diff options
Diffstat (limited to 'src/libffmpeg/libavcodec/h261.c')
| -rw-r--r-- | src/libffmpeg/libavcodec/h261.c | 1041 |
1 files changed, 1041 insertions, 0 deletions
diff --git a/src/libffmpeg/libavcodec/h261.c b/src/libffmpeg/libavcodec/h261.c new file mode 100644 index 000000000..aceebaa38 --- /dev/null +++ b/src/libffmpeg/libavcodec/h261.c @@ -0,0 +1,1041 @@ +/* + * H261 decoder + * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at> + * Copyright (c) 2004 Maarten Daniels + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +/** + * @file h261.c + * h261codec. + */ + +#include "common.h" +#include "dsputil.h" +#include "avcodec.h" +#include "mpegvideo.h" +#include "h261data.h" + + +#define H261_MBA_VLC_BITS 9 +#define H261_MTYPE_VLC_BITS 6 +#define H261_MV_VLC_BITS 7 +#define H261_CBP_VLC_BITS 9 +#define TCOEFF_VLC_BITS 9 + +#define MBA_STUFFING 33 +#define MBA_STARTCODE 34 +#define IS_FIL(a) ((a)&MB_TYPE_H261_FIL) + +/** + * H261Context + */ +typedef struct H261Context{ + MpegEncContext s; + + int current_mba; + int previous_mba; + int mba_diff; + int mtype; + int current_mv_x; + int current_mv_y; + int gob_number; + int gob_start_code_skipped; // 1 if gob start code is already read before gob header is read +}H261Context; + +void ff_h261_loop_filter(MpegEncContext *s){ + H261Context * h= (H261Context*)s; + const int linesize = s->linesize; + const int uvlinesize= s->uvlinesize; + uint8_t *dest_y = s->dest[0]; + uint8_t *dest_cb= s->dest[1]; + uint8_t *dest_cr= s->dest[2]; + + if(!(IS_FIL (h->mtype))) + return; + + s->dsp.h261_loop_filter(dest_y , linesize); + s->dsp.h261_loop_filter(dest_y + 8, linesize); + s->dsp.h261_loop_filter(dest_y + 8 * linesize , linesize); + s->dsp.h261_loop_filter(dest_y + 8 * linesize + 8, linesize); + s->dsp.h261_loop_filter(dest_cb, uvlinesize); + s->dsp.h261_loop_filter(dest_cr, uvlinesize); +} + +static int ff_h261_get_picture_format(int width, int height){ + // QCIF + if (width == 176 && height == 144) + return 0; + // CIF + else if (width == 352 && height == 288) + return 1; + // ERROR + else + return -1; +} + +static void h261_encode_block(H261Context * h, DCTELEM * block, + int n); +static int h261_decode_block(H261Context *h, DCTELEM *block, + int n, int coded); + +void ff_h261_encode_picture_header(MpegEncContext * s, int picture_number){ + H261Context * h = (H261Context *) s; + int format, temp_ref; + + align_put_bits(&s->pb); + + /* Update the pointer to last GOB */ + s->ptr_lastgob = pbBufPtr(&s->pb); + + put_bits(&s->pb, 20, 0x10); /* PSC */ + + temp_ref= s->picture_number * (int64_t)30000 * s->avctx->frame_rate_base / + (1001 * (int64_t)s->avctx->frame_rate); + put_bits(&s->pb, 5, temp_ref & 0x1f); /* TemporalReference */ + + put_bits(&s->pb, 1, 0); /* split screen off */ + put_bits(&s->pb, 1, 0); /* camera off */ + put_bits(&s->pb, 1, 0); /* freeze picture release off */ + + format = ff_h261_get_picture_format(s->width, s->height); + + put_bits(&s->pb, 1, format); /* 0 == QCIF, 1 == CIF */ + + put_bits(&s->pb, 1, 0); /* still image mode */ + put_bits(&s->pb, 1, 0); /* reserved */ + + put_bits(&s->pb, 1, 0); /* no