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/*

 * Common code for the RTP depacketization of MPEG-4 formats.

 * Copyright (c) 2010 Fabrice Bellard

 *                    Romain Degez

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * @brief MPEG4 / RTP Code

 * @author Fabrice Bellard

 * @author Romain Degez

 */

#include "rtpdec_formats.h"

#include "internal.h"

#include "libavutil/attributes.h"

#include "libavutil/avstring.h"

#include "libavcodec/get_bits.h"

/** Structure listing useful vars to parse RTP packet payload */

struct PayloadContext {

    int sizelength;

    int indexlength;

    int indexdeltalength;

    int profile_level_id;

    int streamtype;

    int objecttype;

    char *mode;

    /** mpeg 4 AU headers */

    struct AUHeaders {

        int size;

        int index;

        int cts_flag;

        int cts;

        int dts_flag;

        int dts;

        int rap_flag;

        int streamstate;

    } *au_headers;

    int au_headers_allocated;

    int nb_au_headers;

    int au_headers_length_bytes;

    int cur_au_index;

    uint8_t buf[RTP_MAX_PACKET_LENGTH];

    int buf_pos, buf_size;

};

typedef struct {

    const char *str;

    uint16_t    type;

    uint32_t    offset;

} AttrNameMap;

/* All known fmtp parameters and the corresponding RTPAttrTypeEnum */

#define ATTR_NAME_TYPE_INT 0

#define ATTR_NAME_TYPE_STR 1

static const AttrNameMap attr_names[] = {

    { "SizeLength",       ATTR_NAME_TYPE_INT,

      offsetof(PayloadContext, sizelength) },

    { "IndexLength",      ATTR_NAME_TYPE_INT,

      offsetof(PayloadContext, indexlength) },

    { "IndexDeltaLength", ATTR_NAME_TYPE_INT,

      offsetof(PayloadContext, indexdeltalength) },

    { "profile-level-id", ATTR_NAME_TYPE_INT,

      offsetof(PayloadContext, profile_level_id) },

    { "StreamType",       ATTR_NAME_TYPE_INT,

      offsetof(PayloadContext, streamtype) },

    { "mode",             ATTR_NAME_TYPE_STR,

      offsetof(PayloadContext, mode) },

    { NULL, -1, -1 },

};

static PayloadContext *new_context(void)

{

    return av_mallocz(sizeof(PayloadContext));

}

static void free_context(PayloadContext *data)

{

    av_free(data->au_headers);

    av_free(data->mode);

    av_free(data);

}

static int parse_fmtp_config(AVCodecContext *codec, char *value)

{

    /* decode the hexa encoded parameter */

    int len = ff_hex_to_data(NULL, value);

    av_free(codec->extradata);

    if (ff_alloc_extradata(codec, len))

        return AVERROR(ENOMEM);

    ff_hex_to_data(codec->extradata, value);

    return 0;

}

static int rtp_parse_mp4_au(PayloadContext *data, const uint8_t *buf, int len)

{

    int au_headers_length, au_header_size, i;

    GetBitContext getbitcontext;

    if (len < 2)

        return AVERROR_INVALIDDATA;

    /* decode the first 2 bytes where the AUHeader sections are stored

       length in bits */

    au_headers_length = AV_RB16(buf);

    if (au_headers_length > RTP_MAX_PACKET_LENGTH)

      return -1;

    data->au_headers_length_bytes = (au_headers_length + 7) / 8;

    /* skip AU headers length section (2 bytes) */

    buf += 2;

    len -= 2;

    if (len < data->au_headers_length_bytes)

        return AVERROR_INVALIDDATA;

    init_get_bits(&getbitcontext, buf, data->au_headers_length_bytes * 8);

    /* XXX: Wrong if optional additional sections are present (cts, dts etc...) */

    au_header_size = data->sizelength + data->indexlength;

    if (au_header_size <= 0 || (au_headers_length % au_header_size != 0))

        return -1;

    data->nb_au_headers = au_headers_length / au_header_size;

    if (!data->au_headers || data->au_headers_allocated < data->nb_au_headers) {

        av_free(data->au_headers);

        data->au_headers = av_malloc(sizeof(struct AUHeaders) * data->nb_au_headers);

        if (!data->au_headers)

            return AVERROR(ENOMEM);

        data->au_headers_allocated = data->nb_au_headers;

