www.pudn.com > mpeg2win-0.4-source.zip > decode.c
/*
* decode.c
* Copyright (C) 1999-2001 Aaron Holtzman
*
* This file is part of mpeg2dec, a free MPEG-2 video stream decoder.
*
* mpeg2dec is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* mpeg2dec is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "config.h"
#include
#include /* memcpy/memset, try to remove */
#include
#include
#include "video_out.h"
#include "mpeg2.h"
#include "mpeg2_internal.h"
#include "mm_accel.h"
#include "attributes.h"
#include "mmx.h"
#ifdef HAVE_MEMALIGN
/* some systems have memalign() but no declaration for it */
void * memalign (size_t align, size_t size);
#else
/* assume malloc alignment is sufficient */
#define memalign(align,size) malloc (size)
#endif
mpeg2_config_t config;
void mpeg2_init (mpeg2dec_t * mpeg2dec, uint32_t mm_accel,
vo_instance_t * output)
{
static int do_init = 1;
if (do_init) {
do_init = 0;
config.flags = mm_accel;
idct_init ();
motion_comp_init ();
}
mpeg2dec->chunk_buffer = memalign (16, 224 * 1024 + 4);
mpeg2dec->picture = memalign (16, sizeof (picture_t));
mpeg2dec->shift = 0;
mpeg2dec->is_sequence_needed = 1;
mpeg2dec->drop_flag = 0;
mpeg2dec->drop_frame = 0;
mpeg2dec->in_slice = 0;
mpeg2dec->output = output;
mpeg2dec->chunk_ptr = mpeg2dec->chunk_buffer;
mpeg2dec->code = 0xff;
memset (mpeg2dec->picture, 0, sizeof (picture_t));
/* initialize supstructures */
header_state_init (mpeg2dec->picture);
}
static int parse_chunk (mpeg2dec_t * mpeg2dec, int code, uint8_t * buffer)
{
picture_t * picture;
int is_frame_done;
/* wait for sequence_header_code */
if (mpeg2dec->is_sequence_needed && (code != 0xb3))
{
return 0;
}
stats_header (code, buffer);
picture = mpeg2dec->picture;
is_frame_done = mpeg2dec->in_slice && ((!code) || (code >= 0xb0));
if (is_frame_done) {
mpeg2dec->in_slice = 0;
if (((picture->picture_structure == FRAME_PICTURE) ||
(picture->second_field)) &&
(!(mpeg2dec->drop_frame))) {
vo_draw ((picture->picture_coding_type == B_TYPE) ?
picture->current_frame :
picture->forward_reference_frame);
#ifdef ARCH_X86
if (config.flags & MM_ACCEL_X86_MMX)
emms ();
#endif
}
}
switch (code) {
case 0x00: /* picture_start_code */
if (header_process_picture_header (picture, buffer)) {
fprintf (stderr, "bad picture header\n");
exit (1);
}
mpeg2dec->drop_frame =
mpeg2dec->drop_flag && (picture->picture_coding_type == B_TYPE);
break;
case 0xb3: /* sequence_header_code */
if (header_process_sequence_header (picture, buffer)) {
fprintf (stderr, "bad sequence header\n");
exit (1);
}
if (mpeg2dec->is_sequence_needed) {
mpeg2dec->is_sequence_needed = 0;
if (vo_setup (mpeg2dec->output, picture->coded_picture_width,
picture->coded_picture_height)) {
fprintf (stderr, "display setup failed\n");
exit (1);
}
picture->forward_reference_frame =
vo_get_frame (mpeg2dec->output,
VO_PREDICTION_FLAG | VO_BOTH_FIELDS);
picture->backward_reference_frame =
vo_get_frame (mpeg2dec->output,
VO_PREDICTION_FLAG | VO_BOTH_FIELDS);
}
mpeg2dec->frame_rate_code = picture->frame_rate_code; /* FIXME */
break;
case 0xb5: /* extension_start_code */
if (header_process_extension (picture, buffer)) {
fprintf (stderr, "bad extension\n");
exit (1);
}
break;
default:
if (code >= 0xb9)
fprintf (stderr, "stream not demultiplexed ?\n");
if (code >= 0xb0)
break;
if (!(mpeg2dec->in_slice)) {
mpeg2dec->in_slice = 1;
if (picture->second_field) {
vo_field (picture->current_frame, picture->picture_structure);
} else {
if (picture->picture_coding_type == B_TYPE)
picture->current_frame =
vo_get_frame (mpeg2dec->output,
picture->picture_structure);
else {
picture->current_frame =
vo_get_frame (mpeg2dec->output,
(VO_PREDICTION_FLAG |
picture->picture_structure));
picture->forward_reference_frame =
picture->backward_reference_frame;
picture->backward_reference_frame = picture->current_frame;
}
}
}
if (!(mpeg2dec->drop_frame)) {
slice_process (picture, code, buffer);
#ifdef ARCH_X86
if (config.flags & MM_ACCEL_X86_MMX)
emms ();
#endif
}
}
return is_frame_done;
}
int mpeg2_decode_data (mpeg2dec_t * mpeg2dec, uint8_t * current, uint8_t * end)
{
uint32_t shift;
uint8_t * chunk_ptr;
uint8_t byte;
int ret = 0;
shift = mpeg2dec->shift;
chunk_ptr = mpeg2dec->chunk_ptr;
while (current != end) {
while (1) {
byte = *current++;
if (shift != 0x00000100) {
*chunk_ptr++ = byte;
shift = (shift | byte) << 8;
if (current != end)
continue;
mpeg2dec->chunk_ptr = chunk_ptr;
mpeg2dec->shift = shift;
return ret;
}
break;
}
/* found start_code following chunk */
ret += parse_chunk (mpeg2dec, mpeg2dec->code, mpeg2dec->chunk_buffer);
/* done with header or slice, prepare for next one */
mpeg2dec->code = byte;
chunk_ptr = mpeg2dec->chunk_buffer;
shift = 0xffffff00;
}
mpeg2dec->chunk_ptr = chunk_ptr;
mpeg2dec->shift = shift;
return ret;
}
void mpeg2_close (mpeg2dec_t * mpeg2dec)
{
static uint8_t finalizer[] = {0,0,1,0};
mpeg2_decode_data (mpeg2dec, finalizer, finalizer+4);
if (! (mpeg2dec->is_sequence_needed))
vo_draw (mpeg2dec->picture->backward_reference_frame);
free (mpeg2dec->chunk_buffer);
free (mpeg2dec->picture);
}
void mpeg2_drop (mpeg2dec_t * mpeg2dec, int flag)
{
mpeg2dec->drop_flag = flag;
}