src/gallium/state_trackers/vdpau/mpeg2_bitstream_parser.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2010 Thomas Balling Sørensen.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28 #include "mpeg2_bitstream_parser.h"
  29
  30 int
  31 vlVdpMPEG2NextStartCode(struct vdpMPEG2BitstreamParser *parser)
  32 {
  33         uint32_t integer = 0;
  34         uint32_t bytes_to_end;
  35
  36         /* Move cursor to the start of a byte */
  37         while(parser->cursor % 8)
  38                 parser->cursor++;
  39
  40         bytes_to_end = parser->cur_bitstream_length - parser->cursor/8 - 1;
  41
  42         /* Read byte after byte, until startcode is found */
  43         while(integer != 0x00000100)
  44         {
  45                 if (bytes_to_end < 0)
  46                 {
  47                         parser->state = MPEG2_HEADER_DONE;
  48                         return 1;
  49                 }
  50
  51                 integer << 8;
  52                 integer = integer & (unsigned char)(parser->ptr_bitstream + parser->cursor/8)[0];
  53
  54                 bytes_to_end--;
  55                 parser->cursor += 8;
  56
  57         }
  58
  59         /* start_code found. rewind cursor a byte */
  60         parser->cursor -= 8;
  61
  62         return 0;
  63 }
  64
  65 int
  66 vlVdpMPEG2BitstreamToMacroblock (
  67                   struct pipe_screen *screen,
  68                   VdpBitstreamBuffer const *bitstream_buffers,
  69                   uint32_t bitstream_buffer_count,
  70           unsigned int *num_macroblocks,
  71           struct pipe_mpeg12_macroblock **pipe_macroblocks)
  72 {
  73         bool b_header_done = false;
  74         struct vdpMPEG2BitstreamParser parser;
  75
  76         debug_printf("[VDPAU] Starting decoding MPEG2 stream");
  77
  78         num_macroblocks[0] = 0;
  79
  80         memset(&parser,0,sizeof(parser));
  81         parser.state = MPEG2_HEADER_START_CODE;
  82         parser.cur_bitstream_length = bitstream_buffers[0].bitstream_bytes;
  83         parser.ptr_bitstream = (unsigned char *)bitstream_buffers[0].bitstream;
  84
  85         /* Main header parser loop */
  86         while(!b_header_done)
  87         {
  88                 switch (parser.state)
  89                 {
  90                 case MPEG2_HEADER_START_CODE:
  91                         if (vlVdpMPEG2NextStartCode(&parser))
  92                                 continue;
  93
  94                         /* Start_code found */
  95                         switch ((parser.ptr_bitstream + parser.cursor/8)[0])
  96                         {
  97                                 /* sequence_header_code */
  98                                 case 0xB3:
  99                                 debug_printf("[VDPAU][Bitstream parser] Sequence header code found at cursor pos: %d\n", parser.cursor);
 100                                 exit(1);
 101                                 break;
 102                         }
 103
 104                 break;
 105                 case MPEG2_HEADER_DONE:
 106                         debug_printf("[VDPAU][Bitstream parser] Done parsing current header\n");
 107                 break;
 108
 109                 }
 110
 111
 112         }
 113
 114
 115         return 0;
 116 }
 117