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/* gethdr.c, header decoding */
/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */
/*
* Disclaimer of Warranty
*
* These software programs are available to the user without any license fee or
* royalty on an "as is" basis. The MPEG Software Simulation Group disclaims
* any and all warranties, whether express, implied, or statuary, including any
* implied warranties or merchantability or of fitness for a particular
* purpose. In no event shall the copyright-holder be liable for any
* incidental, punitive, or consequential damages of any kind whatsoever
* arising from the use of these programs.
*
* This disclaimer of warranty extends to the user of these programs and user's
* customers, employees, agents, transferees, successors, and assigns.
*
* The MPEG Software Simulation Group does not represent or warrant that the
* programs furnished hereunder are free of infringement of any third-party
* patents.
*
* Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
* are subject to royalty fees to patent holders. Many of these patents are
* general enough such that they are unavoidable regardless of implementation
* design.
*
*/
#include "config.h"
#include "global.h"
/* private prototypes */
static void sequence_header _ANSI_ARGS_((void));
static void group_of_pictures_header _ANSI_ARGS_((void));
static void picture_header _ANSI_ARGS_((void));
static void extension_and_user_data _ANSI_ARGS_((void));
static void sequence_extension _ANSI_ARGS_((void));
static void sequence_display_extension _ANSI_ARGS_((void));
static void quant_matrix_extension _ANSI_ARGS_((void));
static void sequence_scalable_extension _ANSI_ARGS_((void));
static void picture_display_extension _ANSI_ARGS_((void));
static void picture_coding_extension _ANSI_ARGS_((void));
static void picture_spatial_scalable_extension _ANSI_ARGS_((void));
static void picture_temporal_scalable_extension _ANSI_ARGS_((void));
static int extra_bit_information _ANSI_ARGS_((void));
static void copyright_extension _ANSI_ARGS_((void));
static void user_data _ANSI_ARGS_((void));
static void user_data _ANSI_ARGS_((void));
/* introduced in September 1995 to assist spatial scalable decoding */
static void Update_Temporal_Reference_Tacking_Data _ANSI_ARGS_((void));
/* private variables */
static int Temporal_Reference_Base = 0;
static int True_Framenum_max = -1;
static int Temporal_Reference_GOP_Reset = 0;
#define RESERVED -1
static double frame_rate_Table[16] =
{
0.0,
((23.0*1000.0)/1001.0),
24.0,
25.0,
((30.0*1000.0)/1001.0),
30.0,
50.0,
((60.0*1000.0)/1001.0),
60.0,
RESERVED,
RESERVED,
RESERVED,
RESERVED,
RESERVED,
RESERVED,
RESERVED
};
/*
* decode headers from one input stream
* until an End of Sequence or picture start code
* is found
*/
int Get_Hdr()
{
unsigned int code;
for (;;)
{
/* look for next_start_code */
next_start_code();
code = Get_Bits32();
switch (code)
{
case SEQUENCE_HEADER_CODE:
sequence_header();
break;
case GROUP_START_CODE:
group_of_pictures_header();
break;
case PICTURE_START_CODE:
picture_header();
return 1;
break;
case SEQUENCE_END_CODE:
return 0;
break;
default:
if (!Quiet_Flag)
cprintf("Unexpected next_start_code %08x (ignored)\n",code);
break;
}
}
}
/* align to start of next next_start_code */
