/* * MPEG1 encoder / MPEG2 decoder * Copyright (c) 2000,2001 Gerard Lantau. * * This program 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #include "avcodec.h" #include "dsputil.h" #include "mpegvideo.h" #include "mpeg12data.h" //#define DEBUG #ifdef DEBUG #define dprintf(fmt,args...) printf(fmt, ## args) #else #define dprintf(fmt,args...) #endif /* Start codes. */ #define SEQ_END_CODE 0x000001b7 #define SEQ_START_CODE 0x000001b3 #define GOP_START_CODE 0x000001b8 #define PICTURE_START_CODE 0x00000100 #define SLICE_MIN_START_CODE 0x00000101 #define SLICE_MAX_START_CODE 0x000001af #define EXT_START_CODE 0x000001b5 #define USER_START_CODE 0x000001b2 static void mpeg1_encode_block(MpegEncContext *s, DCTELEM *block, int component); static void mpeg1_encode_motion(MpegEncContext *s, int val); static void mpeg1_skip_picture(MpegEncContext *s, int pict_num); static int mpeg1_decode_block(MpegEncContext *s, DCTELEM *block, int n); static int mpeg2_decode_block_non_intra(MpegEncContext *s, DCTELEM *block, int n); static int mpeg2_decode_block_intra(MpegEncContext *s, DCTELEM *block, int n); static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred); static void put_header(MpegEncContext *s, int header) { align_put_bits(&s->pb); put_bits(&s->pb, 32, header); } /* put sequence header if needed */ static void mpeg1_encode_sequence_header(MpegEncContext *s) { unsigned int vbv_buffer_size; unsigned int fps, v; int n; UINT64 time_code; if ((s->picture_number % s->gop_size) == 0) { /* mpeg1 header repeated every gop */ put_header(s, SEQ_START_CODE); /* search closest frame rate */ { int i, dmin, d; s->frame_rate_index = 0; dmin = 0x7fffffff; for(i=1;i<9;i++) { d = abs(s->frame_rate - frame_rate_tab[i]); if (d < dmin) { dmin = d; s->frame_rate_index = i; } } } put_bits(&s->pb, 12, s->width); put_bits(&s->pb, 12, s->height); put_bits(&s->pb, 4, 1); /* 1/1 aspect ratio */ put_bits(&s->pb, 4, s->frame_rate_index); v = s->bit_rate / 400; if (v > 0x3ffff) v = 0x3ffff; put_bits(&s->pb, 18, v); put_bits(&s->pb, 1, 1); /* marker */ /* vbv buffer size: slightly greater than an I frame. We add some margin just in case */ vbv_buffer_size = (3 * s->I_frame_bits) / (2 * 8); put_bits(&s->pb, 10, (vbv_buffer_size + 16383) / 16384); put_bits(&s->pb, 1, 1); /* constrained parameter flag */ put_bits(&s->pb, 1, 0); /* no custom intra matrix */ put_bits(&s->pb, 1, 0); /* no custom non intra matrix */ put_header(s, GOP_START_CODE); put_bits(&s->pb, 1, 0); /* do drop frame */ /* time code : we must convert from the real frame rate to a fake mpeg frame rate in case of low frame rate */ fps = frame_rate_tab[s->frame_rate_index]; time_code = s->fake_picture_number * FRAME_RATE_BASE; s->gop_picture_number = s->fake_picture_number; put_bits(&s->pb, 5, (time_code / (fps * 3600)) % 24); put_bits(&s->pb, 6, (time_code / (fps * 60)) % 60); put_bits(&s->pb, 1, 1); put_bits(&s->pb, 6, (time_code / fps) % 60); put_bits(&s->pb, 6, (time_code % fps) / FRAME_RATE_BASE); put_bits(&s->pb, 1, 1); /* closed gop */ put_bits(&s->pb, 1, 0); /* broken link */ } if (s->frame_rate < (24 * FRAME_RATE_BASE) && s->picture_number > 0) { /* insert empty P pictures to slow down to the desired frame rate. Each fake pictures takes about 20 bytes */ fps = frame_rate_tab[s->frame_rate_index]; n = ((s->picture_number * fps) / s->frame_rate) - 1; while (s->fake_picture_number < n) { mpeg1_skip_picture(s, s->fake_picture_number - s->gop_picture_number); s->fake_picture_number++; } } s->fake_picture_number++; } /* insert a fake P picture */ static void mpeg1_skip_picture(MpegEncContext *s, int pict_num) { unsigned int mb_incr; /* mpeg1 picture header */ put_header(s, PICTURE_START_CODE); /* temporal reference */ put_bits(&s->pb, 10, pict_num & 0x3ff); put_bits(&s->pb, 3, P_TYPE); put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */ put_bits(&s->pb, 1, 1); /* integer coordinates */ put_bits(&s->pb, 3, 1); /* forward_f_code */ put_bits(&s->pb, 1, 0); /* extra bit picture */ /* only one slice */ put_header(s, SLICE_MIN_START_CODE); put_bits(&s->pb, 5, 1); /* quantizer scale */ put_bits(&s->pb, 1, 0); /* slice extra information */ mb_incr = 1; put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], mbAddrIncrTable[mb_incr - 1][0]); /* empty macroblock */ put_bits(&s->pb, 3, 1); /* motion only */ /* zero motion x & y */ put_bits(&s->pb, 1, 1); put_bits(&s->pb, 1, 1); /* output a number of empty slice */ mb_incr = s->mb_width * s->mb_height - 1; while (mb_incr > 33) { put_bits(&s->pb, 11, 0x008); mb_incr -= 33; } put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], mbAddrIncrTable[mb_incr - 1][0]); /* empty macroblock */ put_bits(&s->pb, 3, 1); /* motion only */ /* zero motion x & y */ put_bits(&s->pb, 1, 1); put_bits(&s->pb, 1, 1); } void mpeg1_encode_picture_header(MpegEncContext *s, int picture_number) { static int done; if (!done) { done = 1; init_rl(&rl_mpeg1); } mpeg1_encode_sequence_header(s); /* mpeg1 picture header */ put_header(s, PICTURE_START_CODE); /* temporal reference */ put_bits(&s->pb, 10, (s->fake_picture_number - s->gop_picture_number) & 0x3ff); put_bits(&s->pb, 3, s->pict_type); put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */ if (s->pict_type == P_TYPE) { put_bits(&s->pb, 1, 0); /* half pel coordinates */ put_bits(&s->pb, 3, s->f_code); /* forward_f_code */ } put_bits(&s->pb, 1, 0); /* extra bit picture */ /* only one slice */ put_header(s, SLICE_MIN_START_CODE); put_bits(&s->pb, 5, s->qscale); /* quantizer scale */ put_bits(&s->pb, 1, 0); /* slice extra information */ } void mpeg1_encode_mb(MpegEncContext *s, DCTELEM block[6][64], int motion_x, int motion_y) { int mb_incr, i, cbp, mb_x, mb_y; mb_x = s->mb_x; mb_y = s->mb_y; /* compute cbp */ cbp = 0; for(i=0;i<6;i++) { if (s->block_last_index[i] >= 0) cbp |= 1 << (5 - i); } /* skip macroblock, except if first or last macroblock of a slice */ if ((cbp | motion_x | motion_y) == 0 && (!((mb_x | mb_y) == 0 || (mb_x == s->mb_width - 1 && mb_y == s->mb_height - 1)))) { s->mb_incr++; } else { /* output mb incr */ mb_incr = s->mb_incr; while (mb_incr > 33) { put_bits(&s->pb, 11, 0x008); mb_incr -= 33; } put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], mbAddrIncrTable[mb_incr - 1][0]); if (s->pict_type == I_TYPE) { put_bits(&s->pb, 1, 1); /* macroblock_type : macroblock_quant = 0 */ } else { if (s->mb_intra) { put_bits(&s->pb, 5, 0x03); } else { if (cbp != 0) { if (motion_x == 0 && motion_y == 0) { put_bits(&s->pb, 2, 1); /* macroblock_pattern only */ put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]); } else { put_bits(&s->pb, 1, 1); /* motion + cbp */ mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]); mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]); put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]); } } else { put_bits(&s->pb, 3, 1); /* motion only */ mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]); mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]); } } } for(i=0;i<6;i++) { if (cbp & (1 << (5 - i))) { mpeg1_encode_block(s, block[i], i); } } s->mb_incr = 1; } s->last_mv[0][0][0] = motion_x; s->last_mv[0][0][1] = motion_y; } static void mpeg1_encode_motion(MpegEncContext *s, int val) { int code, bit_size, l, m, bits, range, sign; if (val == 0) { /* zero vector */ code = 0; put_bits(&s->pb, mbMotionVectorTable[0][1], mbMotionVectorTable[0][0]); } else { bit_size = s->f_code - 1; range = 1 << bit_size; /* modulo encoding */ l = 16 * range; m = 2 * l; if (val < -l) { val += m; } else if (val >= l) { val -= m; } if (val >= 0) { val--; code = (val >> bit_size) + 1; bits = val & (range - 1); sign = 0; } else { val = -val; val--; code = (val >> bit_size) + 1; bits = val & (range - 1); sign = 1; } put_bits(&s->pb, mbMotionVectorTable[code][1], mbMotionVectorTable[code][0]); put_bits(&s->pb, 1, sign); if (bit_size > 0) { put_bits(&s->pb, bit_size, bits); } } } static inline void encode_dc(MpegEncContext *s, int diff, int component) { int adiff, index; adiff = abs(diff); index = vlc_dc_table[adiff]; if (component == 0) { put_bits(&s->pb, vlc_dc_lum_bits[index], vlc_dc_lum_code[index]); } else { put_bits(&s->pb, vlc_dc_chroma_bits[index], vlc_dc_chroma_code[index]); } if (diff > 0) { put_bits(&s->pb, index, (diff & ((1 << index) - 1))); } else if (diff < 0) { put_bits(&s->pb, index, ((diff - 1) & ((1 << index) - 1))); } } static void mpeg1_encode_block(MpegEncContext *s, DCTELEM *block, int n) { int alevel, level, last_non_zero, dc, diff, i, j, run, last_index, sign; int code, component; RLTable *rl = &rl_mpeg1; last_index = s->block_last_index[n]; /* DC coef */ if (s->mb_intra) { component = (n <= 3 ? 