nihav-codec-support/src/codecs/h263/decoder.rs

   1 //use std::mem;
   2 use nihav_core::codecs::DecoderError;
   3 use nihav_core::frame::*;
   4 use super::super::*;
   5 use super::super::blockdsp;
   6 use super::*;
   7 //use super::code::*;
   8 use nihav_core::formats;
   9
  10 #[allow(dead_code)]
  11 struct MVInfo {
  12     mv:         Vec<MV>,
  13     mb_w:       usize,
  14     mb_stride:  usize,
  15     mb_start:   usize,
  16     top:        bool,
  17     mvmode:     MVMode,
  18 }
  19
  20 impl MVInfo {
  21     fn new() -> Self { MVInfo{ mv: Vec::new(), mb_w: 0, mb_stride: 0, mb_start: 0, top: true, mvmode: MVMode::Old } }
  22     fn reset(&mut self, mb_w: usize, mb_start: usize, mvmode: MVMode) {
  23         self.mb_start  = mb_start;
  24         self.mb_w      = mb_w;
  25         self.mb_stride = mb_w * 2 + 2;
  26         self.mv.resize(self.mb_stride * 3, ZERO_MV);
  27         self.mvmode    = mvmode;
  28     }
  29     fn update_row(&mut self) {
  30         self.mb_start = self.mb_w + 1;
  31         self.top      = false;
  32         for i in 0..self.mb_stride {
  33             self.mv[i] = self.mv[self.mb_stride * 2 + i];
  34         }
  35     }
  36     #[allow(non_snake_case)]
  37     fn predict(&mut self, mb_x: usize, blk_no: usize, use4: bool, diff: MV, first_line: bool, first_mb: bool) -> MV {
  38         let A;
  39         let B;
  40         let C;
  41         let last = mb_x == self.mb_w - 1;
  42         match blk_no {
  43             0 => {
  44                     if mb_x != self.mb_start {
  45                         A = if !first_mb   { self.mv[self.mb_stride + mb_x * 2 - 1] } else { ZERO_MV };
  46                         B = if !first_line { self.mv[                 mb_x * 2] } else { A };
  47                         C = if !first_line && !last { self.mv[mb_x * 2 + 2] } else { ZERO_MV };
  48                     } else {
  49                         A = ZERO_MV; B = ZERO_MV; C = ZERO_MV;
  50                     }
  51                 },
  52             1 => {
  53                     A = self.mv[self.mb_stride + mb_x * 2];
  54                     B = if !first_line { self.mv[mb_x * 2 + 1] } else { A };
  55                     C = if !first_line && !last { self.mv[mb_x * 2 + 2] } else { ZERO_MV/*A*/ };
  56                 },
  57             2 => {
  58                     A = if mb_x != self.mb_start { self.mv[self.mb_stride * 2 + mb_x * 2 - 1] } else { ZERO_MV };
  59                     B = self.mv[self.mb_stride + mb_x * 2];
  60                     C = self.mv[self.mb_stride + mb_x * 2 + 1];
  61                 },
  62             3 => {
  63                     A = self.mv[self.mb_stride * 2 + mb_x * 2];
  64                     B = self.mv[self.mb_stride * 1 + mb_x * 2 + 1];
  65                     C = self.mv[self.mb_stride * 1 + mb_x * 2];
  66                 },
  67             _ => { return ZERO_MV; }
  68         }
  69         let pred_mv = MV::pred(A, B, C);
