370 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			370 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Common code for the RTP depacketization of MPEG-4 formats.
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 * Copyright (c) 2010 Fabrice Bellard
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 *                    Romain Degez
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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
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 * @brief MPEG-4 / RTP Code
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 * @author Fabrice Bellard
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 * @author Romain Degez
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 */
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#include "rtpdec_formats.h"
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#include "internal.h"
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#include "libavutil/attributes.h"
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#include "libavutil/avstring.h"
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#include "libavcodec/get_bits.h"
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#define MAX_AAC_HBR_FRAME_SIZE 8191
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/** Structure listing useful vars to parse RTP packet payload */
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struct PayloadContext {
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    int sizelength;
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    int indexlength;
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    int indexdeltalength;
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    int profile_level_id;
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    int streamtype;
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    int objecttype;
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    char *mode;
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    /** mpeg 4 AU headers */
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    struct AUHeaders {
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        int size;
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        int index;
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        int cts_flag;
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        int cts;
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        int dts_flag;
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        int dts;
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        int rap_flag;
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        int streamstate;
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    } *au_headers;
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    int au_headers_allocated;
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    int nb_au_headers;
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    int au_headers_length_bytes;
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    int cur_au_index;
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    uint8_t buf[FFMAX(RTP_MAX_PACKET_LENGTH, MAX_AAC_HBR_FRAME_SIZE)];
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    int buf_pos, buf_size;
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    uint32_t timestamp;
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};
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typedef struct AttrNameMap {
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    const char *str;
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    uint16_t    type;
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    uint32_t    offset;
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    /** Range for integer values */
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    struct Range {
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        int min;
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        int max;
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    } range;
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} AttrNameMap;
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/* All known fmtp parameters and the corresponding RTPAttrTypeEnum */
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#define ATTR_NAME_TYPE_INT 0
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#define ATTR_NAME_TYPE_STR 1
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static const AttrNameMap attr_names[] = {
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    { "SizeLength",       ATTR_NAME_TYPE_INT,
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      offsetof(PayloadContext, sizelength),
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      {0, 32} }, // SizeLength number of bits used to encode AU-size integer value
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    { "IndexLength",      ATTR_NAME_TYPE_INT,
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      offsetof(PayloadContext, indexlength),
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      {0, 32} }, // IndexLength number of bits used to encode AU-Index integer value
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    { "IndexDeltaLength", ATTR_NAME_TYPE_INT,
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      offsetof(PayloadContext, indexdeltalength),
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      {0, 32} }, // IndexDeltaLength number of bits to encode AU-Index-delta integer value
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    { "profile-level-id", ATTR_NAME_TYPE_INT,
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      offsetof(PayloadContext, profile_level_id),
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      {INT32_MIN, INT32_MAX} }, // It differs depending on StreamType
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    { "StreamType",       ATTR_NAME_TYPE_INT,
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      offsetof(PayloadContext, streamtype),
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      {0x00, 0x3F} }, // Values from ISO/IEC 14496-1, 'StreamType Values' table
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    { "mode",             ATTR_NAME_TYPE_STR,
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      offsetof(PayloadContext, mode),
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       {0} },
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    { NULL, -1, -1, {0} },
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};
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static void close_context(PayloadContext *data)
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{
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    av_freep(&data->au_headers);
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    av_freep(&data->mode);
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}
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static int parse_fmtp_config(AVCodecParameters *par, const char *value)
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{
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    /* decode the hexa encoded parameter */
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    int len = ff_hex_to_data(NULL, value), ret;
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    if ((ret = ff_alloc_extradata(par, len)) < 0)
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        return ret;
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    ff_hex_to_data(par->extradata, value);
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    return 0;
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}
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static int rtp_parse_mp4_au(PayloadContext *data, const uint8_t *buf, int len)
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{
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    int au_headers_length, au_header_size, i;
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    GetBitContext getbitcontext;
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    int ret;
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    if (len < 2)
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        return AVERROR_INVALIDDATA;
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    /* decode the first 2 bytes where the AUHeader sections are stored
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       length in bits */
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    au_headers_length = AV_RB16(buf);