0 : n - 4 + 1); dc = block[0]; /* overflow is impossible */ diff = dc - s->last_dc[component]; encode_dc(s, diff, component); s->last_dc[component] = dc; i = 1; } else { /* encode the first coefficient : needs to be done here because it is handled slightly differently */ level = block[0]; if (abs(level) == 1) { code = ((UINT32)level >> 31); /* the sign bit */ put_bits(&s->pb, 2, code | 0x02); i = 1; } else { i = 0; last_non_zero = -1; goto next_coef; } } /* now quantify & encode AC coefs */ last_non_zero = i - 1; for(;i<=last_index;i++) { j = zigzag_direct[i]; level = block[j]; next_coef: #if 0 if (level != 0) dprintf("level[%d]=%d\n", i, level); #endif /* encode using VLC */ if (level != 0) { run = i - last_non_zero - 1; sign = 0; alevel = level; if (alevel < 0) { sign = 1; alevel = -alevel; } code = get_rl_index(rl, 0, run, alevel); put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]); if (code != rl->n) { put_bits(&s->pb, 1, sign); } else { /* escape: only clip in this case */ put_bits(&s->pb, 6, run); if (alevel < 128) { put_bits(&s->pb, 8, level & 0xff); } else { if (level < 0) { put_bits(&s->pb, 16, 0x8001 + level + 255); } else { put_bits(&s->pb, 16, level & 0xffff); } } } last_non_zero = i; } } /* end of block */ put_bits(&s->pb, 2, 0x2); } /******************************************/ /* decoding */ static VLC dc_lum_vlc; static VLC dc_chroma_vlc; static VLC mv_vlc; static VLC mbincr_vlc; static VLC mb_ptype_vlc; static VLC mb_btype_vlc; static VLC mb_pat_vlc; void mpeg1_init_vlc(MpegEncContext *s) { static int done = 0; if (!done) { init_vlc(&dc_lum_vlc, 9, 12, vlc_dc_lum_bits, 1, 1, vlc_dc_lum_code, 2, 2); init_vlc(&dc_chroma_vlc, 9, 12, vlc_dc_chroma_bits, 1, 1, vlc_dc_chroma_code, 2, 2); init_vlc(&mv_vlc, 9, 17, &mbMotionVectorTable[0][1], 2, 1, &mbMotionVectorTable[0][0], 2, 1); init_vlc(&mbincr_vlc, 9, 34, &mbAddrIncrTable[0][1], 2, 1, &mbAddrIncrTable[0][0], 2, 1); init_vlc(&mb_pat_vlc, 9, 63, &mbPatTable[0][1], 2, 1, &mbPatTable[0][0], 2, 1); init_vlc(&mb_ptype_vlc, 6, 32, &table_mb_ptype[0][1], 2, 1, &table_mb_ptype[0][0], 2, 1); init_vlc(&mb_btype_vlc, 6, 32, &table_mb_btype[0][1], 2, 1, &table_mb_btype[0][0], 2, 1); init_rl(&rl_mpeg1); init_rl(&rl_mpeg2); /* cannot use generic init because we must add the EOB code */ init_vlc(&rl_mpeg1.vlc, 9, rl_mpeg1.n + 2, &rl_mpeg1.table_vlc[0][1], 4, 2, &rl_mpeg1.table_vlc[0][0], 4, 2); init_vlc(&rl_mpeg2.vlc, 9, rl_mpeg2.n + 2, &rl_mpeg2.table_vlc[0][1], 4, 2, &rl_mpeg2.table_vlc[0][0], 4, 2); } } static inline int get_dmv(MpegEncContext *s) { if(get_bits(&s->gb, 1)) return 1 - (get_bits(&s->gb, 1) << 1); else return 0; } /* motion type (for mpeg2) */ #define MT_FIELD 1 #define MT_FRAME 2 #define MT_16X8 2 #define MT_DMV 3 static int mpeg_decode_mb(MpegEncContext *s, DCTELEM block[6][64]) { int i, j, k, cbp, val, code, mb_type, motion_type; /* skip mb handling */ if (s->mb_incr == 0) { /* read again increment */ s->mb_incr = 1; for(;;) { code = get_vlc(&s->gb, &mbincr_vlc); if (code < 0) return 1; /* error = end of slice */ if (code >= 33) { if (code == 33) { s->mb_incr += 33; } /* otherwise, stuffing, nothing to do */ } else { s->mb_incr += code; break; } } } if (++s->mb_x >= s->mb_width) { s->mb_x = 0; if (s->mb_y >= (s->mb_height - 1)) return -1; s->mb_y++; } dprintf("decode_mb: x=%d y=%d\n", s->mb_x, s->mb_y); if (--s->mb_incr != 0) { /* skip mb */ s->mb_intra = 0; for(i=0;i<6;i++) s->block_last_index[i] = -1; s->mv_type = MV_TYPE_16X16; if (s->pict_type == P_TYPE) { /* if P type, zero motion vector is implied */ s->mv_dir = MV_DIR_FORWARD; s->mv[0][0][0] = s->mv[0][0][1] = 0; s->last_mv[0][0][0] = s->last_mv[0][0][1] = 0; } else { /* if B type, reuse previous vectors and directions */ s->mv[0][0][0] = s->last_mv[0][0][0]; s->mv[0][0][1] = s->last_mv[0][0][1]; s->mv[1][0][0] = s->last_mv[1][0][0]; s->mv[1][0][1] = s->last_mv[1][0][1]; } s->mb_skiped = 1; return 0; } switch(s->pict_type) { default: case I_TYPE: if (get_bits(&s->gb, 1) == 0) { if (get_bits(&s->gb, 1) == 0) return -1; mb_type = MB_QUANT | MB_INTRA; } else { mb_type = MB_INTRA; } break; case