PEI */ + if(format == 0) + h->gob_number = -1; + else + h->gob_number = 0; + h->current_mba = 0; +} + +/** + * Encodes a group of blocks header. + */ +static void h261_encode_gob_header(MpegEncContext * s, int mb_line){ + H261Context * h = (H261Context *)s; + if(ff_h261_get_picture_format(s->width, s->height) == 0){ + h->gob_number+=2; // QCIF + } + else{ + h->gob_number++; // CIF + } + put_bits(&s->pb, 16, 1); /* GBSC */ + put_bits(&s->pb, 4, h->gob_number); /* GN */ + put_bits(&s->pb, 5, s->qscale); /* GQUANT */ + put_bits(&s->pb, 1, 0); /* no GEI */ + h->current_mba = 0; + h->previous_mba = 0; + h->current_mv_x=0; + h->current_mv_y=0; +} + +void ff_h261_reorder_mb_index(MpegEncContext* s){ + int index= s->mb_x + s->mb_y*s->mb_width; + + if(index % 33 == 0) + h261_encode_gob_header(s,0); + + /* for CIF the GOB's are fragmented in the middle of a scanline + that's why we need to adjust the x and y index of the macroblocks */ + if(ff_h261_get_picture_format(s->width,s->height) == 1){ // CIF + s->mb_x = index % 11 ; index /= 11; + s->mb_y = index % 3 ; index /= 3; + s->mb_x+= 11*(index % 2); index /= 2; + s->mb_y+= 3*index; + + ff_init_block_index(s); + ff_update_block_index(s); + } +} + +static void h261_encode_motion(H261Context * h, int val){ + MpegEncContext * const s = &h->s; + int sign, code; + if(val==0){ + code = 0; + put_bits(&s->pb,h261_mv_tab[code][1],h261_mv_tab[code][0]); + } + else{ + if(val > 15) + val -=32; + if(val < -16) + val+=32; + sign = val < 0; + code = sign ? -val : val; + put_bits(&s->pb,h261_mv_tab[code][1],h261_mv_tab[code][0]); + put_bits(&s->pb,1,sign); + } +} + +static inline int get_cbp(MpegEncContext * s, + DCTELEM block[6][64]) +{ + int i, cbp; + cbp= 0; + for (i = 0; i < 6; i++) { + if (s->block_last_index[i] >= 0) + cbp |= 1 << (5 - i); + } + return cbp; +} +void ff_h261_encode_mb(MpegEncContext * s, + DCTELEM block[6][64], + int motion_x, int motion_y) +{ + H261Context * h = (H261Context *)s; + int mvd, mv_diff_x, mv_diff_y, i, cbp; + cbp = 63; // avoid warning + mvd = 0; + + h->current_mba++; + h->mtype = 0; + + if (!s->mb_intra){ + /* compute cbp */ + cbp= get_cbp(s, block); + + /* mvd indicates if this block is motion compensated */ + mvd = motion_x | motion_y; + + if((cbp | mvd | s->dquant ) == 0) { + /* skip macroblock */ + s->skip_count++; + h->current_mv_x=0; + h->current_mv_y=0; + return; + } + } + + /* MB is not skipped, encode MBA */ + put_bits(&s->pb, h261_mba_bits[(h->current_mba-h->previous_mba)-1], h261_mba_code[(h->current_mba-h->previous_mba)-1]); + + /* calculate MTYPE */ + if(!s->mb_intra){ + h->mtype++; + + if(mvd || s->loop_filter) + h->mtype+=3; + if(s->loop_filter) + h->mtype+=3; + if(cbp || s->dquant) + h->mtype++; + assert(h->mtype > 1); + } + + if(s->dquant) + h->mtype++; + + put_bits(&s->pb, h261_mtype_bits[h->mtype], h261_mtype_code[h->mtype]); + + h->mtype = h261_mtype_map[h->mtype]; + + if(IS_QUANT(h->mtype)){ + ff_set_qscale(s,s->qscale+s->dquant); + put_bits(&s->pb, 5, s->qscale); + } + + if(IS_16X16(h->mtype)){ + mv_diff_x = (motion_x >> 1) - h->current_mv_x; + mv_diff_y = (motion_y >> 