void next_start_code()
{
/* byte align */
Flush_Buffer(ld->Incnt&7);
while (Show_Bits(24)!=0x01L)
Flush_Buffer(8);
}
/* decode sequence header */
static void sequence_header()
{
int i;
int pos;
pos = ld->Bitcnt;
horizontal_size = Get_Bits(12);
vertical_size = Get_Bits(12);
aspect_ratio_information = Get_Bits(4);
frame_rate_code = Get_Bits(4);
bit_rate_value = Get_Bits(18);
marker_bit("sequence_header()");
vbv_buffer_size = Get_Bits(10);
constrained_parameters_flag = Get_Bits(1);
if((ld->load_intra_quantizer_matrix = Get_Bits(1)))
{
for (i=0; i<64; i++)
ld->intra_quantizer_matrix[scan[ZIG_ZAG][i]] = Get_Bits(8);
}
else
{
for (i=0; i<64; i++)
ld->intra_quantizer_matrix[i] = default_intra_quantizer_matrix[i];
}
if((ld->load_non_intra_quantizer_matrix = Get_Bits(1)))
{
for (i=0; i<64; i++)
ld->non_intra_quantizer_matrix[scan[ZIG_ZAG][i]] = Get_Bits(8);
}
else
{
for (i=0; i<64; i++)
ld->non_intra_quantizer_matrix[i] = 16;
}
/* copy luminance to chrominance matrices */
for (i=0; i<64; i++)
{
ld->chroma_intra_quantizer_matrix[i] =
ld->intra_quantizer_matrix[i];
ld->chroma_non_intra_quantizer_matrix[i] =
ld->non_intra_quantizer_matrix[i];
}
#ifdef VERBOSE
if (Verbose_Flag > NO_LAYER)
{
cprintf("sequence header (byte %d)\n",(pos>>3)-4);
if (Verbose_Flag > SEQUENCE_LAYER)
{
cprintf(" horizontal_size=%d\n",horizontal_size);
cprintf(" vertical_size=%d\n",vertical_size);
cprintf(" aspect_ratio_information=%d\n",aspect_ratio_information);
cprintf(" frame_rate_code=%d",frame_rate_code);
cprintf(" bit_rate_value=%d\n",bit_rate_value);
cprintf(" vbv_buffer_size=%d\n",vbv_buffer_size);
cprintf(" constrained_parameters_flag=%d\n",constrained_parameters_flag);
cprintf(" load_intra_quantizer_matrix=%d\n",ld->load_intra_quantizer_matrix);
cprintf(" load_non_intra_quantizer_matrix=%d\n",ld->load_non_intra_quantizer_matrix);
}
}
#endif /* VERBOSE */
#ifdef VERIFY
verify_sequence_header++;
#endif /* VERIFY */
extension_and_user_data();
}
/* decode group of pictures header */
/* ISO/IEC 13818-2 section 6.2.2.6 */
static void group_of_pictures_header()
{
int pos;
if (ld == &base)
{
Temporal_Reference_Base = True_Framenum_max + 1; /* *CH* */
Temporal_Reference_GOP_Reset = 1;
}
pos = ld->Bitcnt;
drop_flag = Get_Bits(1);
hour = Get_Bits(5);
minute = Get_Bits(6);
marker_bit("group_of_pictures_header()");
sec = Get_Bits(6);
frame = Get_Bits(6);
closed_gop = Get_Bits(1);
broken_link = Get_Bits(1);
#ifdef VERBOSE
if (Verbose_Flag > NO_LAYER)
{
cprintf("group of pictures (byte %d)\n",(pos>>3)-4);
if (Verbose_Flag > SEQUENCE_LAYER)
{
cprintf(" drop_flag=%d\n",drop_flag);
cprintf(" timecode %d:%02d:%02d:%02d\n",hour,minute,sec,frame);
cprintf(" closed_gop=%d\n",closed_gop);
cprintf(" broken_link=%d\n",broken_link);
}
}
#endif /* VERBOSE */
#ifdef VERIFY
verify_group_of_pictures_header++;
#endif /* VERIFY */
extension_and_user_data();
}
/* decode picture header */
/* ISO/IEC 13818-2 section 6.2.3 */
static void picture_header()
{
int pos;
int Extra_Information_Byte_Count;
/* unless later overwritten by picture_spatial_scalable_extension() */
ld->pict_scal = 0;
pos = ld->Bitcnt;
temporal_reference = Get_Bits(10);
picture_coding_type = Get_Bits(3);
vbv_delay = Get_Bits(16);
if (picture_coding_type==P_TYPE || picture_coding_type==B_TYPE)
