Author: ods15 Date: Sat Nov 18 14:31:03 2006 New Revision: 236 Modified: trunk/libnut/demuxer.c Log: clean up some of binary_search Modified: trunk/libnut/demuxer.c ============================================================================== --- trunk/libnut/demuxer.c (original) +++ trunk/libnut/demuxer.c Sat Nov 18 14:31:03 2006 @@ -977,17 +977,28 @@ return 0; } +#define INTERPOLATE_WEIGHT (19./20) +static off_t seek_interpolate(int max_distance, double time_pos, off_t lo, off_t hi, double lo_pd, double hi_pd) { + off_t guess; + if (hi - lo < max_distance) guess = lo + 16; + else { // linear interpolation + double a = (double)(hi - lo) / (hi_pd - lo_pd); + guess = lo + a * (time_pos - lo_pd); + guess = guess * INTERPOLATE_WEIGHT + (lo+hi)/2. * (1 - INTERPOLATE_WEIGHT); + if (hi - guess < max_distance) guess = hi - max_distance; //(lo + hi)/2; + } + if (guess < lo + 16) guess = lo + 16; + return guess; +} + static int binary_search_syncpoint(nut_context_t * nut, double time_pos, off_t * start, off_t * end, syncpoint_t * stopper) { int i, err = 0; syncpoint_t s; - off_t hi, lo; - uint64_t hip, lop; + off_t fake_hi; uint64_t timebases[nut->timebase_count]; syncpoint_list_t * sl = &nut->syncpoints; int a = 0; - for (i = 0; i < nut->timebase_count; i++) timebases[i] = (uint64_t)(time_pos / nut->tb[i].nom * nut->tb[i].den); - assert(sl->len); // it is impossible for the first syncpoint to not have been read // find last syncpoint if it's not already found @@ -1023,60 +1034,40 @@ i--; - lo = sl->s[i].pos; - lop = sl->s[i].pts; - hi = sl->s[i+1].pos; - hip = sl->s[i+1].pts; - if (nut->seek_status) hi = nut->seek_status; - - while (!sl->s[i].seen_next) { - // start binary search between sl->s[i].pos (lo) to sl->s[i+1].pos (hi) ... - off_t guess; - int res, tmp; - double hi_pd = TO_DOUBLE_PTS(hip); - double lo_pd = TO_DOUBLE_PTS(lop); +#define LO (sl->s[i]) +#define HI (sl->s[i+1]) + fake_hi = nut->seek_status ? nut->seek_status : HI.pos; + + while (!LO.seen_next) { + // start binary search between LO (sl->s[i].pos) to HI (sl->s[i+1].pos) ... + off_t guess = seek_interpolate(nut->max_distance*2, time_pos, LO.pos, fake_hi, TO_DOUBLE_PTS(LO.pts), TO_DOUBLE_PTS(HI.pts)); + + fprintf(stderr, "\n%d [ (%d,%.3f) .. (%d,%.3f) .. (%d,%.3f) ] ", i, (int)LO.pos, TO_DOUBLE_PTS(LO.pts), (int)guess, time_pos, + (int)fake_hi, TO_DOUBLE_PTS(HI.pts)); a++; - if (hi - lo < nut->max_distance*2) guess = lo + 16; - else { // linear interpolation -#define INTERPOLATE_WEIGHT (19./20) - double a = (double)(hi - lo) / (hi_pd - lo_pd); - guess = lo + a * (time_pos - lo_pd); - guess = guess * INTERPOLATE_WEIGHT + (lo+hi)/2 * (1 - INTERPOLATE_WEIGHT); - if (hi - guess < nut->max_distance*2) guess = hi - nut->max_distance*2; //(lo + hi)/2; - } - if (guess < lo + 8) guess = lo + 16; - fprintf(stderr, "\n%d [ (%d,%.3f) .. (%d,%.3f) .. (%d,%.3f) ] ", i, (int)lo, lo_pd, (int)guess, time_pos, (int)hi, hi_pd); + if (!nut->seek_status) seek_buf(nut->i, guess, SEEK_SET); - nut->seek_status = hi; // so we know where to continue off... - CHECK(find_syncpoint(nut, 0, &s, hi)); + nut->seek_status = fake_hi; // so we know where to continue off... + CHECK(find_syncpoint(nut, 0, &s, fake_hi)); nut->seek_status = 0; - if (s.seen_next == 1 || s.pos >= hi) { // we got back to 'hi' - // either we scanned everything from lo to hi, or we keep trying - if (guess <= lo + 16) sl->s[i].seen_next = 1; // we are done! - else hi = guess; + if (s.seen_next == 1 || s.pos >= fake_hi) { // we got back to 'HI' + // either we scanned everything from LO to HI, or we keep trying + if (guess <= LO.pos + 16) LO.seen_next = 1; // we are done! + else fake_hi = guess; continue; } - res = (s.pts / nut->timebase_count > timebases[s.pts % nut->timebase_count]); - if (res) { - hi = s.pos; - hip = s.pts; - } else { - lo = s.pos; - lop = s.pts; - } - CHECK(add_syncpoint(nut, s, NULL, NULL, &tmp)); // unconditionally even without syncpoint cache - if (!res) i = tmp; + CHECK(add_syncpoint(nut, s, NULL, NULL, timebases[s.pts%nut->timebase_count] < s.pts/nut->timebase_count ? NULL : &i)); + fake_hi = HI.pos; } fprintf(stderr, "\n[ (%d,%d) .. %d .. (%d,%d) ] => %d (%d seeks) %d\n", - (int)lo, (int)lop, (int)timebases[0], (int)hi, (int)hip, (int)(lo - sl->s[i].back_ptr), a, sl->s[i].back_ptr); - // at this point, s[i].pts < P < s[i+1].pts, and s[i].flag is set - // meaning, there are no more syncpoints between s[i] to s[i+1] - *start = sl->s[i].pos - sl->s[i].back_ptr; - *end = sl->s[i+1].pos; - *stopper = sl->s[i+1]; + (int)LO.pos, (int)LO.pts, (int)timebases[0], (int)fake_hi, (int)HI.pts, (int)(LO.pos - LO.back_ptr), a, LO.back_ptr); + // at this point, s[i].pts < P < s[i+1].pts, and s[i].seen_next is set + *start = LO.pos - LO.back_ptr; + *end = HI.pos; + *stopper = HI; err_out: if (err == NUT_ERR_EAGAIN) nut->i->buf_ptr = nut->i->buf; return err;