  70         let new_mv = MV::add_umv(pred_mv, diff, self.mvmode);
  71         if !use4 {
  72             self.mv[self.mb_stride * 1 + mb_x * 2 + 0] = new_mv;
  73             self.mv[self.mb_stride * 1 + mb_x * 2 + 1] = new_mv;
  74             self.mv[self.mb_stride * 2 + mb_x * 2 + 0] = new_mv;
  75             self.mv[self.mb_stride * 2 + mb_x * 2 + 1] = new_mv;
  76         } else {
  77             match blk_no {
  78                 0 => { self.mv[self.mb_stride * 1 + mb_x * 2 + 0] = new_mv; },
  79                 1 => { self.mv[self.mb_stride * 1 + mb_x * 2 + 1] = new_mv; },
  80                 2 => { self.mv[self.mb_stride * 2 + mb_x * 2 + 0] = new_mv; },
  81                 3 => { self.mv[self.mb_stride * 2 + mb_x * 2 + 1] = new_mv; },
  82                 _ => {},
  83             };
  84         }
  85
  86         new_mv
  87     }
  88     fn set_zero_mv(&mut self, mb_x: usize) {
  89         self.mv[self.mb_stride * 1 + mb_x * 2 + 0] = ZERO_MV;
  90         self.mv[self.mb_stride * 1 + mb_x * 2 + 1] = ZERO_MV;
  91         self.mv[self.mb_stride * 2 + mb_x * 2 + 0] = ZERO_MV;
  92         self.mv[self.mb_stride * 2 + mb_x * 2 + 1] = ZERO_MV;
  93     }
  94     fn get_mv(&self, mb_x: usize, blk_no: usize) -> MV {
  95         self.mv[self.mb_stride + mb_x * 2 + (blk_no & 1) + (blk_no >> 1) * self.mb_stride]
  96     }
  97 }
  98
  99 #[allow(dead_code)]
 100 #[derive(Clone,Copy)]
 101 struct BMB {
 102     num_mv: usize,
 103     mv_f:   [MV; 4],
 104     mv_b:   [MV; 4],
 105     fwd:    bool,
 106     blk:    [[i16; 64]; 6],
 107     cbp:    u8,
 108 }
 109
 110 impl BMB {
 111     fn new() -> Self { BMB {blk: [[0; 64]; 6], cbp: 0, fwd: false, mv_f: [ZERO_MV; 4], mv_b: [ZERO_MV; 4], num_mv: 0} }
 112 }
 113
 114 #[derive(Clone,Copy)]
 115 struct PredCoeffs {
 116     hor: [[i16; 8]; 6],
 117     ver: [[i16; 8]; 6],
 118 }
 119
 120 const ZERO_PRED_COEFFS: PredCoeffs = PredCoeffs { hor: [[0; 8]; 6], ver: [[0; 8]; 6] };
 121
 122 pub struct H263BaseDecoder {
 123     w:          usize,
 124     h:          usize,
 125     mb_w:       usize,
 126     mb_h:       usize,
 127     num_mb:     usize,
 128     ftype:      Type,
 129     ipbs:       IPBShuffler,
 130     next_ts:    u16,
 131     last_ts:    u16,
 132     tsdiff:     u16,
 133     has_b:      bool,
 134     b_data:     Vec<BMB>,
 135     pred_coeffs: Vec<PredCoeffs>,
 136     is_gob:     bool,
 137     slice_reset: bool,
 138     may_have_b_frames: bool,
 139     mv_data:    Vec<BlockMVInfo>,
 140 }
 141
 142 #[inline]
 143 fn clip_dc(dc: i16) -> i16 {
 144     if dc <= 0 { 0 }
 145     else if dc > 2046 { 2047 }
 146     else { dc | 1 }
 147 }
 148
 149 #[inline]
 150 fn clip_ac(ac: i16) -> i16 {
 151     if ac < -2048 { -2048 }
 152     else if ac > 2047 { 2047 }
 153     else { ac }
 154 }
 155
 156 #[allow(dead_code)]
 157 impl H263BaseDecoder {
 158     pub fn new_with_opts(is_gob: bool, slice_reset: bool, may_have_b_frames: bool) -> Self {
 159         H263BaseDecoder{
