/*
  * RTP H264 Protocol (RFC3984)

  * Copyright (c) 2006 Ryan Martell

  *
  * 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 libavformat/rtp_h264.c

  * @brief H.264 / RTP Code (RFC3984)
  * @author Ryan Martell <rdm4@martellventures.com>
  *
  * @note Notes:
  * Notes:
  * This currently supports packetization mode:
  * Single Nal Unit Mode (0), or
  * Non-Interleaved Mode (1).  It currently does not support
  * Interleaved Mode (2). (This requires implementing STAP-B, MTAP16, MTAP24, FU-B packet types)
  *
  * @note TODO:
  * 1) RTCP sender reports for udp streams are required..
  *
  */
 

 #include "libavutil/base64.h"
 #include "libavutil/avstring.h"
 #include "libavcodec/bitstream.h"

 #include "avformat.h"
 #include "mpegts.h"
 
 #include <unistd.h>

 #include "network.h"

 #include <assert.h>
 

 #include "rtpdec.h"

 #include "rtp_h264.h"
 
 /**
     RTP/H264 specific private data.
 */

 struct PayloadContext {

     unsigned long cookie;       ///< sanity check, to make sure we get the pointer we're expecting.
 
     //sdp setup parameters
     uint8_t profile_idc;        ///< from the sdp setup parameters.
     uint8_t profile_iop;        ///< from the sdp setup parameters.
     uint8_t level_idc;          ///< from the sdp setup parameters.
     int packetization_mode;     ///< from the sdp setup parameters.
 #ifdef DEBUG
     int packet_types_received[32];
 #endif

 };

 
 #define MAGIC_COOKIE (0xdeadbeef)       ///< Cookie for the extradata; to verify we are what we think we are, and that we haven't been freed.
 #define DEAD_COOKIE (0xdeaddead)        ///< Cookie for the extradata; once it is freed.
 
 /* ---------------- private code */
 static void sdp_parse_fmtp_config_h264(AVStream * stream,

                                        PayloadContext * h264_data,

                                        char *attr, char *value)
 {
     AVCodecContext *codec = stream->codec;
     assert(codec->codec_id == CODEC_ID_H264);
     assert(h264_data != NULL);
 
     if (!strcmp(attr, "packetization-mode")) {

         av_log(NULL, AV_LOG_DEBUG, "H.264/RTP Packetization Mode: %d\n", atoi(value));
         h264_data->packetization_mode = atoi(value);

         /*
            Packetization Mode:
            0 or not present: Single NAL mode (Only nals from 1-23 are allowed)
            1: Non-interleaved Mode: 1-23, 24 (STAP-A), 28 (FU-A) are allowed.
            2: Interleaved Mode: 25 (STAP-B), 26 (MTAP16), 27 (MTAP24), 28 (FU-A), and 29 (FU-B) are allowed.
          */
         if (h264_data->packetization_mode > 1)
             av_log(stream, AV_LOG_ERROR,
                    "H.264/RTP Interleaved RTP mode is not supported yet.");
     } else if (!strcmp(attr, "profile-level-id")) {
         if (strlen(value) == 6) {
             char buffer[3];
             // 6 characters=3 bytes, in hex.
             uint8_t profile_idc;
             uint8_t profile_iop;
             uint8_t level_idc;
 
             buffer[0] = value[0]; buffer[1] = value[1]; buffer[2] = '\0';
             profile_idc = strtol(buffer, NULL, 16);
             buffer[0] = value[2]; buffer[1] = value[3];
             profile_iop = strtol(buffer, NULL, 16);
             buffer[0] = value[4]; buffer[1] = value[5];
             level_idc = strtol(buffer, NULL, 16);
 
             // set the parameters...
             av_log(NULL, AV_LOG_DEBUG,
                    "H.264/RTP Profile IDC: %x Profile IOP: %x Level: %x\n",
                    profile_idc, profile_iop, level_idc);
             h264_data->profile_idc = profile_idc;
             h264_data->profile_iop = profile_iop;
             h264_data->level_idc = level_idc;
         }
     } else  if (!strcmp(attr, "sprop-parameter-sets")) {
         uint8_t start_sequence[]= { 0, 0, 1 };
         codec->extradata_size= 0;
         codec->extradata= NULL;
 
         while (*value) {
             char base64packet[1024];
             uint8_t decoded_packet[1024];
             uint32_t packet_size;
             char *dst = base64packet;
 
             while (*value && *value != ','
                    && (dst - base64packet) < sizeof(base64packet) - 1) {
                 *dst++ = *value++;
             }
             *dst++ = '\0';
 
             if (*value == ',')
                 value++;
 
