/***************************************************************************** * * XVID MPEG-4 VIDEO CODEC * - Bitstream reader/writer functions - * * Copyright (C) 2001-2002 - Peter Ross * * This file is part of XviD, a free MPEG-4 video encoder/decoder * * XviD 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. * * This program 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 * * Under section 8 of the GNU General Public License, the copyright * holders of XVID explicitly forbid distribution in the following * countries: * * - Japan * - United States of America * * Linking XviD statically or dynamically with other modules is making a * combined work based on XviD. Thus, the terms and conditions of the * GNU General Public License cover the whole combination. * * As a special exception, the copyright holders of XviD give you * permission to link XviD with independent modules that communicate with * XviD solely through the VFW1.1 and DShow interfaces, regardless of the * license terms of these independent modules, and to copy and distribute * the resulting combined work under terms of your choice, provided that * every copy of the combined work is accompanied by a complete copy of * the source code of XviD (the version of XviD used to produce the * combined work), being distributed under the terms of the GNU General * Public License plus this exception. An independent module is a module * which is not derived from or based on XviD. * * Note that people who make modified versions of XviD are not obligated * to grant this special exception for their modified versions; it is * their choice whether to do so. The GNU General Public License gives * permission to release a modified version without this exception; this * exception also makes it possible to release a modified version which * carries forward this exception. * * $Id: bitstream.c,v 1.37 2002/12/15 01:21:12 edgomez Exp $ * ****************************************************************************/ #include "bitstream.h" #include "zigzag.h" #include "../quant/quant_matrix.h" /***************************************************************************** * Functions ****************************************************************************/ static uint32_t __inline log2bin(uint32_t value) { /* Changed by Chenm001 */ #if !defined(_MSC_VER) int n = 0; while (value) { value >>= 1; n++; } return n; #else __asm { bsr eax, value inc eax } #endif } static const uint32_t intra_dc_threshold_table[] = { 32, /* never use */ 13, 15, 17, 19, 21, 23, 1, }; void bs_get_matrix(Bitstream * bs, uint8_t * matrix) { int i = 0; int last, value = 0; do { last = value; value = BitstreamGetBits(bs, 8); matrix[scan_tables[0][i++]] = value; } while (value != 0 && i < 64); i--; /* fix little bug at coeff not full */ while (i < 64) { matrix[scan_tables[0][i++]] = last; } } /* for PVOP addbits == fcode - 1 */ /* for BVOP addbits == max(fcode,bcode) - 1 */ /* returns mbpos */ int