 160             w: 0, h: 0, mb_w: 0, mb_h: 0, num_mb: 0,
 161             ftype: Type::Special,
 162             ipbs: IPBShuffler::new(),
 163             last_ts: 0, next_ts: 0, tsdiff: 0,
 164             has_b: false, b_data: Vec::new(),
 165             pred_coeffs: Vec::new(),
 166             is_gob, slice_reset,
 167             may_have_b_frames,
 168             mv_data: Vec::new(),
 169         }
 170     }
 171     pub fn new(is_gob: bool) -> Self {
 172         Self::new_with_opts(is_gob, true, false)
 173     }
 174     pub fn new_b_frames(is_gob: bool) -> Self {
 175         Self::new_with_opts(is_gob, true, true)
 176     }
 177
 178     pub fn is_intra(&self) -> bool { self.ftype == Type::I }
 179     pub fn get_frame_type(&self) -> FrameType {
 180         match self.ftype {
 181             Type::I       => FrameType::I,
 182             Type::P       => FrameType::P,
 183             Type::B       => FrameType::B,
 184             Type::PB      => FrameType::P,
 185             Type::Skip    => FrameType::Skip,
 186             Type::Special => FrameType::Skip,
 187         }
 188     }
 189     pub fn get_dimensions(&self) -> (usize, usize) { (self.w, self.h) }
 190
 191     pub fn parse_frame(&mut self, bd: &mut BlockDecoder, bdsp: &BlockDSP) -> DecoderResult<NABufferType> {
 192         let pinfo = bd.decode_pichdr()?;
 193         let mut mvi = MVInfo::new();
 194         let mut mvi2 = MVInfo::new();
 195         let mut cbpi = CBPInfo::new();
 196
 197 //todo handle res change
 198         self.w = pinfo.w;
 199         self.h = pinfo.h;
 200         self.mb_w = (pinfo.w + 15) >> 4;
 201         self.mb_h = (pinfo.h + 15) >> 4;
 202         self.num_mb = self.mb_w * self.mb_h;
 203         self.ftype = pinfo.mode;
 204         self.has_b = pinfo.is_pb();
 205
 206         if self.has_b {
 207             self.mv_data.truncate(0);
 208         }
 209
 210         let save_b_data = pinfo.mode.is_ref() && self.may_have_b_frames;
 211         if save_b_data {
 212             self.mv_data.truncate(0);
 213         }
 214         let is_b = pinfo.mode == Type::B;
 215
 216         if is_b && (self.mv_data.len() < self.mb_w * self.mb_h) {
 217             return Err(DecoderError::MissingReference);
 218         }
 219
 220         let tsdiff = if pinfo.is_pb() { pinfo.ts.wrapping_sub(self.last_ts) >> 1 }
 221                      else { self.last_ts.wrapping_sub(self.next_ts) >> 1 };
 222         let bsdiff = if pinfo.is_pb() { (pinfo.get_pbinfo().get_trb() as u16) << 7 }
 223                      else { pinfo.ts.wrapping_sub(self.next_ts) >> 1 };
 224
 225         let fmt = formats::YUV420_FORMAT;
 226         let vinfo = NAVideoInfo::new(self.w, self.h, false, fmt);
 227         let bufinfo = alloc_video_buffer(vinfo, 4)?;
 228         let mut buf = bufinfo.get_vbuf().unwrap();
 229
 230         let mut slice = if self.is_gob {
 231                 SliceInfo::get_default_slice(&pinfo)
 232             } else {
 233                 bd.decode_slice_header(&pinfo)?