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    if (au_headers_length > RTP_MAX_PACKET_LENGTH)
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      return -1;
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    data->au_headers_length_bytes = (au_headers_length + 7) / 8;
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    /* skip AU headers length section (2 bytes) */
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    buf += 2;
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    len -= 2;
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    if (len < data->au_headers_length_bytes)
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        return AVERROR_INVALIDDATA;
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    ret = init_get_bits(&getbitcontext, buf, data->au_headers_length_bytes * 8);
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    if (ret < 0)
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        return ret;
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    /* XXX: Wrong if optional additional sections are present (cts, dts etc...) */
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    au_header_size = data->sizelength + data->indexlength;
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    if (au_header_size <= 0 || (au_headers_length % au_header_size != 0))
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        return -1;
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    data->nb_au_headers = au_headers_length / au_header_size;
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    if (!data->au_headers || data->au_headers_allocated < data->nb_au_headers) {
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        av_free(data->au_headers);
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        data->au_headers = av_malloc(sizeof(struct AUHeaders) * data->nb_au_headers);
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        if (!data->au_headers)
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            return AVERROR(ENOMEM);
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        data->au_headers_allocated = data->nb_au_headers;
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    }
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    for (i = 0; i < data->nb_au_headers; ++i) {
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        data->au_headers[i].size  = get_bits_long(&getbitcontext, data->sizelength);
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        data->au_headers[i].index = get_bits_long(&getbitcontext, data->indexlength);
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    }
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    return 0;
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}
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/* Follows RFC 3640 */
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static int aac_parse_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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    int ret;
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    if (!buf) {
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        if (data->cur_au_index > data->nb_au_headers) {
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            av_log(ctx, AV_LOG_ERROR, "Invalid parser state\n");
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            return AVERROR_INVALIDDATA;
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        }
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        if (data->buf_size - data->buf_pos < data->au_headers[data->cur_au_index].size) {
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            av_log(ctx, AV_LOG_ERROR, "Invalid AU size\n");
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            return AVERROR_INVALIDDATA;
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        }
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        if ((ret = av_new_packet(pkt, data->au_headers[data->cur_au_index].size)) < 0) {
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            av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
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            return ret;
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        }
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        memcpy(pkt->data, &data->buf[data->buf_pos], data->au_headers[data->cur_au_index].size);
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        data->buf_pos += data->au_headers[data->cur_au_index].size;
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        pkt->stream_index = st->index;
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        data->cur_au_index++;
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        if (data->cur_au_index == data->nb_au_headers) {
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            data->buf_pos = 0;
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            return 0;
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        }
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        return 1;
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    }
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    if (rtp_parse_mp4_au(data, buf, len)) {
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        av_log(ctx, AV_LOG_ERROR, "Error parsing AU headers\n");
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        return -1;
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    }
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    buf += data->au_headers_length_bytes + 2;
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    len -= data->au_headers_length_bytes + 2;
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    if (data->nb_au_headers == 1 && len < data->au_headers[0].size) {
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        /* Packet is fragmented */
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        if (!data->buf_pos) {
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            if (data->au_headers[0].size > MAX_AAC_HBR_FRAME_SIZE) {
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                av_log(ctx, AV_LOG_ERROR, "Invalid AU size\n");
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                return AVERROR_INVALIDDATA;
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            }
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            data->buf_size = data->au_headers[0].size;
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            data->timestamp = *timestamp;
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        }
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        if (data->timestamp != *timestamp ||
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            data->au_headers[0].size != data->buf_size ||
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            data->buf_pos + len > MAX_AAC_HBR_FRAME_SIZE) {
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            data->buf_pos = 0;
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            data->buf_size = 0;
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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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        memcpy(&data->buf[data->buf_pos], buf, len);
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        data->buf_pos += len;
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        if (!(flags & RTP_FLAG_MARKER))
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            return AVERROR(EAGAIN);
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        if (data->buf_pos != data->buf_size) {
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            data->buf_pos = 0;
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            av_log(ctx, AV_LOG_ERROR, "Missed some packets, discarding frame\n");
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            return AVERROR_INVALIDDATA;
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        }
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        data->buf_pos = 0;
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        ret = av_new_packet(pkt, data->buf_size);
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        if (ret < 0) {
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            av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
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            return ret;