{
full_pel_forward_vector = Get_Bits(1);
forward_f_code = Get_Bits(3);
}
if (picture_coding_type==B_TYPE)
{
full_pel_backward_vector = Get_Bits(1);
backward_f_code = Get_Bits(3);
}
#ifdef VERBOSE
if (Verbose_Flag>NO_LAYER)
{
cprintf("picture header (byte %d)\n",(pos>>3)-4);
if (Verbose_Flag>SEQUENCE_LAYER)
{
cprintf(" temporal_reference=%d\n",temporal_reference);
cprintf(" picture_coding_type=%d\n",picture_coding_type);
cprintf(" vbv_delay=%d\n",vbv_delay);
if (picture_coding_type==P_TYPE || picture_coding_type==B_TYPE)
{
cprintf(" full_pel_forward_vector=%d\n",full_pel_forward_vector);
cprintf(" forward_f_code =%d\n",forward_f_code);
}
if (picture_coding_type==B_TYPE)
{
cprintf(" full_pel_backward_vector=%d\n",full_pel_backward_vector);
cprintf(" backward_f_code =%d\n",backward_f_code);
}
}
}
#endif /* VERBOSE */
#ifdef VERIFY
verify_picture_header++;
#endif /* VERIFY */
Extra_Information_Byte_Count =
extra_bit_information();
extension_and_user_data();
/* update tracking information used to assist spatial scalability */
Update_Temporal_Reference_Tacking_Data();
}
/* decode slice header */
/* ISO/IEC 13818-2 section 6.2.4 */
int slice_header()
{
int slice_vertical_position_extension;
int quantizer_scale_code;
int pos;
int slice_picture_id_enable = 0;
int slice_picture_id = 0;
int extra_information_slice = 0;
pos = ld->Bitcnt;
slice_vertical_position_extension =
(ld->MPEG2_Flag && vertical_size>2800) ? Get_Bits(3) : 0;
if (ld->scalable_mode==SC_DP)
ld->priority_breakpoint = Get_Bits(7);
quantizer_scale_code = Get_Bits(5);
ld->quantizer_scale =
ld->MPEG2_Flag ? (ld->q_scale_type ? Non_Linear_quantizer_scale[quantizer_scale_code] : quantizer_scale_code<<1) : quantizer_scale_code;
/* slice_id introduced in March 1995 as part of the video corridendum
(after the IS was drafted in November 1994) */
if (Get_Bits(1))
{
ld->intra_slice = Get_Bits(1);
slice_picture_id_enable = Get_Bits(1);
slice_picture_id = Get_Bits(6);
extra_information_slice = extra_bit_information();
}
else
ld->intra_slice = 0;
#ifdef VERBOSE
if (Verbose_Flag>PICTURE_LAYER)
{
cprintf("slice header (byte %d)\n",(pos>>3)-4);
if (Verbose_Flag>SLICE_LAYER)
{
if (ld->MPEG2_Flag && vertical_size>2800)
cprintf(" slice_vertical_position_extension=%d\n",slice_vertical_position_extension);
if (ld->scalable_mode==SC_DP)
cprintf(" priority_breakpoint=%d\n",ld->priority_breakpoint);
cprintf(" quantizer_scale_code=%d\n",quantizer_scale_code);
cprintf(" slice_picture_id_enable = %d\n", slice_picture_id_enable);
if(slice_picture_id_enable)
cprintf(" slice_picture_id = %d\n", slice_picture_id);
}
}
#endif /* VERBOSE */
#ifdef VERIFY
verify_slice_header++;
#endif /* VERIFY */
return slice_vertical_position_extension;
}
/* decode extension and user data */
/* ISO/IEC 13818-2 section 6.2.2.2 */
static void extension_and_user_data()
{
int code,ext_ID;
next_start_code();
while ((code = Show_Bits(32))==EXTENSION_START_CODE || code==USER_DATA_START_CODE)
{
if (code==EXTENSION_START_CODE)
{
Flush_Buffer32();
ext_ID = Get_Bits(4);
switch (ext_ID)
{
case SEQUENCE_EXTENSION_ID:
sequence_extension();
break;
case SEQUENCE_DISPLAY_EXTENSION_ID:
sequence_display_extension();
break;
case QUANT_MATRIX_EXTENSION_ID:
quant_matrix_extension();
break;
