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 const unsigned char ps2_header[] = {
  35   0x00, 0x00, 0x01, 0xba, 0x44, 0x00, 0x04, 0x00,
  36   0x04, 0x01, 0x01, 0x86, 0xa3, 0xf8
  37 };
  38
  39
  40 static const unsigned char ps1_header[] = {
  41   0x00, 0x00, 0x01, 0xba, 0x21, 0x00,
  42   0xb9, 0x37, 0x83, 0x80, 0xc3, 0x51,
  43 };
  44
  45 /* Send MPEG <type> PES packet */
  46 static int
  47 send_mpeg_pes_packet_ll(unsigned char *data, int len, int id, uint64_t pts,
  48                       int type, unsigned char *header, int header_len,
  49                       int align4, int my_write (const unsigned char *data, int len))
  50 {
  51   int ptslen = (pts ? 5 : 0);
  52   int n = 0;
  53   int idx, plen;
  54   int hdr;
  55   unsigned char pes_header[PES_MAX_SIZE];
  56
  57   mp_msg (MSGT_HEADER, MSGL_DBG2,
  58           "MPEG%d PES packet: 0x%x => %lu   \n", type, id, pts);
  59   memset (pes_header, '\0', PES_MAX_SIZE);
  60
  61   /* startcode */
  62   pes_header[0] = 0;
  63   pes_header[1] = 0;
  64   pes_header[2] = 0x01;
  65   pes_header[3] = id; /* stream id */
  66
  67   while (len > 0)
  68   {
  69     int payload_size = len;  /* data + PTS */
  70     if(type == 2)
  71         hdr = 3;
  72     else
  73         hdr = (ptslen ? 0 : 1);
  74     if (6 + hdr + ptslen + payload_size + header_len > PES_MAX_SIZE)
  75       payload_size = PES_MAX_SIZE - 6 - hdr - ptslen - header_len;
  76     if(align4)
  77       payload_size &= ~3;
  78
  79     /* construct PES header: packetize */
  80     plen = payload_size + hdr + ptslen + header_len;
  81     pes_header[4] = plen >> 8;
  82     pes_header[5] = plen & 255;
  83     idx = 6;
  84
  85     if (ptslen)
  86     {
  87       int x;
  88
  89       if(type == 2)
  90       {
  91         pes_header[idx++] = 0x81;
  92         pes_header[idx++] = 0x80;
  93         pes_header[idx++] = ptslen;
  94       }
  95
  96       /* presentation time stamp */
  97       x = (0x02 << 4) | (((pts >> 30) & 0x07) << 1) | 1;
  98       pes_header[idx++] = x;
  99
 100       x = ((((pts >> 15) & 0x7fff) << 1) | 1);
 101       pes_header[idx++] = x >>8;
 102       pes_header[idx++] = x & 255;
 103
 104       x = (((pts & 0x7fff) << 1) | 1);
 105       pes_header[idx++] = x >> 8;
 106       pes_header[idx++] = x & 255;
 107     }
 108     else
 109     {
 110       if(type == 2)
 111       {
 112         pes_header[idx++] = 0x81;
 113         pes_header[idx++] = 0x00;
 114         pes_header[idx++] = 0x00;
 115       }
 116       else
 117         pes_header[idx++] = 0x0f;
 118     }
 119
 120     if(header_len)
 121     {
 122         memcpy(&pes_header[idx], header, header_len);
 123         idx += header_len;
 124     }
 125
 126     my_write (pes_header, idx);
 127     n = my_write (data, payload_size);
 128
 129     len -= n;
 130     data += n;
 131     ptslen = 0; /* store PTS only once, at first packet! */
 132     if(align4 && len < 4)
 133       break;
 134   }
 135
 136   return n;
 137 }
 138
 139 int
 140 send_mpeg_pes_packet (unsigned char *data, int len, int id, uint64_t pts,
 141                       int type, int my_write (const unsigned char *data, int len))
 142 {
 143     return send_mpeg_pes_packet_ll(data, len, id, pts, type, NULL, 0, 0, my_write);
 144 }
 145
 146
 147 /* Send MPEG <type> PS packet */
 148 int
 149 send_mpeg_ps_packet(unsigned char *data, int len, int id, uint64_t pts, int type,
 150                       int my_write (const unsigned char *data, int len))
 151 {
 152   if(type == 2)
 153     my_write (ps2_header, sizeof (ps2_header));
 154   else
 155     my_write (ps1_header, sizeof (ps1_header));
 156   return send_mpeg_pes_packet (data, len, id, pts, type, my_write);
 157 }
 158
 159 /* Send MPEG 2 LPCM packet */
 160 int
 161 send_mpeg_lpcm_packet(unsigned char* data, int len,
 162                        int id, uint64_t pts, int freq_id,
 163                        int my_write (const unsigned char *data, int len))
 164 {
 165     unsigned char header[7] = {0xA0, 0x07, 0x00, 0x04, 0x0C, 1 | (freq_id << 4), 0x80};
 166     return send_mpeg_pes_packet_ll(data, len, 0xBD, pts, 2, header, sizeof(header), 1, my_write);
 167 }