read_video_packet_header(Bitstream *bs, const int addbits, int * quant) { int nbits; int mbnum; int hec; nbits = NUMBITS_VP_RESYNC_MARKER + addbits; BitstreamSkip(bs, BitstreamNumBitsToByteAlign(bs)); BitstreamSkip(bs, nbits); DPRINTF(DPRINTF_STARTCODE, ""); /* if (dec->shape != VIDOBJLAY_SHAPE_RECTANGULAR) { */ /* hec */ /* vop_width */ /* marker_bit */ /* vop_height */ /* marker_bit */ /*} */ mbnum = BitstreamGetBits(bs, 9); DPRINTF(DPRINTF_HEADER, "mbnum %i", mbnum); /* if (dec->shape != VIDOBJLAY_SHAPE_BINARYONLY) */ *quant = BitstreamGetBits(bs, 5); DPRINTF(DPRINTF_HEADER, "quant %i", *quant); /* if (dec->shape != VIDOBJLAY_SHAPE_RECTANGULAR) */ hec = BitstreamGetBit(bs); DPRINTF(DPRINTF_HEADER, "header_extension_code %i", hec); /* if (hec) */ /* .. decoder hec-header ... */ return mbnum; } /* decode headers returns coding_type, or -1 if error */ #define VIDOBJ_START_CODE_MASK 0x0000001f #define VIDOBJLAY_START_CODE_MASK 0x0000000f int BitstreamReadHeaders(Bitstream * bs, DECODER * dec, uint32_t * rounding, uint32_t * quant, uint32_t * fcode_forward, uint32_t * fcode_backward, uint32_t * intra_dc_threshold) { uint32_t vol_ver_id; static uint32_t time_increment_resolution; uint32_t coding_type; uint32_t start_code; uint32_t time_incr = 0; int32_t time_increment = 0; do { BitstreamByteAlign(bs); start_code = BitstreamShowBits(bs, 32); if (start_code == VISOBJSEQ_START_CODE) { int profile; DPRINTF(DPRINTF_STARTCODE, ""); BitstreamSkip(bs, 32); /* visual_object_sequence_start_code */ profile = BitstreamGetBits(bs, 8); /* profile_and_level_indication */ DPRINTF(DPRINTF_HEADER, "profile_and_level_indication %i", profile); } else if (start_code == VISOBJSEQ_STOP_CODE) { BitstreamSkip(bs, 32); /* visual_object_sequence_stop_code */ DPRINTF(DPRINTF_STARTCODE, ""); } else if (start_code == VISOBJ_START_CODE) { DPRINTF(DPRINTF_STARTCODE, ""); BitstreamSkip(bs, 32); /* visual_object_start_code */ if (BitstreamGetBit(bs)) /* is_visual_object_identified */ { vol_ver_id = BitstreamGetBits(bs, 4); /* visual_object_ver_id */ DPRINTF(DPRINTF_HEADER,"ver_id %i", vol_ver_id); BitstreamSkip(bs, 3); /* visual_object_priority */ } else { vol_ver_id = 1; } if (BitstreamShowBits(bs, 4) != VISOBJ_TYPE_VIDEO) /* visual_object_type */ { DPRINTF(DPRINTF_ERROR, "visual_object_type != video"); return -1; } BitstreamSkip(bs, 4); /* video_signal_type */ if (BitstreamGetBit(bs)) /* video_signal_type */ { DPRINTF(DPRINTF_HEADER,"+ video_signal_type"); BitstreamSkip(bs, 3); /* video_format */ BitstreamSkip(bs, 1); /* video_range */ if (BitstreamGetBit(bs)) /* color_description */ { DPRINTF(DPRINTF_HEADER,"+ color_description"); BitstreamSkip(bs, 8); /* color_primaries */ BitstreamSkip(bs, 8); /* transfer_characteristics */ BitstreamSkip(bs, 8); /* matrix_coefficients */ } } } else if ((start_code & ~VIDOBJ_START_CODE_MASK) == VIDOBJ_START_CODE) { DPRINTF(DPRINTF_STARTCODE, ""); DPRINTF(DPRINTF_HEADER, "vo id %i", start_code & VIDOBJ_START_CODE_MASK); BitstreamSkip(bs, 