P_TYPE: mb_type = get_vlc(&s->gb, &mb_ptype_vlc); if (mb_type < 0) return -1; break; case B_TYPE: mb_type = get_vlc(&s->gb, &mb_btype_vlc); if (mb_type < 0) return -1; break; } dprintf("mb_type=%x\n", mb_type); motion_type = 0; /* avoid warning */ if (mb_type & (MB_FOR|MB_BACK)) { /* get additionnal motion vector type */ if (s->picture_structure == PICT_FRAME && s->frame_pred_frame_dct) motion_type = MT_FRAME; else motion_type = get_bits(&s->gb, 2); } /* compute dct type */ if (s->picture_structure == PICT_FRAME && !s->frame_pred_frame_dct && (mb_type & (MB_PAT | MB_INTRA))) { s->interlaced_dct = get_bits(&s->gb, 1); #ifdef DEBUG if (s->interlaced_dct) printf("interlaced_dct\n"); #endif } else { s->interlaced_dct = 0; /* frame based */ } if (mb_type & MB_QUANT) { if (s->mpeg2) { if (s->q_scale_type) { s->qscale = non_linear_qscale[get_bits(&s->gb, 5)]; } else { s->qscale = get_bits(&s->gb, 5) << 1; } } else { /* for mpeg1, we use the generic unquant code */ s->qscale = get_bits(&s->gb, 5); } } if (mb_type & MB_INTRA) { if (s->concealment_motion_vectors) { /* just parse them */ if (s->picture_structure != PICT_FRAME) get_bits(&s->gb, 1); /* field select */ mpeg_decode_motion(s, s->mpeg_f_code[0][0], 0); mpeg_decode_motion(s, s->mpeg_f_code[0][1], 0); } s->mb_intra = 1; cbp = 0x3f; memset(s->last_mv, 0, sizeof(s->last_mv)); /* reset mv prediction */ } else { s->mb_intra = 0; cbp = 0; } /* special case of implicit zero motion vector */ if (s->pict_type == P_TYPE && !(mb_type & MB_FOR)) { s->mv_dir = MV_DIR_FORWARD; s->mv_type = MV_TYPE_16X16; s->last_mv[0][0][0] = 0; s->last_mv[0][0][1] = 0; s->mv[0][0][0] = 0; s->mv[0][0][1] = 0; } else if (mb_type & (MB_FOR | MB_BACK)) { /* motion vectors */ s->mv_dir = 0; for(i=0;i<2;i++) { if (mb_type & (MB_FOR >> i)) { s->mv_dir |= (MV_DIR_FORWARD >> i); dprintf("mv_type=%d\n", motion_type); switch(motion_type) { case MT_FRAME: /* or MT_16X8 */ if (s->picture_structure == PICT_FRAME) { /* MT_FRAME */ s->mv_type = MV_TYPE_16X16; for(k=0;k<2;k++) { val = mpeg_decode_motion(s, s->mpeg_f_code[i][k], s->last_mv[i][0][k]); s->last_mv[i][0][k] = val; s->last_mv[i][1][k] = val; /* full_pel: only for mpeg1 */ if (s->full_pel[i]) val = val << 1; s->mv[i][0][k] = val; dprintf("mv%d: %d\n", k, val); } } else { /* MT_16X8 */ s->mv_type = MV_TYPE_16X8; for(j=0;j<2;j++) { s->field_select[i][j] = get_bits(&s->gb, 1); for(k=0;k<2;k++) { val = mpeg_decode_motion(s, s->mpeg_f_code[i][k], s->last_mv[i][j][k]); s->last_mv[i][j][k] = val; s->mv[i][j][k] = val; } } } break; case MT_FIELD: if (s->picture_structure == PICT_FRAME) { s->mv_type = MV_TYPE_FIELD; for(j=0;j<2;j++) { s->field_select[i][j] = get_bits(&s->gb, 1); val = mpeg_decode_motion(s, s->mpeg_f_code[i][0], s->last_mv[i][j][0]); s->last_mv[i][j][0] = val; s->mv[i][j][0] = val; dprintf("fmx=%d\n", val); val = mpeg_decode_motion(s, s->mpeg_f_code[i][1], s->last_mv[i][j][1] >> 1); s->last_mv[i][j][1] = val << 1; s->mv[i][j][1] = val; dprintf("fmy=%d\n", val); } } else { s->mv_type = MV_TYPE_16X16; s->field_select[i][0] = get_bits(&s->gb, 1); for(k=0;k<2;k++) { val = mpeg_decode_motion(s, s->mpeg_f_code[i][k], s->last_mv[i][0][k]); s->last_mv[i][0][k] = val; s->last_mv[i][1][k] = val; s->mv[i][0][k] = val; } } break; case MT_DMV: { int dmx, dmy, mx, my, m; mx = mpeg_decode_motion(s, s->mpeg_f_code[i][0], s->last_mv[i][0][0]); s->last_mv[i][0][0] = mx; s->last_mv[i][1][0] = mx; dmx = get_dmv(s); my = mpeg_decode_motion(s, s->mpeg_f_code[i][1], s->last_mv[i][0][1] >> 1); dmy = get_dmv(s); s->mv_type = MV_TYPE_DMV; /* XXX: totally broken */ if (s->picture_structure == PICT_FRAME) { s->last_mv[i][0][1] = my << 1; s->last_mv[i][1][1] = my << 1; m = s->top_field_first ? 