case SEQUENCE_SCALABLE_EXTENSION_ID:
sequence_scalable_extension();
break;
case PICTURE_DISPLAY_EXTENSION_ID:
picture_display_extension();
break;
case PICTURE_CODING_EXTENSION_ID:
picture_coding_extension();
break;
case PICTURE_SPATIAL_SCALABLE_EXTENSION_ID:
picture_spatial_scalable_extension();
break;
case PICTURE_TEMPORAL_SCALABLE_EXTENSION_ID:
picture_temporal_scalable_extension();
break;
case COPYRIGHT_EXTENSION_ID:
copyright_extension();
break;
default:
cprintf("reserved extension start code ID %d\n",ext_ID);
break;
}
next_start_code();
}
else
{
#ifdef VERBOSE
if (Verbose_Flag>NO_LAYER)
cprintf("user data\n");
#endif /* VERBOSE */
Flush_Buffer32();
user_data();
}
}
}
/* decode sequence extension */
/* ISO/IEC 13818-2 section 6.2.2.3 */
static void sequence_extension()
{
int horizontal_size_extension;
int vertical_size_extension;
int bit_rate_extension;
int vbv_buffer_size_extension;
/* derive bit position for trace */
#ifdef VERBOSE
pos = ld->Bitcnt;
#endif
ld->MPEG2_Flag = 1;
ld->scalable_mode = SC_NONE; /* unless overwritten by sequence_scalable_extension() */
layer_id = 0; /* unless overwritten by sequence_scalable_extension() */
profile_and_level_indication = Get_Bits(8);
progressive_sequence = Get_Bits(1);
chroma_format = Get_Bits(2);
horizontal_size_extension = Get_Bits(2);
vertical_size_extension = Get_Bits(2);
bit_rate_extension = Get_Bits(12);
marker_bit("sequence_extension");
vbv_buffer_size_extension = Get_Bits(8);
low_delay = Get_Bits(1);
frame_rate_extension_n = Get_Bits(2);
frame_rate_extension_d = Get_Bits(5);
frame_rate = frame_rate_Table[frame_rate_code] *
((frame_rate_extension_n+1)/(frame_rate_extension_d+1));
/* special case for 422 profile & level must be made */
if((profile_and_level_indication>>7) & 1)
{ /* escape bit of profile_and_level_indication set */
/* 4:2:2 Profile @ Main Level */
if((profile_and_level_indication&15)==5)
{
profile = PROFILE_422;
level = MAIN_LEVEL;
}
}
else
{
profile = profile_and_level_indication >> 4; /* Profile is upper nibble */
level = profile_and_level_indication & 0xF; /* Level is lower nibble */
}
horizontal_size = (horizontal_size_extension<<12) | (horizontal_size&0x0fff);
vertical_size = (vertical_size_extension<<12) | (vertical_size&0x0fff);
/* ISO/IEC 13818-2 does not define bit_rate_value to be composed of
* both the original bit_rate_value parsed in sequence_header() and
* the optional bit_rate_extension in sequence_extension_header().
* However, we use it for bitstream verification purposes.
*/
bit_rate_value += (bit_rate_extension << 18);
bit_rate = ((double) bit_rate_value) * 400.0;
vbv_buffer_size += (vbv_buffer_size_extension << 10);
#ifdef VERBOSE
if (Verbose_Flag>NO_LAYER)
{
cprintf("sequence extension (byte %d)\n",(pos>>3)-4);
if (Verbose_Flag>SEQUENCE_LAYER)
{
cprintf(" profile_and_level_indication=%d\n",profile_and_level_indication);
if (profile_and_level_indication<128)
{
cprintf(" profile=%d, level=%d\n",profile,level);
}
cprintf(" progressive_sequence=%d\n",progressive_sequence);
cprintf(" chroma_format=%d\n",chroma_format);
cprintf(" horizontal_size_extension=%d\n",horizontal_size_extension);
cprintf(" vertical_size_extension=%d\n",vertical_size_extension);
cprintf(" bit_rate_extension=%d\n",bit_rate_extension);