 234             };
 235         mvi.reset(self.mb_w, 0, pinfo.get_mvmode());
 236         if is_b || pinfo.is_pb() {
 237             mvi2.reset(self.mb_w, 0, pinfo.get_mvmode());
 238         }
 239         cbpi.reset(self.mb_w);
 240
 241         let mut blk: [[i16; 64]; 6] = [[0; 64]; 6];
 242         let mut sstate = SliceState::new(pinfo.mode == Type::I);
 243         let mut mb_pos = 0;
 244         let apply_acpred = (pinfo.mode == Type::I) && pinfo.plusinfo.is_some() && pinfo.plusinfo.unwrap().aic;
 245         if apply_acpred {
 246             self.pred_coeffs.truncate(0);
 247             self.pred_coeffs.resize(self.mb_w * self.mb_h, ZERO_PRED_COEFFS);
 248         }
 249         sstate.quant = slice.quant;
 250         for mb_y in 0..self.mb_h {
 251             for mb_x in 0..self.mb_w {
 252                 for i in 0..6 { for j in 0..64 { blk[i][j] = 0; } }
 253
 254                 if slice.is_at_end(mb_pos) || (slice.needs_check() && mb_pos > 0 && bd.is_slice_end()) {
 255                     slice = bd.decode_slice_header(&pinfo)?;
 256                     if !self.is_gob && self.slice_reset {
 257                         mvi.reset(self.mb_w, mb_x, pinfo.get_mvmode());
 258                         if is_b || pinfo.is_pb() {
 259                             mvi2.reset(self.mb_w, mb_x, pinfo.get_mvmode());
 260                         }
 261                         cbpi.reset(self.mb_w);
 262                         sstate.reset_slice(mb_x, mb_y);
 263                         sstate.quant = slice.quant;
 264                     }
 265                 }
 266
 267                 let binfo = bd.decode_block_header(&pinfo, &slice, &sstate)?;
 268                 let cbp = binfo.get_cbp();
 269                 cbpi.set_cbp(mb_x, cbp);
 270                 cbpi.set_q(mb_x, binfo.get_q());
 271                 sstate.quant = binfo.get_q();
 272                 if binfo.is_intra() {
 273                     if save_b_data {
 274                         self.mv_data.push(BlockMVInfo::Intra);
 275                     }
 276                     for i in 0..6 {
 277                         bd.decode_block_intra(&binfo, &sstate, binfo.get_q(), i, (cbp & (1 << (5 - i))) != 0, &mut blk[i])?;
 278                         if apply_acpred && (binfo.acpred != ACPredMode::None) {
 279                             let has_b = (i == 1) || (i == 3) || !sstate.first_mb;
 280                             let has_a = (i == 2) || (i == 3) || !sstate.first_line;
 281                             let (b_mb, b_blk) = if has_b {
 282                                     if (i == 1) || (i == 3) {
 283                                         (mb_pos, i - 1)
 284                                     } else if i < 4 {
 285                                         (mb_pos - 1, i + 1)
 286                                     } else {
 287                                         (mb_pos - 1, i)
 288                                     }
 289                                 } else { (0, 0) };
 290                             let (a_mb, a_blk) = if has_a {
 291                                     if (i == 2) || (i == 3) {
 292                                         (mb_pos, i - 2)
 293                                     } else if i < 4 {
 294                                         (mb_pos - self.mb_w, i + 2)
 295                                     } else {
 296                                         (mb_pos - self.mb_w, i)
 297                                     }
 298                                 } else { (0, 0) };
 299                             match binfo.acpred {
 300                                 ACPredMode::DC   => {
 301                                             let dc;
 302                                             if has_a && has_b {
 303                                                 dc = (self.pred_coeffs[b_mb].hor[b_blk][0] + self.pred_coeffs[a_mb].ver[a_blk][0]) / 2;
