libmpdemux/mpeg_packetizer.c

   1 /*
   2  *  Copyright (C) 2006 Benjamin Zores
   3  *   Set of helper routines for building MPEG 1/2 PS/PES packets.
   4  *
   5  *   Based on various code bororwed from vo_mpegpes/vo_dxr2 :
   6  *      (C) 2000 Ralph Metzler <ralph@convergence.de>
   7  *               Marcus Metzler <marcus@convergence.de>
   8  *               Gerard Lantau
   9  *
  10  *   This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *   This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *   You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to the Free Software Foundation,
  22  *  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23  */
  24
  25 #include <unistd.h>
  26 #include <string.h>
  27 #include <inttypes.h>
  28
  29 #include "mp_msg.h"
  30 #include "mpeg_packetizer.h"
  31
  32 #define PES_MAX_SIZE 2048
  33
  34 static unsigned char pes_header[PES_MAX_SIZE];
  35
  36 static unsigned char ps2_header[] = {
  37   0x00, 0x00, 0x01, 0xba, 0x44, 0x00, 0x04, 0x00,
  38   0x04, 0x01, 0x01, 0x86, 0xa3, 0xf8
  39 };
  40
  41
  42 static unsigned char ps1_header[] = {
  43   0x00, 0x00, 0x01, 0xba, 0x21, 0x00,
  44   0xb9, 0x37, 0x83, 0x80, 0xc3, 0x51,
  45 };
  46
  47 /* Send MPEG <type> PES packet */
  48 static int
  49 send_mpeg_pes_packet_ll(unsigned char *data, int len, int id, uint64_t pts,
  50                       int type, unsigned char *header, int header_len,
  51                       int align4, int my_write (unsigned char *data, int len))
  52 {
  53   int ptslen = (pts ? 5 : 0);
  54   int n = 0;
  55   int idx, plen;
  56   int hdr;
  57
  58   mp_msg (MSGT_HEADER, MSGL_DBG2,
  59           "MPEG%d PES packet: 0x%x => %lu   \n", type, id, pts);
  60   memset (pes_header, '\0', PES_MAX_SIZE);
  61
  62   /* startcode */
  63   pes_header[0] = 0;
  64   pes_header[1] = 0;
  65   pes_header[2] = 0x01;
  66   pes_header[3] = id; /* stream id */
  67
  68   while (len > 0)
  69   {
  70     int payload_size = len;  /* data + PTS */
  71     if(type == 2)
  72         hdr = 3;
  73     else
  74         hdr = (ptslen ? 0 : 1);
  75     if (6 + hdr + ptslen + payload_size + header_len > PES_MAX_SIZE)
  76       payload_size = PES_MAX_SIZE - 6 - hdr - ptslen - header_len;
  77     if(align4)
  78       payload_size &= ~3;
  79
  80     /* construct PES header: packetize */
  81     plen = payload_size + hdr + ptslen + header_len;
  82     pes_header[4] = plen >> 8;
  83     pes_header[5] = plen & 255;
  84     idx = 6;
  85
  86     if (ptslen)
  87     {
  88       int x;
  89
  90       if(type == 2)
  91       {
  92         pes_header[idx++] = 0x81;
  93         pes_header[idx++] = 0x80;
  94         pes_header[idx++] = ptslen;
  95       }
  96
  97       /* presentation time stamp */
  98       x = (0x02 << 4) | (((pts >> 30) & 0x07) << 1) | 1;
  99       pes_header[idx++] = x;
 100
 101       x = ((((pts >> 15) & 0x7fff) << 1) | 1);
 102       pes_header[idx++] = x >>8;
 103       pes_header[idx++] = x & 255;
 104
 105       x = (((pts & 0x7fff) << 1) | 1);
 106       pes_header[idx++] = x >> 8;
 107       pes_header[idx++] = x & 255;
 108     }
 109     else
 110     {
 111       if(type == 2)
 112       {
 113         pes_header[idx++] = 0x81;
 114         pes_header[idx++] = 0x00;
 115         pes_header[idx++] = 0x00;
 116       }
 117       else
 118         pes_header[idx++] = 0x0f;
 119     }
 120
 121     if(header_len)
 122     {
 123         memcpy(&pes_header[idx], header, header_len);
 124         idx += header_len;
 125     }
 126
 127     my_write (pes_header, idx);
 128     n = my_write (data, payload_size);
 129
 130     len -= n;
 131     data += n;
 132     ptslen = 0; /* store PTS only once, at first packet! */
 133     if(align4 && len < 4)
 134       break;
 135   }
 136
 137   return n;
 138 }
 139
 140 int
 141 send_mpeg_pes_packet (unsigned char *data, int len, int id, uint64_t pts,
 142                       int type, int my_write (unsigned char *data, int len))
 143 {
 144     return send_mpeg_pes_packet_ll(data, len, id, pts, type, NULL, 0, 0, my_write);
 145 }
 146
 147
 148 /* Send MPEG <type> PS packet */
 149 int
 150 send_mpeg_ps_packet(unsigned char *data, int len, int id, uint64_t pts, int type,
 151                       int my_write (unsigned char *data, int len))
 152 {
 153   if(type == 2)
 154     my_write (ps2_header, sizeof (ps2_header));
 155   else
 156     my_write (ps1_header, sizeof (ps1_header));
 157   return send_mpeg_pes_packet (data, len, id, pts, type, my_write);
 158 }
 159
 160 /* Send MPEG 2 LPCM packet */
 161 int
 162 send_mpeg_lpcm_packet(unsigned char* data, int len,
 163                        int id, uint64_t pts, int freq_id,
 164                        int my_write (unsigned char *data, int len))
 165 {
 166     unsigned char header[7] = {0xA0, 0x07, 0x00, 0x04, 0x0C, 1 | (freq_id << 4), 0x80};
 167     return send_mpeg_pes_packet_ll(data, len, 0xBD, pts, 2, header, sizeof(header), 1, my_write);
 168 }