cprintf(" vbv_buffer_size_extension=%d\n",vbv_buffer_size_extension);
cprintf(" low_delay=%d\n",low_delay);
cprintf(" frame_rate_extension_n=%d\n",frame_rate_extension_n);
cprintf(" frame_rate_extension_d=%d\n",frame_rate_extension_d);
}
}
#endif /* VERBOSE */
#ifdef VERIFY
verify_sequence_extension++;
#endif /* VERIFY */
}
/* decode sequence display extension */
static void sequence_display_extension()
{
int pos;
pos = ld->Bitcnt;
video_format = Get_Bits(3);
color_description = Get_Bits(1);
if (color_description)
{
color_primaries = Get_Bits(8);
transfer_characteristics = Get_Bits(8);
matrix_coefficients = Get_Bits(8);
}
display_horizontal_size = Get_Bits(14);
marker_bit("sequence_display_extension");
display_vertical_size = Get_Bits(14);
#ifdef VERBOSE
if (Verbose_Flag>NO_LAYER)
{
cprintf("sequence display extension (byte %d)\n",(pos>>3)-4);
if (Verbose_Flag>SEQUENCE_LAYER)
{
cprintf(" video_format=%d\n",video_format);
cprintf(" color_description=%d\n",color_description);
if (color_description)
{
cprintf(" color_primaries=%d\n",color_primaries);
cprintf(" transfer_characteristics=%d\n",transfer_characteristics);
cprintf(" matrix_coefficients=%d\n",matrix_coefficients);
}
cprintf(" display_horizontal_size=%d\n",display_horizontal_size);
cprintf(" display_vertical_size=%d\n",display_vertical_size);
}
}
#endif /* VERBOSE */
#ifdef VERIFY
verify_sequence_display_extension++;
#endif /* VERIFY */
}
/* decode quant matrix entension */
/* ISO/IEC 13818-2 section 6.2.3.2 */
static void quant_matrix_extension()
{
int i;
int pos;
pos = ld->Bitcnt;
if((ld->load_intra_quantizer_matrix = Get_Bits(1)))
{
for (i=0; i<64; i++)
{
ld->chroma_intra_quantizer_matrix[scan[ZIG_ZAG][i]]
= ld->intra_quantizer_matrix[scan[ZIG_ZAG][i]]
= Get_Bits(8);
}
}
if((ld->load_non_intra_quantizer_matrix = Get_Bits(1)))
{
for (i=0; i<64; i++)
{
ld->chroma_non_intra_quantizer_matrix[scan[ZIG_ZAG][i]]
= ld->non_intra_quantizer_matrix[scan[ZIG_ZAG][i]]
= Get_Bits(8);
}
}
if((ld->load_chroma_intra_quantizer_matrix = Get_Bits(1)))
{
for (i=0; i<64; i++)
ld->chroma_intra_quantizer_matrix[scan[ZIG_ZAG][i]] = Get_Bits(8);
}
if((ld->load_chroma_non_intra_quantizer_matrix = Get_Bits(1)))
{
for (i=0; i<64; i++)
ld->chroma_non_intra_quantizer_matrix[scan[ZIG_ZAG][i]] = Get_Bits(8);
}
#ifdef VERBOSE
if (Verbose_Flag>NO_LAYER)
{
cprintf("quant matrix extension (byte %d)\n",(pos>>3)-4);
cprintf(" load_intra_quantizer_matrix=%d\n",
ld->load_intra_quantizer_matrix);
cprintf(" load_non_intra_quantizer_matrix=%d\n",
ld->load_non_intra_quantizer_matrix);
cprintf(" load_chroma_intra_quantizer_matrix=%d\n",
ld->load_chroma_intra_quantizer_matrix);
cprintf(" load_chroma_non_intra_quantizer_matrix=%d\n",
ld->load_chroma_non_intra_quantizer_matrix);
}
#endif /* VERBOSE */
#ifdef VERIFY
verify_quant_matrix_extension++;
#endif /* VERIFY */
}
/* decode sequence scalable extension */
/* ISO/IEC 13818-2 section 6.2.2.5 */
static void sequence_scalable_extension()
{
int pos;
pos = ld->Bitcnt;
/* values (without the +1 offset) of scalable_mode are defined in
Table 6-10 of ISO/IEC 13818-2 */
ld->scalable_mode = Get_Bits(2) + 1; /* add 1 to make SC_DP != SC_NONE */
layer_id = Get_Bits(4);
if (ld->scalable_mode==SC_SPAT)
{
lower_layer_prediction_horizontal_size = Get_Bits(14);