 304                                             } else if has_a {
 305                                                 dc = self.pred_coeffs[a_mb].ver[a_blk][0];
 306                                             } else if has_b {
 307                                                 dc = self.pred_coeffs[b_mb].hor[b_blk][0];
 308                                             } else {
 309                                                 dc = 1024;
 310                                             }
 311                                             blk[i][0] = clip_dc(blk[i][0] + dc);
 312                                         },
 313                                 ACPredMode::Hor  => {
 314                                         if has_b {
 315                                             for k in 0..8 {
 316                                                 blk[i][k * 8] += self.pred_coeffs[b_mb].hor[b_blk][k];
 317                                             }
 318                                             for k in 1..8 {
 319                                                 blk[i][k * 8] = clip_ac(blk[i][k * 8]);
 320                                             }
 321                                         } else {
 322                                             blk[i][0] += 1024;
 323                                         }
 324                                         blk[i][0] = clip_dc(blk[i][0]);
 325                                     },
 326                                 ACPredMode::Ver  => {
 327                                         if has_a {
 328                                             for k in 0..8 {
 329                                                 blk[i][k] += self.pred_coeffs[a_mb].ver[a_blk][k];
 330                                             }
 331                                             for k in 1..8 {
 332                                                 blk[i][k] = clip_ac(blk[i][k]);
 333                                             }
 334                                         } else {
 335                                             blk[i][0] += 1024;
 336                                         }
 337                                         blk[i][0] = clip_dc(blk[i][0]);
 338                                     },
 339                                 ACPredMode::None => {},
 340                             };
 341                             for t in 0..8 { self.pred_coeffs[mb_pos].hor[i][t] = blk[i][t * 8]; }
 342                             for t in 0..8 { self.pred_coeffs[mb_pos].ver[i][t] = blk[i][t]; }
 343                         }
 344                         bdsp.idct(&mut blk[i]);
 345                     }
 346                     blockdsp::put_blocks(&mut buf, mb_x, mb_y, &blk);
 347                     mvi.set_zero_mv(mb_x);
 348                     if is_b {
 349                         mvi2.set_zero_mv(mb_x);
 350                     } else if pinfo.is_pb() {
 351                         mvi2.predict(mb_x, 0, false, binfo.get_mv2(0), sstate.first_line, sstate.first_mb);
 352                     }
 353                 } else if (binfo.mode != Type::B) && !binfo.is_skipped() {
 354                     if binfo.get_num_mvs() == 1 {
 355                         let mv = mvi.predict(mb_x, 0, false, binfo.get_mv(0), sstate.first_line, sstate.first_mb);
 356                         if save_b_data {
 357                             self.mv_data.push(BlockMVInfo::Inter_1MV(mv));
 358                         }
 359                         if let Some(ref srcbuf) = self.ipbs.get_lastref() {
 360                             bdsp.copy_blocks(&mut buf, srcbuf.clone(), mb_x * 16, mb_y * 16, mv);
 361                         }
 362                         if pinfo.is_pb() {
 363                             mvi2.predict(mb_x, 0, false, binfo.get_mv(0), sstate.first_line, sstate.first_mb);