    }

    for (i = 0; i < data->nb_au_headers; ++i) {

        data->au_headers[i].size  = get_bits_long(&getbitcontext, data->sizelength);

        data->au_headers[i].index = get_bits_long(&getbitcontext, data->indexlength);

    }

    return 0;

}

/* Follows RFC 3640 */

static int aac_parse_packet(AVFormatContext *ctx, PayloadContext *data,

                            AVStream *st, AVPacket *pkt, uint32_t *timestamp,

                            const uint8_t *buf, int len, uint16_t seq,

                            int flags)

{

    int ret;

    if (!buf) {

        if (data->cur_au_index > data->nb_au_headers)

            return AVERROR_INVALIDDATA;

        if (data->buf_size - data->buf_pos < data->au_headers[data->cur_au_index].size)

            return AVERROR_INVALIDDATA;

        if ((ret = av_new_packet(pkt, data->au_headers[data->cur_au_index].size)) < 0)

            return ret;

        memcpy(pkt->data, &data->buf[data->buf_pos], data->au_headers[data->cur_au_index].size);

        data->buf_pos += data->au_headers[data->cur_au_index].size;

        pkt->stream_index = st->index;

        data->cur_au_index++;

        return data->cur_au_index < data->nb_au_headers;

    }

    if (rtp_parse_mp4_au(data, buf, len))

        return -1;

    buf += data->au_headers_length_bytes + 2;

    len -= data->au_headers_length_bytes + 2;

    if (len < data->au_headers[0].size)

        return AVERROR_INVALIDDATA;

    if ((ret = av_new_packet(pkt, data->au_headers[0].size)) < 0)

        return ret;

    memcpy(pkt->data, buf, data->au_headers[0].size);

    len -= data->au_headers[0].size;

    buf += data->au_headers[0].size;

    pkt->stream_index = st->index;

    if (len > 0 && data->nb_au_headers > 1) {

        data->buf_size = FFMIN(len, sizeof(data->buf));

        memcpy(data->buf, buf, data->buf_size);

        data->cur_au_index = 1;

        data->buf_pos = 0;

        return 1;

    }

    return 0;

}

static int parse_fmtp(AVStream *stream, PayloadContext *data,

                      char *attr, char *value)

{

    AVCodecContext *codec = stream->codec;

    int res, i;

    if (!strcmp(attr, "config")) {

        res = parse_fmtp_config(codec, value);

        if (res < 0)

            return res;

    }

    if (codec->codec_id == AV_CODEC_ID_AAC) {

        /* Looking for a known attribute */

        for (i = 0; attr_names[i].str; ++i) {

            if (!av_strcasecmp(attr, attr_names[i].str)) {

                if (attr_names[i].type == ATTR_NAME_TYPE_INT) {

                    *(int *)((char *)data+

                        attr_names[i].offset) = atoi(value);

                } else if (attr_names[i].type == ATTR_NAME_TYPE_STR)

                    *(char **)((char *)data+

                        attr_names[i].offset) = av_strdup(value);

            }

        }

    }

    return 0;

}

static int parse_sdp_line(AVFormatContext *s, int st_index,

                          PayloadContext *data, const char *line)

{

    const char *p;

    if (st_index < 0)

        return 0;

    if (av_strstart(line, "fmtp:", &p))

        return ff_parse_fmtp(s->streams[st_index], data, p, parse_fmtp);

    return 0;

}

static av_cold int init_video(AVFormatContext *s, int st_index,

                              PayloadContext *data)

{

    if (st_index < 0)

        return 0;

    s->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;

    return 0;

}

RTPDynamicProtocolHandler ff_mp4v_es_dynamic_handler = {

    .enc_name           = "MP4V-ES",

    .codec_type         = AVMEDIA_TYPE_VIDEO,

    .codec_id           = AV_CODEC_ID_MPEG4,

    .init               = init_video,

    .parse_sdp_a_line   = parse_sdp_line,

};

RTPDynamicProtocolHandler ff_mpeg4_generic_dynamic_handler = {

    .enc_name           = "mpeg4-generic",

    .codec_type         = AVMEDIA_TYPE_AUDIO,

    .codec_id           = AV_CODEC_ID_AAC,

    .parse_sdp_a_line   = parse_sdp_line,

    .alloc              = new_context,

    .free               = free_context,

    .parse_packet       = aac_parse_packet

};