             packet_size= av_base64_decode(decoded_packet, base64packet, sizeof(decoded_packet));
             if (packet_size) {
                 uint8_t *dest= av_malloc(packet_size+sizeof(start_sequence)+codec->extradata_size);
                 if(dest)
                 {
                     if(codec->extradata_size)
                     {
                         // av_realloc?
                         memcpy(dest, codec->extradata, codec->extradata_size);
                         av_free(codec->extradata);
                     }
 
                     memcpy(dest+codec->extradata_size, start_sequence, sizeof(start_sequence));
                     memcpy(dest+codec->extradata_size+sizeof(start_sequence), decoded_packet, packet_size);
 
                     codec->extradata= dest;
                     codec->extradata_size+= sizeof(start_sequence)+packet_size;
                 } else {
                     av_log(NULL, AV_LOG_ERROR, "H.264/RTP Unable to allocate memory for extradata!");
                 }
             }
         }
         av_log(NULL, AV_LOG_DEBUG, "H.264/RTP Extradata set to %p (size: %d)!", codec->extradata, codec->extradata_size);
     }
 }
 
 // return 0 on packet, no more left, 1 on packet, 1 on partial packet...

 static int h264_handle_packet(AVFormatContext *ctx,
                               PayloadContext *data,

                               AVStream *st,

                               AVPacket * pkt,
                               uint32_t * timestamp,
                               const uint8_t * buf,

                               int len, int flags)

 {
     uint8_t nal = buf[0];
     uint8_t type = (nal & 0x1f);
     int result= 0;
     uint8_t start_sequence[]= {0, 0, 1};
 

 #ifdef DEBUG

     assert(data);
     assert(data->cookie == MAGIC_COOKIE);

 #endif

     assert(buf);
 
     if (type >= 1 && type <= 23)
         type = 1;              // simplify the case. (these are all the nal types used internally by the h264 codec)
     switch (type) {
     case 0:                    // undefined;
         result= -1;
         break;
 
     case 1:
         av_new_packet(pkt, len+sizeof(start_sequence));
         memcpy(pkt->data, start_sequence, sizeof(start_sequence));
         memcpy(pkt->data+sizeof(start_sequence), buf, len);
 #ifdef DEBUG
         data->packet_types_received[nal & 0x1f]++;
 #endif
         break;
 
     case 24:                   // STAP-A (one packet, multiple nals)
         // consume the STAP-A NAL
         buf++;
         len--;
         // first we are going to figure out the total size....
         {
             int pass= 0;
             int total_length= 0;
             uint8_t *dst= NULL;
 
             for(pass= 0; pass<2; pass++) {
                 const uint8_t *src= buf;
                 int src_len= len;
 
                 do {

                     uint16_t nal_size = AV_RB16(src); // this going to be a problem if unaligned (can it be?)

 
                     // consume the length of the aggregate...
                     src += 2;
                     src_len -= 2;
 
                     if (nal_size <= src_len) {
                         if(pass==0) {
                             // counting...
                             total_length+= sizeof(start_sequence)+nal_size;
                         } else {
                             // copying
                             assert(dst);
                             memcpy(dst, start_sequence, sizeof(start_sequence));
                             dst+= sizeof(start_sequence);
                             memcpy(dst, src, nal_size);
 #ifdef DEBUG
                             data->packet_types_received[*src & 0x1f]++;
 #endif
                             dst+= nal_size;
                         }
                     } else {
                         av_log(NULL, AV_LOG_ERROR,
                                "nal size exceeds length: %d %d\n", nal_size, src_len);
                     }
 
                     // eat what we handled...
                     src += nal_size;
                     src_len -= nal_size;
 
                     if (src_len < 0)
                         av_log(NULL, AV_LOG_ERROR,
                                "Consumed more bytes than we got! (%d)\n", src_len);
                 } while (src_len > 2);      // because there could be rtp padding..
 
                 if(pass==0) {
                     // now we know the total size of the packet (with the start sequences added)
                     av_new_packet(pkt, total_length);
                     dst= pkt->data;
                 } else {
                     assert(dst-pkt->data==total_length);
                 }
             }
         }
         break;
 
     case 25:                   // STAP-B
     case 26:                   // MTAP-16
     case 27:                   // MTAP-24
     case 29:                   // FU-B
         av_log(NULL, AV_LOG_ERROR,
                "Unhandled type (%d) (See RFC for implementation details\n",
                type);
         result= -1;
         break;
 
     case 28:                   // FU-A (fragmented nal)
         buf++;
         len--;                  // skip the fu_indicator
         {
             // these are the same as above, we just redo them here for clarity...
             uint8_t fu_indicator = nal;
             uint8_t fu_header = *buf;   // read the fu_header.

             uint8_t start_bit = fu_header >> 7;

