libmpdemux/mpeg_packetizer.c

   1 /*
   2  * set of helper routines for building MPEG 1/2 PS/PES packets
   3  *
   4  * Copyright (C) 2006 Benjamin Zores
   5  *
   6  * Based on code borrowed from vo_mpegpes/vo_dxr2:
   7  *    (C) 2000 Ralph Metzler <ralph@convergence.de>
   8  *             Marcus Metzler <marcus@convergence.de>
   9  *             Gerard Lantau
  10  *
  11  * This file is part of MPlayer.
  12  *
  13  * MPlayer is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * MPlayer is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License along
  24  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  25  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  26  */
  27
  28 #include <unistd.h>
  29 #include <string.h>
  30 #include <inttypes.h>
  31
  32 #include "mp_msg.h"
  33 #include "mpeg_packetizer.h"
  34
  35 #define PES_MAX_SIZE 2048
  36
  37 static const unsigned char ps2_header[] = {
  38   0x00, 0x00, 0x01, 0xba, 0x44, 0x00, 0x04, 0x00,
  39   0x04, 0x01, 0x01, 0x86, 0xa3, 0xf8
  40 };
  41
  42
  43 static const unsigned char ps1_header[] = {
  44   0x00, 0x00, 0x01, 0xba, 0x21, 0x00,
  45   0xb9, 0x37, 0x83, 0x80, 0xc3, 0x51,
  46 };
  47
  48 /* Send MPEG <type> PES packet */
  49 static int
  50 send_mpeg_pes_packet_ll(unsigned char *data, int len, int id, uint64_t pts,
  51                       int type, unsigned char *header, int header_len,
  52                       int align4, int my_write (const unsigned char *data, int len))
  53 {
  54   int ptslen = (pts ? 5 : 0);
  55   int n = 0;
  56   int idx, plen;
  57   int hdr;
  58   unsigned char pes_header[PES_MAX_SIZE];
  59
  60   mp_msg (MSGT_HEADER, MSGL_DBG2,
  61           "MPEG%d PES packet: 0x%x => %"PRIu64"   \n", type, id, pts);
  62   memset (pes_header, '\0', PES_MAX_SIZE);
  63
  64   /* startcode */
  65   pes_header[0] = 0;
  66   pes_header[1] = 0;
  67   pes_header[2] = 0x01;
  68   pes_header[3] = id; /* stream id */
  69
  70   while (len > 0)
  71   {
  72     int payload_size = len;  /* data + PTS */
  73     if(type == 2)
  74         hdr = 3;
  75     else
  76         hdr = (ptslen ? 0 : 1);
  77     if (6 + hdr + ptslen + payload_size + header_len > PES_MAX_SIZE)
  78       payload_size = PES_MAX_SIZE - 6 - hdr - ptslen - header_len;
  79     if(align4)
  80       payload_size &= ~3;
  81
  82     /* construct PES header: packetize */
  83     plen = payload_size + hdr + ptslen + header_len;
  84     pes_header[4] = plen >> 8;
  85     pes_header[5] = plen & 255;
  86     idx = 6;
  87
  88     if (ptslen)
  89     {
  90       int x;
  91
  92       if(type == 2)
  93       {
  94         pes_header[idx++] = 0x81;
  95         pes_header[idx++] = 0x80;
  96         pes_header[idx++] = ptslen;
  97       }
  98
  99       /* presentation time stamp */
 100       x = (0x02 << 4) | (((pts >> 30) & 0x07) << 1) | 1;
 101       pes_header[idx++] = x;
 102
 103       x = ((((pts >> 15) & 0x7fff) << 1) | 1);
 104       pes_header[idx++] = x >>8;
 105       pes_header[idx++] = x & 255;
 106
 107       x = (((pts & 0x7fff) << 1) | 1);
 108       pes_header[idx++] = x >> 8;
 109       pes_header[idx++] = x & 255;
 110     }
 111     else
 112     {
 113       if(type == 2)
 114       {
 115         pes_header[idx++] = 0x81;
 116         pes_header[idx++] = 0x00;
 117         pes_header[idx++] = 0x00;
 118       }
 119       else
 120         pes_header[idx++] = 0x0f;
 121     }
 122
 123     if(header_len)
 124     {
 125         memcpy(&pes_header[idx], header, header_len);
 126         idx += header_len;
 127     }
 128
 129     my_write (pes_header, idx);
 130     n = my_write (data, payload_size);
 131
 132     len -= n;
 133     data += n;
 134     ptslen = 0; /* store PTS only once, at first packet! */
 135     if(align4 && len < 4)
 136       break;
 137   }
 138
 139   return n;
 140 }
 141
 142 int
 143 send_mpeg_pes_packet (unsigned char *data, int len, int id, uint64_t pts,
 144                       int type, int my_write (const unsigned char *data, int len))
 145 {
 146     return send_mpeg_pes_packet_ll(data, len, id, pts, type, NULL, 0, 0, my_write);
 147 }
 148
 149
 150 /* Send MPEG <type> PS packet */
 151 int
 152 send_mpeg_ps_packet(unsigned char *data, int len, int id, uint64_t pts, int type,
 153                       int my_write (const unsigned char *data, int len))
 154 {
 155   if(type == 2)
 156     my_write (ps2_header, sizeof (ps2_header));
 157   else
 158     my_write (ps1_header, sizeof (ps1_header));
 159   return send_mpeg_pes_packet (data, len, id, pts, type, my_write);
 160 }
 161
 162 /* Send MPEG 2 LPCM packet */
 163 int
 164 send_mpeg_lpcm_packet(unsigned char* data, int len,
 165                        int id, uint64_t pts, int freq_id,
 166                        int my_write (const unsigned char *data, int len))
 167 {
 168     unsigned char header[7] = {0xA0, 0x07, 0x00, 0x04, 0x0C, 1 | (freq_id << 4), 0x80};
 169     return send_mpeg_pes_packet_ll(data, len, 0xBD, pts, 2, header, sizeof(header), 1, my_write);
 170 }