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ffmpeg / libavformat / rtpdec_xiph.c @ 2874c81c

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/*
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 * Xiph RTP Protocols
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 * Copyright (c) 2009 Colin McQuillian
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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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/**
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 * @file libavformat/rtpdec_xiph.c
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 * @brief Xiph / RTP Code
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 * @author Colin McQuillan <m.niloc@gmail.com>
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 * @author Josh Allmann <joshua.allmann@gmail.com>
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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 "libavcodec/bytestream.h"
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#include <assert.h>
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#include "rtpdec.h"
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#include "rtpdec_xiph.h"
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/**
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 * RTP/Xiph specific private data.
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 */
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struct PayloadContext {
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    unsigned ident;             ///< 24-bit stream configuration identifier
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    uint32_t timestamp;
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    ByteIOContext* fragment;    ///< buffer for split payloads
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};
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static PayloadContext *xiph_new_context(void)
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{
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    return av_mallocz(sizeof(PayloadContext));
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}
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static inline void free_fragment_if_needed(PayloadContext * data)
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{
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    if (data->fragment) {
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        uint8_t* p;
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        url_close_dyn_buf(data->fragment, &p);
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        av_free(p);
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        data->fragment = NULL;
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    }
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}
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static void xiph_free_context(PayloadContext * data)
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{
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    free_fragment_if_needed(data);
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    av_free(data);
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}
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static int xiph_handle_packet(AVFormatContext * ctx,
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                              PayloadContext * data,
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                              AVStream * st,
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                              AVPacket * pkt,
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                              uint32_t * timestamp,
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                              const uint8_t * buf, int len, int flags)
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{
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    int ident, fragmented, tdt, num_pkts, pkt_len;
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    if (len < 6) {
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        av_log(ctx, AV_LOG_ERROR, "Invalid %d byte packet\n", len);
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        return AVERROR_INVALIDDATA;
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    }
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    // read xiph rtp headers
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    ident       = AV_RB24(buf);
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    fragmented  = buf[3] >> 6;
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    tdt         = (buf[3] >> 4) & 3;
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    num_pkts    = buf[3] & 7;
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    pkt_len     = AV_RB16(buf + 4);
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    if (pkt_len > len - 6) {
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        av_log(ctx, AV_LOG_ERROR,
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               "Invalid packet length %d in %d byte packet\n", pkt_len,
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               len);
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        return AVERROR_INVALIDDATA;
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    }
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    if (ident != data->ident) {
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        av_log(ctx, AV_LOG_ERROR,
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               "Unimplemented Xiph SDP configuration change detected\n");
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        return AVERROR_PATCHWELCOME;
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    }
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    if (tdt) {
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        av_log(ctx, AV_LOG_ERROR,
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               "Unimplemented RTP Xiph packet settings (%d,%d,%d)\n",
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               fragmented, tdt, num_pkts);
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        return AVERROR_PATCHWELCOME;
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    }
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    buf += 6; // move past header bits
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    len -= 6;
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    if (fragmented == 0) {
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        // whole frame(s)
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        int i, data_len, write_len;
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        buf -= 2;
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        len += 2;
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        // fast first pass to calculate total length
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        for (i = 0, data_len = 0;  (i < num_pkts) && (len >= 2);  i++) {
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            int off   = data_len + (i << 1);
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            pkt_len   = AV_RB16(buf + off);
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            data_len += pkt_len;
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            len      -= pkt_len + 2;
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        }
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        if (len < 0 || i < num_pkts) {
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            av_log(ctx, AV_LOG_ERROR,
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                   "Bad packet: %d bytes left at frame %d of %d\n",
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                   len, i, num_pkts);
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            return AVERROR_INVALIDDATA;
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        }
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        if (av_new_packet(pkt, data_len)) {
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            av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
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            return AVERROR(ENOMEM);
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        }
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        pkt->stream_index = st->index;
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        // concatenate frames
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        for (i = 0, write_len = 0; write_len < data_len; i++) {
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            pkt_len = AV_RB16(buf);
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            buf += 2;
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            memcpy(pkt->data + write_len, buf, pkt_len);
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            write_len += pkt_len;
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            buf += pkt_len;
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        }
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        assert(write_len == data_len);
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        return 0;
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    } else if (fragmented == 1) {
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        // start of xiph data fragment