32); /* video_object_start_code */ } else if ((start_code & ~VIDOBJLAY_START_CODE_MASK) == VIDOBJLAY_START_CODE) { DPRINTF(DPRINTF_STARTCODE, ""); DPRINTF(DPRINTF_HEADER, "vol id %i", start_code & VIDOBJLAY_START_CODE_MASK); BitstreamSkip(bs, 32); /* video_object_layer_start_code */ BitstreamSkip(bs, 1); /* random_accessible_vol */ /* video_object_type_indication */ if (BitstreamShowBits(bs, 8) != VIDOBJLAY_TYPE_SIMPLE && BitstreamShowBits(bs, 8) != VIDOBJLAY_TYPE_CORE && BitstreamShowBits(bs, 8) != VIDOBJLAY_TYPE_MAIN && BitstreamShowBits(bs, 8) != 0) /* BUGGY DIVX */ { DPRINTF(DPRINTF_ERROR,"video_object_type_indication %i not supported ", BitstreamShowBits(bs, 8)); return -1; } BitstreamSkip(bs, 8); if (BitstreamGetBit(bs)) /* is_object_layer_identifier */ { DPRINTF(DPRINTF_HEADER, "+ is_object_layer_identifier"); vol_ver_id = BitstreamGetBits(bs, 4); /* video_object_layer_verid */ DPRINTF(DPRINTF_HEADER,"ver_id %i", vol_ver_id); BitstreamSkip(bs, 3); /* video_object_layer_priority */ } else { vol_ver_id = 1; } if (BitstreamGetBits(bs, 4) == VIDOBJLAY_AR_EXTPAR) /* aspect_ratio_info */ { DPRINTF(DPRINTF_HEADER, "+ aspect_ratio_info"); BitstreamSkip(bs, 8); /* par_width */ BitstreamSkip(bs, 8); /* par_height */ } if (BitstreamGetBit(bs)) /* vol_control_parameters */ { DPRINTF(DPRINTF_HEADER, "+ vol_control_parameters"); BitstreamSkip(bs, 2); /* chroma_format */ dec->low_delay = (uint8_t)BitstreamGetBit(bs); /* low_delay */ DPRINTF(DPRINTF_HEADER, "low_delay %i", dec->low_delay); if (BitstreamGetBit(bs)) /* vbv_parameters */ { DPRINTF(DPRINTF_HEADER,"+ vbv_parameters"); BitstreamSkip(bs, 15); /* first_half_bitrate */ READ_MARKER(); BitstreamSkip(bs, 15); /* latter_half_bitrate */ READ_MARKER(); BitstreamSkip(bs, 15); /* first_half_vbv_buffer_size */ READ_MARKER(); BitstreamSkip(bs, 3); /* latter_half_vbv_buffer_size */ BitstreamSkip(bs, 11); /* first_half_vbv_occupancy */ READ_MARKER(); BitstreamSkip(bs, 15); /* latter_half_vbv_occupancy */ READ_MARKER(); } } dec->shape = BitstreamGetBits(bs, 2); /* video_object_layer_shape */ DPRINTF(DPRINTF_HEADER, "shape %i", dec->shape); if (dec->shape == VIDOBJLAY_SHAPE_GRAYSCALE && vol_ver_id != 1) { BitstreamSkip(bs, 4); /* video_object_layer_shape_extension */ } READ_MARKER(); /* *************************** for decode B-frame time *********************** */ time_increment_resolution = BitstreamGetBits(bs, 16); /* vop_time_increment_resolution */ DPRINTF(DPRINTF_HEADER,"vop_time_increment_resolution %i", time_increment_resolution); /* time_increment_resolution--; */ if (time_increment_resolution > 0) { dec->time_inc_bits = log2bin(time_increment_resolution-1); } else { /* dec->time_inc_bits = 0; */ /* for "old" xvid compatibility, set time_inc_bits = 1 */ dec->time_inc_bits = 1; } READ_MARKER(); if (BitstreamGetBit(bs)) /* fixed_vop_rate */ { DPRINTF(DPRINTF_HEADER, "+ fixed_vop_rate"); BitstreamSkip(bs, dec->time_inc_bits); /* fixed_vop_time_increment */ } if (dec->shape != VIDOBJLAY_SHAPE_BINARY_ONLY) { if (dec->shape == VIDOBJLAY_SHAPE_RECTANGULAR) { uint32_t width, height; READ_MARKER(); width = BitstreamGetBits(bs, 13); /* video_object_layer_width */ READ_MARKER(); height = BitstreamGetBits(bs, 13); /* video_object_layer_height */ READ_MARKER(); DPRINTF(DPRINTF_HEADER, "width %i", width); DPRINTF(DPRINTF_HEADER, "height %i", height); /* for auto set width & height */ if (dec->width == 0) dec->width = width; if (dec->height == 0) dec->height = height; if (width != dec->width || height != dec->height) { DPRINTF(DPRINTF_ERROR, "XVID_DEC_PARAM width/height does not match bitstream"); return -1; } } dec->interlacing = BitstreamGetBit(bs); DPRINTF(DPRINTF_HEADER, "interlace", dec->interlacing); if (!BitstreamGetBit(bs)) /* obmc_disable */ { DPRINTF(DPRINTF_ERROR, "obmc_disabled==false not supported"); /* TODO */ /* fucking divx4.02 has this enabled */ } if (BitstreamGetBits(bs, (vol_ver_id == 1 ? 1 : 2))) /* sprite_enable */ { DPRINTF(DPRINTF_ERROR, "spriate_enabled not supported"); return -1; } if (vol_ver_id != 1 && dec->shape != VIDOBJLAY_SHAPE_RECTANGULAR) { BitstreamSkip(bs, 1); /* sadct_disable */ } if (BitstreamGetBit(bs)) /* not_8_bit */ { DPRINTF(DPRINTF_HEADER, "not_8_bit==true (ignored)"); dec->quant_bits = BitstreamGetBits(bs, 4); /* quant_precision */ BitstreamSkip(bs, 4); /* bits_per_pixel */ } else { dec->quant_bits = 5; } if (dec->shape == VIDOBJLAY_SHAPE_GRAYSCALE) { BitstreamSkip(bs, 1); /* no_gray_quant_update */ BitstreamSkip(bs, 1); /* composition_method */ BitstreamSkip(bs, 1); /* linear_composition */ } dec->quant_type = BitstreamGetBit(bs); /* quant_type */ DPRINTF(DPRINTF_HEADER, "quant_type %i", dec->quant_type); if (dec->quant_type) { if (BitstreamGetBit(bs)) /* load_intra_quant_mat */ { uint8_t matrix[64]; DPRINTF(DPRINTF_HEADER, "load_intra_quant_mat"); bs_get_matrix(bs, matrix); set_intra_matrix(matrix); } else set_intra_matrix(get_default_intra_matrix()); if (BitstreamGetBit(bs)) /* load_inter_quant_mat */ { uint8_t matrix[64]; DPRINTF(DPRINTF_HEADER, "load_inter_quant_mat"); bs_get_matrix(bs, matrix); set_inter_matrix(matrix); } else set_inter_matrix(get_default_inter_matrix()); if (dec->shape == VIDOBJLAY_SHAPE_GRAYSCALE) { DPRINTF(DPRINTF_ERROR, "greyscale matrix not supported"); return -1; } } if (vol_ver_id != 1) { DPRINTF(DPRINTF_DEBUG, "QUARTERPEL BITSTREAM"); dec->quarterpel = BitstreamGetBit(bs); /* quarter_sample */ } else dec->quarterpel = 0; if (!BitstreamGetBit(bs)) /* complexity_estimation_disable */ { DPRINTF(DPRINTF_ERROR, "complexity_estimation not supported"); return -1; } BitstreamSkip(bs, 1); /* resync_marker_disable */ if (BitstreamGetBit(bs)) /* data_partitioned */ { DPRINTF(DPRINTF_ERROR, "data_partitioned not supported"); BitstreamSkip(bs, 1); /* reversible_vlc */ } if (vol_ver_id != 1) { if (BitstreamGetBit(bs)) /* newpred_enable */ { DPRINTF(DPRINTF_HEADER, "+ newpred_enable"); BitstreamSkip(bs, 2); /* requested_upstream_message_type */ BitstreamSkip(bs, 1); /* newpred_segment_type */ } if (BitstreamGetBit(bs)) /* reduced_resolution_vop_enable */ { DPRINTF(DPRINTF_ERROR, "reduced_resolution_vop not supported"); return -1; } } if ((dec->scalability = (int8_t)BitstreamGetBit(bs))) /* scalability */ { DPRINTF(DPRINTF_ERROR, "scalability not supported"); return -1; } } else /* dec->shape == BINARY_ONLY */ { if (vol_ver_id != 1) { if (BitstreamGetBit(bs)) /* scalability */ { DPRINTF(DPRINTF_ERROR, "scalability not supported"); return -1; } } BitstreamSkip(bs, 1); /* resync_marker_disable */ } } else if (start_code == GRPOFVOP_START_CODE) { DPRINTF(DPRINTF_STARTCODE, ""); BitstreamSkip(bs, 32); { int hours, minutes, seconds; hours = BitstreamGetBits(bs, 5); minutes = BitstreamGetBits(bs, 6); READ_MARKER(); seconds = BitstreamGetBits(bs, 6); DPRINTF(DPRINTF_HEADER, "time %ih%im%is", hours); } BitstreamSkip(bs, 1); /* closed_gov */ BitstreamSkip(bs, 1); /* broken_link */ } else if (start_code == VOP_START_CODE) { DPRINTF(DPRINTF_STARTCODE, ""); BitstreamSkip(bs, 32); /* vop_start_code */ coding_type = BitstreamGetBits(bs, 2); /* vop_coding_type */ DPRINTF(DPRINTF_HEADER, "coding_type %i", coding_type); /* *************************** for decode B-frame time *********************** */ while (BitstreamGetBit(bs) != 0) /* time_base */ time_incr++; READ_MARKER(); if (dec->time_inc_bits) { time_increment = (BitstreamGetBits(bs, dec->time_inc_bits)); /* vop_time_increment */ } DPRINTF(DPRINTF_HEADER, "time_base %i", time_incr); DPRINTF(DPRINTF_HEADER, "time_increment %i", time_increment); DPRINTF(DPRINTF_TIMECODE, "%c %i:%i", coding_type == I_VOP ? 'I' : coding_type == P_VOP ? 'P' : 'B', time_incr, time_increment); if (coding_type != B_VOP) { dec->last_time_base = dec->time_base; dec->time_base += time_incr; dec->time = time_increment; /* dec->time_base * time_increment_resolution + time_increment; */ dec->time_pp = (uint32_t) (time_increment_resolution + dec->time - dec->last_non_b_time)%time_increment_resolution; dec->last_non_b_time = dec->time; } else { dec->time = time_increment; /* (dec->last_time_base + time_incr) * time_increment_resolution + time_increment; */ dec->time_bp = (uint32_t) (time_increment_resolution + dec->last_non_b_time - dec->time)%time_increment_resolution; } READ_MARKER(); if (!BitstreamGetBit(bs)) /* vop_coded */ { DPRINTF(DPRINTF_HEADER, "vop_coded==false"); return N_VOP; } /* if (newpred_enable) { } */ /* fix a little bug by MinChen */ if ((dec->shape != VIDOBJLAY_SHAPE_BINARY_ONLY) && (coding_type == P_VOP)) { *rounding = BitstreamGetBit(bs); /* rounding_type */ DPRINTF(DPRINTF_HEADER, "rounding %i", *rounding); } /* if (reduced_resolution_enable) { } */ if (dec->shape != VIDOBJLAY_SHAPE_RECTANGULAR) { uint32_t width, height; uint32_t horiz_mc_ref, vert_mc_ref; width = BitstreamGetBits(bs, 13); READ_MARKER(); height = BitstreamGetBits(bs, 13); READ_MARKER(); horiz_mc_ref = BitstreamGetBits(bs, 13); READ_MARKER(); vert_mc_ref = BitstreamGetBits(bs, 13); READ_MARKER(); DPRINTF(DPRINTF_HEADER, "width %i", width); DPRINTF(DPRINTF_HEADER, "height %i", height); DPRINTF(DPRINTF_HEADER, "horiz_mc_ref %i", horiz_mc_ref); DPRINTF(DPRINTF_HEADER, "vert_mc_ref %i", vert_mc_ref); BitstreamSkip(bs, 1); /* change_conv_ratio_disable */ if (BitstreamGetBit(bs)) /* vop_constant_alpha */ { BitstreamSkip(bs, 8); /* vop_constant_alpha_value */ } } if (dec->shape != VIDOBJLAY_SHAPE_BINARY_ONLY) { /* intra_dc_vlc_threshold */ *intra_dc_threshold = intra_dc_threshold_table[BitstreamGetBits(bs, 3)]; if (dec->interlacing) { dec->top_field_first = BitstreamGetBit(bs); DPRINTF(DPRINTF_HEADER, "interlace top_field_first %i", dec->top_field_first); dec->alternate_vertical_scan = BitstreamGetBit(bs); DPRINTF(DPRINTF_HEADER, "interlace alternate_vertical_scan %i", dec->alternate_vertical_scan); } } if ((*quant = BitstreamGetBits(bs, dec->quant_bits)) < 1) /* vop_quant */ *quant = 1; DPRINTF(DPRINTF_HEADER, "quant %i", *quant); if (coding_type != I_VOP) { *fcode_forward = BitstreamGetBits(bs, 3); /* fcode_forward */ DPRINTF(DPRINTF_HEADER, "fcode_forward %i", *fcode_forward); } if (coding_type == B_VOP) { *fcode_backward = BitstreamGetBits(bs, 3); /* fcode_backward */ DPRINTF(DPRINTF_HEADER, "fcode_backward %i", *fcode_backward); } if (!dec->scalability) { if ((dec->shape != VIDOBJLAY_SHAPE_RECTANGULAR) && (coding_type != I_VOP)) { BitstreamSkip(bs, 1); /* vop_shape_coding_type */ } } return coding_type; } else if (start_code == USERDATA_START_CODE) { DPRINTF(DPRINTF_STARTCODE, ""); BitstreamSkip(bs, 32); /* user_data_start_code */ } else /* start_code == ? */ { if (BitstreamShowBits(bs, 24) == 0x000001) { DPRINTF(DPRINTF_STARTCODE, "", BitstreamShowBits(bs, 32)); } BitstreamSkip(bs, 8); } } while ((BitstreamPos(bs) >> 3) < bs->length); /*DPRINTF("*** WARNING: no vop_start_code found"); */ return -1; /* ignore it */ } /* write custom quant matrix */ static void bs_put_matrix(Bitstream * bs, const int16_t * matrix) { int i, j; const int last = matrix[scan_tables[0][63]]; for (j = 63; j > 0 && matrix[scan_tables[0][j - 1]] == last; j--); for (i = 0; i <= j; i++) { BitstreamPutBits(bs, matrix[scan_tables[0][i]], 8); } if (j < 63) { BitstreamPutBits(bs, 0, 8); } } /* write vol header */ void BitstreamWriteVolHeader(Bitstream * const bs, const MBParam * pParam, const FRAMEINFO * frame) { /* video object_start_code & vo_id */ BitstreamPad(bs); BitstreamPutBits(bs, VO_START_CODE, 27); BitstreamPutBits(bs, 0, 5); /* video_object_layer_start_code & vol_id */ BitstreamPutBits(bs, VOL_START_CODE, 28); BitstreamPutBits(bs, 0, 4); BitstreamPutBit(bs, 0); /* random_accessible_vol */ BitstreamPutBits(bs, 0, 8); /* video_object_type_indication */ BitstreamPutBit(bs, 0); /* is_object_layer_identified (0=not given) */ BitstreamPutBits(bs, 1, 4); /* aspect_ratio_info (1=1:1) */ BitstreamPutBit(bs, 1); /* vol_control_parameters */ BitstreamPutBits(bs, 1, 2); /* chroma_format 1="4:2:0" */ BitstreamPutBit(bs, 1); /* low_delay */ BitstreamPutBit(bs, 0); /* vbv_parameters (0=not given) */ BitstreamPutBits(bs, 0, 2); /* video_object_layer_shape (0=rectangular) */ WRITE_MARKER(); /* * time_increment_resolution; ignored by current decore versions * eg. 2fps res=2 inc=1 * 25fps res=25 inc=1 * 29.97fps res=30000 inc=1001 */ BitstreamPutBits(bs, pParam->fbase, 16); WRITE_MARKER(); BitstreamPutBit(bs, 1); /* fixed_vop_rate = 1 */ BitstreamPutBits(bs, pParam->fincr, log2bin(pParam->fbase)); /* fixed_vop_time_increment */ WRITE_MARKER(); BitstreamPutBits(bs, pParam->width, 13); /* width */ WRITE_MARKER(); BitstreamPutBits(bs, pParam->height, 13); /* height */ WRITE_MARKER(); BitstreamPutBit(bs, frame->global_flags & XVID_INTERLACING); /* interlace */ BitstreamPutBit(bs, 1); /* obmc_disable (overlapped block motion compensation) */ BitstreamPutBit(bs, 0); /* sprite_enable */ BitstreamPutBit(bs, 0); /* not_in_bit */ /* quant_type 0=h.263 1=mpeg4(quantizer tables) */ BitstreamPutBit(bs, pParam->m_quant_type); if (pParam->m_quant_type) { BitstreamPutBit(bs, get_intra_matrix_status()); /* load_intra_quant_mat */ if (get_intra_matrix_status()) { bs_put_matrix(bs, get_intra_matrix()); } BitstreamPutBit(bs, get_inter_matrix_status()); /* load_inter_quant_mat */ if (get_inter_matrix_status()) { bs_put_matrix(bs, get_inter_matrix()); } } BitstreamPutBit(bs, 1); /* complexity_estimation_disable */ BitstreamPutBit(bs, 1); /* resync_marker_disable */ BitstreamPutBit(bs, 0); /* data_partitioned */ BitstreamPutBit(bs, 0); /* scalability */ } /* write vop header NOTE: doesnt handle bother with time_base & time_inc time_base = n seconds since last resync (eg. last iframe) time_inc = nth of a second since last resync (decoder uses these values to determine precise time since last resync) */ void BitstreamWriteVopHeader(Bitstream * const bs, const MBParam * pParam, const FRAMEINFO * frame, int vop_coded) { uint32_t i; BitstreamPad(bs); BitstreamPutBits(bs, VOP_START_CODE, 32); BitstreamPutBits(bs, frame->coding_type, 2); /* time_base = 0 write n x PutBit(1), PutBit(0) */ for (i = 0; i < frame->seconds; i++) { BitstreamPutBit(bs, 1); } BitstreamPutBit(bs, 0); WRITE_MARKER(); /* time_increment: value=nth_of_sec, nbits = log2(resolution) */ BitstreamPutBits(bs, frame->ticks, log2bin(pParam->fbase)); WRITE_MARKER(); if (!vop_coded) { BitstreamPutBits(bs, 0, 1); return; } BitstreamPutBits(bs, 1, 1); /* vop_coded */ if (frame->coding_type == P_VOP) BitstreamPutBits(bs, frame->rounding_type, 1); BitstreamPutBits(bs, 0, 3); /* intra_dc_vlc_threshold */ if (frame->global_flags & XVID_INTERLACING) { BitstreamPutBit(bs, 1); /* top field first */ BitstreamPutBit(bs, 0); /* alternate vertical scan */ } BitstreamPutBits(bs, frame->quant, 5); /* quantizer */ if (frame->coding_type != I_VOP) BitstreamPutBits(bs, frame->fcode, 3); /* forward_fixed_code */ if (frame->coding_type == B_VOP) BitstreamPutBits(bs, frame->bcode, 3); /* backward_fixed_code */ }