1 : 3; /* top -> top pred */ s->mv[i][0][0] = mx; s->mv[i][0][1] = my << 1; s->mv[i][1][0] = ((mx * m + (mx > 0)) >> 1) + dmx; s->mv[i][1][1] = ((my * m + (my > 0)) >> 1) + dmy - 1; m = 4 - m; s->mv[i][2][0] = mx; s->mv[i][2][1] = my << 1; s->mv[i][3][0] = ((mx * m + (mx > 0)) >> 1) + dmx; s->mv[i][3][1] = ((my * m + (my > 0)) >> 1) + dmy + 1; } else { s->last_mv[i][0][1] = my; s->last_mv[i][1][1] = my; s->mv[i][0][0] = mx; s->mv[i][0][1] = my; s->mv[i][1][0] = ((mx + (mx > 0)) >> 1) + dmx; s->mv[i][1][1] = ((my + (my > 0)) >> 1) + dmy - 1 /* + 2 * cur_field */; } } break; } } } } if ((mb_type & MB_INTRA) && s->concealment_motion_vectors) { get_bits(&s->gb, 1); /* marker */ } if (mb_type & MB_PAT) { cbp = get_vlc(&s->gb, &mb_pat_vlc); if (cbp < 0) return -1; cbp++; } dprintf("cbp=%x\n", cbp); if (s->mpeg2) { if (s->mb_intra) { for(i=0;i<6;i++) { if (cbp & (1 << (5 - i))) { if (mpeg2_decode_block_intra(s, block[i], i) < 0) return -1; } } } else { for(i=0;i<6;i++) { if (cbp & (1 << (5 - i))) { if (mpeg2_decode_block_non_intra(s, block[i], i) < 0) return -1; } } } } else { for(i=0;i<6;i++) { if (cbp & (1 << (5 - i))) { if (mpeg1_decode_block(s, block[i], i) < 0) return -1; } } } return 0; } /* as h263, but only 17 codes */ static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred) { int code, sign, val, m, l, shift; code = get_vlc(&s->gb, &mv_vlc); if (code < 0) { return 0xffff; } if (code == 0) { return pred; } sign = get_bits(&s->gb, 1); shift = fcode - 1; val = (code - 1) << shift; if (shift > 0) val |= get_bits(&s->gb, shift); val++; if (sign) val = -val; val += pred; /* modulo decoding */ l = (1 << shift) * 16; m = 2 * l; if (val < -l) { val += m; } else if (val >= l) { val -= m; } return val; } static inline int decode_dc(MpegEncContext *s, int component) { int code, diff; if (component == 0) { code = get_vlc(&s->gb, &dc_lum_vlc); } else { code = get_vlc(&s->gb, &dc_chroma_vlc); } if (code < 0) return 0xffff; if (code == 0) { diff = 0; } else { diff = get_bits(&s->gb, code); if ((diff & (1 << (code - 1))) == 0) diff = (-1 << code) | (diff + 1); } return diff; } static int mpeg1_decode_block(MpegEncContext *s, DCTELEM *block, int n) { int level, dc, diff, i, j, run; int code, component; RLTable *rl = &rl_mpeg1; if (s->mb_intra) { /* DC coef */ component = (n <= 3 ? 0 : n - 4 + 1); diff = decode_dc(s, component); if (diff >= 0xffff) return -1; dc = s->last_dc[component]; dc += diff; s->last_dc[component] = dc; block[0] = dc; dprintf("dc=%d diff=%d\n", dc, diff); i = 1; } else { int bit_cnt, v; UINT32 bit_buf; UINT8 *buf_ptr; i = 0; /* special case for the first coef. no need to add a second vlc table */ SAVE_BITS(&s->gb); SHOW_BITS(&s->gb, v, 2); if (v & 2) { run = 0; level = 1 - ((v & 1) << 1); FLUSH_BITS(2); RESTORE_BITS(&s->gb); goto add_coef; } RESTORE_BITS(&s->gb); } /* now quantify & encode AC coefs */ for(;;) { code = get_vlc(&s->gb, &rl->vlc); if (code < 0) { return -1; } if (code == 112) { break; } else if (code == 111) { /* escape */ run = get_bits(&s->gb, 6); level = get_bits(&s->gb, 8); level = (level << 24) >> 24; if (level == -128) { level = get_bits(&s->gb, 8) - 256; } else if (level == 0) { level = get_bits(&s->gb, 8); } } else { run = rl->table_run[code]; level = rl->table_level[code]; if (get_bits(&s->gb, 1)) level = -level; } i += run; if (i >= 64) return -1; add_coef: dprintf("%d: run=%d level=%d\n", n, run, level); j = zigzag_direct[i]; block[j] = level; i++; } s->block_last_index[n] = i; return 0; } /* Also does unquantization here, since I will never support mpeg2 encoding */ static int mpeg2_decode_block_non_intra(MpegEncContext *s, DCTELEM *block, int n) { int level, i, j, run; int code; RLTable *rl = &rl_mpeg1; const UINT8 *scan_table; const UINT16 *matrix; int mismatch; if (s->alternate_scan) scan_table = ff_alternate_vertical_scan; else scan_table = zigzag_direct; mismatch = 1; { int bit_cnt, v; UINT32 bit_buf; UINT8 *buf_ptr; i = 0; if (n < 4) matrix = s->non_intra_matrix; else matrix = s->chroma_non_intra_matrix; /* special case for the first coef. no need to add a second vlc table */ SAVE_BITS(&s->gb); SHOW_BITS(&s->gb, v, 2); if (v & 2) { run = 0; level = 1 - ((v & 1) << 1); FLUSH_BITS(2); RESTORE_BITS(&s->gb); goto add_coef; } RESTORE_BITS(&s->gb); } /* now quantify & encode AC coefs */ for(;;) { code = get_vlc(&s->gb, &rl->vlc); if (code < 0) return -1; if (code == 112) { break; } else if (code == 111) { /* escape */ run = get_bits(&s->gb, 6); level = get_bits(&s->gb, 12); level = (level << 20) >> 20; } else { run = rl->table_run[code]; level = rl->table_level[code]; if (get_bits(&s->gb, 1)) level = -level; } i += run; if (i >= 64) return -1; add_coef: j = scan_table[i]; dprintf("%d: run=%d level=%d\n", n, run, level); level = ((level * 2 + 1) * s->qscale * matrix[j]) / 32; /* XXX: is it really necessary to saturate since the encoder knows whats going on ? */ mismatch ^= level; block[j] = level; i++; } block[63] ^= (mismatch & 1); s->block_last_index[n] = i; return 0; } static int mpeg2_decode_block_intra(MpegEncContext *s, DCTELEM *block, int n) { int level, dc, diff, i, j, run; int code, component; RLTable *rl; const UINT8 *scan_table; const UINT16 *matrix; int mismatch; if (s->alternate_scan) scan_table = ff_alternate_vertical_scan; else scan_table = zigzag_direct; mismatch = 1; /* DC coef */ component = (n <= 3 ? 