 364                         }
 365                     } else {
 366                         let mut mv: [MV; 4] = [ZERO_MV, ZERO_MV, ZERO_MV, ZERO_MV];
 367                         for blk_no in 0..4 {
 368                             mv[blk_no] = mvi.predict(mb_x, blk_no, true, binfo.get_mv(blk_no), sstate.first_line, sstate.first_mb);
 369                         }
 370                         if let Some(ref srcbuf) = self.ipbs.get_lastref() {
 371                             bdsp.copy_blocks8x8(&mut buf, srcbuf.clone(), mb_x * 16, mb_y * 16, &mv);
 372                         }
 373                         if pinfo.is_pb() {
 374                             for blk_no in 0..4 {
 375                                 mvi2.predict(mb_x, blk_no, true, binfo.get_mv(blk_no), sstate.first_line, sstate.first_mb);
 376                             }
 377                         }
 378                         if save_b_data {
 379                             self.mv_data.push(BlockMVInfo::Inter_4MV(mv));
 380                         }
 381                     }
 382                     for i in 0..6 {
 383                         bd.decode_block_inter(&binfo, &sstate, binfo.get_q(), i, ((cbp >> (5 - i)) & 1) != 0, &mut blk[i])?;
 384                         bdsp.idct(&mut blk[i]);
 385                     }
 386                     blockdsp::add_blocks(&mut buf, mb_x, mb_y, &blk);
 387                     if is_b && !pinfo.is_pb() {
 388                         mvi2.set_zero_mv(mb_x);
 389                     }
 390                 } else if binfo.mode != Type::B {
 391                     self.mv_data.push(BlockMVInfo::Inter_1MV(ZERO_MV));
 392                     mvi.set_zero_mv(mb_x);
 393                     if is_b || pinfo.is_pb() {
 394                         mvi2.set_zero_mv(mb_x);
 395                     }
 396                     if let Some(ref srcbuf) = self.ipbs.get_lastref() {
 397                         bdsp.copy_blocks(&mut buf, srcbuf.clone(), mb_x * 16, mb_y * 16, ZERO_MV);
 398                     }
 399                 } else {
 400                     let ref_mv_info = self.mv_data[mb_pos];
 401                     let has_fwd = binfo.get_num_mvs() > 0;
 402                     let has_bwd = binfo.get_num_mvs2() > 0;
 403 //todo refactor
 404                     if has_fwd || has_bwd {
 405                         let fwd_mv;
 406                         if has_fwd {
 407                             fwd_mv = mvi.predict(mb_x, 0, false, binfo.get_mv(0), sstate.first_line, sstate.first_mb);
 408                         } else {
 409                             fwd_mv = ZERO_MV;
 410                             mvi.set_zero_mv(mb_x);
 411                         }
 412                         let bwd_mv;
 413                         if has_bwd {
 414                             bwd_mv = mvi2.predict(mb_x, 0, false, binfo.get_mv2(0), sstate.first_line, sstate.first_mb);
 415                         } else {
 416                             bwd_mv = ZERO_MV;
 417                             mvi2.set_zero_mv(mb_x);
 418                         }
 419                         if let (Some(ref fwd_buf), Some(ref bck_buf)) = (self.ipbs.get_nextref(), self.ipbs.get_lastref()) {
 420                             if has_fwd && has_bwd {
 421                                 bdsp.copy_blocks(&mut buf, fwd_buf.clone(), mb_x * 16, mb_y * 16, fwd_mv);
 422                                 bdsp.avg_blocks (&mut buf, bck_buf.clone(), mb_x * 16, mb_y * 16, bwd_mv);
 423                             } else if has_fwd {
 424                                 bdsp.copy_blocks(&mut buf, fwd_buf.clone(), mb_x * 16, mb_y * 16, fwd_mv);
 425                             } else {
 426                                 bdsp.copy_blocks(&mut buf, bck_buf.clone(), mb_x * 16, mb_y * 16, bwd_mv);
 427                             }
 428                         }
 429                     } else {