marker_bit("sequence_scalable_extension()");
lower_layer_prediction_vertical_size = Get_Bits(14);
horizontal_subsampling_factor_m = Get_Bits(5);
horizontal_subsampling_factor_n = Get_Bits(5);
vertical_subsampling_factor_m = Get_Bits(5);
vertical_subsampling_factor_n = Get_Bits(5);
}
if (ld->scalable_mode==SC_TEMP)
Error("temporal scalability not implemented\n");
#ifdef VERBOSE
if (Verbose_Flag>NO_LAYER)
{
cprintf("sequence scalable extension (byte %d)\n",(pos>>3)-4);
if (Verbose_Flag>SEQUENCE_LAYER)
{
cprintf(" scalable_mode=%d\n",ld->scalable_mode-1);
cprintf(" layer_id=%d\n",layer_id);
if (ld->scalable_mode==SC_SPAT)
{
cprintf(" lower_layer_prediction_horiontal_size=%d\n",
lower_layer_prediction_horizontal_size);
cprintf(" lower_layer_prediction_vertical_size=%d\n",
lower_layer_prediction_vertical_size);
cprintf(" horizontal_subsampling_factor_m=%d\n",
horizontal_subsampling_factor_m);
cprintf(" horizontal_subsampling_factor_n=%d\n",
horizontal_subsampling_factor_n);
cprintf(" vertical_subsampling_factor_m=%d\n",
vertical_subsampling_factor_m);
cprintf(" vertical_subsampling_factor_n=%d\n",
vertical_subsampling_factor_n);
}
}
}
#endif /* VERBOSE */
#ifdef VERIFY
verify_sequence_scalable_extension++;
#endif /* VERIFY */
}
/* decode picture display extension */
/* ISO/IEC 13818-2 section 6.2.3.3. */
static void picture_display_extension()
{
int i;
int number_of_frame_center_offsets;
int pos;
pos = ld->Bitcnt;
/* based on ISO/IEC 13818-2 section 6.3.12
(November 1994) Picture display extensions */
/* derive number_of_frame_center_offsets */
if(progressive_sequence)
{
if(repeat_first_field)
{
if(top_field_first)
number_of_frame_center_offsets = 3;
else
number_of_frame_center_offsets = 2;
}
else
{
number_of_frame_center_offsets = 1;
}
}
else
{
if(picture_structure!=FRAME_PICTURE)
{
number_of_frame_center_offsets = 1;
}
else
{
if(repeat_first_field)
number_of_frame_center_offsets = 3;
else
number_of_frame_center_offsets = 2;
}
}
/* now parse */
for (i=0; i<number_of_frame_center_offsets; i++)
{
frame_center_horizontal_offset[i] = Get_Bits(16);
marker_bit("picture_display_extension, first marker bit");
frame_center_vertical_offset[i] = Get_Bits(16);
marker_bit("picture_display_extension, second marker bit");
}
#ifdef VERBOSE
if (Verbose_Flag>NO_LAYER)
{
cprintf("picture display extension (byte %d)\n",(pos>>3)-4);
if (Verbose_Flag>SEQUENCE_LAYER)
{
for (i=0; i<number_of_frame_center_offsets; i++)
{
cprintf(" frame_center_horizontal_offset[%d]=%d\n",i,
frame_center_horizontal_offset[i]);
cprintf(" frame_center_vertical_offset[%d]=%d\n",i,
frame_center_vertical_offset[i]);
}
}
}
#endif /* VERBOSE */
#ifdef VERIFY
verify_picture_display_extension++;
#endif /* VERIFY */
}
/* decode picture coding extension */
static void picture_coding_extension()
{
int pos;
pos = ld->Bitcnt;
f_code[0][0] = Get_Bits(4);
f_code[0][1] = Get_Bits(4);
f_code[1][0] = Get_Bits(4);
f_code[1][1] = Get_Bits(4);
intra_dc_precision = Get_Bits(2);
picture_structure = Get_Bits(2);
top_field_first = Get_Bits(1);
frame_pred_frame_dct = Get_Bits(1);
concealment_motion_vectors = Get_Bits(1);
ld->q_scale_type = Get_Bits(1);
intra_vlc_format = Get_Bits(1);
ld->alternate_scan = Get_Bits(1);
repeat_first_field = Get_Bits(1);