0 : n - 4 + 1); diff = decode_dc(s, component); if (diff >= 0xffff) return -1; dc = s->last_dc[component]; dc += diff; s->last_dc[component] = dc; block[0] = dc << (3 - s->intra_dc_precision); dprintf("dc=%d\n", block[0]); i = 1; if (s->intra_vlc_format) rl = &rl_mpeg2; else rl = &rl_mpeg1; if (n < 4) matrix = s->intra_matrix; else matrix = s->chroma_intra_matrix; /* now quantify & encode AC coefs */ for(;;) { code = get_vlc(&s->gb, &rl->vlc); if (code < 0) return -1; if (code == 112) { break; } else if (code == 111) { /* escape */ run = get_bits(&s->gb, 6); level = get_bits(&s->gb, 12); level = (level << 20) >> 20; } else { run = rl->table_run[code]; level = rl->table_level[code]; if (get_bits(&s->gb, 1)) level = -level; } i += run; if (i >= 64) return -1; j = scan_table[i]; dprintf("%d: run=%d level=%d\n", n, run, level); level = (level * s->qscale * matrix[j]) / 16; /* XXX: is it really necessary to saturate since the encoder knows whats going on ? */ mismatch ^= level; block[j] = level; i++; } block[63] ^= (mismatch & 1); s->block_last_index[n] = i; return 0; } /* compressed picture size */ #define PICTURE_BUFFER_SIZE 100000 typedef struct Mpeg1Context { MpegEncContext mpeg_enc_ctx; UINT32 header_state; int start_code; /* current start code */ UINT8 buffer[PICTURE_BUFFER_SIZE]; UINT8 *buf_ptr; int buffer_size; int mpeg_enc_ctx_allocated; /* true if decoding context allocated */ } Mpeg1Context; static int mpeg_decode_init(AVCodecContext *avctx) { Mpeg1Context *s = avctx->priv_data; s->header_state = 0xff; s->mpeg_enc_ctx_allocated = 0; s->buffer_size = PICTURE_BUFFER_SIZE; s->start_code = -1; s->buf_ptr = s->buffer; s->mpeg_enc_ctx.picture_number = 0; return 0; } /* return the 8 bit start code value and update the search state. Return -1 if no start code found */ static int find_start_code(UINT8 **pbuf_ptr, UINT8 *buf_end, UINT32 *header_state) { UINT8 *buf_ptr; unsigned int state, v; int val; state = *header_state; buf_ptr = *pbuf_ptr; while (buf_ptr < buf_end) { v = *buf_ptr++; if (state == 0x000001) { state = ((state << 8) | v) & 0xffffff; val = state; goto found; } state = ((state << 8) | v) & 0xffffff; } val = -1; found: *pbuf_ptr = buf_ptr; *header_state = state; return val; } static int mpeg1_decode_picture(AVCodecContext *avctx, UINT8 *buf, int buf_size) { Mpeg1Context *s1 = avctx->priv_data; MpegEncContext *s = &s1->mpeg_enc_ctx; int ref, f_code; init_get_bits(&s->gb, buf, buf_size); ref = get_bits(&s->gb, 10); /* temporal ref */ s->pict_type = get_bits(&s->gb, 3); dprintf("pict_type=%d\n", s->pict_type); get_bits(&s->gb, 16); if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) { s->full_pel[0] = get_bits(&s->gb, 1); f_code = get_bits(&s->gb, 3); if (f_code == 0) return -1; s->mpeg_f_code[0][0] = f_code; s->mpeg_f_code[0][1] = f_code; } if (s->pict_type == B_TYPE) { s->full_pel[1] = get_bits(&s->gb, 1); f_code = get_bits(&s->gb, 3); if (f_code == 0) return -1; s->mpeg_f_code[1][0] = f_code; s->mpeg_f_code[1][1] = f_code; } s->y_dc_scale = 8; s->c_dc_scale = 8; s->first_slice = 1; return 0; } static void mpeg_decode_sequence_extension(MpegEncContext *s) { int horiz_size_ext, vert_size_ext; int bit_rate_ext, vbv_buf_ext, low_delay; int frame_rate_ext_n, frame_rate_ext_d; get_bits(&s->gb, 8); /* profil and level */ get_bits(&s->gb, 1); /* progressive_sequence */ get_bits(&s->gb, 2); /* chroma_format */ horiz_size_ext = get_bits(&s->gb, 2); vert_size_ext = get_bits(&s->gb, 2); s->width |= (horiz_size_ext << 12); s->height |= (vert_size_ext << 12); bit_rate_ext = get_bits(&s->gb, 12); /* XXX: handle it */ s->bit_rate = ((s->bit_rate / 400) | (bit_rate_ext << 12)) * 