 430                         if let BlockMVInfo::Inter_4MV(mvs) = ref_mv_info {
 431                             let mut mv_f = [ZERO_MV; 4];
 432                             let mut mv_b = [ZERO_MV; 4];
 433                             for blk_no in 0..4 {
 434                                 let ref_mv = mvs[blk_no];
 435                                 let ref_mv_fwd = ref_mv.scale(bsdiff, tsdiff);
 436                                 let ref_mv_bwd = ref_mv - ref_mv_fwd;
 437                                 mv_f[blk_no] = ref_mv_fwd;
 438                                 mv_b[blk_no] = ref_mv_bwd;
 439                             }
 440                             if let (Some(ref fwd_buf), Some(ref bck_buf)) = (self.ipbs.get_nextref(), self.ipbs.get_lastref()) {
 441                                 bdsp.copy_blocks8x8(&mut buf, fwd_buf.clone(), mb_x * 16, mb_y * 16, &mv_f);
 442                                 bdsp.avg_blocks8x8 (&mut buf, bck_buf.clone(), mb_x * 16, mb_y * 16, &mv_b);
 443                             }
 444                         } else {
 445                             let ref_mv = if let BlockMVInfo::Inter_1MV(mv_) = ref_mv_info { mv_ } else { ZERO_MV };
 446                             let ref_mv_fwd = ref_mv.scale(bsdiff, tsdiff);
 447                             let ref_mv_bwd = MV::b_sub(ref_mv, ref_mv_fwd, ZERO_MV, bsdiff, tsdiff);
 448
 449                             if let (Some(ref fwd_buf), Some(ref bck_buf)) = (self.ipbs.get_nextref(), self.ipbs.get_lastref()) {
 450                                 bdsp.copy_blocks(&mut buf, fwd_buf.clone(), mb_x * 16, mb_y * 16, ref_mv_fwd);
 451                                 bdsp.avg_blocks (&mut buf, bck_buf.clone(), mb_x * 16, mb_y * 16, ref_mv_bwd);
 452                             }
 453                         }
 454                         mvi.set_zero_mv(mb_x);
 455                         mvi2.set_zero_mv(mb_x);
 456                     }
 457                     if cbp != 0 {
 458                         for i in 0..6 {
 459                             bd.decode_block_inter(&binfo, &sstate, binfo.get_q(), i, ((cbp >> (5 - i)) & 1) != 0, &mut blk[i])?;
 460                             bdsp.idct(&mut blk[i]);
 461                         }
 462                         blockdsp::add_blocks(&mut buf, mb_x, mb_y, &blk);
 463                     }
 464                 }
 465                 if pinfo.is_pb() {
 466                     let mut b_mb = BMB::new();
 467                     let cbp = binfo.get_cbp_b();
 468                     let bq = (((pinfo.get_pbinfo().get_dbquant() + 5) as u16) * (binfo.get_q() as u16)) >> 2;
 469                     let bquant;
 470                     if bq < 1 { bquant = 1; }
 471                     else if bq > 31 { bquant = 31; }
 472                     else { bquant = bq as u8; }
 473
 474                     b_mb.cbp = cbp;
 475                     for i in 0..6 {
 476                         bd.decode_block_inter(&binfo, &sstate, bquant, i, (cbp & (1 << (5 - i))) != 0, &mut b_mb.blk[i])?;
 477                         bdsp.idct(&mut b_mb.blk[i]);
 478                     }
 479
 480                     let is_fwd = binfo.is_b_fwd();
 481                     b_mb.fwd = is_fwd;
 482                     if binfo.get_num_mvs() != 4 {
 483                         let ref_mv = mvi2.get_mv(mb_x, 0);
 484                         let b_mv = if binfo.is_intra() { binfo.get_mv2(1) } else { binfo.get_mv2(0) };
 485                         let src_mv = if is_fwd { ZERO_MV } else { ref_mv.scale(bsdiff, tsdiff) };
 486                         let mv_f = MV::add_umv(src_mv, b_mv, pinfo.get_mvmode());
 487                         let mv_b = MV::b_sub(ref_mv, mv_f, b_mv, bsdiff, tsdiff);
 488                         b_mb.mv_f[0] = mv_f;
 489                         b_mb.mv_b[0] = mv_b;
 490                         b_mb.num_mv = 1;
 491                     } else {