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        }
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        pkt->stream_index = st->index;
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        memcpy(pkt->data, data->buf, data->buf_size);
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        return 0;
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    }
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    if (len < data->au_headers[0].size) {
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        av_log(ctx, AV_LOG_ERROR, "First AU larger than packet size\n");
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        return AVERROR_INVALIDDATA;
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    }
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    if ((ret = av_new_packet(pkt, data->au_headers[0].size)) < 0) {
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        av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
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        return ret;
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    }
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    memcpy(pkt->data, buf, data->au_headers[0].size);
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    len -= data->au_headers[0].size;
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    buf += data->au_headers[0].size;
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    pkt->stream_index = st->index;
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    if (len > 0 && data->nb_au_headers > 1) {
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        data->buf_size = FFMIN(len, sizeof(data->buf));
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        memcpy(data->buf, buf, data->buf_size);
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        data->cur_au_index = 1;
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        data->buf_pos = 0;
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        return 1;
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    }
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    return 0;
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}
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static int parse_fmtp(AVFormatContext *s,
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                      AVStream *stream, PayloadContext *data,
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                      const char *attr, const char *value)
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{
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    AVCodecParameters *par = stream->codecpar;
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    int res, i;
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    if (!strcmp(attr, "config")) {
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        res = parse_fmtp_config(par, value);
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        if (res < 0)
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            return res;
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    }
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    if (par->codec_id == AV_CODEC_ID_AAC) {
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        /* Looking for a known attribute */
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        for (i = 0; attr_names[i].str; ++i) {
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            if (!av_strcasecmp(attr, attr_names[i].str)) {
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                if (attr_names[i].type == ATTR_NAME_TYPE_INT) {
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                    char *end_ptr = NULL;
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                    long long int val = strtoll(value, &end_ptr, 10);
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                    if (end_ptr == value || end_ptr[0] != '\0') {
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                        av_log(s, AV_LOG_ERROR,
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                               "The %s field value is not a valid number: %s\n",
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                               attr, value);
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                        return AVERROR_INVALIDDATA;
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                    }
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                    if (val < attr_names[i].range.min ||
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                        val > attr_names[i].range.max) {
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                        av_log(s, AV_LOG_ERROR,
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                            "fmtp field %s should be in range [%d,%d] (provided value: %lld)",
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                            attr, attr_names[i].range.min, attr_names[i].range.max, val);
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                        return  AVERROR_INVALIDDATA;
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                    }
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                    *(int *)((char *)data+
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                        attr_names[i].offset) = (int) val;
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                } else if (attr_names[i].type == ATTR_NAME_TYPE_STR) {
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                    char *val = av_strdup(value);
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                    if (!val)
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                        return AVERROR(ENOMEM);
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                    *(char **)((char *)data+
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                        attr_names[i].offset) = val;
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                }
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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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static int 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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    if (st_index < 0)
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        return 0;
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    if (av_strstart(line, "fmtp:", &p))
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        return ff_parse_fmtp(s, s->streams[st_index], data, p, parse_fmtp);
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    return 0;
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}
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const RTPDynamicProtocolHandler ff_mp4v_es_dynamic_handler = {
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    .enc_name           = "MP4V-ES",
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    .codec_type         = AVMEDIA_TYPE_VIDEO,
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    .codec_id           = AV_CODEC_ID_MPEG4,
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    .need_parsing       = AVSTREAM_PARSE_FULL,
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    .priv_data_size     = sizeof(PayloadContext),
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    .parse_sdp_a_line   = parse_sdp_line,
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};
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const RTPDynamicProtocolHandler ff_mpeg4_generic_dynamic_handler = {
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    .enc_name           = "mpeg4-generic",
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    .codec_type         = AVMEDIA_TYPE_AUDIO,
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    .codec_id           = AV_CODEC_ID_AAC,
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    .priv_data_size     = sizeof(PayloadContext),
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    .parse_sdp_a_line   = parse_sdp_line,
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    .close              = close_context,
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    .parse_packet       = aac_parse_packet,
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};
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