1) - h->current_mv_y; + h->current_mv_x = (motion_x >> 1); + h->current_mv_y = (motion_y >> 1); + h261_encode_motion(h,mv_diff_x); + h261_encode_motion(h,mv_diff_y); + } + + h->previous_mba = h->current_mba; + + if(HAS_CBP(h->mtype)){ + put_bits(&s->pb,h261_cbp_tab[cbp-1][1],h261_cbp_tab[cbp-1][0]); + } + for(i=0; i<6; i++) { + /* encode each block */ + h261_encode_block(h, block[i], i); + } + + if ( ( h->current_mba == 11 ) || ( h->current_mba == 22 ) || ( h->current_mba == 33 ) || ( !IS_16X16 ( h->mtype ) )){ + h->current_mv_x=0; + h->current_mv_y=0; + } +} + +void ff_h261_encode_init(MpegEncContext *s){ + static int done = 0; + + if (!done) { + done = 1; + init_rl(&h261_rl_tcoeff, 1); + } + + s->min_qcoeff= -127; + s->max_qcoeff= 127; + s->y_dc_scale_table= + s->c_dc_scale_table= ff_mpeg1_dc_scale_table; +} + + +/** + * encodes a 8x8 block. + * @param block the 8x8 block + * @param n block index (0-3 are luma, 4-5 are chroma) + */ +static void h261_encode_block(H261Context * h, DCTELEM * block, int n){ + MpegEncContext * const s = &h->s; + int level, run, last, i, j, last_index, last_non_zero, sign, slevel, code; + RLTable *rl; + + rl = &h261_rl_tcoeff; + if (s->mb_intra) { + /* DC coef */ + level = block[0]; + /* 255 cannot be represented, so we clamp */ + if (level > 254) { + level = 254; + block[0] = 254; + } + /* 0 cannot be represented also */ + else if (level < 1) { + level = 1; + block[0] = 1; + } + if (level == 128) + put_bits(&s->pb, 8, 0xff); + else + put_bits(&s->pb, 8, level); + i = 1; + } else if((block[0]==1 || block[0] == -1) && (s->block_last_index[n] > -1)){ + //special case + put_bits(&s->pb,2,block[0]>0 ? 2 : 3 ); + i = 1; + } else { + i = 0; + } + + /* AC coefs */ + last_index = s->block_last_index[n]; + last_non_zero = i - 1; + for (; i <= last_index; i++) { + j = s->intra_scantable.permutated[i]; + level = block[j]; + if (level) { + run = i - last_non_zero - 1; + last = (i == last_index); + sign = 0; + slevel = level; + if (level < 0) { + sign = 1; + level = -level; + } + code = get_rl_index(rl, 0 /*no last in H.261, EOB is used*/, run, level); + if(run==0 && level < 16) + code+=1; + put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]); + if (code == rl->n) { + put_bits(&s->pb, 6, run); + assert(slevel != 0); + assert(level <= 127); + put_bits(&s->pb, 8, slevel & 0xff); + } else { + put_bits(&s->pb, 1, sign); + } + last_non_zero = i; + } + } + if(last_index > -1){ + put_bits(&s->pb, rl->table_vlc[0][1], rl->table_vlc[0][0]);// END OF BLOCK + } +} + +/***********************************************/ +/* decoding */ + +static VLC h261_mba_vlc; +static VLC h261_mtype_vlc; +static VLC h261_mv_vlc; +static VLC h261_cbp_vlc; + +void init_vlc_rl(RLTable *rl, int use_static); + +static void h261_decode_init_vlc(H261Context *h){ + static int done = 0; + + if(!done){ + done = 1; + init_vlc(&h261_mba_vlc, H261_MBA_VLC_BITS, 35, + h261_mba_bits, 1, 1, + h261_mba_code, 1, 1, 1); + init_vlc(&h261_mtype_vlc, H261_MTYPE_VLC_BITS, 10, + h261_mtype_bits, 1, 1, + h261_mtype_code, 1, 1, 1); + init_vlc(&h261_mv_vlc, H261_MV_VLC_BITS, 17, + &h261_mv_tab[0][1], 2, 