 492                         for blk_no in 0..4 {
 493                             let src_mv = if is_fwd { ZERO_MV } else { mvi2.get_mv(mb_x, blk_no).scale(bsdiff, tsdiff) };
 494                             let mv_f = MV::add_umv(src_mv, binfo.get_mv2(0), pinfo.get_mvmode());
 495                             let mv_b = MV::b_sub(mvi2.get_mv(mb_x, blk_no), mv_f, binfo.get_mv2(0), bsdiff, tsdiff);
 496                             b_mb.mv_f[blk_no] = mv_f;
 497                             b_mb.mv_b[blk_no] = mv_b;
 498                         }
 499                         b_mb.num_mv = 4;
 500                     }
 501                     self.b_data.push(b_mb);
 502                 }
 503                 sstate.next_mb();
 504                 mb_pos += 1;
 505             }
 506             if let Some(plusinfo) = pinfo.plusinfo {
 507                 if plusinfo.deblock {
 508                     bdsp.filter_row(&mut buf, mb_y, self.mb_w, &cbpi);
 509                 }
 510             }
 511             mvi.update_row();
 512             if is_b || pinfo.is_pb() {
 513                 mvi2.update_row();
 514             }
 515             cbpi.update_row();
 516             sstate.new_row();
 517         }
 518
 519         if pinfo.mode.is_ref() {
 520             self.ipbs.add_frame(buf);
 521             self.next_ts = self.last_ts;
 522             self.last_ts = pinfo.ts;
 523             self.tsdiff  = tsdiff;
 524         }
 525
 526         Ok(bufinfo)
 527     }
 528     pub fn flush(&mut self) {
 529         self.ipbs.clear();
 530     }
 531
 532     pub fn get_bframe(&mut self, bdsp: &BlockDSP) -> DecoderResult<NABufferType> {
 533         if !self.has_b || self.ipbs.get_lastref().is_none() || self.ipbs.get_nextref().is_none() {
 534             return Err(DecoderError::MissingReference);
 535         }
 536         self.has_b = false;
 537
 538         let fmt = formats::YUV420_FORMAT;
 539         let vinfo = NAVideoInfo::new(self.w, self.h, false, fmt);
 540         let bufinfo = alloc_video_buffer(vinfo, 4)?;
 541         let b_buf = bufinfo.get_vbuf().unwrap();
 542
 543         if let (Some(ref bck_buf), Some(ref fwd_buf)) = (self.ipbs.get_nextref(), self.ipbs.get_lastref()) {
 544             recon_b_frame(b_buf, fwd_buf.clone(), bck_buf.clone(), self.mb_w, self.mb_h, self.b_data.as_slice(), bdsp);
 545         }
 546
 547         self.b_data.truncate(0);
 548         Ok(bufinfo)
 549     }
 550 }
 551
 552 fn recon_b_frame(mut b_buf: NAVideoBufferRef<u8>, bck_buf: NAVideoBufferRef<u8>, fwd_buf: NAVideoBufferRef<u8>,
 553                  mb_w: usize, mb_h: usize, b_data: &[BMB], bdsp: &BlockDSP) {
 554     let mut cbpi = CBPInfo::new();
 555     let mut cur_mb = 0;
 556     cbpi.reset(mb_w);
 557     for mb_y in 0..mb_h {
 558         for mb_x in 0..mb_w {
 559             let num_mv = b_data[cur_mb].num_mv;
 560             let is_fwd = b_data[cur_mb].fwd;
 561             let cbp    = b_data[cur_mb].cbp;
 562             cbpi.set_cbp(mb_x, cbp);
 563             if num_mv == 1 {
 564                 bdsp.copy_blocks(&mut b_buf, fwd_buf.clone(), mb_x * 16, mb_y * 16, b_data[cur_mb].mv_b[0]);
 565                 if !is_fwd {
 566                     bdsp.avg_blocks(&mut b_buf, bck_buf.clone(), mb_x * 16, mb_y * 16, b_data[cur_mb].mv_f[0]);
 567                 }
 568             } else {
 569                 bdsp.copy_blocks8x8(&mut b_buf, fwd_buf.clone(), mb_x * 16, mb_y * 16, &b_data[cur_mb].mv_b);
 570                 if !is_fwd {
 571                     bdsp.avg_blocks8x8(&mut b_buf, bck_buf.clone(), mb_x * 16, mb_y * 16, &b_data[cur_mb].mv_f);
 572                 }
 573             }
 574             if cbp != 0 {
 575                 blockdsp::add_blocks(&mut b_buf, mb_x, mb_y, &b_data[cur_mb].blk);
 576             }
 577             cur_mb += 1;
 578         }
 579         cbpi.update_row();
 580     }
 581 }