400; get_bits(&s->gb, 1); /* marker */ vbv_buf_ext = get_bits(&s->gb, 8); low_delay = get_bits(&s->gb, 1); frame_rate_ext_n = get_bits(&s->gb, 2); frame_rate_ext_d = get_bits(&s->gb, 5); if (frame_rate_ext_d >= 1) s->frame_rate = (s->frame_rate * frame_rate_ext_n) / frame_rate_ext_d; dprintf("sequence extension\n"); s->mpeg2 = 1; } static void mpeg_decode_quant_matrix_extension(MpegEncContext *s) { int i, v; if (get_bits(&s->gb, 1)) { for(i=0;i<64;i++) { v = get_bits(&s->gb, 8); s->intra_matrix[i] = v; s->chroma_intra_matrix[i] = v; } } if (get_bits(&s->gb, 1)) { for(i=0;i<64;i++) { v = get_bits(&s->gb, 8); s->non_intra_matrix[i] = v; s->chroma_non_intra_matrix[i] = v; } } if (get_bits(&s->gb, 1)) { for(i=0;i<64;i++) { v = get_bits(&s->gb, 8); s->chroma_intra_matrix[i] = v; } } if (get_bits(&s->gb, 1)) { for(i=0;i<64;i++) { v = get_bits(&s->gb, 8); s->chroma_non_intra_matrix[i] = v; } } } static void mpeg_decode_picture_coding_extension(MpegEncContext *s) { s->full_pel[0] = s->full_pel[1] = 0; s->mpeg_f_code[0][0] = get_bits(&s->gb, 4); s->mpeg_f_code[0][1] = get_bits(&s->gb, 4); s->mpeg_f_code[1][0] = get_bits(&s->gb, 4); s->mpeg_f_code[1][1] = get_bits(&s->gb, 4); s->intra_dc_precision = get_bits(&s->gb, 2); s->picture_structure = get_bits(&s->gb, 2); s->top_field_first = get_bits(&s->gb, 1); s->frame_pred_frame_dct = get_bits(&s->gb, 1); s->concealment_motion_vectors = get_bits(&s->gb, 1); s->q_scale_type = get_bits(&s->gb, 1); s->intra_vlc_format = get_bits(&s->gb, 1); s->alternate_scan = get_bits(&s->gb, 1); s->repeat_first_field = get_bits(&s->gb, 1); s->chroma_420_type = get_bits(&s->gb, 1); s->progressive_frame = get_bits(&s->gb, 1); /* composite display not parsed */ dprintf("dc_preci=%d\n", s->intra_dc_precision); dprintf("pict_structure=%d\n", s->picture_structure); dprintf("conceal=%d\n", s->concealment_motion_vectors); dprintf("intrafmt=%d\n", s->intra_vlc_format); dprintf("frame_pred_frame_dct=%d\n", s->frame_pred_frame_dct); } static void mpeg_decode_extension(AVCodecContext *avctx, UINT8 *buf, int buf_size) { Mpeg1Context *s1 = avctx->priv_data; MpegEncContext *s = &s1->mpeg_enc_ctx; int ext_type; init_get_bits(&s->gb, buf, buf_size); ext_type = get_bits(&s->gb, 4); switch(ext_type) { case 0x1: /* sequence ext */ mpeg_decode_sequence_extension(s); break; case 0x3: /* quant matrix extension */ mpeg_decode_quant_matrix_extension(s); break; case 0x8: /* picture extension */ mpeg_decode_picture_coding_extension(s); break; } } /* return 1 if end of frame */ static int mpeg_decode_slice(AVCodecContext *avctx, AVPicture *pict, int start_code, UINT8 *buf, int buf_size) { Mpeg1Context *s1 = avctx->priv_data; MpegEncContext *s = &s1->mpeg_enc_ctx; int ret; DCTELEM block[6][64]; start_code = (start_code - 1) & 0xff; if (start_code >= s->mb_height) return -1; s->last_dc[0] = 1 << (7 + s->intra_dc_precision); s->last_dc[1] = s->last_dc[0]; s->last_dc[2] = s->last_dc[0]; memset(s->last_mv, 0, sizeof(s->last_mv)); s->mb_x = -1; s->mb_y = start_code; s->mb_incr = 0; /* start frame decoding */ if (s->first_slice) { s->first_slice = 0; MPV_frame_start(s); } init_get_bits(&s->gb, buf, buf_size); s->qscale = get_bits(&s->gb, 5); /* extra slice info */ while (get_bits(&s->gb, 1) != 0) { get_bits(&s->gb, 8); } for(;;) { memset(block, 0, sizeof(block)); ret = mpeg_decode_mb(s, block); dprintf("ret=%d\n", ret); if (ret < 0) return -1; if (ret == 1) break; MPV_decode_mb(s, block); } /* end of slice reached */ if (s->mb_x == (s->mb_width - 1) && s->mb_y == (s->mb_height - 1)) { /* end of image */ UINT8 **picture; MPV_frame_end(s); /* XXX: incorrect reported qscale for mpeg2 */ if (s->pict_type == B_TYPE) { picture = s->current_picture; avctx->quality = s->qscale; } else { /* latency of 1 frame for I and P frames */ /* XXX: use another variable than picture_number */ if (s->picture_number == 0) { picture = NULL; } else { picture = s->last_picture; avctx->quality = s->last_qscale; } s->last_qscale = s->qscale; s->picture_number++; } if (picture) { pict->data[0] = picture[0]; pict->data[1] = picture[1]; pict->data[2] = picture[2]; pict->linesize[0] = s->linesize; pict->linesize[1] = s->linesize / 2; pict->linesize[2] = s->linesize / 2; return 1; } else { return 0; } } else { return 