chroma_420_type = Get_Bits(1);
progressive_frame = Get_Bits(1);
composite_display_flag = Get_Bits(1);
if (composite_display_flag)
{
v_axis = Get_Bits(1);
field_sequence = Get_Bits(3);
sub_carrier = Get_Bits(1);
burst_amplitude = Get_Bits(7);
sub_carrier_phase = Get_Bits(8);
}
#ifdef VERBOSE
if (Verbose_Flag>NO_LAYER)
{
cprintf("picture coding extension (byte %d)\n",(pos>>3)-4);
if (Verbose_Flag>SEQUENCE_LAYER)
{
cprintf(" forward horizontal f_code=%d\n", f_code[0][0]);
cprintf(" forward vertical f_code=%d\n", f_code[0][1]);
cprintf(" backward horizontal f_code=%d\n", f_code[1][0]);
cprintf(" backward_vertical f_code=%d\n", f_code[1][1]);
cprintf(" intra_dc_precision=%d\n",intra_dc_precision);
cprintf(" picture_structure=%d\n",picture_structure);
cprintf(" top_field_first=%d\n",top_field_first);
cprintf(" frame_pred_frame_dct=%d\n",frame_pred_frame_dct);
cprintf(" concealment_motion_vectors=%d\n",concealment_motion_vectors);
cprintf(" q_scale_type=%d\n",ld->q_scale_type);
cprintf(" intra_vlc_format=%d\n",intra_vlc_format);
cprintf(" alternate_scan=%d\n",ld->alternate_scan);
cprintf(" repeat_first_field=%d\n",repeat_first_field);
cprintf(" chroma_420_type=%d\n",chroma_420_type);
cprintf(" progressive_frame=%d\n",progressive_frame);
cprintf(" composite_display_flag=%d\n",composite_display_flag);
if (composite_display_flag)
{
cprintf(" v_axis=%d\n",v_axis);
cprintf(" field_sequence=%d\n",field_sequence);
cprintf(" sub_carrier=%d\n",sub_carrier);
cprintf(" burst_amplitude=%d\n",burst_amplitude);
cprintf(" sub_carrier_phase=%d\n",sub_carrier_phase);
}
}
}
#endif /* VERBOSE */
#ifdef VERIFY
verify_picture_coding_extension++;
#endif /* VERIFY */
}
/* decode picture spatial scalable extension */
/* ISO/IEC 13818-2 section 6.2.3.5. */
static void picture_spatial_scalable_extension()
{
int pos;
pos = ld->Bitcnt;
ld->pict_scal = 1; /* use spatial scalability in this picture */
lower_layer_temporal_reference = Get_Bits(10);
marker_bit("picture_spatial_scalable_extension(), first marker bit");
lower_layer_horizontal_offset = Get_Bits(15);
if (lower_layer_horizontal_offset>=16384)
lower_layer_horizontal_offset-= 32768;
marker_bit("picture_spatial_scalable_extension(), second marker bit");
lower_layer_vertical_offset = Get_Bits(15);
if (lower_layer_vertical_offset>=16384)
lower_layer_vertical_offset-= 32768;
spatial_temporal_weight_code_table_index = Get_Bits(2);
lower_layer_progressive_frame = Get_Bits(1);
lower_layer_deinterlaced_field_select = Get_Bits(1);
#ifdef VERBOSE
if (Verbose_Flag>NO_LAYER)
{
cprintf("picture spatial scalable extension (byte %d)\n",(pos>>3)-4);
if (Verbose_Flag>SEQUENCE_LAYER)
{
cprintf(" lower_layer_temporal_reference=%d\n",lower_layer_temporal_reference);
cprintf(" lower_layer_horizontal_offset=%d\n",lower_layer_horizontal_offset);
cprintf(" lower_layer_vertical_offset=%d\n",lower_layer_vertical_offset);
cprintf(" spatial_temporal_weight_code_table_index=%d\n",
spatial_temporal_weight_code_table_index);
cprintf(" lower_layer_progressive_frame=%d\n",lower_layer_progressive_frame);
cprintf(" lower_layer_deinterlaced_field_select=%d\n",lower_layer_deinterlaced_field_select);
}
}
#endif /* VERBOSE */
#ifdef VERIFY
verify_picture_spatial_scalable_extension++;
#endif /* VERIFY */
}
