modules/codec/h264_nal.h

   1 /*****************************************************************************
   2  * Copyright © 2010-2011 VideoLAN
   3  *
   4  * Authors: Jean-Baptiste Kempf <jb@videolan.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 /* Parse the SPS/PPS Metadata and convert it to annex b format */
  22 static int convert_sps_pps( decoder_t *p_dec, const uint8_t *p_buf,
  23                             uint32_t i_buf_size, uint8_t *p_out_buf,
  24                             uint32_t i_out_buf_size, uint32_t *p_sps_pps_size,
  25                             uint32_t *p_nal_size)
  26 {
  27     int i_profile;
  28     uint32_t i_data_size = i_buf_size, i_nal_size, i_sps_pps_size = 0;
  29     unsigned int i_loop_end;
  30
  31     /* */
  32     if( i_data_size < 7 )
  33     {
  34         msg_Err( p_dec, "Input Metadata too small" );
  35         return VLC_ENOMEM;
  36     }
  37
  38     /* Read infos in first 6 bytes */
  39     i_profile    = (p_buf[1] << 16) | (p_buf[2] << 8) | p_buf[3];
  40     if (p_nal_size)
  41         *p_nal_size  = (p_buf[4] & 0x03) + 1;
  42     p_buf       += 5;
  43     i_data_size -= 5;
  44
  45     for ( unsigned int j = 0; j < 2; j++ )
  46     {
  47         /* First time is SPS, Second is PPS */
  48         if( i_data_size < 1 )
  49         {
  50             msg_Err( p_dec, "PPS too small after processing SPS/PPS %u",
  51                     i_data_size );
  52             return VLC_ENOMEM;
  53         }
  54         i_loop_end = p_buf[0] & (j == 0 ? 0x1f : 0xff);
  55         p_buf++; i_data_size--;
  56
  57         for ( unsigned int i = 0; i < i_loop_end; i++)
  58         {
  59             if( i_data_size < 2 )
  60             {
  61                 msg_Err( p_dec, "SPS is too small %u", i_data_size );
  62                 return VLC_ENOMEM;
  63             }
  64
  65             i_nal_size = (p_buf[0] << 8) | p_buf[1];
  66             p_buf += 2;
  67             i_data_size -= 2;
  68
  69             if( i_data_size < i_nal_size )
  70             {
  71                 msg_Err( p_dec, "SPS size does not match NAL specified size %u",
  72                         i_data_size );
  73                 return VLC_ENOMEM;
  74             }
  75             if( i_sps_pps_size + 4 + i_nal_size > i_out_buf_size )
  76             {
  77                 msg_Err( p_dec, "Output SPS/PPS buffer too small" );
  78                 return VLC_ENOMEM;
  79             }
  80
  81             p_out_buf[i_sps_pps_size++] = 0;
  82             p_out_buf[i_sps_pps_size++] = 0;
  83             p_out_buf[i_sps_pps_size++] = 0;
  84             p_out_buf[i_sps_pps_size++] = 1;
  85
  86             memcpy( p_out_buf + i_sps_pps_size, p_buf, i_nal_size );
  87             i_sps_pps_size += i_nal_size;
  88
  89             p_buf += i_nal_size;
  90             i_data_size -= i_nal_size;
  91         }
  92     }
  93
  94     *p_sps_pps_size = i_sps_pps_size;
  95
  96     return VLC_SUCCESS;
  97 }
  98