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        int res;
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        // end packet has been lost somewhere, so drop buffered data
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        free_fragment_if_needed(data);
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        if((res = url_open_dyn_buf(&data->fragment)) < 0)
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            return res;
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        put_buffer(data->fragment, buf, pkt_len);
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        data->timestamp = *timestamp;
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    } else {
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        assert(fragmented < 4);
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        if (data->timestamp != *timestamp) {
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            // skip if fragmented timestamp is incorrect;
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            // a start packet has been lost somewhere
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            free_fragment_if_needed(data);
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            av_log(ctx, AV_LOG_ERROR, "RTP timestamps don't match!\n");
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            return AVERROR_INVALIDDATA;
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        }
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        // copy data to fragment buffer
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        put_buffer(data->fragment, buf, pkt_len);
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        if (fragmented == 3) {
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            // end of xiph data packet
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            uint8_t* xiph_data;
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            int frame_size = url_close_dyn_buf(data->fragment, &xiph_data);
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            if (frame_size < 0) {
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                av_log(ctx, AV_LOG_ERROR,
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                       "Error occurred when getting fragment buffer.");
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                return frame_size;
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            }
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            if (av_new_packet(pkt, frame_size)) {
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                av_log(ctx, AV_LOG_ERROR, "Out of memory.\n");
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                return AVERROR(ENOMEM);
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            }
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            memcpy(pkt->data, xiph_data, frame_size);
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            pkt->stream_index = st->index;
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            av_free(xiph_data);
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            data->fragment = NULL;
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            return 0;
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        }
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    }
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   return AVERROR(EAGAIN);
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}
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/**
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 * Length encoding described in RFC5215 section 3.1.1.
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 */
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static int get_base128(const uint8_t ** buf, const uint8_t * buf_end)
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{
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    int n = 0;
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    for (; *buf < buf_end; ++*buf) {
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        n <<= 7;
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        n += **buf & 0x7f;
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        if (!(**buf & 0x80)) {
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            ++*buf;
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            return n;
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        }
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    }
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    return 0;
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}
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/**
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 * Based off parse_packed_headers in Vorbis RTP
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 */
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static unsigned int
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parse_packed_headers(const uint8_t * packed_headers,
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                     const uint8_t * packed_headers_end,
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                     AVCodecContext * codec, PayloadContext * xiph_data)
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{
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    unsigned num_packed, num_headers, length, length1, length2, extradata_alloc;
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    uint8_t *ptr;
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    if (packed_headers_end - packed_headers < 9) {
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        av_log(codec, AV_LOG_ERROR,
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               "Invalid %d byte packed header.",
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               packed_headers_end - packed_headers);
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        return AVERROR_INVALIDDATA;
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    }
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    num_packed         = bytestream_get_be32(&packed_headers);
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    xiph_data->ident   = bytestream_get_be24(&packed_headers);
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    length             = bytestream_get_be16(&packed_headers);
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    num_headers        = get_base128(&packed_headers, packed_headers_end);
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    length1            = get_base128(&packed_headers, packed_headers_end);
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    length2            = get_base128(&packed_headers, packed_headers_end);
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    if (num_packed != 1 || num_headers > 3) {
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        av_log(codec, AV_LOG_ERROR,
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               "Unimplemented number of headers: %d packed headers, %d headers\n",
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               num_packed, num_headers);
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        return AVERROR_PATCHWELCOME;
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    }
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    if (packed_headers_end - packed_headers != length ||
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        length1 > length || length2 > length - length1) {
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        av_log(codec, AV_LOG_ERROR,
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               "Bad packed header lengths (%d,%d,%d,%d)\n", length1,
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               length2, packed_headers_end - packed_headers, length);
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        return AVERROR_INVALIDDATA;
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    }
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    /* allocate extra space:
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     * -- length/255 +2 for xiphlacing
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     * -- one for the '2' marker
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     * -- FF_INPUT_BUFFER_PADDING_SIZE required */
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    extradata_alloc = length + length/255 + 3 + FF_INPUT_BUFFER_PADDING_SIZE;
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    ptr = codec->extradata = av_malloc(extradata_alloc);
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    if (!ptr) {
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        av_log(codec, AV_LOG_ERROR, "Out of memory\n");
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        return AVERROR(ENOMEM);
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    }
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    *ptr++ = 2;
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    ptr += av_xiphlacing(ptr, length1);
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    ptr += av_xiphlacing(ptr, length2);
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    memcpy(ptr, packed_headers, length);
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    ptr += length;
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    codec->extradata_size = ptr - codec->extradata;