1, + &h261_mv_tab[0][0], 2, 1, 1); + init_vlc(&h261_cbp_vlc, H261_CBP_VLC_BITS, 63, + &h261_cbp_tab[0][1], 2, 1, + &h261_cbp_tab[0][0], 2, 1, 1); + init_rl(&h261_rl_tcoeff, 1); + init_vlc_rl(&h261_rl_tcoeff, 1); + } +} + +static int h261_decode_init(AVCodecContext *avctx){ + H261Context *h= avctx->priv_data; + MpegEncContext * const s = &h->s; + + // set defaults + MPV_decode_defaults(s); + s->avctx = avctx; + + s->width = s->avctx->coded_width; + s->height = s->avctx->coded_height; + s->codec_id = s->avctx->codec->id; + + s->out_format = FMT_H261; + s->low_delay= 1; + avctx->pix_fmt= PIX_FMT_YUV420P; + + s->codec_id= avctx->codec->id; + + h261_decode_init_vlc(h); + + h->gob_start_code_skipped = 0; + + return 0; +} + +/** + * decodes the group of blocks header or slice header. + * @return <0 if an error occured + */ +static int h261_decode_gob_header(H261Context *h){ + unsigned int val; + MpegEncContext * const s = &h->s; + + if ( !h->gob_start_code_skipped ){ + /* Check for GOB Start Code */ + val = show_bits(&s->gb, 15); + if(val) + return -1; + + /* We have a GBSC */ + skip_bits(&s->gb, 16); + } + + h->gob_start_code_skipped = 0; + + h->gob_number = get_bits(&s->gb, 4); /* GN */ + s->qscale = get_bits(&s->gb, 5); /* GQUANT */ + + /* Check if gob_number is valid */ + if (s->mb_height==18){ //cif + if ((h->gob_number<=0) || (h->gob_number>12)) + return -1; + } + else{ //qcif + if ((h->gob_number!=1) && (h->gob_number!=3) && (h->gob_number!=5)) + return -1; + } + + /* GEI */ + while (get_bits1(&s->gb) != 0) { + skip_bits(&s->gb, 8); + } + + if(s->qscale==0) + return -1; + + // For the first transmitted macroblock in a GOB, MBA is the absolute address. For + // subsequent macroblocks, MBA is the difference between the absolute addresses of + // the macroblock and the last transmitted macroblock. + h->current_mba = 0; + h->mba_diff = 0; + + return 0; +} + +/** + * decodes the group of blocks / video packet header. + * @return <0 if no resync found + */ +static int ff_h261_resync(H261Context *h){ + MpegEncContext * const s = &h->s; + int left, ret; + + if ( h->gob_start_code_skipped ){ + ret= h261_decode_gob_header(h); + if(ret>=0) + return 0; + } + else{ + if(show_bits(&s->gb, 15)==0){ + ret= h261_decode_gob_header(h); + if(ret>=0) + return 0; + } + //ok, its not where its supposed to be ... + s->gb= s->last_resync_gb; + align_get_bits(&s->gb); + left= s->gb.size_in_bits - get_bits_count(&s->gb); + + for(;left>15+1+4+5; left-=8){ + if(show_bits(&s->gb, 15)==0){ + GetBitContext bak= s->gb; + + ret= h261_decode_gob_header(h); + if(ret>=0) + return 0; + + s->gb= bak; + } + skip_bits(&s->gb, 8); + } + } + + return -1; +} + +/** + * decodes skipped macroblocks + * @return 0 + */ +static int h261_decode_mb_skipped(H261Context *h, int mba1, int mba2 ) +{ + MpegEncContext * const s = &h->s; + int i; + + s->mb_intra = 0; + + for(i=mba1; i<mba2; i++){ + int j, xy; + + s->mb_x= ((h->gob_number-1) % 2) * 11 + i % 11; + s->mb_y= ((h->gob_number-1) / 2) * 3 + i / 11; + xy = s->mb_x + s->mb_y * s->mb_stride; + ff_init_block_index(s); + ff_update_block_index(s); + s->dsp.clear_blocks(s->block[0]); + + for(j=0;j<6;j++) + s->block_last_index[j] = -1; + + s->mv_dir = MV_DIR_FORWARD; + s->mv_type = MV_TYPE_16X16; + s->current_picture.mb_type[xy]= MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0; + s->mv[0][0][0] = 0; + s->mv[0][0][1] = 0; + s->mb_skiped = 1; + h->mtype &= ~MB_TYPE_H261_FIL; + + MPV_decode_mb(s, s->block); + } + + return 0; +} + +static int decode_mv_component(GetBitContext *gb, int v){ + int mv_diff = get_vlc2(gb, h261_mv_vlc.table, H261_MV_VLC_BITS, 2); + + /* check if mv_diff is valid */ + if ( mv_diff < 0 ) + return v; + + mv_diff = mvmap[mv_diff]; + + if(mv_diff && !get_bits1(gb)) + mv_diff= -mv_diff; + + v += mv_diff; + if (v <=-16) v+= 32; + else if(v >= 16) v-= 32; + + return v; +} + +static int h261_decode_mb(H261Context *h){ + MpegEncContext * const s = &h->s; + int i, cbp, xy; + + cbp = 63; + // Read mba + do{ + h->mba_diff = get_vlc2(&s->gb, h261_mba_vlc.table, H261_MBA_VLC_BITS, 2); + + /* Check for slice end */ + /* NOTE: GOB can be empty (no MB data) or exist only of MBA_stuffing */ + if (h->mba_diff == MBA_STARTCODE){ // start code + h->gob_start_code_skipped = 1; + return SLICE_END; + } + } + while( h->mba_diff == MBA_STUFFING ); // stuffing + + if ( h->mba_diff < 0 ){ + if ( get_bits_count(&s->gb) + 7 >= s->gb.size_in_bits ) + return SLICE_END; + + av_log(s->avctx, AV_LOG_ERROR, "illegal mba at %d %d\n", s->mb_x, s->mb_y); + return SLICE_ERROR; + } + + h->mba_diff += 1; + h->current_mba += h->mba_diff; + + if ( h->current_mba > MBA_STUFFING ) + return SLICE_ERROR; + + s->mb_x= ((h->gob_number-1) % 2) * 11 + ((h->current_mba-1) % 11); + s->mb_y= ((h->gob_number-1) / 2) * 3 + ((h->current_mba-1) / 11); + xy = s->mb_x + s->mb_y * s->mb_stride; + ff_init_block_index(s); + ff_update_block_index(s); + s->dsp.clear_blocks(s->block[0]); + + // Read mtype + h->mtype = get_vlc2(&s->gb, h261_mtype_vlc.table, H261_MTYPE_VLC_BITS, 2); + h->mtype = h261_mtype_map[h->mtype]; + + // Read mquant + if ( IS_QUANT ( h->mtype ) ){ + ff_set_qscale(s, get_bits(&s->gb, 5)); + } + + s->mb_intra = IS_INTRA4x4(h->mtype); + + // Read mv + if ( IS_16X16 ( h->mtype ) ){ + // Motion vector data is included for all MC macroblocks. MVD is obtained from the macroblock vector by subtracting the + // vector of the preceding macroblock. For this calculation the vector of the preceding macroblock is regarded as zero in the + // following three situations: + // 1) evaluating MVD for macroblocks 1, 12 and 23; + // 2) evaluating MVD for macroblocks in which MBA does not represent a difference of 1; + // 3) MTYPE of the previous macroblock was not MC. + if ( ( h->current_mba == 1 ) || ( h->current_mba == 12 ) || ( h->current_mba == 23 ) || + ( h->mba_diff != 1)) + { + h->current_mv_x = 0; + h->current_mv_y = 0; + } + + h->current_mv_x= decode_mv_component(&s->gb, h->current_mv_x); + h->current_mv_y= decode_mv_component(&s->gb, h->current_mv_y); + }else{ + h->current_mv_x = 0; + h->current_mv_y = 0; + } + + // Read cbp + if ( HAS_CBP( h->mtype ) ){ + cbp = get_vlc2(&s->gb, h261_cbp_vlc.table, H261_CBP_VLC_BITS, 2) + 1; + } + + if(s->mb_intra){ + s->current_picture.mb_type[xy]= MB_TYPE_INTRA; + goto intra; + } + + //set motion vectors + s->mv_dir = MV_DIR_FORWARD; + s->mv_type = MV_TYPE_16X16; + s->current_picture.mb_type[xy]= MB_TYPE_16x16 | MB_TYPE_L0; + s->mv[0][0][0] = h->current_mv_x * 2;//gets divided by 2 in motion compensation + s->mv[0][0][1] = h->current_mv_y * 2; + +intra: + /* decode each block */ + if(s->mb_intra || HAS_CBP(h->mtype)){ + for (i = 0; i < 6; i++) { + if (h261_decode_block(h, s->block[i], i, cbp&32) < 0){ + return SLICE_ERROR; + } + cbp+=cbp; + } + } + + MPV_decode_mb(s, s->block); + + return SLICE_OK; +} + +/** + * decodes a macroblock + * @return <0 if an error occured + */ +static int h261_decode_block(H261Context * h, DCTELEM * block, + int n, int coded) +{ + MpegEncContext * const s = &h->s; + int code, level, i, j, run; + RLTable *rl = &h261_rl_tcoeff; + const uint8_t *scan_table; + + // For the variable length encoding there are two code tables, one being used for + // the first transmitted LEVEL in INTER, INTER+MC and INTER+MC+FIL blocks, the second + // for all other LEVELs except the first one in INTRA blocks which is fixed length + // coded with 8 bits. + // NOTE: the two code tables only differ in one VLC so we handle that manually. + scan_table = s->intra_scantable.permutated; + if (s->mb_intra){ + /* DC coef */ + level = get_bits(&s->gb, 8); + // 0 (00000000b) and -128 (10000000b) are FORBIDDEN + if((level&0x7F) == 0){ + av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y); + return -1; + } + // The code 1000 0000 is not used, the reconstruction level of 1024 being coded as 1111 1111. + if (level == 255) + level = 128; + block[0] = level; + i = 1; + }else if(coded){ + // Run Level Code + // EOB Not possible for first level when cbp is available (that's why the table is different) + // 0 1 1s + // * * 0* + int check = show_bits(&s->gb, 2); + i = 0; + if ( check & 0x2 ){ + skip_bits(&s->gb, 2); + block[0] = ( check & 0x1 ) ? -1 : 1; + i = 1; + } + }else{ + i = 0; + } + if(!coded){ + s->block_last_index[n] = i - 1; + return 0; + } + for(;;){ + code = get_vlc2(&s->gb, rl->vlc.table, TCOEFF_VLC_BITS, 2); + if (code < 0){ + av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y); + return -1; + } + if (code == rl->n) { + /* escape */ + // The remaining combinations of (run, level) are encoded with a 20-bit word consisting of 6 bits escape, 6 bits run and 8 bits level. + run = get_bits(&s->gb, 6); + level = get_sbits(&s->gb, 8); + }else if(code == 0){ + break; + }else{ + run = rl->table_run[code]; + level = rl->table_level[code]; + if (get_bits1(&s->gb)) + level = -level; + } + i += run; + if (i >= 64){ + av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d\n", s->mb_x, s->mb_y); + return -1; + } + j = scan_table[i]; + block[j] = level; + i++; + } + s->block_last_index[n] = i-1; + return 0; +} + +/** + * decodes the H261 picture header. + * @return <0 if no startcode found + */ +int h261_decode_picture_header(H261Context *h){ + MpegEncContext * const s = &h->s; + int format, i; + uint32_t startcode= 0; + + for(i= s->gb.size_in_bits - get_bits_count(&s->gb); i>24; i-=1){ + startcode = ((startcode << 1) | get_bits(&s->gb, 1)) & 0x000FFFFF; + + if(startcode == 0x10) + break; + } + + if (startcode != 0x10){ + av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n"); + return -1; + } + + /* temporal reference */ + s->picture_number = get_bits(&s->gb, 5); /* picture timestamp */ + + /* PTYPE starts here */ + skip_bits1(&s->gb); /* split screen off */ + skip_bits1(&s->gb); /* camera off */ + skip_bits1(&s->gb); /* freeze picture release off */ + + format = get_bits1(&s->gb); + + //only 2 formats possible + if (format == 0){//QCIF + s->width = 176; + s->height = 144; + s->mb_width = 11; + s->mb_height = 9; + }else{//CIF + s->width = 352; + s->height = 288; + s->mb_width = 22; + s->mb_height = 18; + } + + s->mb_num = s->mb_width * s->mb_height; + + skip_bits1(&s->gb); /* still image mode off */ + skip_bits1(&s->gb); /* Reserved */ + + /* PEI */ + while (get_bits1(&s->gb) != 0){ + skip_bits(&s->gb, 8); + } + + // h261 has no I-FRAMES, but if we pass I_TYPE for the first frame, the codec crashes if it does + // not contain all I-blocks (e.g. when a packet is lost) + s->pict_type = P_TYPE; + + h->gob_number = 0; + return 0; +} + +static int h261_decode_gob(H261Context *h){ + MpegEncContext * const s = &h->s; + + ff_set_qscale(s, s->qscale); + + /* decode mb's */ + while(h->current_mba <= MBA_STUFFING) + { + int ret; + /* DCT & quantize */ + ret= h261_decode_mb(h); + if(ret<0){ + if(ret==SLICE_END){ + h261_decode_mb_skipped(h, h->current_mba, 33); + return 0; + } + av_log(s->avctx, AV_LOG_ERROR, "Error at MB: %d\n", s->mb_x + s->mb_y*s->mb_stride); + return -1; + } + + h261_decode_mb_skipped(h, h->current_mba-h->mba_diff, h->current_mba-1); + } + + return -1; +} + +static int h261_find_frame_end(ParseContext *pc, AVCodecContext* avctx, const uint8_t *buf, int buf_size){ + int vop_found, i, j; + uint32_t state; + + vop_found= pc->frame_start_found; + state= pc->state; + + for(i=0; i<buf_size && !vop_found; i++){ + state= (state<<8) | buf[i]; + for(j=0; j<8; j++){ + if(((state>>j)&0xFFFFF) == 0x00010){ + i++; + vop_found=1; + break; + } + } + } + if(vop_found){ + for(; i<buf_size; i++){ + state= (state<<8) | buf[i]; + for(j=0; j<8; j++){ + if(((state>>j)&0xFFFFF) == 0x00010){ + pc->frame_start_found=0; + pc->state= state>>(2*8); + return i-1; + } + } + } + } + + pc->frame_start_found= vop_found; + pc->state= state; + return END_NOT_FOUND; +} + +static int h261_parse(AVCodecParserContext *s, + AVCodecContext *avctx, + uint8_t **poutbuf, int *poutbuf_size, + const uint8_t *buf, int buf_size) +{ + ParseContext *pc = s->priv_data; + int next; + + next= h261_find_frame_end(pc,avctx, buf, buf_size); + if (ff_combine_frame(pc, next, (uint8_t **)&buf, &buf_size) < 0) { + *poutbuf = NULL; + *poutbuf_size = 0; + return buf_size; + } + *poutbuf = (uint8_t *)buf; + *poutbuf_size = buf_size; + return next; +} + +/** + * returns the number of bytes consumed for building the current frame + */ +static int get_consumed_bytes(MpegEncContext *s, int buf_size){ + int pos= get_bits_count(&s->gb)>>3; + if(pos==0) pos=1; //avoid infinite loops (i doubt thats needed but ...) + if(pos+10>buf_size) pos=buf_size; // oops ;) + + return pos; +} + +static int h261_decode_frame(AVCodecContext *avctx, + void *data, int *data_size, + uint8_t *buf, int buf_size) +{ + H261Context *h= avctx->priv_data; + MpegEncContext *s = &h->s; + int ret; + AVFrame *pict = data; + +#ifdef DEBUG + printf("*****frame %d size=%d\n", avctx->frame_number, buf_size); + printf("bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]); +#endif + s->flags= avctx->flags; + s->flags2= avctx->flags2; + + h->gob_start_code_skipped=0; + +retry: + + init_get_bits(&s->gb, buf, buf_size*8); + + if(!s->context_initialized){ + if (MPV_common_init(s) < 0) //we need the idct permutaton for reading a custom matrix + return -1; + } + + //we need to set current_picture_ptr before reading the header, otherwise we cant store anyting im there + if(s->current_picture_ptr==NULL || s->current_picture_ptr->data[0]){ + int i= ff_find_unused_picture(s, 0); + s->current_picture_ptr= &s->picture[i]; + } + + ret = h261_decode_picture_header(h); + + /* skip if the header was thrashed */ + if (ret < 0){ + av_log(s->avctx, AV_LOG_ERROR, "header damaged\n"); + return -1; + } + + if (s->width != avctx->coded_width || s->height != avctx->coded_height){ + ParseContext pc= s->parse_context; //FIXME move these demuxng hack to avformat + s->parse_context.buffer=0; + MPV_common_end(s); + s->parse_context= pc; + } + if (!s->context_initialized) { + avcodec_set_dimensions(avctx, s->width, s->height); + + goto retry; + } + + // for hurry_up==5 + s->current_picture.pict_type= s->pict_type; + s->current_picture.key_frame= s->pict_type == I_TYPE; + + /* skip everything if we are in a hurry>=5 */ + if(avctx->hurry_up>=5) return get_consumed_bytes(s, buf_size); + + if(MPV_frame_start(s, avctx) < 0) + return -1; + + ff_er_frame_start(s); + + /* decode each macroblock */ + s->mb_x=0; + s->mb_y=0; + + while(h->gob_number < (s->mb_height==18 ? 12 : 5)){ + if(ff_h261_resync(h)<0) + break; + h261_decode_gob(h); + } + MPV_frame_end(s); + +assert(s->current_picture.pict_type == s->current_picture_ptr->pict_type); +assert(s->current_picture.pict_type == s->pict_type); + *pict= *(AVFrame*)s->current_picture_ptr; + ff_print_debug_info(s, pict); + + /* Return the Picture timestamp as the frame number */ + /* we substract 1 because it is added on utils.c */ + avctx->frame_number = s->picture_number - 1; + + *data_size = sizeof(AVFrame); + + return get_consumed_bytes(s, buf_size); +} + +static int h261_decode_end(AVCodecContext *avctx) +{ + H261Context *h= avctx->priv_data; + MpegEncContext *s = &h->s; + + MPV_common_end(s); + return 0; +} + +#ifdef CONFIG_ENCODERS +AVCodec h261_encoder = { + "h261", + CODEC_TYPE_VIDEO, + CODEC_ID_H261, + sizeof(H261Context), + MPV_encode_init, + MPV_encode_picture, + MPV_encode_end, +}; +#endif + +AVCodec h261_decoder = { + "h261", + CODEC_TYPE_VIDEO, + CODEC_ID_H261, + sizeof(H261Context), + h261_decode_init, + NULL, + h261_decode_end, + h261_decode_frame, + CODEC_CAP_DR1, +}; + +AVCodecParser h261_parser = { + { CODEC_ID_H261 }, + sizeof(ParseContext), + NULL, + h261_parse, + ff_parse_close, +}; |