/* decode picture temporal scalable extension
*
* not implemented
*/
/* ISO/IEC 13818-2 section 6.2.3.4. */
static void picture_temporal_scalable_extension()
{
Error("temporal scalability not supported\n");
#ifdef VERIFY
verify_picture_temporal_scalable_extension++;
#endif /* VERIFY */
}
/* decode extra bit information */
/* ISO/IEC 13818-2 section 6.2.3.4. */
static int extra_bit_information()
{
int Byte_Count = 0;
while (Get_Bits1())
{
Flush_Buffer(8);
Byte_Count++;
}
return(Byte_Count);
}
/* ISO/IEC 13818-2 section 5.3 */
/* Purpose: this function is mainly designed to aid in bitstream conformance
testing. A simple Flush_Buffer(1) would do */
void marker_bit(text)
char *text;
{
int marker;
marker = Get_Bits(1);
#ifdef VERIFY
if(!marker)
cprintf("ERROR: %s--marker_bit set to 0",text);
#endif
}
/* ISO/IEC 13818-2 sections 6.3.4.1 and 6.2.2.2.2 */
static void user_data()
{
/* skip ahead to the next start code */
next_start_code();
}
/* Copyright extension */
/* ISO/IEC 13818-2 section 6.2.3.6. */
/* (header added in November, 1994 to the IS document) */
static void copyright_extension()
{
int pos;
int reserved_data;
pos = ld->Bitcnt;
copyright_flag = Get_Bits(1);
copyright_identifier = Get_Bits(8);
original_or_copy = Get_Bits(1);
/* reserved */
reserved_data = Get_Bits(7);
marker_bit("copyright_extension(), first marker bit");
copyright_number_1 = Get_Bits(20);
marker_bit("copyright_extension(), second marker bit");
copyright_number_2 = Get_Bits(22);
marker_bit("copyright_extension(), third marker bit");
copyright_number_3 = Get_Bits(22);
if(Verbose_Flag>NO_LAYER)
{
cprintf("copyright_extension (byte %d)\n",(pos>>3)-4);
if (Verbose_Flag>SEQUENCE_LAYER)
{
cprintf(" copyright_flag =%d\n",copyright_flag);
cprintf(" copyright_identifier=%d\n",copyright_identifier);
cprintf(" original_or_copy = %d (original=1, copy=0)\n",
original_or_copy);
cprintf(" copyright_number_1=%d\n",copyright_number_1);
cprintf(" copyright_number_2=%d\n",copyright_number_2);
cprintf(" copyright_number_3=%d\n",copyright_number_3);
}
}
#ifdef VERIFY
verify_copyright_extension++;
#endif /* VERIFY */
}
/* introduced in September 1995 to assist Spatial Scalability */
static void Update_Temporal_Reference_Tacking_Data()
{
static int temporal_reference_wrap = 0;
static int temporal_reference_old = 0;
if (ld == &base) /* *CH* */
{
if (picture_coding_type!=B_TYPE && temporal_reference!=temporal_reference_old)
/* check first field of */
{
/* non-B-frame */
if (temporal_reference_wrap)
{/* wrap occured at previous I- or P-frame */
/* now all intervening B-frames which could
still have high temporal_reference values are done */
Temporal_Reference_Base += 1024;
temporal_reference_wrap = 0;
}
/* distinguish from a reset */
if (temporal_reference<temporal_reference_old && !Temporal_Reference_GOP_Reset)
temporal_reference_wrap = 1; /* we must have just passed a GOP-Header! */
temporal_reference_old = temporal_reference;
Temporal_Reference_GOP_Reset = 0;
}
True_Framenum = Temporal_Reference_Base + temporal_reference;
/* temporary wrap of TR at 1024 for M frames */
if (temporal_reference_wrap && temporal_reference <= temporal_reference_old)
True_Framenum += 1024;
True_Framenum_max = (True_Framenum > True_Framenum_max) ?
True_Framenum : True_Framenum_max;
}
}