 //            uint8_t end_bit = (fu_header & 0x40) >> 6;
             uint8_t nal_type = (fu_header & 0x1f);
             uint8_t reconstructed_nal;
 
             // reconstruct this packet's true nal; only the data follows..
             reconstructed_nal = fu_indicator & (0xe0);  // the original nal forbidden bit and NRI are stored in this packet's nal;

             reconstructed_nal |= nal_type;

 
             // skip the fu_header...
             buf++;
             len--;
 
 #ifdef DEBUG
             if (start_bit)

                 data->packet_types_received[nal_type]++;

 #endif
             if(start_bit) {
                 // copy in the start sequence, and the reconstructed nal....
                 av_new_packet(pkt, sizeof(start_sequence)+sizeof(nal)+len);
                 memcpy(pkt->data, start_sequence, sizeof(start_sequence));
                 pkt->data[sizeof(start_sequence)]= reconstructed_nal;
                 memcpy(pkt->data+sizeof(start_sequence)+sizeof(nal), buf, len);
             } else {
                 av_new_packet(pkt, len);
                 memcpy(pkt->data, buf, len);
             }
         }
         break;
 
     case 30:                   // undefined
     case 31:                   // undefined
     default:
         av_log(NULL, AV_LOG_ERROR, "Undefined type (%d)", type);
         result= -1;
         break;
     }
 
     return result;
 }
 
 /* ---------------- public code */

 static PayloadContext *h264_new_extradata(void)

 {

     PayloadContext *data =
         av_mallocz(sizeof(PayloadContext) +

                    FF_INPUT_BUFFER_PADDING_SIZE);
 
     if (data) {
         data->cookie = MAGIC_COOKIE;
     }
 
     return data;
 }
 

 static void h264_free_extradata(PayloadContext *data)

 {
 #ifdef DEBUG
     int ii;
 
     for (ii = 0; ii < 32; ii++) {
         if (data->packet_types_received[ii])
             av_log(NULL, AV_LOG_DEBUG, "Received %d packets of type %d\n",
                    data->packet_types_received[ii], ii);
     }
 #endif
 
     assert(data);
     assert(data->cookie == MAGIC_COOKIE);
 
     // avoid stale pointers (assert)
     data->cookie = DEAD_COOKIE;
 
     // and clear out this...
     av_free(data);
 }
 

 static int parse_h264_sdp_line(AVFormatContext *s, int st_index,
                                PayloadContext *h264_data, const char *line)

 {

     AVStream *stream = s->streams[st_index];

     AVCodecContext *codec = stream->codec;
     const char *p = line;
 
     assert(h264_data->cookie == MAGIC_COOKIE);
 

     if (av_strstart(p, "framesize:", &p)) {

         char buf1[50];
         char *dst = buf1;
 
         // remove the protocol identifier..
         while (*p && *p == ' ') p++; // strip spaces.
         while (*p && *p != ' ') p++; // eat protocol identifier
         while (*p && *p == ' ') p++; // strip trailing spaces.
         while (*p && *p != '-' && (buf1 - dst) < sizeof(buf1) - 1) {
             *dst++ = *p++;
         }
         *dst = '\0';
 
         // a='framesize:96 320-240'
         // set our parameters..
         codec->width = atoi(buf1);
         codec->height = atoi(p + 1); // skip the -
         codec->pix_fmt = PIX_FMT_YUV420P;

     } else if (av_strstart(p, "fmtp:", &p)) {

         char attr[256];
         char value[4096];
 
         // remove the protocol identifier..
         while (*p && *p == ' ') p++; // strip spaces.
         while (*p && *p != ' ') p++; // eat protocol identifier
         while (*p && *p == ' ') p++; // strip trailing spaces.
 
         /* loop on each attribute */
         while (rtsp_next_attr_and_value
                (&p, attr, sizeof(attr), value, sizeof(value))) {
             /* grab the codec extra_data from the config parameter of the fmtp line */
             sdp_parse_fmtp_config_h264(stream, h264_data, attr, value);
         }

     } else if (av_strstart(p, "cliprect:", &p)) {

         // could use this if we wanted.
     }
 
     av_set_pts_info(stream, 33, 1, 90000);      // 33 should be right, because the pts is 64 bit? (done elsewhere; this is a one time thing)
 
     return 0;                   // keep processing it the normal way...
 }
 
 /**
 This is the structure for expanding on the dynamic rtp protocols (makes everything static. yay!)
 */
 RTPDynamicProtocolHandler ff_h264_dynamic_handler = {
     "H264",
     CODEC_TYPE_VIDEO,
     CODEC_ID_H264,
     parse_h264_sdp_line,
     h264_new_extradata,
     h264_free_extradata,
     h264_handle_packet
 };