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    // clear out remaining parts of the buffer
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    memset(ptr, 0, extradata_alloc - codec->extradata_size);
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    return 0;
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}
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static int xiph_parse_fmtp_pair(AVCodecContext * codec,
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                                PayloadContext *xiph_data,
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                                char *attr, char *value)
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{
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    int result = 0;
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    if (!strcmp(attr, "sampling")) {
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        return AVERROR_PATCHWELCOME;
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    } else if (!strcmp(attr, "width")) {
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        /* This is an integer between 1 and 1048561
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         * and MUST be in multiples of 16. */
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        codec->width = atoi(value);
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        return 0;
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    } else if (!strcmp(attr, "height")) {
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        /* This is an integer between 1 and 1048561
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         * and MUST be in multiples of 16. */
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        codec->height = atoi(value);
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        return 0;
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    } else if (!strcmp(attr, "delivery-method")) {
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        /* Possible values are: inline, in_band, out_band/specific_name. */
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        return AVERROR_PATCHWELCOME;
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    } else if (!strcmp(attr, "configuration-uri")) {
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        /* NOTE: configuration-uri is supported only under 2 conditions:
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         *--after the delivery-method tag
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         * --with a delivery-method value of out_band */
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        return AVERROR_PATCHWELCOME;
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    } else if (!strcmp(attr, "configuration")) {
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        /* NOTE: configuration is supported only AFTER the delivery-method tag
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         * The configuration value is a base64 encoded packed header */
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        uint8_t *decoded_packet = NULL;
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        int packet_size;
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        size_t decoded_alloc = strlen(value) / 4 * 3 + 4;
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        if (decoded_alloc <= INT_MAX) {
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            decoded_packet = av_malloc(decoded_alloc);
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            if (decoded_packet) {
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                packet_size =
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                    av_base64_decode(decoded_packet, value, decoded_alloc);
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                result = parse_packed_headers
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                    (decoded_packet, decoded_packet + packet_size, codec,
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                    xiph_data);
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            } else {
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                av_log(codec, AV_LOG_ERROR,
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                       "Out of memory while decoding SDP configuration.\n");
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                result = AVERROR(ENOMEM);
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            }
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        } else {
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            av_log(codec, AV_LOG_ERROR, "Packet too large\n");
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            result = AVERROR_INVALIDDATA;
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        }
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        av_free(decoded_packet);
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    }
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    return result;
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}
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static int xiph_parse_sdp_line(AVFormatContext *s, int st_index,
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                                 PayloadContext *data, const char *line)
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{
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    const char *p;
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    char *value;
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    char attr[25];
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    int value_size = strlen(line), attr_size = sizeof(attr), res = 0;
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    AVCodecContext* codec = s->streams[st_index]->codec;
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    assert(codec->id == CODEC_ID_THEORA);
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    assert(data);
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    if (!(value = av_malloc(value_size))) {
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        av_log(codec, AV_LOG_ERROR, "Out of memory\n");
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        return AVERROR(ENOMEM);
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    }
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    if (av_strstart(line, "fmtp:", &p)) {
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        // remove protocol identifier
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        while (*p && *p == ' ') p++; // strip spaces
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        while (*p && *p != ' ') p++; // eat protocol identifier
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        while (*p && *p == ' ') p++; // strip trailing spaces
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        while (ff_rtsp_next_attr_and_value(&p,
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                                           attr, attr_size,
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                                           value, value_size)) {
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            res = xiph_parse_fmtp_pair(codec, data, attr, value);
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            if (res < 0 && res != AVERROR_PATCHWELCOME)
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                return res;
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        }
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    }
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    av_free(value);
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    return 0;
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}
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RTPDynamicProtocolHandler ff_theora_dynamic_handler = {
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    .enc_name         = "theora",
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    .codec_type       = AVMEDIA_TYPE_VIDEO,
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    .codec_id         = CODEC_ID_THEORA,
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    .parse_sdp_a_line = xiph_parse_sdp_line,
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    .open             = xiph_new_context,
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    .close            = xiph_free_context,
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    .parse_packet     = xiph_handle_packet
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};
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RTPDynamicProtocolHandler ff_vorbis_dynamic_handler = {
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    .enc_name         = "vorbis",
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    .codec_type       = AVMEDIA_TYPE_AUDIO,
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    .codec_id         = CODEC_ID_VORBIS,
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    .parse_sdp_a_line = xiph_parse_sdp_line,
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    .open             = xiph_new_context,
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    .close            = xiph_free_context,
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    .parse_packet     = xiph_handle_packet
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};