/*

  * 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 MPEG-4 / 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"

 #define MAX_AAC_HBR_FRAME_SIZE 8191
 

 /** 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[FFMAX(RTP_MAX_PACKET_LENGTH, MAX_AAC_HBR_FRAME_SIZE)];

     int buf_pos, buf_size;

     uint32_t timestamp;

 };

 typedef struct AttrNameMap {

     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 void close_context(PayloadContext *data)

 {

     av_freep(&data->au_headers);
     av_freep(&data->mode);

 }
 

 static int parse_fmtp_config(AVCodecParameters *par, const char *value)

 {
     /* decode the hexa encoded parameter */

     int len = ff_hex_to_data(NULL, value);

     av_freep(&par->extradata);
     if (ff_alloc_extradata(par, len))

         return AVERROR(ENOMEM);

     ff_hex_to_data(par->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) {
             av_log(ctx, AV_LOG_ERROR, "Invalid parser state\n");

             return AVERROR_INVALIDDATA;

         }
         if (data->buf_size - data->buf_pos < data->au_headers[data->cur_au_index].size) {
             av_log(ctx, AV_LOG_ERROR, "Invalid AU size\n");

             return AVERROR_INVALIDDATA;

         }
         if ((ret = av_new_packet(pkt, data->au_headers[data->cur_au_index].size)) < 0) {
             av_log(ctx, AV_LOG_ERROR, "Out of memory\n");

             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++;

 
         if (data->cur_au_index == data->nb_au_headers) {
             data->buf_pos = 0;
             return 0;
         }
 
         return 1;

     }
 

     if (rtp_parse_mp4_au(data, buf, len)) {
         av_log(ctx, AV_LOG_ERROR, "Error parsing AU headers\n");

         return -1;

     }

     buf += data->au_headers_length_bytes + 2;
     len -= data->au_headers_length_bytes + 2;

     if (data->nb_au_headers == 1 && len < data->au_headers[0].size) {
         /* Packet is fragmented */
 
         if (!data->buf_pos) {
             if (data->au_headers[0].size > MAX_AAC_HBR_FRAME_SIZE) {
                 av_log(ctx, AV_LOG_ERROR, "Invalid AU size\n");
                 return AVERROR_INVALIDDATA;
             }
 
             data->buf_size = data->au_headers[0].size;
             data->timestamp = *timestamp;
         }
 

         if (data->timestamp != *timestamp ||
             data->au_headers[0].size != data->buf_size ||
             data->buf_pos + len > MAX_AAC_HBR_FRAME_SIZE) {

             data->buf_pos = 0;
             data->buf_size = 0;
             av_log(ctx, AV_LOG_ERROR, "Invalid packet received\n");
             return AVERROR_INVALIDDATA;
         }
 
         memcpy(&data->buf[data->buf_pos], buf, len);
         data->buf_pos += len;
 
         if (!(flags & RTP_FLAG_MARKER))
             return AVERROR(EAGAIN);

         if (data->buf_pos != data->buf_size) {
             data->buf_pos = 0;
             av_log(ctx, AV_LOG_ERROR, "Missed some packets, discarding frame\n");
             return AVERROR_INVALIDDATA;
         }
 
         data->buf_pos = 0;
         ret = av_new_packet(pkt, data->buf_size);
         if (ret < 0) {
             av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
             return ret;
         }
         pkt->stream_index = st->index;
 
         memcpy(pkt->data, data->buf, data->buf_size);
 
         return 0;
     }
 
     if (len < data->au_headers[0].size) {
         av_log(ctx, AV_LOG_ERROR, "First AU larger than packet size\n");

         return AVERROR_INVALIDDATA;

     }
     if ((ret = av_new_packet(pkt, data->au_headers[0].size)) < 0) {
         av_log(ctx, AV_LOG_ERROR, "Out of memory\n");

         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(AVFormatContext *s,
                       AVStream *stream, PayloadContext *data,

                       const char *attr, const char *value)

 {

     AVCodecParameters *par = stream->codecpar;

     int res, i;
 

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

         res = parse_fmtp_config(par, value);

         if (res < 0)
             return res;
     }

     if (par->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 val = atoi(value);
                     if (val > 32) {
                         av_log(s, AV_LOG_ERROR,

                                "The %s field size is invalid (%d)\n",

                                attr, val);
                         return AVERROR_INVALIDDATA;
                     }

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

                         attr_names[i].offset) = val;
                 } else if (attr_names[i].type == ATTR_NAME_TYPE_STR) {
                     char *val = av_strdup(value);
                     if (!val)
                         return AVERROR(ENOMEM);

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

                         attr_names[i].offset) = val;
                 }

             }

         }

     }
     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, s->streams[st_index], data, p, parse_fmtp);

     return 0;

 }
 
 RTPDynamicProtocolHandler ff_mp4v_es_dynamic_handler = {
     .enc_name           = "MP4V-ES",
     .codec_type         = AVMEDIA_TYPE_VIDEO,

     .codec_id           = AV_CODEC_ID_MPEG4,

     .need_parsing       = AVSTREAM_PARSE_FULL,

     .priv_data_size     = sizeof(PayloadContext),

     .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,

     .priv_data_size     = sizeof(PayloadContext),

     .parse_sdp_a_line   = parse_sdp_line,

     .close              = close_context,

     .parse_packet       = aac_parse_packet,

 };