0; } } static int mpeg1_decode_sequence(AVCodecContext *avctx, UINT8 *buf, int buf_size) { Mpeg1Context *s1 = avctx->priv_data; MpegEncContext *s = &s1->mpeg_enc_ctx; int width, height, i, v; init_get_bits(&s->gb, buf, buf_size); width = get_bits(&s->gb, 12); height = get_bits(&s->gb, 12); get_bits(&s->gb, 4); s->frame_rate_index = get_bits(&s->gb, 4); if (s->frame_rate_index == 0) return -1; s->bit_rate = get_bits(&s->gb, 18) * 400; if (get_bits(&s->gb, 1) == 0) /* marker */ return -1; if (width <= 0 || height <= 0 || (width % 2) != 0 || (height % 2) != 0) return -1; if (width != s->width || height != s->height) { /* start new mpeg1 context decoding */ s->out_format = FMT_MPEG1; if (s1->mpeg_enc_ctx_allocated) { MPV_common_end(s); } s->width = width; s->height = height; s->has_b_frames = 1; avctx->width = width; avctx->height = height; avctx->frame_rate = frame_rate_tab[s->frame_rate_index]; avctx->bit_rate = s->bit_rate; if (MPV_common_init(s) < 0) return -1; mpeg1_init_vlc(s); s1->mpeg_enc_ctx_allocated = 1; } get_bits(&s->gb, 10); /* vbv_buffer_size */ get_bits(&s->gb, 1); /* get matrix */ if (get_bits(&s->gb, 1)) { for(i=0;i<64;i++) { v = get_bits(&s->gb, 8); s->intra_matrix[i] = v; s->chroma_intra_matrix[i] = v; } } else { for(i=0;i<64;i++) { v = default_intra_matrix[i]; s->intra_matrix[i] = v; s->chroma_intra_matrix[i] = v; } } if (get_bits(&s->gb, 1)) { for(i=0;i<64;i++) { v = get_bits(&s->gb, 8); s->non_intra_matrix[i] = v; s->chroma_non_intra_matrix[i] = v; } } else { for(i=0;i<64;i++) { v = default_non_intra_matrix[i]; s->non_intra_matrix[i] = v; s->chroma_non_intra_matrix[i] = v; } } /* we set mpeg2 parameters so that it emulates mpeg1 */ s->progressive_sequence = 1; s->progressive_frame = 1; s->picture_structure = PICT_FRAME; s->frame_pred_frame_dct = 1; s->mpeg2 = 0; return 0; } /* handle buffering and image synchronisation */ static int mpeg_decode_frame(AVCodecContext *avctx, void *data, int *data_size, UINT8 *buf, int buf_size) { Mpeg1Context *s = avctx->priv_data; UINT8 *buf_end, *buf_ptr, *buf_start; int len, start_code_found, ret, code, start_code, input_size; AVPicture *picture = data; dprintf("fill_buffer\n"); *data_size = 0; /* special case for last picture */ if (buf_size == 0) { MpegEncContext *s2 = &s->mpeg_enc_ctx; if (s2->picture_number > 0) { picture->data[0] = s2->next_picture[0]; picture->data[1] = s2->next_picture[1]; picture->data[2] = s2->next_picture[2]; picture->linesize[0] = s2->linesize; picture->linesize[1] = s2->linesize / 2; picture->linesize[2] = s2->linesize / 2; *data_size = sizeof(AVPicture); } return 0; } buf_ptr = buf; buf_end = buf + buf_size; while (buf_ptr < buf_end) { buf_start = buf_ptr; /* find start next code */ code = find_start_code(&buf_ptr, buf_end, &s->header_state); if (code >= 0) { start_code_found = 1; } else { start_code_found = 0; } /* copy to buffer */ len = buf_ptr - buf_start; if (len + (s->buf_ptr - s->buffer) > s->buffer_size) { /* data too big : flush */ s->buf_ptr = s->buffer; if (start_code_found) s->start_code = code; } else { memcpy(s->buf_ptr, buf_start, len); s->buf_ptr += len; if (start_code_found) { /* prepare data for next start code */ input_size = s->buf_ptr - s->buffer; start_code = s->start_code; s->buf_ptr = s->buffer; s->start_code = code; switch(start_code) { case SEQ_START_CODE: mpeg1_decode_sequence(avctx, s->buffer, input_size); break; case PICTURE_START_CODE: /* we have a complete image : we try to decompress it */ mpeg1_decode_picture(avctx, s->buffer, input_size); break; case EXT_START_CODE: mpeg_decode_extension(avctx, s->buffer, input_size); break; default: if (start_code >= SLICE_MIN_START_CODE && start_code <= SLICE_MAX_START_CODE) { ret = mpeg_decode_slice(avctx, picture, start_code, s->buffer, input_size); if (ret == 1) { /* got a picture: exit */ *data_size = sizeof(AVPicture); goto the_end; } } break; } } } } the_end: return buf_ptr - buf; } static int mpeg_decode_end(AVCodecContext *avctx) { Mpeg1Context *s = avctx->priv_data; if (s->mpeg_enc_ctx_allocated) MPV_common_end(&s->mpeg_enc_ctx); return 0; } AVCodec mpeg_decoder = { "mpegvideo", CODEC_TYPE_VIDEO, CODEC_ID_MPEG1VIDEO, sizeof(Mpeg1Context), mpeg_decode_init, NULL, mpeg_decode_end, mpeg_decode_frame, };