extradata2config(c);
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            }
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            av_strlcatf(buff, size, "a=rtpmap:%d MP4V-ES/90000\r\n"
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                                    "a=fmtp:%d profile-level-id=1%s\r\n",
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                                     payload_type,
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                                     payload_type, config ? config : "");
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            break;
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        case CODEC_ID_AAC:
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            if (c->extradata_size) {
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                config = extradata2config(c);
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            } else {
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                /* FIXME: maybe we can forge config information based on the
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                 *        codec parameters...
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                 */
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                av_log(c, AV_LOG_ERROR, "AAC with no global headers is currently not supported\n");
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                return NULL;
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            }
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            if (config == NULL) {
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                return NULL;
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            }
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            av_strlcatf(buff, size, "a=rtpmap:%d MPEG4-GENERIC/%d/%d\r\n"
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                                    "a=fmtp:%d profile-level-id=1;"
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                                    "mode=AAC-hbr;sizelength=13;indexlength=3;"
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                                    "indexdeltalength=3%s\r\n",
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                                     payload_type, c->sample_rate, c->channels,
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                                     payload_type, config);
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            break;
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        case CODEC_ID_PCM_S16BE:
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            if (payload_type >= 96)
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                av_strlcatf(buff, size, "a=rtpmap:%d L16/%d/%d\r\n",
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                                         payload_type,
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                                         c->sample_rate, c->channels);
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            break;
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        case CODEC_ID_PCM_MULAW:
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            if (payload_type >= 96)
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                av_strlcatf(buff, size, "a=rtpmap:%d PCMU/%d/%d\r\n",
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                                         payload_type,
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                                         c->sample_rate, c->channels);
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            break;
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        case CODEC_ID_PCM_ALAW:
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            if (payload_type >= 96)
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                av_strlcatf(buff, size, "a=rtpmap:%d PCMA/%d/%d\r\n",
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                                         payload_type,
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                                         c->sample_rate, c->channels);
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            break;
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        default:
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            /* Nothing special to do, here... */
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            break;
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    }
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    av_free(config);
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    return buff;
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}
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static void sdp_write_media(char *buff, int size, AVCodecContext *c, const char *dest_addr, int port, int ttl)
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{
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    const char *type;
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    int payload_type;
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    payload_type = rtp_get_payload_type(c);
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    if (payload_type < 0) {
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        payload_type = 96;  /* FIXME: how to assign a private pt? rtp.c is broken too */
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    }
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    switch (c->codec_type) {
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        case CODEC_TYPE_VIDEO   : type = "video"      ; break;
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        case CODEC_TYPE_AUDIO   : type = "audio"      ; break;
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        case CODEC_TYPE_SUBTITLE: type = "text"       ; break;
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        default                 : type = "application"; break;
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    }
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    av_strlcatf(buff, size, "m=%s %d RTP/AVP %d\r\n", type, port, payload_type);
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    dest_write(buff, size, dest_addr, ttl);
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    if (c->bit_rate) {
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        av_strlcatf(buff, size, "b=AS:%d\r\n", c->bit_rate / 1000);
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    }
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    sdp_media_attributes(buff, size, c, payload_type);
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}
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int avf_sdp_create(AVFormatContext *ac[], int n_files, char *buff, int size)
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{
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    struct sdp_session_level s;
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    int i, j, port, ttl;
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    char dst[32];
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    memset(buff, 0, size);
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    memset(&s, 0, sizeof(struct sdp_session_level));
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    s.user = "-";
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    s.src_addr = "127.0.0.1";    /* FIXME: Properly set this */
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    s.name = ac[0]->title;
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    port = 0;
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    ttl = 0;
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    if (n_files == 1) {
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        port = get_address(dst, sizeof(dst), &ttl, ac[0]->filename);
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        if (port > 0) {
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            s.dst_addr = dst;
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            s.ttl = ttl;
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        }
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    }
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    sdp_write_header(buff, size, &s);
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    dst[0] = 0;
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    for (i = 0; i < n_files; i++) {
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        if (n_files != 1) {
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            port = get_address(dst, sizeof(dst), &ttl, ac[i]->filename);
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        }
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        for (j = 0; j < ac[i]->nb_streams; j++) {
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            sdp_write_media(buff, size,
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                                  ac[i]->streams[j]->codec, dst[0] ? dst : NULL,
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                                  (port > 0) ? port + j * 2 : 0, ttl);
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            if (port <= 0) {
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                av_strlcatf(buff, size,
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                                   "a=control:streamid=%d\r\n", i + j);
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            }
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        }
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    }
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    return 0;
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}
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#else
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int avf_sdp_create(AVFormatContext *ac[], int n_files, char *buff, int size)
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{
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    return AVERROR(ENOSYS);
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}
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#endif